AD31P oil in coolant tank, won't rev above 3000.

Helidan

Helidan

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Boat came out of the water recently and the boatyard offered to winterize the engine. Had a call from the engineer to say oil found in the coolant tank along with slight play in the turbo. I've never been able to get the engine to rev above 3000 under load. So I'm guessing I need the turbo reconditioned. Any idea on cost? Also what else might result in oil in the cooling water AND rpm loss? Engine has done 750 hours according to tachometer. Hoping a strip down isn't required. Otherwise engine seems to run very well, instant start, very little if any smoke, doesn't stall, good temps, good oil pressure, pulls good up to 3000.
 
I had a turbo recon in 2016 on a very similar kad32 and it cost £1158 incl the turbo repair , parts and labour and including the intercooler cleaned out
 
A_8 said:
Likely the head gasket leaking.
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the engineer did mention this is a possibility, he will be doing some tests hopefully today. They did have another boat in with similar issues recently which did turn out to be the turbo.
 
petem said:
I know little about the AD31 but failed turbo gaskets are a common cause of coolant leaks for KAD series engines.

If the boat isn't achieving full revs and is on the original turbo, this is where I'd start.
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I don't think it's leaking coolant (will be checked though), main concern is oil in the coolant bottle. Engineer does suspect turbo is the culprit based on previous jobs. Really hope it's not the head gasket!!
ps, I do believe it's the original turbo from 2001.
 
Helidan said:
Boat came out of the water recently and the boatyard offered to winterize the engine. Had a call from the engineer to say oil found in the coolant tank along with slight play in the turbo. I've never been able to get the engine to rev above 3000 under load. So I'm guessing I need the turbo reconditioned. Any idea on cost? Also what else might result in oil in the cooling water AND rpm loss? Engine has done 750 hours according to tachometer. Hoping a strip down isn't required. Otherwise engine seems to run very well, instant start, very little if any smoke, doesn't stall, good temps, good oil pressure, pulls good up to 3000.
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Souds like head gasket atb with thst
 
Straight forward job tho time consuming due to removal of all ancillaries.
Check head for distortion.
Push rod engine easy to set up injector fuel lines can be a pain to re-seat
Good opportunity to give block etc good coat of paint
 
Head gasket will bow out / loose coolant .Also you can buy a simple test kit for the coolant which picks up combustion products.

I doubt the “ engineer “ does not know this ?

Dx 1 the turbo bearing spindle makes more sense .

Additionally a blown HG has little influence rpm ceiling .
Op has not stated he has been topping up the coolant before every trip or reported any rises in jacket temps .Or any smoke behind ( other than normal ) Or any burning smells - you can smell burning coolant the exhaust fumes docking etc .

An oil to water breach in the head would not occur independently from a cylinder gas breach to the circulating coolant .

Could be a oil cooler leaky if it’s got one and it’s closed water cooled ? I,am not detailed familiar with the exact set up ?Presume said “ engineer “ is .
 
Portofino said:
Head gasket will bow out / loose coolant .Also you can buy a simple test kit for the coolant which picks up combustion products.

I doubt the “ engineer “ does not know this ?

Dx 1 the turbo bearing spindle makes more sense .

Additionally a blown HG has little influence rpm ceiling .
Op has not stated he has been topping up the coolant before every trip or reported any rises in jacket temps .Or any smoke behind ( other than normal ) Or any burning smells - you can smell burning coolant the exhaust fumes docking etc .

An oil to water breach in the head would not occur independently from a cylinder gas breach to the circulating coolant .

Could be a oil cooler leaky if it’s got one and it’s closed water cooled ? I,am not detailed familiar with the exact set up ?Presume said “ engineer “ is .
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we've not had the boat long, I haven't topped up any fluids yet but I have been checking that levels are correct. Engine temperatures are within normal operating range (as indicated on the gauge panel), no high temp alarms have sounded. Definitely no burning smells and cruising at 3000rpm there is no smoke. There is no evidence of coolant in the oil, dipstick shows normal oil and there is no emulsified oil inside the rocker covers. Engine oil pressure always within normal range.

Engine does have an oil cooler and is closed water system.

Engineer has reported play found in the turbo spindle.
 
The oil cooler is seawater cooled and this does not have to be an either or issue it can be both. I agree a gasket issue will not pull the revs down that much but it will get some oil and exhaust fumes in the coolant AND likely some coolant in the oil which might be easy to spot .
 
A_8 said:
The oil cooler is seawater cooled and this does not have to be an either or issue it can be both. I agree a gasket issue will not pull the revs down that much but it will get some oil and exhaust fumes in the coolant AND likely some coolant in the oil which might be easy to spot .
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I've looked a few times and I really can't see evidence of coolant in the oil, it looks like normal colour oil and smells right.
 
stelican said:
Well if your only getting 3000 rpm maybe the turbo is tired.
Did it used to give more
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Previous owner mentioned they have had revs above 3000 in the past but used to cruise around 2000-2500. Supposedly they never liked to thrash the engine (I personally have no issues going to full power assuming everything is ok).
 
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