Sudden oil loss TAMD41A

[tonyp]

Can anybody explain why I am suddenly lossing oil (5 litres on a 20 mile trip) through the crank case breather on an engine that previously used little oil. Could it be the head gasket or piston rings? I would be grateful for any advice. thanks.

 

[tonyp]

OOPS! I have just noticed an identical post form John_Pierce on 18/10/02, a very spooky coincidence that we should both be experiencing the same promblem at the same time.

 

[John_Pierce]

YES I have exactly the same problem !

My engine has been fine but recently loses oil from the crankcase breather above 3000 revs.
Are you getting much crankcase backpressure !, but would this push the oil out ??
One possible issue is a partial oil blockage that does not allow the oil from the rockers to return to the sump. and fill up the camshaft followers area, that then allows the oil to fill up the breather.

On mine, the oil just flows down the outside of the canister, there does not seem to be much pressure "blowing it out"

Keep intouch we will try and discover the problem, could be piston rings, that is allowing positive crankcase pressure, but the faulty engine is no different to the good engine.

Regards

John

 

[Guest]

Hi guys,

I had a ad31p that had only done 90 hours before it completely blew up! The reason for this was that I was travelling at 3500 rpm when the oil was pushed out of the breather tube, the engine run out of oil completely and stopped. Only then did the warning alarm come on! The problem turned out to be a known fault with some turbo's on Volvo's, they leak pressure into the crank case - in extreme cases they cause all the oil to be blown out completely.

After a big tussle with Volvo they decided they would repair the engine. Since then, and with new pistons and turbo installed I found that I had the same problem over 3500rpm, oil started to come out of the breather tube. Volvo investigated and said that the standard tube that links the air filter to the top of the engine was not big enough (the size was restructed, due to some EC regulation), and this was causing back pressure. since that time the oil seems to have stayed in the crank case, but it always seems like touch and go to me. All a bit worrying when you've only got one engine to rely on!

How old is your engine? How much oil have you lost?

Regards

Andy Coggin

 

[rlw]

check out the volvo forum on www.boatdiesel.com

Rob

 

[tr7v8]

As a general thing all Turbo engines have an increased blowby the pistons into the Crankcase. This is why generally Turbo motors have larger breathers than non turbo's.
Sounds to me like it could be Volvo's piston rings are struggling to cope with the boost pressures involved. The other thing seen on high output blocks is that the block is moving enough to allow blowby.

Jim
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[John_Pierce]

After modifying both engines to the B breather spec, two weeks ago at 3000 RPM, the STBD engine just blew all its oil out via the oil extraction tube. There was excessive crankcase pressure, and checking cylinder pressures found No 1 AND 2 down to 50 PSI, I have had the head off, and there is scoring of the liners on both liners.

So today I took the boat down to the lifts, and had the engine took out to have repairs

On the way back in the marina, and tick over speed, the other engine did exactly the same thing !!!!!!!!!!!!!!!!!!

ANY suggestions, to what the root cause is, there was no oil pressure loss initially, and the engines did not over heat.

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