Low oil pressure and overheating related?

[Rift065]

Well my car has been overheating, not going into the red, but getting warmer then usual, and the temp guage acts funny sometimes. I already posted about that though. Recently my oil pressure guage has been dropping really low. It goes way up past the middle ofwhen I first start the car, but then gradually drops as I drive it. It usually stays right around a quarter of the way up from 0 oil pressure, right on the first line on the guage. What is going on here? There is plenty of oil in the car. Is it related to the mysterious overheating problem which I can't seem to figure out?

[Matt95GT]

After the car is warmed up, at idle the normal idle pressure reading will be about where the first quarter mark is. (halfway between 0 and the center of the gauge range) While the car is cold, the gauge will read rather high.

If you are lacking oil pressure you'd surely notice a ruckus... not just higher than usual coolant temps.

[doobiess]

no they arent related.. but as for the oil pressure.. its normal for the pressure to go to half because of the oil being cold its more thick.. and as heat is generated it will naturally thin down.. making less pressure... just make sure your oil is full and replace the oil if you havent in 3 months or 3000 miles... and go from there.. but just keep an eye on it for now but I say your fine.

As for the temp. best things are when was the last time you replaced your coolant.. should do it once a year.. if you havent have it replaced... if you have.. .maybe time to replace your resivior tank cap. they are cheap and can cause this prob.. If its fine.. then there maybe a chance you got air in the system so use the bleeder screw to try and release any air. If it still acts up.. well going past halfway is fine.. but keep an eye on it.. making sure it dont overheat if it does could relate to a stuck thermostat.. which are cheap and a bit of a job to replace...

Just make sure both fluids are fresh and go from there

[Rift065]

Both fluids were changed when I bought the car about 3 weeks ago. It was done by a professional so I don't think there are any air bubbles or anything. The oil pressure doesnt just go that low at idle, it stays that low throughout all rpms once the car has warmed up. I was under the impression it should stay at about the midway mark on the guage? Also is it alright just to take the thermostat out and not put a new one in? I don't need heat since it's summer.

[Rift065]

Ive been reading too and I found that 220 is way too hot for my motor to be running. 220 is right in the middle of the guage and thats where it usually runs at when it's not overheating. Should it be lower?

[rixGAphx]

SPOBI!!
Stop
Putting
Out
Bogus
Information!!!

#1 Bogus:
NOBODY reputable recommends changing coolant every year!!
'Regular antifreeze' (green) should last 100,000 miles!!
DexCool (orange) and other extended life coolants last 150k miles.

If the AF (green or orange, or enviro-friendly 'Sierra') is mixed with distilled or purified water, there is absolutely NO NEED to flush, change, or otherwise fiddle with the coolant.
Just top-off the bottle to the 'fill' line to account for minor normal evaporation and weepage.
Period.
* * * *
#2 Bogus:
Inadequate oil pressure (say, 10-15 psi) will NOT necessarily make a lot of noise and commotion.
True, the bearings are wearing, and are in danger of 'spinning'. A spun bearing will indeed make a ruckus :eek:

But to suggest he has no problem simply because there is presently no rukus isn't good advice.

Immediate attention is required.
Ultimately, at least a 'bottom end job' (crank and rod bearings, new oil pump) will be in order. $$$.
* * * *
220*F is the top of the 'OK' range (for the '96 V-6).
220*F is what my car ran at yesterday afternoon.
I was in stop-n-go traffic, AC 'on', and the air temp was 111*F.
Everybody not in Phoenix should be running cooler than that.
If you're running hotter, something's wrong.
* * * *
Low oil pressure rarely results in higher engine coolant temperatures.
High coolant temperature will result in a 'slightly' lower oil pressure, but only measurable in a lab wih precise gages, not something you'd notice on a dashboard.

So, consider these as two separate conditions.
* * * *
NEVER remove a t'stat and leave the housing empty.
The proper flow of coolant thru the engine is dependent on significant backpressure created by the t'stat as a normal obstruction.
* * * *
Your oil pressure is a problem, but not unexpected for a 12-year old 4 cyl engine. The bearings wearout, creating more space for the oil to pass, and that results in lower pressure.
Engines have been doing that since the Model T.
* You may have a problem with the gage.
* * The GA is very fussy about good battery connections, including ground cables. If the connection is lousy, and the gage reading will be inaccurately low.
* * Go to a mechanic, and have a mechanical gage temporarily fitted. This will confirm the actual pressure, and tell you if your gage is inaccurate.

* You *prolly* have worn bearings, tho you don't indicate how many miles on the vehicle.
* * Use a heavier oil, that's what they are for: to provide adequate oil pressure at the bearings even though the space between the bearing and the journal has increased from wear.
* * Probably 10w30 or even 20w40 for the summer; 5w20 or 10w30 for the winter.
* * This is only temporary, 5k-10k miles. Plan on new bearings within the next year.

* The oil pump is *prolly* slightly worn, and producing less psi all across the rpm range. Heavier oil will help, but there is no cure, other than replacement.
I don't know for your engine, but most oil pumps are inside the crankcase, and kinda PITA to replace.
Yours may be a fortunate case and be relatively easy to replace.
* * * *

Finally, there are many threads in this forum regarding overheating.
Do a 'search'.

One of the easiest things you can check is to make sure the airflow thru the radiatior is unobstructed.
Butterflies, leaves, plastic shopping bags can get platered to the AC condenser and really block the air.
Don't try 'blasting' stuff loose with a garden hose since the water pressure will only bend and crimp the delicate fins, further obstructing the air.

Good luck.
-Rick

[Matt95GT]

Originally posted by rixGAphx
SPOBI!!
Stop
Putting
Out
Bogus
Information!!!


No offense, but right back at ya. I don't post information that I'm guessing at. He isn't sure what values he should be seeing as he is new to this car... I have 5+ years experience between 2 of them with this engine. Although your reply makes sense to engines in general, the information as it applies to the Quad 4 is inaccurate.


Originally posted by rixGAphx
Inadequate oil pressure (say, 10-15 psi) will NOT necessarily make a lot of noise and commotion.
True, the bearings are wearing, and are in danger of 'spinning'. A spun bearing will indeed make a ruckus :eek:

But to suggest he has no problem simply because there is presently no rukus isn't good advice.

Immediate attention is required.
Ultimately, at least a 'bottom end job' (crank and rod bearings, new oil pump) will be in order. $$$.
[/B]

When I say inadequate oil pressure, I mean little to no pressure at all. It will indeed make a ruckus if oil is not reaching the top of the engine. After starting a Quad 4 that sat for a long time or was just filled with oil you'll hear plenty of lifter noise for about 2-3 seconds.

I am suggesting there is no problem... because 15 PSI (1st quarter mark on gauge) is normal at idle. See specs here:
http://www.beretta.net/how_to/b-tech/2.3_specs.htm
Oil Pressure @ Operating Temperature
2000 RPM 30 PSI 207 kPa
900 RPM 15 PSI 103 kPa

The stock gauge is not the most accurate instrument in the world, but what he describes is the same behavior as my cars... and it's been that way for years. Therefore, I do not think he has an issue with oil pressure... but it may be wise to hook up an accurate test gauge to investigate. How much oil is burned between oil changes?

--

It does sound like there is a cooling issue tho... it's rare my cars run above 200... does your radiator fan come on at 220? Are you running the AC or no?

[Rift065]

I have only had the car 3 weeks so I have only changed the oil once when I first bought it, so I don't know how much it is burning. The car has 135,000 miles on it. The engine is loud all the time though, it is hard to explain what it sounds like, not like any specific ticking or knocking, but it is loud. This has nothing to do with exhaust noise, the noise is coming from the motor itself.

[Brad97GS]

A typical source of "loudness" from the Quad 4 is the timing chain. It tends to loosen up with age and slap against the housing. The oil pressure does sound relatively normal for a Quad, but I agree that hooking up a mechanical gauge is the best idea. The factory gauge is not the most accurate - and the sending units are known to fail.

The temperature does sound a bit too high. I haven't read your overheating thread yet, but one possibility I'd throw out there is that the thermostat is in need of replacing. The '94, IIRC, has a 180 degree thermostat from the factory, so 220 is pretty hot. Also, the thermostat in that model year is near the water pump (under the exhaust manifold), not in the upper radiator hose housing, as it was in the years prior to that.

[cargasmic]

it could b related u might have a bad head gasket that is what was wrong with mine and it was causing the coooling fan to not turn on.. and over heating.. oil leeks out less oil lower pressure