Looking for ways to prove out a cracked engine block - started getting a lifter knock and it got worse over time. Noticed oil in the antifreeze resevoir. It appears the cracked block leaned out one of the lifters. Does this make sense? The engine is the 3.4 -6 cylinder with 100K on it.


Mechanic wants about $2K to drop a used one in there and will buy the car for $1,000 if I don''t want to fix.


Thanks for any input.

Are you sure the block is cracked? It could be the intake manifold gaskets. They are known to fail.

Nope - I''m not sure the block is cracked. That''s just what the mechanic told me. I don''t think it''s the intake manifolds gaskets. Those have already been done. The mechanic said since there is oil in the antifreeze resevoir, the only way that can happen on the 3.4 is from a cracked block. I''m a little skeptical and that''s why I''m trying to prove out the block is indeed cracked. Thanks.

Matt

I had oil in my overflow tank when my intake manifold gaskets failed. And just because they have been done before doesn''t mean they wont fail again. I need to do mine again because oil is seeping out between the intake manifold and the block.


Did he say where the crack was? Has your car been overheating? I''m not saying that its not cracked but the way the economy is I wouldn''t put it past a mech to say something is wrong when its not just to make money. Is your mech from a dealership?


I would look under the throttle body, where the intake manifold and the block meet and the intake manifold and the heads meet, if you see seeping by the gaskets thats probably the problem.


I would think if there is a crack in the block the oil would be leaving the block, not going into the coolant, unless its and internal crack which he wouldn''t be able to tell unless he took the motor apart.

One more thing about the oil in the coolant, the oil pressure is greater than the pressure in the cooling system so if there was a bad gasket the oil would enter the coolant before the coolant entered the oil. Is there any coolant in you oil? Look under the oil fill cap and dipstick, if its got a milky looking color on it you have coolant in the oil and shouldn''t drive the car if you haven''t already stopped driving it.

Thanks for the info on the engine. There is only 100K on the engine and that''s another reason why I don''t think think the block is cracked. It''s my understanding the manifold gaskets should be replaced around 100K. We had a gasket replaced on that last fall - I just don''t remember which one was done. This same mechanic did the gasket job that''s looking at it now so maybe it needs another looking at. The mechanic is not from a dealership. Learned my lesson long ago never to trust them. I''m confident I can trust him - I''m just not entirely sold on the cracked block theory.


The car has not been overheating - maybe even opposite. It takes a while to get warm when it''s cold outside.


There is oil leaking onto the ground. The same mechanic said it was something with the oil pump?? I''m not familiar with that as much as the gaskets.


We stopped driving the car a while ago to be safe.





thanks for the info.

I''m with rusty on this one-it could very well be a lower or upper intake manifold gasket leak. When you had them replaced, was the new style gasket used?


Sometimes LIM or UIM leaks do allow coolant in the oil, even though rusty is right about the oil pressure being higher. The cooling system retains pressure for a while after the car is shut down, allowing coolant to bleed into the oil system sometimes. It depends on how big and exactly where your leak is, whether that happens or not.


A cracked block can happen with 5 miles on the car, or 150,000, although it gets more likely the more miles you have. I think I''d have the manifolds taken off to get a look at the gaskets before spending $2K on a new engine.

Just talked to the mechanic - the lower intake manifold gasket was replaced 11/2007. I asked him about the possibility of the problem being a manifold gasket and he didn''t think so because with the lifter knock, he said the problem is on the bottom end.


The oil leak appears to be coming from a bad O ring on the oil pump drive.


Assuming the lower intake manifold gasket is still good - could these symptoms come from the upper manifold gasket being bad?


thanks

Well I know the 3400''s are known to have lifter knock, usually at start up then it goes away.


I would get a second opinion form another mech in my opinion. For one the lifters are in the heads, on top the engine, and really have nothing to do with the bottom end of the motor.


The o ring on the oil pump drive should have been changed when the intake manifold gaskets were changed, they are known to leak also.

Thanks - maybe I assumed it was the lifter knock and never actually clarified with the mechanic what the noise was. This noise sounds like a card in the spokes of a bike. From the mechanic, he thought the noise was coming from the bottom end.


Is that O ring on the oil pump drive hard to do? What needsto come off for that job?


I''''m in Minneapolis - anybody want a weekend job?? [img]smileys/smiley4.gif[/img]Edited by: mcuhan