crankshaft bearings? ea82

[blazelate]

I have had this low oil pressure problem with my ea82.

 

The oil rides normal when cold, but once it warms up the oil pressure rides near 0 psi while highway cruising and at idle. Other than that it goes up to nearly 30psi when around town.

 

My mechanic said it could be a faulty wastegate on my oil pump, releaving pressure when its not supposed to. Now today he said he thinks its worn out bearings on the crank/rods. I was trying to get him to explain, but it didn;t make sense how worn out bearings in the bottom end would make the oil level drop.

 

Anoyone ever heard of this happening? Worn bearings causing drop in oil pressure?

[john in KY]

Happens all the time. Clearances between bearing shell and journal just increases to the point the pump can't maintain pressure. Think garden hose with finger over the end and same hose with no finger. Lots of pressure one way and very little the other. But this engine has hydraulics. If the engine isn't ticking like mad then it has enough oil pressure. Been driving an XT6 for 10 years that shows zero pressure (hot) and maybe 20 pounds cruising. Subaru gauges can be way off.

[blazelate]

Well it is ticking like mad, goes up with the rpms.

 

Does it sound like the bearings? will i have to replace them, now? i just had these guys do new heads on it, so the last thing i want to do is pull the motor again..

[GeneralDisorder]

Your bearings are likely fine. The ticking is the valve adjusters. Replace the oil pump, seals, cam carrier o-rings and if the ticking doesn't stop replace or rebuild the lifters.

 

If/when you lose a rod bearing you'll know it. They give very little warning and will end up shooting out the case under the intake manifold. The telltale sign is NOT low oil pressure but a metallic knocking while under load - it's actually not as loud or annoying as the lifter ticking you have now. In any case EA82's are not worth the trouble to replace the main/rod bearings as it requires a complete engine tear-down and rebuild. It is not a simple thing. You would be better off getting a used engine.

 

I can count the number of times I've seen or heard of rod/main bearing failure on an EA series engine on ONE HAND. I've been on this forum for 7 years and I've got 12,000+ posts. I'll bet your mechanic $10 your bearings are just fine.

 

Your low oil pressure is probably due to a fualty pump, sending unit, or electrical issue. On these engines the pressure reading is taken directly off the pump and even if the rod/main bearings are totally wasted it will only make a small difference in your oil pressure reading. They also don't wear much before they just grenade - not enough to notice a big difference in oil pressure.

 

GD

Edited October 21, 2009 by GeneralDisorder

[blazelate]

GD thank you very much, you are very knowledgeable.

 

The thing that leads me to believe it has nothing to do with the bearings is that the pressure fluctuates often, and only drops when i am cruising or idling. If it were worn bearings i would expect the oil pressure to be low much more often, is that right?

[GeneralDisorder]

That sounds like a pretty normal low-reading gauge/sending unit. At idle and cruise you are at lower RPM than at other times.

 

Oil pressure is purely a function of RPM. As the RPM's climb the oil pressure does also to a point. That point is where the bypass valve opens and allows the pump to return extra oil pressure back to it's own inlet.

 

Tell me - did the "mechanic" test your oil pressure with a known-good shop gauge? Do you have test readings from said gauge at various RPM's - taken cold, warm, and hot with temp gun readings to match?

 

If not your mechanic is a hack.

 

GD