Overheating Problem
08-17-2009, 11:31 AM
#1
Burning Brakes
Thread Starter
Overheating Problem
Yesterday I left the car idling outside while I went in to see my neighbor. No more than 10 minutes. When I returned to the car, the temp was in the red and the light was on. I drove the car and reved the motor till the temp came right down to normal. Back at home I checked the fluid and it is fine.
I replaced the following in 2004 and later
Fan clutch in 2004 with new from Porsche ($300)
Lower temp thermostat
Lower temp electric fan switch.
And I am sending the Radiator out to get flushed and put through the vat this week.
Any other thought?
I replaced the following in 2004 and later
Fan clutch in 2004 with new from Porsche ($300)
Lower temp thermostat
Lower temp electric fan switch.
And I am sending the Radiator out to get flushed and put through the vat this week.
Any other thought?
08-17-2009, 01:32 PM
#2
Team Owner
What year is your car??
check the fan switch and check the fan clutch does it seem that there is a lot of oily stains around the hoses and such behind the fan?? if so then your new clutch is leaking .
Possibly replace the thermostat and its rear seal and the coolant bottle cap, also check your heater control valve if its older than 5 years it would be wise to replace the short hose and the valve since your going to open up the coolant system.
Also there is a possibility of the water pump impeller being loose, this would make the car get hot in a hurry
The radiator is probably fine
check the fan switch and check the fan clutch does it seem that there is a lot of oily stains around the hoses and such behind the fan?? if so then your new clutch is leaking .
Possibly replace the thermostat and its rear seal and the coolant bottle cap, also check your heater control valve if its older than 5 years it would be wise to replace the short hose and the valve since your going to open up the coolant system.
Also there is a possibility of the water pump impeller being loose, this would make the car get hot in a hurry
The radiator is probably fine
08-17-2009, 01:39 PM
#4
Nordschleife Master
08-17-2009, 02:53 PM
#5
Burning Brakes
Thread Starter
The car is a 82. The electric fan does come on a cycle with the 75 degree switch at the 3rd bar, between the mid and hot point. The fan cluch was new in 2004 and the other stuff was replaced in 2005. The water pump was replaced in 2003 but the car always ran hot. If i sit in traffic the needle will climb from mid to 3/4.
08-17-2009, 05:16 PM
#7
Nordschleife Master
Brad, I can't think of anything you are leaving out... My '81 has been running hot this summer too. We put in a new rad and converted it over to electric fan cooling. We DID NOT (yet anyway) put in the 75 deg T-stat and fan switch...sounds like it might not make much diff anyway...at least it does not seem to have in your case.
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08-17-2009, 05:51 PM
#8
Team Owner
at the least i would replace the thermostat and its rear seal, the coolant cap, and if your doing your own work pop off the timing belt and check the water pump after you have done the first things and not seen any changes
08-17-2009, 05:56 PM
#9
Rennlist Member
First, get rid of that crappy radiator. Get the one piece aluminum. My car runs much better since I did that. Kept everything else stock car never runs too hot.
08-17-2009, 06:52 PM
#10
Rennlist Member
If that "crappy" radiator is clean (unclogged) and holding pressure it will work as designed, and will not over heat if the rest of the system is working to spec.
May I suggest adding a bottle of “water wetter” with a clean fill of a 50/50 mix of an anti-freeze of fill in “your choice” here.
davek9
May I suggest adding a bottle of “water wetter” with a clean fill of a 50/50 mix of an anti-freeze of fill in “your choice” here.
davek9
08-17-2009, 07:16 PM
#12
Rennlist Member
Don't use an abrasive as you want to keep the thin coating on the connectors, get some electro cleaner and wipe (WD 40 also works).
If they all check out then the Fan motor most likely needs a rebuild.
Let's us know what you find.
Oh don't rule out the fan switch, when hot it should read zero ohms, or close to it.
08-17-2009, 08:55 PM
#14
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Brad--
You can usually do a poor-man's inspection wuth a small mirror and a flashlight in the bottom hose nozzle. Minerals deposits will show up right away, although stray stop-leak and other sift gunk may not. The top nozzle has a diffuser in it so no good way to add light at the other end of the tubes.
Looking at it symptomatically, it could be either low airflow or low coolant flow, since driving the car increases both. Stan's advice about the rear thermostat seal is sound, since those are too often flattened and rusted, allowing coolant flow to leak back into the pump inlet. It's and easy fix while the radiator is out and the system is drained.
I'm also a big fan of Water Wetter in my cars. Made a big difference in the black Explorer boat hauler in the Arizona summer heat. It was the difference between overheat and normal temps at idle in 125º ambient, with no other changes. I also run a light load of coolant, OK here where it never freezes. A gallon or so of Zerex G-05 in distilled water with the Water Wetter for water pump seal protection works great for me.
You can usually do a poor-man's inspection wuth a small mirror and a flashlight in the bottom hose nozzle. Minerals deposits will show up right away, although stray stop-leak and other sift gunk may not. The top nozzle has a diffuser in it so no good way to add light at the other end of the tubes.
Looking at it symptomatically, it could be either low airflow or low coolant flow, since driving the car increases both. Stan's advice about the rear thermostat seal is sound, since those are too often flattened and rusted, allowing coolant flow to leak back into the pump inlet. It's and easy fix while the radiator is out and the system is drained.
I'm also a big fan of Water Wetter in my cars. Made a big difference in the black Explorer boat hauler in the Arizona summer heat. It was the difference between overheat and normal temps at idle in 125º ambient, with no other changes. I also run a light load of coolant, OK here where it never freezes. A gallon or so of Zerex G-05 in distilled water with the Water Wetter for water pump seal protection works great for me.
