Hi All,
A question or two about my engine just stopped with no warning and dipstick blow back. Last week I ran the engine for approx 2 hours at 2-2500 rpm and all of a sudden it stooped with no warning. On inspecting the engine bay the dipstick had blown out and oil was sprayed over the engine, creating a lot of smoke. The coolant started boiling about one minute later too. I anchored and waited for an hour for things to cool down, checked the oil level which was fine, replaced the coolant and started the engine again without a problem. Ran it at 1500 RPM for an hour and had no issues. On return a couple of days later there appeared to be no issue but I did not run above 1500rpm, nor for longer than one hour. I have previously ran the engine at 2000rpm for 2-3 hours and never had a problem. Last service was 12 months ago and I have racked up 120 hours since then. No alarms went off, no oil light or overheat light either, engine just stopped..... any tips on what could have caused this would be greatly appreciated. I know the overheat alarm works due to a clogged heat exchange I discovered a few months back too. Could the pressure have built up over the hours from running the engine at too high RPMs or is it a piston ring problem (hoping not) that blew out the dipstick. Has anyone with a Volvo Penta engine had similar issues before. Is there anything I can check/do myself before calling in the Pros...

Regards,

Steve

First time I've heard of that but pretty keen to hear the explanation. Thanks for posting it.

Hi Saskia.
OK. Let's think this through.
We have .
1. engine stop.
2. dipstick thrown and oil ejected from the dipstick tube.
3. coolant boiling.
4. no high temperature or low oil pressure alarms.
That is the sequence as you saw it, but probably not the sequence of events.

My first guess is loss of cooling leading to high engine/ temperature then to engine momentarily seizing.
This is just a guess with no evidence to back it up.

Now let's check.
1. The engine stopped.=I anchored and waited for an hour....and started the engine again without a problem
This means the engine didn't stop for the usual reason of no fuel, dirty fuel, restricted fuel, faulty fuel pump, leaking fuel lines or faulty injector nozzle. If it were any of them you would have had a problem restarting after the cool down period. So we can eliminate all of those causes.
Rope or something wrapped around the prop? A dive over would maybe reveal some left over evidence on the shaft or prop.

2. dipstick thrown and oil ejected from the dipstick tube.
I put in nine searches along the lines of"volvo penta problem oil leaking dipstick"and came up with nothing solid.

In my view the reason for a dipstick and oil being ejected is high crankcase pressure.
So let's search that. This is what we come up with.
www.bing.com/videos/search?q=volvo+penta+problem+high+crankcase+pressure&view=detail&mid=C222D6DB3EB9FE609656C222D6DB3EB9FE609656&FORM=VIRE

Not your engine and has has almost no oil leaking but he, replaced the crankcase pressure relief valve.
The thing to note here that it was on the advice of a Volvo mechanic. (whatever that is worth)

3. coolant boiling. =The coolant started boiling about one minute later too
Here is something we can deal with.
Your cooling system is actually two systems. Primary seawater system and secondary engine cooling system.
A fault (in flow ) in either system will lead to overheating in the secondary system.
Start with the primary seawater cooling system.
1. Remove hose from seacock. Open cock and check flow. This can be blocked by plastic bags, weed, shells or barnacles or small fish. reconnect hose.
2. remove hose from inlet of circulation pump. Open cock and check flow. reconnect hose.
3. remove hose from pump discharge and run engine for a minute to check flow.
use this process to check every part of the primary system.
Then do the same with the secondary system.
Odds are that it was a plastic bag and will never happen again, but without eliminating all options you can't be sure of anything.

Last service was 12 months ago All well and good but when was the last time the ends were removed from the heat exchanger and the tubes checked for blockage?
The following vid is not really directly connected to you problem, but is a must watch for VP owners.





All the best
Gary

That's an intesting one. My first thought like you, was that it was a compression ring. Given that it seems to be running ok, could it have been a ring sticking? I reckon you should do a compression test quick smart. You can get a tester for diesel engines that allows you to remove the glow plugs and screw an adapter into the hole.

Have a look at this vid too:

Select to expand quote

garymalmgren said..
Hi Saskia.
OK. Let's think this through.
We have .
1. engine stop.
2. dipstick thrown and oil ejected from the dipstick tube.
3. coolant boiling.
4. no high temperature or low oil pressure alarms.
That is the sequence as you saw it, but probably not the sequence of events.

My first guess is loss of cooling leading to high engine/ temperature then to engine momentarily seizing.
This is just a guess with no evidence to back it up.

Now let's check.
1. The engine stopped.=I anchored and waited for an hour....and started the engine again without a problem
This means the engine didn't stop for the usual reason of no fuel, dirty fuel, restricted fuel, faulty fuel pump, leaking fuel lines or faulty injector nozzle. If it were any of them you would have had a problem restarting after the cool down period. So we can eliminate all of those causes.
Rope or something wrapped around the prop? A dive over would maybe reveal some left over evidence on the shaft or prop.

2. dipstick thrown and oil ejected from the dipstick tube.
I put in nine searches along the lines of"volvo penta problem oil leaking dipstick"and came up with nothing solid.

In my view the reason for a dipstick and oil being ejected is high crankcase pressure.
So let's search that. This is what we come up with.
www.bing.com/videos/search?q=volvo+penta+problem+high+crankcase+pressure&view=detail&mid=C222D6DB3EB9FE609656C222D6DB3EB9FE609656&FORM=VIRE

Not your engine and has has almost no oil leaking but he, replaced the crankcase pressure relief valve.
The thing to note here that it was on the advice of a Volvo mechanic. (whatever that is worth)

3. coolant boiling. =The coolant started boiling about one minute later too
Here is something we can deal with.
Your cooling system is actually two systems. Primary seawater system and secondary engine cooling system.
A fault (in flow ) in either system will lead to overheating in the secondary system.
Start with the primary seawater cooling system.
1. Remove hose from seacock. Open cock and check flow. This can be blocked by plastic bags, weed, shells or barnacles or small fish. reconnect hose.
2. remove hose from inlet of circulation pump. Open cock and check flow. reconnect hose.
3. remove hose from pump discharge and run engine for a minute to check flow.
use this process to check every part of the primary system.
Then do the same with the secondary system.
Odds are that it was a plastic bag and will never happen again, but without eliminating all options you can't be sure of anything.

Last service was 12 months ago All well and good but when was the last time the ends were removed from the heat exchanger and the tubes checked for blockage?
The following vid is not really directly connected to you problem, but is a must watch for VP owners.

All the best
Gary

That all makes a lot of sense Gary.
So, for the coolant to boil means that no heat is being drawn off ?
Which would sorta kinda logically point to a lack of salt water.
Salt water system partially blocked? Either the flow or the pressure.

Marine engines is not my strongest point. Is there any link between the saltwater system and the crankcase? ?
A potential lack of pressure in one, and overpressure in the other, all at high revs. Kinda rings a distant bell.

Very thorough analysis Gary! Your advice to check the fresh and seawater cooling systems is wise. I just had my saildrive out to put a seal kit though it. I found several small muscles stuck up in the seawater inlet at the top of the saildrive, inside the leg, I doubt it had 50% flow left there.

While a fouled prop would have stopped the engine, would it cause it to boil? And why would that cause enough blowby to spit the dipstick?

While a fouled prop would have stopped the engine, would it cause it to boil? And why would that cause enough blowby to spit the dipstick?


Good question and I don't know the answer.
The combination of the three problems (not even symptoms) at the same time make this a real puzzle.
My suggestion of something fouling the prop was just to deal with why the engine stopped and then could be restarted.
Trying to keep seizing as a last option.
Boiling!! coolant has to be either primary (seawater ) or secondary (coolant) problem.

Re Shaggy's point. Which would sorta kinda logically point to a lack of salt water.
Salt water system partially blocked? Either the flow or the pressure.

Well, the primary seawater could be flowing freely, but the secondary coolant could have reduced or no flow due to a blockage or pump problem.
That's why I suggested starting at the inlet on the seawater, then move to check all of the secondary cooling functions.
realistically this one has got me a bit stumped.

Bad rings could cause the blowby and high crankcase pressure, but bad rings don't cause boiling coolant.
It sort of goes around in circles, Could be so and so, but .....
gary

Select to expand quote

garymalmgren said..
While a fouled prop would have stopped the engine, would it cause it to boil? And why would that cause enough blowby to spit the dipstick?


Good question and I don't know the answer.
The combination of the three problems (not even symptoms) at the same time make this a real puzzle.
My suggestion of something fouling the prop was just to deal with why the engine stopped and then could be restarted.
Trying to keep seizing as a last option.
Boiling!! coolant has to be either primary (seawater ) or secondary (coolant) problem.

Re Shaggy's point. Which would sorta kinda logically point to a lack of salt water.
Salt water system partially blocked? Either the flow or the pressure.

Well, the primary seawater could be flowing freely, but the secondary coolant could have reduced or no flow due to a blockage or pump problem.
That's why I suggested starting at the inlet on the seawater, then move to check all of the secondary cooling functions.
realistically this one has got me a bit stumped.

Bad rings could cause the blowby and high crankcase pressure, but bad rings don't cause boiling coolant.
It sort of goes around in circles, Could be so and so, but .....
gary

Yep it's a bit of a tricky one, that seizing possibility is niggling isn't it.. Doing the steps we've suggested will hopefully begin to eliminate things and focus in on the issue. So definitely a good look at the cooling systems and verify that they're working properly. I think a compression test to eliminate the ring issue is next, if only to check on the health of the rings if it did seize. I've never had that happen to any engine, I imagine that it would be a pretty energetic event and may produce a spike in heat? but then there's the lack of an overheat alarm.... where's the sensor on that engine?

my first thought was a block in raw water system, leading to a faster than usual heating of the engine oil (because of the higher revs) , which caused the oil to expand and spit the dipstick

I also would remove the exhaust elbow (raw water injection) as these are known to rust on the inside. They are considered a consumable by volvo and severely block water flow.

An excessively overheated engine will lose compression and suffer from excessive blow by due to the fact that the hot oil has lost viscosity and can no longer be retained by the piston rings, losing the ability to create a lubricating seal to the cylinder wall. The oil may even be burning on the cylinder wall.

It sounds like you may have picked up a Mars bar wrapper or similar on the raw water intake. When the engine stopped the obstruction fell off. The fact that the engine started easily after it cooled down indicates it's still OK.

Select to expand quote

cookcanal said..
I also would remove the exhaust elbow (raw water injection) as these are known to rust on the inside. They are considered a consumable by volvo and severely block water flow.

Hullo Cook,
I had this happen just recently, it was 90% blocked.
But a telling symptom of this issue was the inability to rev at all. I couldn't get above 1500 rpm , and the revs continue to drop the more blocked it becomes.
I don't think SAskia had any issues revving?

Diesels are Notorious for blocking with carbon stopping or slowing down the water for cooling , but that would be continuous

The mars bar wrapper theory sounds possible, at 1st I was thinking head gasket but if she lives it must of been a temporary glitch. Change the oil and give it another good burst an see what happens ?

The only thing that bothers me is that Steve didn't get any overtemp warnings and he's positive that the temp sensors and alarms are in working order. I'd be double checking the sensors and alarm system too, just to be sure and fill in the picture a bit more.

Select to expand quote

2bish said..
The only thing that bothers me is that Steve didn't get any overtemp warnings and he's positive that the temp sensors and alarms are in working order. I'd be double checking the sensors and alarm system too, just to be sure and fill in the picture a bit more.

Yep. To have boiling coolant and no corresponding engine temperature doesn't correlate. What could cause the coolant to boil?

That's what initially made me think head gasket, compression leaking in to the cooling jacket can build up pressure quickly and out the cap it goes. I had an old land rover that had that problem, leave the radiator cap loose and you could poke around the bush all day, but if you went down the road for few kms she'd spit the coolant out. Never seized tho

Select to expand quote

shaggybaxter said..

2bish said..
The only thing that bothers me is that Steve didn't get any overtemp warnings and he's positive that the temp sensors and alarms are in working order. I'd be double checking the sensors and alarm system too, just to be sure and fill in the picture a bit more.

Yep. To have boiling coolant and no corresponding engine temperature doesn't correlate. What could cause the coolant to boil?

Pressurization of the cooling system stops coolant boiling,,Most modern engines rely on this. The capacity of coolant, its velocity through the engine and heat removed via heat exchange/ radiator control the temperature of the coolant. The pressurization of the system, usually governed by the radiator cap, provides a buffer zone to control small abnormalities that may bring the coolant temp beyond 100 deg.
An engine that has lost pressure or has excessive pressure relieved will start to boil the water off. If the coolant capacity in the engine is reduced sometimes this can leave temp sensors with out a flow of coolant resulting in an incorrect reading. Senders and sensors are often placed in positions of convenience rather than efficiency

So maybe loose "radiator" cap, allows water to boil, so temp stays at 100 Degrees, no alarm, this circuit boils away until cylinder head distortion or something like that causes a seize.

If it was a car, I'd diagnose it this way.

Check the oil level is correct. If it was even a little over full, a higher temperature and high running speeds can often cause a blow. Usually with the dip stick, but can push out an oil warning sensor too.

Check the coolant thermostat, if it has one. Firstly, get the engine to operating temp. Check all the rubber hoses are at roughly the same temp. If you find a cold one, it could mean the thermostat has jammed shut. Remove it, boil it in water and see if it opens. If it doesn't open, replace it. Or, if it doesn't close when you let it cool, replace it. A thermostat is really important to make sure the engine temperature remains constant, and doesn't fluctuate depending on load. You can remove it to temporarily fix an overheating problem, but you should replace it with a new one as soon as possible. After you replace the thermostat, make sure you bleed the cooling system if necessary. This also helps to make sure you have coolant flow, and that the water pump is working correctly. It's important to remove any air in the system, otherwise your temp sensor will give you a false reading, and possibly cause overheating.

Check your engine's crankcase breathing system. I don't know what kind it has, but there should be a crank ventilation system that breathes to fresh air in the engine bay. Or there could be a valved hose that breathes back to the air intake filter. If this is blocked, crankcase pressure will build and pop out something like a dipstick.

If the above is all OK, then it can only be the raw water intake and exchange. A temporary blockage in the raw water intake, or even an airlock from getting the through hull intake out of the water for a split second. (Ask NSW Sailor how this can happen)

Don't rely on your warning lights. Perhaps the temp sender unit isn't sensitive enough to warn you of overheating early enough. In the old days, if your temp light came on, it was too late. That's why all modern cars now have gauges instead of lights. If the engine overheated, the coolant was almost ready to boil, and the oil would have also been close to expanding to the point of blowing. (Did you over fill the oil at your last top up?)

Not sure if this will help, but it's how I would step through a diagnosis.

:-)

I agree with Michael, thermostats are very important. They restrict the water flow to allow the engine to attain correct temperature. With a missing thermostat the water flow is enough to take the heat away too quickly.
Thermostats usually stick in the open position as the forces that open it are greater than those that close it.

Select to expand quote

samsturdy said..
I agree with Michael, thermostats are very important. They restrict the water flow to allow the engine to attain correct temperature. With a missing thermostat the water flow is enough to take the heat away too quickly.
Thermostats usually stick in the open position as the forces that open it are greater than those that close it.

A missing thermostat can result in an engine that overheats. Without it, the velocity of the coolant through the engine can be too fast, there for not enough sub cooling from the heat exchanger/radiator. In other words the coolant travels through the heat exchanger too quickly to lose an adequate amount of heat before cycling back too the engine.
If you remove a malfunctioning thermostat its best to cut the valve from the seating plate and put the seating plate back in. The seating plate will usually provide adequate restriction to slow the coolant velocity down.

Select to expand quote

Jolene said..

samsturdy said..
I agree with Michael, thermostats are very important. They restrict the water flow to allow the engine to attain correct temperature. With a missing thermostat the water flow is enough to take the heat away too quickly.
Thermostats usually stick in the open position as the forces that open it are greater than those that close it.

A missing thermostat can result in an engine that overheats. Without it, the velocity of the coolant through the engine can be too fast, there for not enough sub cooling from the heat exchanger/radiator. In other words the coolant travels through the heat exchanger too quickly to lose an adequate amount of heat before cycling back too the engine.
If you remove a malfunctioning thermostat its best to cut the valve from the seating plate and put the seating plate back in. The seating plate will usually provide adequate restriction to slow the coolant velocity down.

It is a long time since I studied heat transfer, but from what I remember, higher velocity increases the transfer rate. Yes, the transit time through the heat exchanger will reduce, but given that it is a circuit, the number of transits will increase proportionately. However, on the other side of the heat exchanger the flow and water temperature is the same and the whole system should eventually reach equilibrium. Engineering academics please explain?

Heat transfer rate is accelerated by temperature differential increasing velocity through the cooling circuit increases turbulence which improves mixing. Improved mixing ensures that the temperature of the cooling fluid is more or less uniform rather than hotter near the heat transfer interface. Increased velocity also transports heat away from the internals of the engine to the radiator/raw water heat exchanger at an increased rate thereby reducing the coolant temp and promoting heat transfer from engine to coolant. The art is keeping sufficient fluid velocity without wasting energy pumping fluid around. If you pump rapidly the gains in heat transfer rate are marginal and eventually negligible

So yes yarra you are correct, the system theoretically always reaches equilibrium. In practice if the flow is low enough that the coolant temperature is allowed to rise above a certain temp we all know other things happen that are not good for engines. If the engine could withstand extremely high non practical operating and coolant temps the low flow would be offset by the high temperature differential and heat transfer would occur at an equivalent rate.

Select to expand quote

garymalmgren said..
Hi Saskia.
OK. Let's think this through.
We have .
1. engine stop.
2. dipstick thrown and oil ejected from the dipstick tube.
3. coolant boiling.
4. no high temperature or low oil pressure alarms.
That is the sequence as you saw it, but probably not the sequence of events.

My first guess is loss of cooling leading to high engine/ temperature then to engine momentarily seizing.
This is just a guess with no evidence to back it up.

Now let's check.
1. The engine stopped.=I anchored and waited for an hour....and started the engine again without a problem
This means the engine didn't stop for the usual reason of no fuel, dirty fuel, restricted fuel, faulty fuel pump, leaking fuel lines or faulty injector nozzle. If it were any of them you would have had a problem restarting after the cool down period. So we can eliminate all of those causes.
Rope or something wrapped around the prop? A dive over would maybe reveal some left over evidence on the shaft or prop.

2. dipstick thrown and oil ejected from the dipstick tube.
I put in nine searches along the lines of"volvo penta problem oil leaking dipstick"and came up with nothing solid.

In my view the reason for a dipstick and oil being ejected is high crankcase pressure.
So let's search that. This is what we come up with.
www.bing.com/videos/search?q=volvo+penta+problem+high+crankcase+pressure&view=detail&mid=C222D6DB3EB9FE609656C222D6DB3EB9FE609656&FORM=VIRE

Not your engine and has has almost no oil leaking but he, replaced the crankcase pressure relief valve.
The thing to note here that it was on the advice of a Volvo mechanic. (whatever that is worth)

3. coolant boiling. =The coolant started boiling about one minute later too
Here is something we can deal with.
Your cooling system is actually two systems. Primary seawater system and secondary engine cooling system.
A fault (in flow ) in either system will lead to overheating in the secondary system.
Start with the primary seawater cooling system.
1. Remove hose from seacock. Open cock and check flow. This can be blocked by plastic bags, weed, shells or barnacles or small fish. reconnect hose.
2. remove hose from inlet of circulation pump. Open cock and check flow. reconnect hose.
3. remove hose from pump discharge and run engine for a minute to check flow.
use this process to check every part of the primary system.
Then do the same with the secondary system.
Odds are that it was a plastic bag and will never happen again, but without eliminating all options you can't be sure of anything.

Last service was 12 months ago All well and good but when was the last time the ends were removed from the heat exchanger and the tubes checked for blockage?
The following vid is not really directly connected to you problem, but is a must watch for VP owners.

All the best
Gary

Thanks so much for all info Gary, and everyone else who has contributed. Great to have such a wealth of knowledge and ideas floating about! I'm back on board tomorrow to work though this, so i'll keep everyone posted.

Steve

Good luck with it Steve, look for big bubbles( really big) in the coolant tank (with the cap off ) to satisfy my curiosity

Select to expand quote

Saskia II said.. So i completely stripped, cleaned and put the cooling system back together today. No blockages were found, i cleaned the heat exchanger too and checked the impeller. No issues. Engine started fine again. waited to get to operating temp, thermostat opened and i could feel the system heating up so pump is working ok. Ran the engine up to 3000 rpm for 5 mins and it sounded great. plenty of water spitting out back, no smoke, blue or white was apparent either. Removed oil fill cap and could see oil moving around tappetts too. Guess it's time to do an oil pressure test tomorrow and see what that says. I also took her out last Thursday for twilight racing, ran the engine for 45 mins at 2000rpm to get to the start line and back home again and no issues either.... maybe it's the pressure release valve, or could I have just not pushed the dipstick back in firm enough. I'll also double check the oil level again. it's on the full mark but maybe that's a tad too much ...?????. I'll update my findings soon

Steve

garymalmgren said..
Hi Saskia.
OK. Let's think this through.
We have .
1. engine stop.
2. dipstick thrown and oil ejected from the dipstick tube.
3. coolant boiling.
4. no high temperature or low oil pressure alarms.
That is the sequence as you saw it, but probably not the sequence of events.

My first guess is loss of cooling leading to high engine/ temperature then to engine momentarily seizing.
This is just a guess with no evidence to back it up.

Now let's check.
1. The engine stopped.=I anchored and waited for an hour....and started the engine again without a problem
This means the engine didn't stop for the usual reason of no fuel, dirty fuel, restricted fuel, faulty fuel pump, leaking fuel lines or faulty injector nozzle. If it were any of them you would have had a problem restarting after the cool down period. So we can eliminate all of those causes.
Rope or something wrapped around the prop? A dive over would maybe reveal some left over evidence on the shaft or prop.

2. dipstick thrown and oil ejected from the dipstick tube.
I put in nine searches along the lines of"volvo penta problem oil leaking dipstick"and came up with nothing solid.

In my view the reason for a dipstick and oil being ejected is high crankcase pressure.
So let's search that. This is what we come up with.
www.bing.com/videos/search?q=volvo+penta+problem+high+crankcase+pressure&view=detail&mid=C222D6DB3EB9FE609656C222D6DB3EB9FE609656&FORM=VIRE

Not your engine and has has almost no oil leaking but he, replaced the crankcase pressure relief valve.
The thing to note here that it was on the advice of a Volvo mechanic. (whatever that is worth)

3. coolant boiling. =The coolant started boiling about one minute later too
Here is something we can deal with.
Your cooling system is actually two systems. Primary seawater system and secondary engine cooling system.
A fault (in flow ) in either system will lead to overheating in the secondary system.
Start with the primary seawater cooling system.
1. Remove hose from seacock. Open cock and check flow. This can be blocked by plastic bags, weed, shells or barnacles or small fish. reconnect hose.
2. remove hose from inlet of circulation pump. Open cock and check flow. reconnect hose.
3. remove hose from pump discharge and run engine for a minute to check flow.
use this process to check every part of the primary system.
Then do the same with the secondary system.
Odds are that it was a plastic bag and will never happen again, but without eliminating all options you can't be sure of anything.

Last service was 12 months ago All well and good but when was the last time the ends were removed from the heat exchanger and the tubes checked for blockage?
The following vid is not really directly connected to you problem, but is a must watch for VP owners.

All the best
Gary

Thanks so much for all info Gary, and everyone else who has contributed. Great to have such a wealth of knowledge and ideas floating about! I'm back on board tomorrow to work though this, so i'll keep everyone posted.

Steve

Well, you have done all the steps that I would have and I know it's a puzzle not knowing what the cause is, but it is looking a bit like a plastic bag.

At least you are getting to know the BEAST well.

gary

I'm back on board tomorrow to work though this, so i'll keep everyone posted.

Steve

How'd ya go, Steve?

gary

Select to expand quote

garymalmgren said..
I'm back on board tomorrow to work though this, so i'll keep everyone posted.

Steve

How'd ya go, Steve?

gary

Hi Gary, all seemed fine when I raced a fortnight ago. Motored at 1800rpm for an hour both to the start and return to the Marina, then it happened again last Thursday! Left the marina, pushed the revs up to 2100 and 20 mins later engine shutdown..... had to quickly set sails and attach the anchor (racing so not allowed to have it set up on the bow roller). went below and dipstick had not blown out but coolant was boiling again. We raced and on the sail back i topped up the coolant and she started again fine, 1500rpm back to the berth..... have noticed the paint has darkened around one of the cylinders too. Mmmmm......