Possible Answer To Overheating Problem
Three Wheelin'
Joined: Sep 2002
Posts: 1,477
Likes: 2
From: No Turbo, No SC
I can't wait to see if your idea works. If it drops the over all by at least 5-8 deg. F it would be worth doing IMHO.
I have to admit that Marc T. from DEVEK had told me early on the I should add an extenal oil cooler (s). But untill the other day, I was not sure where I would put it/them as the front of the 928 is fairly tight for room.
Body Mods
Ernest, I was thinking if there is enough interest in vents like these, I would see if I could find a fiberglass body panel company like Better Body's or AIR to make them for us.
I have to admit that Marc T. from DEVEK had told me early on the I should add an extenal oil cooler (s). But untill the other day, I was not sure where I would put it/them as the front of the 928 is fairly tight for room.
Body Mods
Ernest, I was thinking if there is enough interest in vents like these, I would see if I could find a fiberglass body panel company like Better Body's or AIR to make them for us.
Addict
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Joined: May 2001
Posts: 1,197
Likes: 10
From: Spokane, WA
T_Max
I have looked a number of times at an external oil cooler on my 87, there is room to add it in front but then that is only going to mess up the airflow to the radiator. Modding to the MY90+ external oil cooler is likely the easiest way, oil cooler is spendy ($300 I think) but thats about it as your local hose shop should be able to modify the oil cooler lines.
Then when you want to remove the radiator shroud no more messing with the cooler lines !!!
Chris
I have looked a number of times at an external oil cooler on my 87, there is room to add it in front but then that is only going to mess up the airflow to the radiator. Modding to the MY90+ external oil cooler is likely the easiest way, oil cooler is spendy ($300 I think) but thats about it as your local hose shop should be able to modify the oil cooler lines.
Then when you want to remove the radiator shroud no more messing with the cooler lines !!!
Chris
Burning Brakes
Joined: Dec 2002
Posts: 870
Likes: 0
From: Airlie Beach, Australia
Hi Ernest,
I was able to get some temps today that may be of interest to you
I drove the car for about 12 minutes from cold, at an Ambient of 24C
The temp gauge registered - 85C
Vee/Vc temps - 87C
Thermostat housing - 86C
OC top hose - 72C
OC bot hose - 69C
Rad hose top - 71C
Rad hose bot - 71C
When the OP was at/near normal at idle I took an oil sample
from the sump via the dipstick tube, the oil's temp = 60C
1 - Note the coolant's intercooler influence on the oil cooler
2 - Note the actual oil temp
3 - Engine was at/over coolant thermostat "crack" point
4 - OP was at/near "normal" for idle
Don't be misled by low oil cooler temperatures unless the engine is "working". Even then, the oil cooler will shed temperature quickly in normal use and remain closed with "core" oil temperatures below 87C ( see earlier post )
Regards
I was able to get some temps today that may be of interest to you
I drove the car for about 12 minutes from cold, at an Ambient of 24C
The temp gauge registered - 85C
Vee/Vc temps - 87C
Thermostat housing - 86C
OC top hose - 72C
OC bot hose - 69C
Rad hose top - 71C
Rad hose bot - 71C
When the OP was at/near normal at idle I took an oil sample
from the sump via the dipstick tube, the oil's temp = 60C
1 - Note the coolant's intercooler influence on the oil cooler
2 - Note the actual oil temp
3 - Engine was at/over coolant thermostat "crack" point
4 - OP was at/near "normal" for idle
Don't be misled by low oil cooler temperatures unless the engine is "working". Even then, the oil cooler will shed temperature quickly in normal use and remain closed with "core" oil temperatures below 87C ( see earlier post )
Regards
Thread Starter
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Joined: Mar 2003
Posts: 4,328
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From: Nashua, NH
Hi Doug,
Thanks for the information, however I question its relevance to my situation for the following reasons.
1-12 minutes may not be an adequate period for the system to reach equilibrium.
2-your dipstick readings suggest that your oil temperature is 25C BELOW your coolant temperature. This is contrary to expectation and causes me to doubt the validity of the reading.
3-My car is running consistantly at least 5C above yours and the oil thermostat should be reacting to a different remperature.
Having said all of this, I still think it's impossible to predict whether the oil thermostat is playing a part in this drama until it's replaced. Frankly, I'm not expecting it to be the answer, but it is a variable worth exploring for the few dollars involved.
Thanks for the information, however I question its relevance to my situation for the following reasons.
1-12 minutes may not be an adequate period for the system to reach equilibrium.
2-your dipstick readings suggest that your oil temperature is 25C BELOW your coolant temperature. This is contrary to expectation and causes me to doubt the validity of the reading.
3-My car is running consistantly at least 5C above yours and the oil thermostat should be reacting to a different remperature.
Having said all of this, I still think it's impossible to predict whether the oil thermostat is playing a part in this drama until it's replaced. Frankly, I'm not expecting it to be the answer, but it is a variable worth exploring for the few dollars involved.
Burning Brakes
Joined: Apr 2002
Posts: 881
Likes: 0
From: Denmark
Ernest,
I have not BTDT, but it must be possible to check the oil thermostat just by checking the temperature of the hoses from the engine to the oil cooler.
If the oil-thermostate is not opening this hose will stay cold
I have not BTDT, but it must be possible to check the oil thermostat just by checking the temperature of the hoses from the engine to the oil cooler.
If the oil-thermostate is not opening this hose will stay cold
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Burning Brakes
Joined: Dec 2002
Posts: 870
Likes: 0
From: Airlie Beach, Australia
Hi Ernest ,
Your points;
1 - read my earlier posts to see the relevance
2- accept the validity of the reading - I do know what I am doing!
3 - the thermostat is dumb! - ".....reacting to a different temperatute...."??
Basically, they operate at the prescribed temperature or they don't!
Best of luck!
Your points;
1 - read my earlier posts to see the relevance
2- accept the validity of the reading - I do know what I am doing!
3 - the thermostat is dumb! - ".....reacting to a different temperatute...."??
Basically, they operate at the prescribed temperature or they don't!
Best of luck!
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Joined: Jun 2001
Posts: 6,469
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From: Ball Ground, GA
Ernest,
I feel that I should go thru this one more time.
1) During most normal running, the engine cooling system is in a balanced state - that is, there is just as much heat being rejected as is being genterated. If it were not in a balanced state, the coolant temp would be going up or down. If the temp is not changing, the system must be in a balanced state.
2) If the system is in a balanced state, there is almost certainly some reserve cooling available.
3) If the temp is not changing, it is being held at that temp by the thermostat. If more heat is added, such as climbing a hill, the thermostat increases the heat rejection to maintain that stable temperature. If less heat is generated, such as going down a hill, the thermostat decreases the heat rejection to maintain that stable temperaure.
Conclusions: If the coolant temp is stable, it is being controlled by the thermostat, and there is excess cooling capacity.
I feel that I should go thru this one more time.
1) During most normal running, the engine cooling system is in a balanced state - that is, there is just as much heat being rejected as is being genterated. If it were not in a balanced state, the coolant temp would be going up or down. If the temp is not changing, the system must be in a balanced state.
2) If the system is in a balanced state, there is almost certainly some reserve cooling available.
3) If the temp is not changing, it is being held at that temp by the thermostat. If more heat is added, such as climbing a hill, the thermostat increases the heat rejection to maintain that stable temperature. If less heat is generated, such as going down a hill, the thermostat decreases the heat rejection to maintain that stable temperaure.
Conclusions: If the coolant temp is stable, it is being controlled by the thermostat, and there is excess cooling capacity.
Thread Starter
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Joined: Mar 2003
Posts: 4,328
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From: Nashua, NH
Wally,
Is that a slightly condescending tone I hear?
I think I understand a little about dynamic equilibrium.
Stable doesn't mean optimal.
If you present in my office with a stable temperature of 102.5F I'm not going to send you home because you've got 3.5F leeway before you die. I'm going to diagnose a problem and, hopefully, return you to the temperature for which your physiologic processes were designed.
Is that a slightly condescending tone I hear?
I think I understand a little about dynamic equilibrium.
Stable doesn't mean optimal.
If you present in my office with a stable temperature of 102.5F I'm not going to send you home because you've got 3.5F leeway before you die. I'm going to diagnose a problem and, hopefully, return you to the temperature for which your physiologic processes were designed.
Thread Starter
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Joined: Mar 2003
Posts: 4,328
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From: Nashua, NH
Am I missing something here?
Is there not a significant number of 928s out there that are running high on their temperature gauges?
Do we not all share an interest in this particular car?
Am I offending the 928 Gods by investigating all the possibilities?
I can't remember asking anyone to send me money or to come to my house and help me work on the car.
Perhaps I'm one of the few who understands that an issue is not resolved until all the variables have been investigated.
I'm PERFECTLY willing to accept that I don't have a problem WHEN I've proven, to my own satisfaction, that I've done that investigation.
I cordially invite whoever thinks I'm wasting my time or theirs NOT to participate in the issue.
Is there not a significant number of 928s out there that are running high on their temperature gauges?
Do we not all share an interest in this particular car?
Am I offending the 928 Gods by investigating all the possibilities?
I can't remember asking anyone to send me money or to come to my house and help me work on the car.
Perhaps I'm one of the few who understands that an issue is not resolved until all the variables have been investigated.
I'm PERFECTLY willing to accept that I don't have a problem WHEN I've proven, to my own satisfaction, that I've done that investigation.
I cordially invite whoever thinks I'm wasting my time or theirs NOT to participate in the issue.
Drifting
Joined: Jul 2002
Posts: 3,348
Likes: 0
From: Los Angeles, CA
It seems reasonable...
I have had cooling problems with my car in the past.
I fixed them, and now it runs cool in all conditions.
Even in high SoCal temps, and with the AC on, going up a hill, running hard...
Before all my cooling fixes, it would have run hot.
Now, it runs fine.
So for those who think running hot is normal in the 928, it does not have to be.
My problem was simple:
An old radiator, with goopy leak sealers added, reducing efficiency, etc...
Not to mention corrosion, etc...
Plus a bad fan clutch, etc...
I also had my water pump start shearing the plastic splines, so it was running hardly at all, and then failed completely, once the shaft completely sheared itself free of the impeller. Still turns the pulley on the belt, but no water being pumped...
I also had the coolant reservoir crack under pressure, and leak...
Now I have a new water pump, Devek radiator, low temp thermostat, new hoses, new reservoir, and now everything seems to be working well...
So I think it is perfectly valid to try to achieve cool running. There are cars that run cool...
So unless it is a guage problem, I see no reason not to track down the culprit.
I have had cooling problems with my car in the past.
I fixed them, and now it runs cool in all conditions.
Even in high SoCal temps, and with the AC on, going up a hill, running hard...
Before all my cooling fixes, it would have run hot.
Now, it runs fine.
So for those who think running hot is normal in the 928, it does not have to be.
My problem was simple:
An old radiator, with goopy leak sealers added, reducing efficiency, etc...
Not to mention corrosion, etc...
Plus a bad fan clutch, etc...
I also had my water pump start shearing the plastic splines, so it was running hardly at all, and then failed completely, once the shaft completely sheared itself free of the impeller. Still turns the pulley on the belt, but no water being pumped...
I also had the coolant reservoir crack under pressure, and leak...
Now I have a new water pump, Devek radiator, low temp thermostat, new hoses, new reservoir, and now everything seems to be working well...
So I think it is perfectly valid to try to achieve cool running. There are cars that run cool...
So unless it is a guage problem, I see no reason not to track down the culprit.