4A-GTE Oil Pressure Low

**Matt-AE86** · 18-01-2008, 12:56 PM

I had a quick read of your first post and I noticed you replaced the stock oil cooler with another. Are you still running a Standard OEM Oil Cooler fitting on the block.

From my knowledge and what i've recently found out from a friend and a reputable workshop that has worked on 4AGE's for years is that the standard OEM oil cooler fitting on the block can bring the pressure down, just as John farnem has said.

Apparently it was O.K with the standard one or something the size of a transmission cooler but when he put an aftermarket 19row on the pressure dropped even more. The reputable workshop advised to get rid of it and replace it with an aftermarket item and this should help the pressure go to normal.

Maybe this is something you can try, or in the meantime, remove the oil cooler plate on the block and just put a filter on, see if this brings your oil pressure good ?

**LeeRoy** · 18-01-2008, 03:28 PM

Originally Posted by Matt-AE86

I had a quick read of your first post and I noticed you replaced the stock oil cooler with another. Are you still running a Standard OEM Oil Cooler fitting on the block.

The post above yours was my first post, the thread was actually started by someone else but theres no point creating another thread re: the same problems so i just posted here and bumped it up.

I should also mention that the oil system is standard.

**Talasas** · 18-01-2008, 04:37 PM

The only thing I can think of is possibly wear and tear on the oil pump. When the clearances change the pressure could change at idle but behave normally enough when at higher revs.

You can see from the specs I posted earlier that there's a hell of a lot of room for error in oil pressure when it comes to idle, so unless the gauge is virtually bottoming out, I wouldn't be too concerned (I know, if you are like me - you think "I changed nothing on the engine why should the oil pressure be different"

) but as I said, could be a simple as some slight wear. Also, the fact that it's above the solid line on the AE92 gauge when at revs mean you definitely have nothing to worry about, mine sits at the bottom of the solid line almost all the time.

**LeeRoy** · 18-01-2008, 08:19 PM

Yeh i agree with what youve said but even still its something id probably like to fix.

From what ive read, oil pressure can change dramatically in almost an instant once a certain degree of wear is reached. ie it will be fine and then one day it will just drop as the point of wear reached is somewhat of a critical point.

Hopefully ill get a chance tomorrow to check out the gauge/sender/wiring, and if necessary ill move on from there to other culprits probably in the order of.
- Sump off and pickup cleaned
- Inspect the pickup to pump seal as if this is leaking the pump can suck air and result in a low oil pres
- Check oil pump backlash and clearances
- Then hopefully it wont end up here but main clearances

Hopefully i can dig up an oil pressure gauge and get some more accurate readings rather than 1/2 on the gauge.

**Talasas** · 19-01-2008, 11:32 AM

You've probably got it right in the order of things. At least you can get the sump off while the engine's in the car, have a good look around. I doubt you'll have a clogged pickup, but might as well check. Removing the oil pump isn't quite so much fun

**LeeRoy** · 19-01-2008, 04:34 PM

Originally Posted by Talasas

Removing the oil pump isn't quite so much fun

Yeh just had a look in the service manual. Seems to be the fun of a timing belt replacement x3.

**turbo4agte** · 23-01-2008, 03:30 AM

Maybe Im just looking at this too simply, but.. since your running an aftermarket oil cooler which of course will cool the oil better, wouldn't that drop the oil pressure by law of kinetic energy?

**LeeRoy** · 23-01-2008, 03:47 AM

Talasas is, im not.

From my view of things your point is arguable. Wouldnt the oil cooler provide greater resistance and therefore greater pressure? Thats just the way i see it.

**turbo4agte** · 23-01-2008, 03:53 AM

The cooler provides greater volume, so if anything it would drop the pressure anyway. It might add greater resistance by way of flow with narrower bars, but the volume is still larger so it would either drop the pressure or it would stay the same. But shouldn't the temperature drop it even more?

Or am I thinking this all wrong.

**Talasas** · 23-01-2008, 03:35 PM

Being larger won't affect the pressure directly, remember that once it's filled with oil, two coolers of the same design, one being twice as long as the other for instance, should have the same pressure need (someone wish to verify this? *). What I was concerned about was that the cooler was a different design altogether so perhaps some pressure drop can be attributed to less resistance in the cooler.

My change in oil pressure was mainly due to oil grade and bearing clearance. I also suspect that my oil pump could be a little worn too, not being able to build up enough pressure. It's more than within limits though so no matter for concern.

* Water flow is often used as analogy to flow of electrical current, I don't know if it always works backwards, if it did then electrical resistance increases with the length of conductor - meaning fluid pressure would need to increase as pipe length increases...