jsup

The oil temp seems to be running hotter than the water temp.

I think it's because the oil filter is by the header.

When it gets hot, the pressure drops.

Any suggestions?

pkazsr

What type of oil and what temps?

jsup

I'm waiting on my scan tool to come to get exact temps. According to the guage it's over 1/2 way mark. I'll check the numbers.

The oil is castrol synthetic 5-40

I'm thinking of going 20-50 to keep the pressure up.

It gets real hot when I nail it and run it up to 5k or better.

Pete K

Normal.
15 to 20 degrees above coolant temp is typical.

jsup

OK, then the issue is when the car gets hot, the pressure drops....I'm going to 20-50.

I don't recall specifically, but it appeared the oil was cooler than the coolant temp.

What do you consider "too high"?

Thanks Pete.

65Z01

I think that's because you are tunning so lean.

Does it still run hot with the new O2 sensor?

BTW, my oil temp usually runs about 10-15deg F above coolant temp in warm weather.

jsup

NOt as hot as yesterday, but I didn't drive it as long either. I just drove around town a little.

I believe the new, original, non heated O2 sensor is working and going into closed loop. See other thread.

Chatman

Oil temperature will run lower than coolant for the first period of driving, then higher by 15 to 20 degrees. It should stay 15-20 degrees hotter indefinitely. That seems to be true regardless of thermostat used, fan settings, or whatever.

Oil pressure will drop as temperature increases. It's thinner. You are OK as long as real pressure is about 20 lbs. per 1,000 RPMs. I say "real" because the gauges aren't necessarily correct.

Forget the 5 weight oil if you're in the northern hemisphere now. If you have a 5 weight oil, it has lots of additives to allow it to continue to work effectively as temperatures increase. If those additive (protections) are lost for any reason (regular wear, overheating) then you're running on 5 weight oil. Switch to a 10 or 20 base oil for warmer temperatures.

Remember, lower base weight oil is specified to help achieve high government MPG fleet ratings. Not because it is better for your engine.

c4cruiser

How long does it take for the temps to really climb and what RPM? Is the motor under constant load (high RPM and speeds like a track day)?

One track day I ran at Portland International Raceway got the oil temps in my 87 (I run Mobil-1 5W-30 and the4 stock "oil cooler") up to around 270. But the ambient air temp was 102 and the track surface was around 140. We did 10-lap groups (20 miles) and it took almost 5 laps to get the oil to 270. Once it got there it stayed constant with coolant temps around 205-210. On the cool-down lap, temps dropped to normal (190 coolant and 210 oil) in less than one lap.

With a full synthetic, I would think that oil temps around 250-270 may be a bit on the warm side. Beyond that, it's time for an oil cooler.

If the oil filter is too close to the headers, then maybe try a remote filter??

jsup

The car has a stock oil cooler, but yes, I am considering an external one.

The temps aren't over 250 as best as I can tell with the stock gauge.

jsup

I just picked up Castrol 20-50 synthetic. I'll do it tonight or tomorrow. When the engine cools off.

JAKE

,

Of course you can run whatever you want, but the Owner's Manual for my 96 specifically advises against 20w50. 10w40 is the highest recommended viscosity.

Also the Manual says:

The gauges are NOT linear, so don't think that when the gauge needle is at the mid-point on the gauge the temp is half way between full cold and full hot.

Pressure can drop to as low as 6 psi on a fully warmed up engine, in gear, car stopped at idle.

Those are normal.

"real hot" isn't particularly helpful in trying to determine if you have something to be concerned about or not.

I don't know if a scan tool can monitor oil temp. The ones I've used couldn't. Oil temp in the pan is what you'd be concerned about.

In normal conditions, the oil will run hotter than the coolant, as others have already said.

Jake

jsup

The gauge drops to the point where the idiot light comes on and flashes "check gauges".. the needle gets buried in the warning zone.

Is the L98 different since it's a Gen1 small block?

The temp sensor is right after the filter.

Aardwolf

You drained out 20-50, then put 5-40 in, now your back to 20-50? Are there any leaks?

jsup

Yeah, I know.........no leaks. Just the oil pressure issue. I typically ran 20-50 before the mods. I should have stuck with it.

JAKE

Wow, that's a different story.
'
So my thoughts first turn to:

Bad sending unit
Bad oil pump
Partially block oil pump pick-up
Excessive bearing clearances and maybe some others

I'd definitely go with 20W50 just to keep the reading out of the red until the cause could be tracked down.

Isn't your gauge reporting pressure not temperature?

Jake

Pete K

Above 250 makes me uncomfortable.

Check your tune up.
Lean or advanced timing will cause elevated oil temps.

jsup

Just had the motor apart, long story, there's a thread here.

The motor has 30K on it, and is in perfect shape. On bad bearings. Guaranteed.

I had the oil pump out when checking the bearings, put back and triple checked. Oil pump good.

Sending unit? Perhaps. It cold starts at about 60. Then goes down as the motor heats up.

When I turned the oil pump with the primer tool, it went to 60PSI every time. This indicates to me that both the pump and sender are working.

I am going to clean the electrical connector on the sending unit.

There are two gauges, temp and pressure.

jsup

I had the issue of the O2 sensor not reading correctly. I replaced the heated replacment with the stock one. I am fairly certain that the original non heated sensor seems to be going into closed loop, I'll check it tomorrow. If it is, problem solved.

I was getting no reading from the O2 sensor when we got did a scan.

Timing is at 6*.

Aardwolf

Does your year car not give an exact temp? If not I have an idea, measure the sensor itself. There was a chart if I remember in the service manual that converted volts to a temp, that could help tell you where it actually is for a temp.