Diesel Problems...

boatone

boatone

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29 Jul 2001
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Gotta dickie diesel that runs happily at around 3000rpm with temperature gauge normal and stable. Throttle back reasonably quickly to idles speed and temp then starts to rise until just enters red and alarm triggers. After few minutes starts to fall again and alarm stops. WE have identified a coolant leak which 'may' be down to a head gasket but not sure yet.

Now....please read this before jumping in with esoteric conjecture and hearsay...../forums/images/icons/laugh.gif

Has anyone else here actually experienced the same phenomina and what was it tracked down to?

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Have this problem in reverse on a Sabre, we learned to speed up more slowly then all is fine, we have since retorqued the head and the coolant is stable but have not tried a rapid build of revs. What engine are you running? try slowing down slower, if you are turbo'd this is best practice in any case. Good luck.

<hr width=100% size=1>J HAMER
 
Engine is Volvo AQD32A actually indenor/peugeot based block...no turbo or anything else fancy. Engines around 30 years old now.

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My GMC's did that,replaced the head gaskets eventually after cleaning out the heat exchangers etc.What it did was air lock at the top of the block and stop coolant going through the exchanger,bleed it through and it was OK until the engine was stopped and when it was started again it would do it again,sounds like it may be the beginning of head gasket problems(when I took the gaskets off they were very poorly made and covered about 70% of the waterways)The other thing that springs to mind is if you have a heat exchanger/raw water cooling system is that when you throttle back if the exchanger is not clean with the reduced amount of seawater going through it cant cope with cooling down your still hot freshwater coolant.Hope it helps.
Al

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Had same sort of problem on last boat with fresh water cooling tried everthing finaly changed heat exchanger & problem went. Suspect corrosion build up in tubes restricted water circulation on idle. heat held in engine block causing temp to rise. only difference was my engine stayed hot on idle gradualy getting hotter but was fine at anything over 1500 rpm. From cold it would idle for ever without overheating & only got hot after a run.

<hr width=100% size=1>2655
 
Its Knackered. if it was a horse it would have been shot years ago. Use it for a mooring. To repair it is gonna cost more than a new one. Get rid of it.
Its shott, knakered, kaput. Its not an engine anymore its a lump of pig iron!

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captain.gif
 
I wouls clean the heat exchngers by pushing water through ! I even have the tool to do it on An AQD32A it is a 17 inch bit (heaagon?) from Halfords.

also I would fit in a new thrmostat.

Tom

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We have spoken about this but it could be a water pump not flowing enough water at low speed. Might be worth a strip and check. I've seen pumps in the past with virtually no vanes.



<hr width=100% size=1>Jim

Draco 2500
 
You really should have attended the Bucks/Berks/Surrey Chapter Volvo water loss convention last week......

St Col of The Forum had a good look at my engines at weekend and suspected a head gasket but I recall that at SBS the man at Volvo did suggest that TAMD41s tend to lose coolant from a point on the head near the turbo and that a re torque might do the trick before a full head gasket job.

Could this be so?

Nick

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Tony,
Please don't take the head off.
Do this instead...
change Thermostat
Change Jabsco impellor
Take off heat exchanger, soak in patio cleaner and flush through.
It doesn't matter if you changed the thermostat last year, it must be elliminated.
This will solve it.

Sid :-)

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I would go for thermostat stuck slightly open!

<hr width=100% size=1>Alex

boat2.jpg

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See now, I think your all barking up the wrong tree and talking a load of twaddle. Now the rapid temp rise after high revs is no more than a slipping belt. 2 mins and its sorted. The other prob of loosing coolant has nothing whatsoever to do with weeping head gaskets. Your all stabbing at things in the dark. Knowing these engines I would say in my expert opinion its no more than a leaking gasket on the inspection plates on the side of the block.
Also being intimate with all things green. I would also check the 2 core plugs on the back end of the head. These do after approx 30 years of heating and cooling tend to rust and weep around the edges.
The engine not reaching revs is also a red herring. The engine will reach its revs because is a rarely known fact that early tacho's misread. In any case you use these engines by ear. Also the fact that the revs still rise but the tacho doesn't is a bit of a bloody give away.

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No problems only solutions!!

Hi Tony
Simple really just thrash the F**k out off the engines for a while till somethng goes bang!! problem identified !! solution easy !! no conjecture, no guessing, no hearsay !!!!!!

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