Oil temp high
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
Oil temp high
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?
I think it's because the oil filter is by the header.
When it gets hot, the pressure drops.
Any suggestions?
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
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.
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.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
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.
I don't recall specifically, but it appeared the oil was cooler than the coolant temp.
What do you consider "too high"?
Thanks Pete.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
It gets real hot when I nail it and run it up to 5k or better.
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.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
I believe the new, original, non heated O2 sensor is working and going into closed loop. See other thread.
Drifting
Joined: Feb 2003
Posts: 1,614
Likes: 163
From: Davis CA
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.
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.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
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??
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??
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
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??
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??
The temps aren't over 250 as best as I can tell with the stock gauge.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
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.
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.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
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.
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.
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
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
,
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
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
Is the L98 different since it's a Gen1 small block?
The temp sensor is right after the filter.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
'
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
Race Director
Joined: Feb 2004
Posts: 12,517
Likes: 19
Check your tune up.
Lean or advanced timing will cause elevated oil temps.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
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
'
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
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.
Last edited by jsup; May 17, 2008 at 09:05 PM.
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
I was getting no reading from the O2 sensor when we got did a scan.
Timing is at 6*.
Race Director
Joined: Jun 2004
Posts: 13,934
Likes: 704
From: WI
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.