Pressure in coolant KAD 42

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Vecchia Signora

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Last August, we had an engine overheat due to a broken impellor. After changing impellor, we noticed over flowing of the coolant from the expansion tank. Due to the loss of coolant, the engine was overheating again. We also noticed the engine was getting "dirty" with black smoke.
Prior to the coolant spillage, the engine was running normal and temperature was normal too. It was also noticed that on draining some of the coolant, the coolant itself had become greyish in colour.
Our mechanic found that the head gasket was blown which also led to two scored liners. The other four liners were rusted and pitted. The mechanic also said that due to the overheating, the head gasket torque got loose.
Head gasket, six liner kits, valves, thermostat, rod bearings were replaced with new ones.
On sea trial, it was noticed that 2 of the injectors were leaking fuel when the seatings had also been replaced with new ones. All seemed well in the first 10 hours of running at 25000 rpm....except from smoke and fuel coming out of the injectors. After another 5 hours run, the coolant was spilling out of the expansion tank again.
Any help would be greatly appreciated!
 
It sounds to me like the route if the first problem has not been solved. Did the engineer clean out the oil cooler, heat exchanger and intercooler along with a thorough stip down of the raw water pipes, checking the exhaust elbow for blockages. Sounds to me you have had a rebuild but the original problem maybe has blown the head gasket or he has miss seated a liner seal. The copper sleeves have seals on them to that seal against the bore hole in the cylinder head, maybe the compression is blowing past the seal into the water jacket and causing your pressure to build up.
Is the engine overheating? If not then compression is surely the cause of the build of pressure in the cooling system.
 
First of all, welcome to the madhouse.
If you don't mind me asking, what has an "old lady" to see with a relatively modern engine like a KAD42?

Re. your question, if it weren't that volvopaul already answered, I would have suggested to wait for his reply... :)
 
Hi Volvo Paul & MapisM...Thanks for your replies. ::)) I see MapisM is from Italy so I assume he can realize what the "old lady" stands for!!?? :) So back to our problem..Mechanic said he cleaned air cooler and heat exchanger etc, but has nt mentioned he did anything to the exhaust elbow. After changing all the parts mentioned above which cost us 12000 euros, the boat was used twice for around 15 hours...most of the time trawling at only 1200 rpm. When we went on boat for the 3 rd time we noticed coolant was in the bilges and tried throttle without load ..after 5 minutes water spills out. New expansion tank has already disformed. Coolant does nt get hot and no engine did nt overheat again after the complete service. We told the mechanic who said it could either be a cracked head or a cracked manifold!..and we don t know what to believe anymore!!
 
Vecchia Signora said:
Hi Volvo Paul & MapisM...Thanks for your replies. ::)) I see MapisM is from Italy so I assume he can realize what the "old lady" stands for!!?? :) So back to our problem..Mechanic said he cleaned air cooler and heat exchanger etc, but has nt mentioned he did anything to the exhaust elbow. After changing all the parts mentioned above which cost us 12000 euros, the boat was used twice for around 15 hours...most of the time trawling at only 1200 rpm. When we went on boat for the 3 rd time we noticed coolant was in the bilges and tried throttle without load ..after 5 minutes water spills out. New expansion tank has already disformed. Coolant does nt get hot and no engine did nt overheat again after the complete service. We told the mechanic who said it could either be a cracked head or a cracked manifold!..and we don t know what to believe anymore!!
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If the exhaust manifold was cracked you would loose coolant out of the exhaust flowing out with the gas, so it would not pressurise the cooling system.

The Volvo heads don't crack unless they have really been overheated, if this was suspect then before any work was carried out it should have been pressure tested. Was the head checked for straightness, if not then that could be the cause if it's not seating properly.

Has the engineer gas tested the coolant since the second problem?

The early kad series motors had suspect coolant circulation pump, basically the impeller was plastic and pressed on to the pump shaft, has he removed it at any time to check the turbine fan is not loose, they usually fall off. This gives the same symptom you have as the coolant is static in the block which expands as it heats and builds pressure.
 
Its seemed to run fine for the first 10 hours? Up to 2500 rpm

How would one sea trail a rebuild like this ? Was WOT ever done and for how long?
The test on the coolant fluid for compression gases escaping really needs doing ,I,am for head gasket again and it's not been put back together all aligned properly??
 
I do not think it s the fresh water pump as pressure in the coolant was noticed soon after start up while coolant was still cold. No the engineer has not pressure tested the head neither has he checked it for straightness! He worked on it again yesterday and replaced 3 injector sleeves which were leaking both compression and fuel. All 6 injector sleeves had already been replaced while rebuilding. He explained that injectors are water cooled therefore he thinks that compression in coolant was due to that. Personally I don t understand that when you have 6 new sleeves, 3 of them go bad in such a short time unless something else has caused them to go wrong. Also the O ring of the injector sleeve was found torn. Unfortunately the boat is presently on land therefore it cannot be checked under load. We tried engine @ 2000 rpm for a couple of minutes and so far there was no leaks present in injectors and no pressure in coolant but i still believe the problem is nt solved. :((
 
Dont think your new injector sleaves "went bad" , either they didnt get fitted correctly or didnt get changed at all ! (sorry):o
 
Vecchia Signora said:
Hi Volvo Paul & MapisM...Thanks for your replies. ::)) I see MapisM is from Italy so I assume he can realize what the "old lady" stands for!!?? :) So back to our problem..Mechanic said he cleaned air cooler and heat exchanger etc, but has nt mentioned he did anything to the exhaust elbow. After changing all the parts mentioned above which cost us 12000 euros, the boat was used twice for around 15 hours...most of the time trawling at only 1200 rpm. When we went on boat for the 3 rd time we noticed coolant was in the bilges and tried throttle without load ..after 5 minutes water spills out. New expansion tank has already disformed. Coolant does nt get hot and no engine did nt overheat again after the complete service. We told the mechanic who said it could either be a cracked head or a cracked manifold!..and we don t know what to believe anymore!!
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As the boat is now out of the water perhaps you could remove the Injectors and compression check each cylinder to see whether the replaced head gasket is ok or not. As has been stated its possible that the head is warped this happens sometimes after bad overheating and is in need of skimming. The compression check will tell you a lot.
Hope everything goes well.
 
I had a similar problem on my previous boat's KAD 42 engine after a head gasket change. For the first 10 hours or so everything was ok. Then suddenly when loading the engine for a few minutes coolant started to erupt from the expansion tank without overheating. After extensive trouble shooting the problem was found to be that inadequate torque had been applied on the head bolts. On the KAD engine the bolts are tightened so that they stretch a bit and if you re-use the old bolts they might have lost their mechanical properties. Also they have to be cleaned to ensure that the right tightness is achieved. If dirty, the friction can cause wrong torque values. In my case no leak was detected when doing static pressure testing. Only when loading the engine and under normal operating temperature the leak occurred.
 
Im really surprised that my mechanic, who by the way is an authorised Volvo Penta dealer,never mentioned any compression tests , neither did he check anything in the head when the engine was out! I will this time have to make sure the injectors are removed again and the compression test is done as I really don t want to launch the boat again having the same problem...it would be really frustrating! As mentioned also by "baylabayla" it would also be interesting to check the bolts for tightness etc... so I would cover as much possibilities as possible. I would also like to ask one very important question: Is it possible for water to enter the piston cylinders if any of the above is found to be wrong??
 
Yes is the Answer, you could get water or oil into the combustion chamber on the induction stroke of the cylinder, this all depends on if or how the head is leaking and across which part of the head etc. Best to check compression and go forward with what it shows you.
 
I just really hope we did nt ruin the news cylinders!!!!...will definitely have to get the compression test done. Will keep you posted and many thanks for your help :)
 
When the head gasket blows ,coolent is drawn in ( induction ) but if it's a " little" it burns off .
In cars a white/ blue smoke .We all have been behind one on the M way.
This bolt issue - that ties in with the 10 hr seems fixed period .
If i can digress-- early flat 6 Porsche engines were machined to such precise tolerances they actually had no head gaskets ,Yup metal flat surfaces just really FLAT so no need for gasket , just bolted together.Long bolts from head through both 1/2 th of crank case to the head on the other side Remember it's a flat 6
Ok air cooled no water jacket , but still think about the gas pressure trying to escape at the power stroke.
Bolts - they too were made of a special alloy , they too " stretched " and had a vary specific torque ,Never used twice .
but we need Volvo Paul's view on this bolt issue .
 
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Portofino said:
When the head gasket blows ,coolent is drawn in ( induction ) but if it's a " little" it burns off .
In cars a white/ blue smoke .We all have been behind one on the M way.
This bolt issue - that ties in with the 10 hr seems fixed period .
If i can digress-- early flat 6 Porsche engines were machined to such precise tolerances they actually had no head gaskets ,Yup metal flat surfaces just really FLAT so no need for gasket , just bolted together.Long bolts from head through both 1/2 th of crank case to the head on the other side Remember it's a flat 6
Ok air cooled no water jacket , but still think about the gas pressure trying to escape at the power stroke.
Bolts - they too were made of a special alloy , they too " stretched " and had a vary specific torque ,Never used twice .
but we need Volvo Paul's view on this bolt issue .
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Head bolts can be used again, although the setting are something like 60 nm the 90 degrees twice( don't quote me on the 60mn bit it was a guess as I'm stood here.

The fact is the bolts will stretch but are not the design which most modern engines have whereby they stretch to achieve the ability to hold torque and once used are scrap.

There is a measurement in the manual stating overall length, but they can be used again.
 
Vecchia Signora said:
Im really surprised that my mechanic, who by the way is an authorised Volvo Penta dealer,never mentioned any compression tests , neither did he check anything in the head when the engine was out! I will this time have to make sure the injectors are removed again and the compression test is done as I really don t want to launch the boat again having the same problem...it would be really frustrating! As mentioned also by "baylabayla" it would also be interesting to check the bolts for tightness etc... so I would cover as much possibilities as possible. I would also like to ask one very important question: Is it possible for water to enter the piston cylinders if any of the above is found to be wrong??
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I have received your private email, I'll take time to read it.

As it sounds like there has been a. Mistake somewhere by the vp dealer I'd be careful what you write on here as it may get picked u by them and turned against you.

I have been acting now for a client in the uk who has a major battle on with a marine engineering company after a rebuild on his engine, it's been going on since 2007 and yet to be resolved, I can tell you it will take a lot to prove negligence , however we are still battling on with this one as it a considerable amount. I can't say any more till the court case, when I do it will make an excellent post.
 
Thanks Volvo Paul :) I really appreciate! Whatever I said on this forum is the blessed truth :) I agree with you that there has been a mistake somewhere and it is very important for me to find out what it could be. From then on, I assume I would have a clearer picture of the situation. Thanks once again to everyone on here :)
 
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