Detecting Problems From Underneath The Engine - Corolland: the Toyota Corolla Forums

I may get ambitious enough to remove the oil pan from a 4AFE engne that is in a friends '90 Corolla. I'll be able to see the inside of the engine while lying under the car. What problems can I detect from that position?

The engine which has about 200,000 miles on it. We don't think it has a problem with rods, crankshaft or bearings. However, it would be nice to know how to make a routine check. I understand how to check if a rod is actually loose on the crankshaft, but how would I detect a less obvious problem like a "spun" bearing? Would I have to start removing bearing caps?

The engine may have worn rings. I suppose there's no way to check that from underneath the pistons.

Be tough to check the rings from underneath, though it is possible. You can try soaking the top of the piston with a slightly viscous solvent, and see how much slips past the rings. Though a good engine might let a little solvent slip past.

Sludge would be the most telling story. Run a magnet through the bottom of the oil pan - see if it picks up any metal. Wipe the bottom of the oil pan - see what other "stuff" is on the there. To check for spun bearings - have to pull the bearing caps to get a good look at the crank.

If the engine is running OK, no knock, no unusual noise or rattling - then I wouldn't go much further than that. Just check the sump pickup - make sure that is OK, check the pan for shavings, cut open the oil filter - see if there is any glitter in there. If not - that engine is good to go.

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However, it would be nice to know how to make a routine check.

No "routine check" that I ever heard of consisted of removing the oil pan ......

I think you might create a lot of problems that aren't there now and in hindsight you may say "Geez, I wish I hadn't done that !!"

Your friend will hold you responsible.

Life is complicated enough... If it 'aint broke, don't fix it.