i just bough this car a few weeks ago and noticed a small oil leak at the left corner of the exhaust manifold. I found that one of the screws was loose. So, I replaced the exhaust head gasket and the flange gasket as well. also, i added an oil stop treatment to stop the leak. It stoped for a while, however i still get some oil at the exhaust manifold sometimes. It usually happens during initial turn on only, and after that the car is fine, super. what could be the cause of my problem?
“Exhaust head gassket”? “Flange gasket”? Do you perhaps mean the exhaust manifold gasket and the valvecover gasket?
A loose screw could mean that the original gasket was compressed and deteriorated beyond its ability to keep the bolt under load or to hold oil under pressure. My guess on an engine this old is that you have some pressure from the crankcase (normal) that, as can be expected, also creates some pressure under the valvecover and this was pushing some of the oil that lubricates the valvetrain past the tired old gasket. You proabbly have s little puddle that forms in the corner under the valvecover when it’s off and when you start the engine and the crankcase pressure builds it pushes it through.
Honestly, on a 21 year old Corolla I’d just watch the oil level (you should anyway, at least until you become familiar with the car) and wipe the drip occasionally. As long as it has oil it’ll probably run indefintely like this.
Thanks a lot for you inputs. I will keep checking the oil levels as i usually do just to keep track of it. I realy didnt see the problem until i changed the engine oil, not knowing which kind of oil (10-W20,W30 or 50…) was put in before. I think the guys put in the conventional oil into my car. I will switch to a thicker or high milage oil, maybe it could help too. by the way the car only have 129K miles.
Did you replace the valve cover gasket? The oil is most likely coming from the valve cover as ‘the same mountainbike’ stated. While you are in there check the valve clearances as that may not have been done in the life of the engine.