Volvo D12 Turbo Loss of Coolant

[statgar]

At 1000 hrs on my SQ55, from 2009, both Turbos were removed and sent away for servicing. They were refitted according to the engineer both engines started OK. I arrived some weeks later and took the boat to a yard for liftout and pre season maintenance. Port engine started fine but the starboard took quite a while to fire up. During the the 3 mile trip at less than 1000 rpm I noticed some white smoke from the exhaust I took a photograph and sent it to the engineer who said not too worry it was probably some residue in the turbo. Later he visted the yard and found fuel leak on the primer/filter housing thinking this was the starting problem. I had an 8 mile trip to the new marina so another engineer came with me in case the engine failed enroute, white smoke was still evident but the engineer did not seem worried, we had checked levels, Ts & Ps were good we increased to 1800 rpm for 10 minutes, no smoke good Ts & Ps both engines smooth. When we arrived the stbd engine cut out and was restarted, eventually stll white smoke. I asked the Volvo dealers to check the problem out they fitted a new primer/filter housing but coud still not start the engine. They found about 25 litres of coolant in the sump, the cooling system would not hold pressure but both aftercooler and turbo did pass pressure checks. Trying to remove one of the injector they found the engine had siezed so it was decided to remove the cylinder head. The inlet manifold was removed and part of a piston ring found in one of the ports so clearly there is serious damage and the engine has to be removed and stripped. Why should this happen after the turbo was serviced? its just too coincidental that the problem was unrelated. I did hear that it had happened before as either the turbo was incorrectly reassembled or fitted incorrectly, can anyone offer any adice?
Thanks in advance.

 

[wofff]

Sorry to hear about your problems - I would be suspicious of "finding part of a piston ring in the inlet port" more likely a turbo fin. The explosive action in the chamber normally pushes stuff down if anything, and if you had good oil pressure, it shouldn't seize. Another question might be, why were you having the turbos done, and did they find any damage which might have remained in your inlet side just waiting to cause a problem ? Good luck with it anyway, and keep us updated with your findings.

 

[jfm]

Agree. This story has some parts that don't fit:

Piston ring in inlet port sounds highly implausible. Piece of junk in inlet port caused by mistake working on the turbos sounds much more likely.

But a cooling circuit failure, dumping 25 litres coolant in the sump, explains a piston ring failure, the seizure and the white smoke. It would also explain piston ring debris in an exhaust port. Whatever, you do need a re-build, alas.

Bad luck, because D12 is a good engine and rarely fails at only 1000hrs (I have had 4 of them).

I don't remember the detailed set up on D12, but the turbos have an oil supply pipe and a cooling water supply pipe, possibly. If you connect the wrong way round you have 25 litres of water in the sump and all your other symptoms. Not sure that is even possible to get wrong so I'm "just saying", but if you look at the engine you might figure this out.

 

[volvopaul]

The intercooler is cooled by the fresh water circuit not salt water so a failure in its integrity can allow fresh water antifreeze mix eventually into the cylinder , this could be your white smoke .
Had a part of the turbo break off on the inlet side then this will have found its way into the intercooler which in turn may have punctured the body allowing coolant into a cylinder and down past the piston rings .
If the white smoke was caused by ingestion of liquid this would damage the pistons , I’m surprised there was no hydraulic lock .

Another possibility is the injector sleeve failure allowing coolant into the sump , I doubt the oil and cooling pipes could have been mixed up on rebuild of turbos .

 

[SC35]

This all sounds horribly expensive, whatever the root cause

 

[statgar]

Sorry I've not responded but thanks to you all. I will revert when the engine is out and stripped currently there is a delay getting the right loader to lift the engine due to lack of headroom.

 

[Andrew M]

Good luck and hope it's not too bad news as you discover what's happened. And yes please do update as you find out, we've got D12's so am alway interested...Did a complete cooling systems overhaul on ours over this winter and temps are now the best they've been since we got the boat. Good luck.