[Pretty White]

Those who have been thru this please apply. Those with theories please sit back and learn.
My car is overheating when I am driving on the highway with the A/C on. This seems to be a common problem with SR20's as I have found out by checking the mailing list archives. When I turn the A/C off the temps come down. This only happens when the temperatures reach above 90degrees. You would think on the highway it would cool the car down. Any clues?

 

[kris]

I had that problem last summer in my G20. The car had previously been in an accident, so the radiater was preety smashed up. This winter I replaced the radiater, and did a coolant flush. It hasent been warm enough to test it this year, so I cant say if it has worked.

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Kris94G20™
"clears and stickers, the best bang for your buck"
The Beginning.

 

[Guest]

I found that when an auto over heats with AC on it's usually because the fans are not coming on. As soon as the AC is turned on, the fans should also, and stay on at all times while the AC is active. On SR20DE setups, the AC fan relay gets pretty crispy over time. It will some times burn out. That's really the only problem i have seen in this case with these cars. Just let us know if they come on and we can go from there. The problem I just ran into was a bad connection on the Temp Sending Unit which feeds all the temp info to the brain, which then turns on the fans as needed, but does not feed it to the meter. The temp meter is fed by the Thermal Sending Unit next to the Temp Sending Unit. Clean those harness conections if you can get to them.

 

[Pretty White]

<font face="Verdana, Arial" size="2">Originally posted by cossie:
I found that when an auto over heats with AC on it's usually because the fans are not coming on. As soon as the AC is turned on, the fans should also, and stay on at all times while the AC is active. On SR20DE setups, the AC fan relay gets pretty crispy over time. It will some times burn out. That's really the only problem i have seen in this case with these cars. Just let us know if they come on and we can go from there. The problem I just ran into was a bad connection on the Temp Sending Unit which feeds all the temp info to the brain, which then turns on the fans as needed, but does not feed it to the meter. The temp meter is fed by the Thermal Sending Unit next to the Temp Sending Unit. Clean those harness conections if you can get to them. </font>

They both go on. I think the fan doesn't blow strong enough. It is only after 90 degrees that I get that problem.

 

[nsracer]

Actually no, that's not right. The fans don't stay on all the time. Here, take a looksie. Straight from the list archives.

<Begin Jim Wright's Quote>
Ok, instead of taking heresay, I pulled out my trusty (and well worn) FSM. In the EF & EC section for the '91, I found this information:

Radiator Fan Control, ECU Pin 9 will activate the radiator fan relay.
This relay controls both fans in manual transmission cars (I learned
something! Thought both fans were separately controlled.).

AC switch is off:

Coolant Temp | Radiator Fans | Remarks

201(F) or less | Off

203 - 210(F) | Off | Vehicle speed 12MPH or less

203 - 210(F) | On | Vehicle speed 12MPH or more

212(F) or more | On

AC switch is on:

Coolant Temp | Radiator Fans | Remarks

201(F) or less | Off | Vehicle speed 50 or more

201(F) or less | On | Vehicle speed 49 or less

203(F) or more | On

So, the information about the fans cutting out above a certain speed isn't correct, but speed does play a factor depending on the coolant temp according to the above chart. Note that the car will try to keep the coolant temp lower when the AC is on than when it is off, which is nice. I'm assuming that this information will be fairly close for other years besides the '91. If anyone has manuals for other years and can check
this, plesae post if there are any significant differences.

<End Jim's Quote>

[Damn formating!!!!!]

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David
'98 Super Black SE w/stuff

[This message has been edited by nsracer (edited 05-04-2001).]