Just so if any one thinks of fitting a VDO temp gage to there Buhk Diesel with a twin terminal sender you will have a failure problem as for some reason
( depth this can be over come with a spacer ) but ever after making a space they will still fail. Even a Buhk spares seller in the UK told me this when I was researching the sender. What some of the local Walker H28s have done is fit a signal terminal VDO sender in the Buhk engine drain and have no problems since and keeping the original bulk sender ( warning light)in the thermostat housing
Some useless information for Loose Change to store away in his brain archive winking at you loose change
At around $80 each its good advice
the Buhk engine block drain thread is 14 mm so buy a 14 mm sender signal terminal not the one below

andy59 said..
I'll be doing that HG thanks for the tip

Ill get the part number and put it up if you or any one else have a bukh on board MMMMMMMM sounds like a rooster bukh bukh bukh Brizzy Dave would be interested in that

The signal terminal sensor is around the $30 mark

keensailor said..
I use this VDO sensor on my Bukh DV10-LSME and it works fine, it has dual terminals;

I have the same sender here as your part number its just other walker owners (DV 20)have had trouble with it not working after a short time . A friend of mine has tried three so far all have failed . He used a spacer to keep the depth shallow but still had trouble and made sure there was clearance .
I inquired in the UK about this sensor and was told by the Bukh spares part seller they also had trouble . He said they wont last. All these were fitted in a Bukh DV 20.
I wonder if there's a different part number for the DV 10 Thermostat housing than the DV 20. Ill check my spare parts book see what I can find of there is a difference







You would have a different thermostat housing than the DV 20 Ids say I have not removed the housing yet been to busy but might try this week see what I can work out .
Its some thing to do with the combination of the thermostat housing and the sensor I feel on the DV 20.
You cant just screw the sensor in to the DV 20 you have to use a 12 to 14 mm spacer to give it clearance that's all I know at the moment .

I am not professor on electrolysis but the first thing that came to mind ,paint the sensor with anti foul
another comes to mind not sure if it would work heat shrink the probe < D,K, is no professor

Jabberwock said..
Tried that and learnt by experience! If the thick paint or heat shrink comes of as a sheet it plays havoc with thermostat and down stream parts of the water cooling system.

That crossed my mind also mine raw water cool so its only the exhaust water and thermostat.
Thanks for the info thats why my senders still in the packet it came it.
Buit as I said other bukh owners have fitted a single terminal sender for the VDO gauge in the block drain and have had success
you just need a 14 mm single terminal sensor for the gauge

The sender is earthed through the motor and the two terminals are for the alarm and temperature output. If the motor is not earthed or the sender is isolated (ie put in a plastic fitting or in a part of the rubber tubing) then it will not work unless you earthed as you suggested. I don't think that earthing the sender in any other way will make any difference to the electrolytic activity that is going on in the cooling system.
The electrolytic activity is pretty strong as I get through a pencil motor anode within 8-9 months! Warm sea water and a mixture of metals!
It is interesting that the Bukh replacement sender has a red paint coating on the probe (see below and www.frenchmarine.com/product/Bukh-552J0918-Temperature-Sender-2073-3). Also the price! Double what you pay in Oz for a sender from VDO. Suspect that Bukh have worked out that the probe needs protection!

It sounds like you hit the nail on the head. It would definitely be a ground issue when using that spacer. By attaching a ground wire between the washer and hex and running it to a good ground point should resolve any issues.

I received the above reply back from VDO today
I'm not sure if you are using a spacer between the Hex and the sender probe? But that what I will have to do fitting my VDO sensor as its to long.
I have it here so I might as well try it cant return it
But I still like the idea of some sort of electrolysis protection for the sender probe

Jabberwock said..
I do not use a spacer. The sender is screwed into the thermostat housing. If you can get the housing off it is worth considering milling out the indentation for the sender so that your sender fits. That is what I did. There was already enough space but I took a little more off to make sure.

When I took delivery of the boat there was problems with the engine over heating. Found that it was the thermostat that had collapsed blocking the flow of cooling water. The thermostat was eaten away probably due to electrolysis since the pencil anode was completely missing! I routinely change the anode for new one every 6 months.

Ill remove it a mill it down thats a good idea thought there might not be enough room to do thats I just have not removed the thermostat housing except when I first bought the boat and ran vinegar through it nearly 12 months ago.
Thanks for the tip Jabberwock

I ran my engine up today with forward thrust again the pier Im on was not real happy with the amount of water coming out the exhaust so I wanted to remove the thermostat tomorrow and test it so.
I have a 6 bolt flanged water pump and I want to buy the up graded 4 bolt which pumps more water volume .Mines a early Buhk around 1977 I guess
Ive also bought a speed seal kit to suit a four bolt water pump buit I also want to find out mre on the cooling pipes that enter the block as mine are a smaller diameter Maybe 10 mm pipe I believe the four bolt engines use 1/2 barbs plu the piping going to and from the block appear to be different than mine
www.speedseal.com/SpeedsealLife/SpeedsealLife.html

My boat has a four screw Johnson pump (F35B-9) and it sounds likes yours has the older pump. I have no experience of changing pumps. However I have serviced mine - easy to remove. Part of routine maintenance replaced the bushes/oil seals and O-ring. If the DV 24 pump is a bolt on cannot see any problems. You can check detailed drawings on Johnson pump web site and compare them with your model. I have replaced all the tubing associated with the cooling system as a matter of routine maintenance and installed a Vetus syphon breaker. I have also been through the system and found scale build up in the Y tube (diverter) especially the part that goes into the block, the top of the thermostat where the by-pass water mixes with the water coming from the block through the thermostat and the injector into the exhaust. The latter two were really restricting the flow of water.

I was worried about the amount of water coming out of the cooling system especially on cool days when the exhaust has a tendency to steam. Using a bucket to catch the water coming out of the exhaust I measure a rate of about 8 litres/minute at three quarter max revs. Max output is quoted as 11 litres/minute at max revs. Seemed enough so I stopped worrying! Bukh's are also know to steam especially on cool days.

Looking back at our previous posts it is possible that your motor was older than mine. Mine was rebuilt in 2005. I noticed in the copy of the work shop manual I have for DV20 states that it is not possible to use a dual temperature sender as the older thermostat housing does not have enough space.