Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show



How much have you spent on this so far? Sound like you’re into it for a lot of $$, maybe it’s time to re-think things. How many miles on it? What’s it worth? Seems like you’re spending a lot more than it may be worth. Head gasket, timing belt job, oil pump, sending unit, bearings, lifters, valve stem seals, what’s next? Maybe this $2000-3000 car isn’t worth another $2000 in fixing, IDK. Good luck. Rocketman

I can’t help but wonder if the main bearings are shot causing low oil pressure?

it’s 105k miles, and thanks for your input rocketman, however, I posted this to get a possible solution and not just someones opinion on my decisions. Thanks

4.2 psi or higher at idle and 43-100 psi at 3500 rpm is what I see for the oil pressure spec. At an oil temp of 167 to 194 deg F.

I’m sort of surprised by the idle oil pressure spec, as my Ford truck – albeit a very different engine, 302 V8 – it sports an idle oil pressure of 40 psi.

There is a spec for valve thickness to valve guide clearance. Have you checked that?

no I have not checked for the valve thickness or valve guide clearance honestly because I don’t know what the specs are, can i google them? or do I have to call a dealer? also ( I dunno if it matters or not) but this car doesn’t not have adjustable valves, it adjusted by hydralic lash adjusters, lifters.

I understand about the hydraulic lifters and no need for routine valve adjustment, but there is a spec for the other parts too. If they were out of spec noises could result. I think those clearances are usually not worried about unless the engine is being rebuilt. But it sounds like you were close to that, so was wondering if you measured those at the time.

You local public library probably has MOTOR manuals or something equivalent and those should give the complete rebuild specs. Ask the staff there for assistance.

I’m just a driveway DIY’er and have no specific experience w/your car so can’t be of much help beyond that. It does look like your oil pressure meets the specs though. So the sound must be for some different reason.

so you think that 12 psi at idle is not a bit high pressure? and then why does my oil light comes on at idle? would that have anything to do with it?

When the oil light comes on at idle, it might be a good idea to re-measure the oil pressure with a shop gauge. The oil pressure may be dropping for some reason.

well it came on two days after we did everything to it, but i didn’t drive it that much. the first time after its been fixed and idled for 4 hours to make sure that the noise was gone (which it was) i then took it and drove it to my house (22-25miles) but it started knocking shortly after I started driving it, then when I came home the check engine light went on, I just shut it off and went to sleep, then next day I tried starting it, it started twice and stalled right away, then it woulnd’t start at all but cranked fine. So i left it for like 3-4 hours. went picked up OBD and when i got back i decided to try starting it again and it did just fine, I then checked the code it gave me P0300 Random Misfire in cylinder. I erased it and it haven’t came back on ever since and starts just fine each time. Now I get this oil light coming on after the car warmed up. I just checked the oil pressure like 3 hours ago and those are the reading that I posted in my post. So i was hoping that it’s my oil pump, but Im not sure if its normal pressure or too high at idle and too low at higher rpms…

It could be the oil pressure sender unit is not working. That’s a not-unheard-of problem. It could be the oil pressure shop gauge you are using is incorrect too. Or that you are unlucky and the sender unit and gauge you are using are both fine and you just haven’t tested the oil pressure under a condition where it is low. May be time to bring in some professional help at this point, at least until you get a fuller understanding of the oil pressure situation.

you know George, that is EXACTLY why I got on this forum, to GET the professional help, because I know for a FACT (been there done that before too), that going to a dealer or any other random shop is NOT going to help me figure out my problem but charge up a storm and start replacing random stuff that had NOTHING to do with my problem…

The dealer is full of it by stating that 4.5 PSI of oil pressure is fine. That’s not anywhere near acceptable on any kind of engine. If the figure is correct, even 12 PSI at idle is too low.

There’s a number of ways this could go but based on the burned out (?) lifters, powdered (?) rod bearing, sanded crank journals, shimming, and so on I’d hate to recommend anything other than finding another engine.

4.5 psi certainly wouldn’t be the typical oil pressure measurement you’d expect at idle. But the mechanic said it was the spec for the minimum (at idle). Maybe 4.5 psi is what is needed so that the oil pressure light doesn’t come on. Since the OP is measuring 12 psi – if that’s an accurate measurement and the sender until is calibrated correctly – it seems like the oil light shouldn’t be coming on unless it can come on for another reason than oil pressure.

Maybe a pro here can look up the oil pressure specs for the 2004 Eclipse 2.4. No need to speculate.

I don’t have to look it up as my daughter has owned 3 Mitsubishis. It doesn’t even matter because the simple fact of the matter is that 4 or 5 PSI of oil pressure is not going to allow a shell bearing engine of any type to stay in one piece.

Five PSI of oil pressure is not going to maintain much of a film on a crank journal with 1500 PSI beating down on it.

The only engine that can run safely on 5 PSI of oil pressure is something like a Harley with a roller bearing lower end.

@Jeka, I think you’ve already confirmed an oil circulation problem with this engine. For all the lifters to have problems is a bad sign. I’m guessing the oil journals that feed the lifters are plugged up with sludge and proper oil pressure cannot get to them. A flush or sludge buster may not be able to clean this out if the oil cannot flow across it. The oil journals are narrow channels and sludge can easily plug them up. The best way to clean them is to strip the block, remove the journal plugs, tank clean it, then rod out yhe journals. Anything else is hit or miss.

As far as the low oil pressure, I’m still concerned about that bad rod bearing. I can pretty much guaranty the crank bearing surface is no longer truely round. Oil clearances are measured in thousandths of an inch. Having a rod knock on them destroys this tolerance. Even if it is quiet now, the change in clearance greatly affects the oil pressure, and it is my first suspect, not the oil pump.

With all the internal engine problems, this engine should have been pulled and torn apart for a proper rebuild. Thete are too many issues to attempt a piecemeal overhaul.

Thanks all for your advice, I will be getting rid of the car!!!

This is what Wikipedia says about typical oil pressures in internal combustion engines …

"The oil pressure generated in most engines should be about 10 psi per every 1000 revolutions per minute (rpm), peaking around 55-65 psi.[2]

Local pressure (at the crankshaft journal and bearing) is far higher than the 50, 60 psi &c. set by the pump’s relief valve, and will reach hundreds of psi. This higher pressure is developed by the relative speeds in feet per second (not RPM or journal size directly) of the crankshaft journal itself against the bearing, the bearing width (to the closest pressure leak), oil viscosity, and temperature, balanced against the bearing clearance (the leakage rate)."

If the idle speed was 700 rpm, wouldn’t that calculate to about 7 psi at idle? Or am I not understanding something?

@GeorgeSanJose‌, it’s wikipedia. I take any article as no more accurate as my crazy uncle. I’ve rebuilt American and Japanese engines. Fresh and sound, I expect to see 35-45 psi oil pressure at warmed-up idle, between 700-900 rpm. If that pressure drops to 20 psi or lower on a used engine, that is cause for concern. Many oil pressure lights don’t flicker on until oil pressure drops to 6-8 psi, which is deadly to any engine. With a confirmed 12 psi at warmed up idle, I’d start saving for either a replacement car, replacement engine if I liked the car, or an engine rebuild if I loved and valued the car.

My Ford truck has an oil pressure gauge and it reads 35-40 psi at idle, agreeing w/what you are saying BK. The Corolla hasn’t a gauge, so I don’t know what its oil pressure is at idle. Enough to keep the light turned off is all I know.

I’m wondering if the confusion is caused by ambiguity in where in the system the oil pressure is measured? The specs the mechanic quoted may be for the oil pump itself, but the pressure at the sender gauge wouldn’t necessarily match the readings made directly at the oil pump.