OK, What Did I Fix??

R

rickbtbird

Registered User
Over the past year I have been chasing a “Hot Temperature” issue with no resolution until now. Funny how one stumbles upon these. So the car was constantly running hot and last year the radiator blew out. It had holes in it like someone shot it with buck shot. I replace it and also install a new thermostat. Car ran hot to the “M” and over and sort of alarmed me one hot spring day with a check gage light came on just as I pulled in the drive way. Since the car had a vacuum leak around the IC intake I decided to tear it down and address that and give it an inspection as to the root cause of the hot problem.

I give it a new water pump and a new lower radiator hose. I didn’t really find anything wrong with the car. Compression was fine and the block doesn’t seem to have any corrosion in the heater core or other water channels. August rolled around and I’m finally getting the car back together. I give it a couple of day and the temperature seems to be better with the temperature gage hanging at the “O” with occasional spikes to the M and a little bit above. Once that happens I can hear the fan come on and the gage drops. I’m happy with this so I go on to recharging the AC. WOW.. Now that the AC is working, the pusher fan is keeping the car much cooler. Now it never gets into the “O” at all.

WHAT DID I FIX??
 
You could have had something wrong with the fan or IRCM, I know that it automatically comes on high speed with the AC on.
 
bigpoppa822 said:
You could have had something wrong with the fan or IRCM, I know that it automatically comes on high speed with the AC on.
Click to expand...

IRCM maybe, could be possible it's not running the fan at the right time. The 95 has a pusher fan for the AC. The Puller fan has high and low.
 
I think the vacuum leak could have been a real contributor to how hot it was running.

After redoing my exhaust system last year I learned that the EEC strategy for controlling the idle speed (lowering it) is to first adjust the IAC valve to a certian duty cycle, then if idle still doesn't drop down to the range comanded, it pulls timing. Pulling the timing at idle will reduce RPMs but it also causes the motor to run much hotter.

David
 
Did you handle the press-on connector at the temp sender, by the thermostat housing at all?

That connector works loose over time - it can then lead to wandering and/or incorrect temperature readings.

Easy fix....just remove, squeeze down in size a bit, clean it & the post on the sender and replace.
 
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KMT said:
Did you handle the press-on connector at the temp sender, by the thermostat housing at all?

That connector works loose over time - it can then lead to wandering and/or incorrect temperature readings.

Easy fix....just remove, squeeze down in size a bit, clean it & the post on the sender and replace.
Click to expand...

No but I got a brand new one that I haven't installed yet.
 
David Neibert said:
I think the vacuum leak could have been a real contributor to how hot it was running.

After redoing my exhaust system last year I learned that the EEC strategy for controlling the idle speed (lowering it) is to first adjust the IAC valve to a certian duty cycle, then if idle still doesn't drop down to the range comanded, it pulls timing. Pulling the timing at idle will reduce RPMs but it also causes the motor to run much hotter.

David
Click to expand...

Dave,
That's good to know. I would have never guessed that. Thanks!
 
Thats great news you have your issue fixed, my car is the exact way your car was, I have tried everything and it still runs hotter then it should.I gave up I cant stand chasing ghosts on this car.I went as far as replacing every cooling part the car has and including a complete AC rebuild, I did this hoping it would help...as long as the AC is on the car runs nice and cool.
 
having the same problems. i unplugged the temp sensor and the fans started??? the mac reader says that the temp is -40 though.~~~ is with the 94-95's???????????????????
 
This is the second thread I have seen mentioning that the "pusher" fan is related to the AC on 94-95 SC's. That is not my understanding. Looking at the 95 PCED Manual it never says anything about the AC being assoociated with this circuit. It only "says" When additional cooling is desired, the Powertrain Control Module (PCM) will ground the Fan Control (FC) output. This will energize the Fan Control Relay coil and close the relay contacts, turning on the electric cooling fan."

Does someone have other info to add?
 
Duffy Floyd said:
This is the second thread I have seen mentioning that the "pusher" fan is related to the AC on 94-95 SC's. That is not my understanding. Looking at the 95 PCED Manual it never says anything about the AC being assoociated with this circuit. It only "says" When additional cooling is desired, the Powertrain Control Module (PCM) will ground the Fan Control (FC) output. This will energize the Fan Control Relay coil and close the relay contacts, turning on the electric cooling fan."

Does someone have other info to add?
Click to expand...

I assumed that the two were related as I have observed that when I turn on the A/C the pusher fan comes on. It may not come on every single time but, I can't remember ever tuning on the A/C and then standing outside of the car where that fan didn't kick in. Maybe I'm assuming incorrectly.
 
According to the strategy guide, the low speed fan in all the SC's will kick on when the a/c is turned on below 48mph. On the 94/95 cars there is supposedly a medium pressure switch on the a/c system somewhere that when tripped will have the high speed fan kick on.

Also to point out, the 94's use both the low speed and high speed modes on the puller fan, as well as the pusher fan.. but the 95's do not use the high speed mode of the puller fan.

Frit
 
Two speed pusher fan not supported by either the 94 or 95 EVTM. Both show it is not used. Only the low speed is actually hooked to anything.
 
When I run the KOEO test on my 95, I can hear the low and high speed puller engage one after the other and the single speed pusher follows.
 
We had to do some chores so another short trip around town tonight. I ran through another test. After dropping the wife at the grocery store on the way back from Wally World, parked with open windows I shut off the A/C. I could watch the temperature gage raise to the "M" and when it was just to the right of the "M" a fan kicked on. I could hear it as it spun up. Sounded like the high speed. It cooled to the "R" and the fan shut down and the temperature started to rise again. I turned on the AC and the fan stayed on. The temperature gage dropped to the "N" and stayed there the remainder of the trip home.

This is the second fan in this car in two years but it was a used replacement. The old fan did about the same thing. What is my next inspection point?
 
This is completely normal behavior to observe, especially when driving around town at speeds below ~45 mph. With the A/C off, the puller fan only comes on when the coolant temperature reaches the trigger point (IIRC 218* F). This means that it won't come on until the temp gauge reads on the high side of NORM. When the A/C is on, the puller fan is on continuously, therefore the car gets additional cooling all the time and runs cooler, even if the load on the engine is slightly higher as a result of having the A/C on.
 
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