Wanting to lower engine temp.
10-13-2018, 09:07 PM
#21
Advanced
My oil temps run a constant 130+/- regardless of outside temps or how hard I'm getting into it. Coolant temps run about 180 unless its hot out, then it will run up to 240-245 in traffic. Shouldn't my oil temps be running hotter than that?
10-13-2018, 09:22 PM
#22
Team Owner
10-13-2018, 09:59 PM
#24
Team Owner
You need a scanner sooner or later so only thing left is an IR thermometer. Read what the ECM is seeing and confirm it by hitting the sensor with the thermometer.
10-14-2018, 01:17 AM
#25
Team Owner
Pro Mechanic
NO on removing thermostat question. The coolant will actually run thru faster giving it less time to absorb engine heat and less time to get rid of it in the radiator. old time racers ( I am 68) used to put a large washer in to replace the thermos after drilling a large hole in the washer. You need that thermo.
With no stat, the car will run as cool as the capacity of the system will allow. Most of the time it'll run much cooler, but in HOT ambient temps under a higher load, it'll end up ~200 or so with or without a stat. It could help....but it's not the right way to manage your operating temps.
I agree with the poster who recommended cleaning the radiator. I'd also flush the cooling system and it should then run "down against the 'stat" about any time you're underway and have air flow.
10-17-2018, 11:09 PM
#26
Le Mans Master
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St. Jude Donor '05-'06,'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-'19-'20-'21-'22-'23
To keep it simple & answer the original question:
1. Lower temp thermostat
2. Fan on/off temp lowering
3. Oil cooler
This is all assuming you’re running the right viscosity oil, cooling system serviced/good working condition, radiator area is clean of debris and obstructions. I have items 1 & 2 done.
Whether or not that temp your running at is normal, well that’s a separate discussion but many wouldn’t have issue with it.
1. Lower temp thermostat
2. Fan on/off temp lowering
3. Oil cooler
This is all assuming you’re running the right viscosity oil, cooling system serviced/good working condition, radiator area is clean of debris and obstructions. I have items 1 & 2 done.
Whether or not that temp your running at is normal, well that’s a separate discussion but many wouldn’t have issue with it.
10-18-2018, 05:42 PM
#27
Drifting
First - Check the oil and coolant sensors as one of them could be bad Something doesn't sound right as your oil wont generally run 50 degrees warmer than your coolant.
Second - Do not put a 160 stat in your car. Not to start a thermostat war but your car was DESIGNED to run a specific temperatures. Most of the overheating is just a mental concern for most people. Look at the service manual and if you fall within normal driving conditions then it's not a problem that needs to be fixed. Also, to cool of a system is not always better especially if the car is not tuned to take advantage of that additional cooling. A car that runs 215 degrees with a 195 stat will not run cooler with a 160 degree thermostat. It will just delay the time it takes for the car to hit 200 degrees as both thermostats will be fully open at that point anyway. Above about 40-50 MPH the stock fan actually becomes a restriction to airflow so if you are running hot while moving it's not an airflow problem but the cooling system (poor flow, blocked radiator, etc). If your cooling problem is below 40-50 MPG and not above it's an airflow issue (fan).
For your specific issue, I think you more than likely have a sensor calibration related error.
Second - Do not put a 160 stat in your car. Not to start a thermostat war but your car was DESIGNED to run a specific temperatures. Most of the overheating is just a mental concern for most people. Look at the service manual and if you fall within normal driving conditions then it's not a problem that needs to be fixed. Also, to cool of a system is not always better especially if the car is not tuned to take advantage of that additional cooling. A car that runs 215 degrees with a 195 stat will not run cooler with a 160 degree thermostat. It will just delay the time it takes for the car to hit 200 degrees as both thermostats will be fully open at that point anyway. Above about 40-50 MPH the stock fan actually becomes a restriction to airflow so if you are running hot while moving it's not an airflow problem but the cooling system (poor flow, blocked radiator, etc). If your cooling problem is below 40-50 MPG and not above it's an airflow issue (fan).
For your specific issue, I think you more than likely have a sensor calibration related error.
10-19-2018, 07:14 AM
#29
Team Owner
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10-22-2018, 06:33 PM
#30
Just curious if your heater core is bypassed. Miy 94 has a bypassed heater core, and my sons 93 doesn’t. I’ve noticed his Vette runs much cooler. Theory is, the heater core is an important part of the C4 cooling system even when the heat is off hot water circulates through the heater core and helps cool the engine, even when not in use. If this IS a fact I would either recommend replacing heater core, (PITA) or get a larger radiator to make up for the loss of the heater core. 🤔
10-22-2018, 10:39 PM
#31
Team Owner
Pro Mechanic
^That is not a fact. The heater core has zero meaningful affect on cooling the car when heat is not selected. It doesn't even have a meaningful affect when the heat is on full blast.
It will not make a car run, "much cooler".
It will not make a car run, "much cooler".
10-23-2018, 12:55 AM
#32
Beg to differ. The heater core is essentially a small radiator the size of an oil cooler. As water travels through it it is cooled. Even if the fan is off. Maybe not as much, but it is cooled. It also adds to more water volume in the system if it’s connected. If it’s bypassed, then there’s less water in the system. I’ve been able to drive my over heating Jeep back from trail riding on the highway more then once with the heat on and gotten as much as 10 degree drop in temp. Just enough to keep the Jeep from over heating.
10-23-2018, 01:08 AM
#33
Team Owner
Pro Mechanic
I know what a heater core is. I know how it works.
The heater core holds about 1qt of coolant. Maybe 2 on a large one (like a Suburban or a Jeep Wrangler).
The heater core sits in a box. When the heat is off (which is the condition that you originally referenced) there is virtually no heat transfer out of the water going through the core. How could there be?? The core is in a box that is as hot as the core. Keeping the context consistent let's review:
His may....but not b/c of the heater core. The core being connected has nothing to do with your two cars' operating temps.
No. It does NOT help cool the engine when there is zero airflow over it. It does not. No. The core is an important part of the car's HEATING system. It's there for heating the cabin...not cooling the engine. No one increases their radiator when they remove their heater core. No one. Race cars don't use heaters to help with additional cooling. That's not what it's for...it's not what it does -in a meaningful way.
"I’ve been able to drive my over heating Jeep back from trail riding on the highway more then once with the heat on and gotten as much as 10 degree drop in temp. Just enough to keep the Jeep from over heating."
I'm pretty sure that's an oxymoron. Was it overheating or wasn't it? The heater core isn't going to prevent overheating. With the heat full on, obviously you're pulling some more BTU's from the system, but not a lot, and that isn't what you originally said anyway. If you don't agree with any of this....PROVE IT. Take your sons car, run it on a specific loop. By pass the core, run the same loop, same speed, same ambient temp....then report back. I have already done this, in my many years of cars and mechanics. The heater core with the heat full on will make a very marginal difference (maybe like the 10* you mentioned).....a heater core sitting in a hot, heated box w/no air flow ain't gonna do SQUAT. Sorry, but it won't. You asked if your theory was fact....no, it's not.
.
The heater core holds about 1qt of coolant. Maybe 2 on a large one (like a Suburban or a Jeep Wrangler).
The heater core sits in a box. When the heat is off (which is the condition that you originally referenced) there is virtually no heat transfer out of the water going through the core. How could there be?? The core is in a box that is as hot as the core. Keeping the context consistent let's review:
"I’ve been able to drive my over heating Jeep back from trail riding on the highway more then once with the heat on and gotten as much as 10 degree drop in temp. Just enough to keep the Jeep from over heating."
I'm pretty sure that's an oxymoron. Was it overheating or wasn't it? The heater core isn't going to prevent overheating. With the heat full on, obviously you're pulling some more BTU's from the system, but not a lot, and that isn't what you originally said anyway. If you don't agree with any of this....PROVE IT. Take your sons car, run it on a specific loop. By pass the core, run the same loop, same speed, same ambient temp....then report back. I have already done this, in my many years of cars and mechanics. The heater core with the heat full on will make a very marginal difference (maybe like the 10* you mentioned).....a heater core sitting in a hot, heated box w/no air flow ain't gonna do SQUAT. Sorry, but it won't. You asked if your theory was fact....no, it's not.
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Last edited by Tom400CFI; 10-23-2018 at 01:18 AM.
10-23-2018, 12:03 PM
#34
Team Owner
Pro Mechanic
I'd also point out that on all "early" C4, other GM, most European cars, and lots of heavy equipment, there is a heater core bypass VALVE that loops the coolant before the heater core when the heat is off. This completely removes the heater core from the cooling system loops. If the heater core was "an important part of the C4 cooling system even when the heat is off", then why would the OEM install a valve to by pass it? ...and lose all of the "cooling capacity"? Because it's not a meaningful amount of cooling capacity on a correctly operating cooling system.