1999 Coriolla - Engine Noise - Oil Light - Toyota Corolla, Chevy Prizm (1998-2008)

Vehicle has 147K miles and overall, runs good. Last Friday I was on the freeway. After about 5 minutes of 70mph driving, the oil light flickered and then came on steady. I monitored the heat guage, not running hot, and performance seemed fine. Could not hear anything unusual because of road noise. When I exited freeway, I could hear a rather bad sounding rattle coming from under the engine. Sounded like marbles in the engine. I made it to work and parked. On my break, I went out, checked oil level and it was fine. Started car up and it now ran without noise. Later, I left work and the same situation occured, after a bit, the oil light came on and the loud noise. Still, car seemed to drive fine. Talked to friend who suggested I change oil, put in 20W-50 and a decent filter. Did this on Saturday and after completing, started car up and it purred like a kitten. No oil light. Sunday, I drove around town, no highway and probably never went over 40mph. Again, car ran smooth as silk, no oil light. Today, back to work and the same as Friday. Almost at the same location on the freeway, oil light flickered then stayed on, and rattling noise heard when I got off freeway. Any clues? Like I said, performance seems fine but the noise is almost scary. I don't want to hear myself on the traffic report as a "car on fire". As a side note, this has been occuring on and off for awhile now. Just about the time I panic the light goes out, engine stops rattling and all is well for an extended period of time. Any tips/thoughts appreciated!

I would definitely not run the 20W-50 in the car - that is a "bandaid" fix to get a shock proof oil and squeeze out extra oil pressure (due to its heavier weight). The 1ZZ-FE is pretty picky about oil, the internal clearances are very tight, running a heavier oil than spec (a 50 weight vs 30 weight) is a recipe for starved bearings.

First - check the oil pressure sending unit - it will be right by the oil filter. Make sure it has not come loose and reading correctly. If you can, run a secondary pressure gauge to see exactly what the engine is generating pressure-wise. Since this happens at higher RPMs and generally more pressure is generated at higher engine speeds. There is a good chance that the oil pump is starting to fail one you.

Generally they fail all at once, other times, they can take a while. Since you have a audible noise associated with the oil pressure lamp - that goes away once the lamp turn off - this points at a potentially fault oil pump. Some 1ZZ-FE engines developed cracks in the oil pump or had excessive clearance between the case and gerotor. That will cause pressure failure at higher engine speeds.

I would definitely not run the 20W-50 in the car - that is a "bandaid" fix to get a shock proof oil and squeeze out extra oil pressure (due to its heavier weight). The 1ZZ-FE is pretty picky about oil, the internal clearances are very tight, running a heavier oil than spec (a 50 weight vs 30 weight) is a recipe for starved bearings.

First - check the oil pressure sending unit - it will be right by the oil filter. Make sure it has not come loose and reading correctly. If you can, run a secondary pressure gauge to see exactly what the engine is generating pressure-wise. Since this happens at higher RPMs and generally more pressure is generated at higher engine speeds. There is a good chance that the oil pump is starting to fail one you.
Generally they fail all at once, other times, they can take a while. Since you have a audible noise associated with the oil pressure lamp - that goes away once the lamp turn off - this points at a potentially fault oil pump. Some 1ZZ-FE engines developed cracks in the oil pump or had excessive clearance between the case and gerotor. That will cause pressure failure at higher engine speeds.

Thanks! Today the oil light/engine noise started before I even got to the freeway. Can you tell me how difficult it is to replace the oil pump? Is this a shade tree operation? Up to now, the most difficult thing I have done is replace the starter. Also, do you think it could possibly be the timing chain? Would that have any connection to the oil lamp? Thanks again for the advice. What oil weight would you say would be best?

The timing chain would not have any influence on the low oil pressure lamp. Stick with a 30 weight oil, OEM spec's 5W-30 as the recommended viscosity. Depending on where you live at, the ambient temperatures, driving conditions, etc. - might have to deviate from that slightly. Personally, I run a 0W-30 or 5W-30 all year round, as my temps generally run from a low of 20's in the winter-time to highs of 100+ in the summer.

As for the amount of work to get to the oil pump - there is a considerable amount. Would make changing a starter look like a routine oil change. Basically you'll have to pull pretty much everything from the serpentine belt side of the engine off to get to the timing chain cover. You'll have to remove the timing chain itself and the timing chain sprocket to get to the oil pump. Once you are there - it is a simple matter of a handful of bolts and a gasket, and the oil pump is off.

Given the mileage on the car - I'd take this time to check out the timing chain (check for stretch), timing chain guides, etc. Sort of a pain, but if you catch it in time, just have to replace the pump. Wait too long, and you'd be looking at a rebuild or engine swap.