Overheat question (Page 1/2)
Rhodesia1977 DEC 10, 04:23 PM
I was driving my 2.8 1986 GT today. After 2 minutes of driving the temp needle slowly went to the red. It was about 35 F outside. I quickly drove it back home as I was just down the block. Two days ago it kind of did this. The temp needle went to 220 for about 5 seconds but after driving it went back to its normal 170 ish. When I got back today, the front reservoir was overfilling and slowly spewing out coolant. There was no smoke or weird engine sounds or smells. The engine itself felt cold upon touch. I might of heard a little cricket like sound a few days ago but only when I turned on the heater but then it went away. The oil is clear and the coolant is also clear. Any ideas?? She has 95k on the odometer. Is she finally dying or can she be saved? Thank you!
Rhodesia1977 DEC 10, 04:48 PM

quote
Originally posted by Rhodesia1977:

I was driving my 2.8 1986 GT today. After 2 minutes of driving the temp needle slowly went to the red. It was about 35 F outside. I quickly drove it back home as I was just down the block. Two days ago it kind of did this. The temp needle went to 220 for about 5 seconds but after driving it went back to its normal 170 ish. When I got back today, the front reservoir was overfilling and slowly spewing out coolant. There was no smoke or weird engine sounds or smells. The engine itself felt cold upon touch. I might of heard a little cricket like sound a few days ago but only when I turned on the heater but then it went away. The oil is clear and the coolant is also clear. Any ideas?? She has 95k on the odometer. Is she finally dying or can she be saved? Thank you!



I also wanted to add that the radiator was cold and the upper and lower hose appeared cold as well. The fan has been rewired to run all the time when car is on. The coolant spewing out of the front reservoir was not boiling but it was surely full and pouring out. Never had any issue like this in the 5k miles that I have driven it. It would always run normal even in the summer when the temp was 90F.
Patrick DEC 10, 05:36 PM

quote
Originally posted by Rhodesia1977:

The fan has been rewired to run all the time when car is on.



That's usually done as a desperate (and unwise) measure after the car has exhibited some sort of overheating issue. Did you do this? If so, why?
cvxjet DEC 10, 07:15 PM
I have had two overheating issues- One with my Fiero and one with my '73 Mustang; on the Fiero, I installed a new waterpump, which had a PLASTIC impeller...after a few months it developed a problem of overheating- did it the same place on the freeway three times in a row. I tried replacing the T-stat, but finally found out from a fellow Fieroist that the plastic impeller (Exposed directly to the warm coolant) will expand faster than the steel shaft (Not exposed to coolant) and so will start slipping. STEEL impeller only for Fieros.

On the Mustang, I had changed out the hoses...I actually noticed that the metal spring in the lower hose was shorter than the original. The car started overheating at high speeds (Freeways) but would cool down any time I slowed down. That spring is in the hose to keep it from collapsing under suction from the waterpump. Wrecked my engine (351C 2 bbl) so I installed a 5.0 FI engine (And made sure the lower hose had a proper spring in it)

I'm not totally sure, but I don't think any of the Fiero hoses have springs in them- but it is something to keep in mind (Pattern of overheating/cooling off points to this problem)
Rhodesia1977 DEC 10, 10:55 PM

quote
Originally posted by Patrick:

That's usually done as a desperate (and unwise) measure after the car has exhibited some sort of overheating issue. Did you do this? If so, why?



Not sure why the previous owner did it but I unplugged it a couple of years ago and drove to see if it was covering up anything. The car never overheated, it was about 70F out. After a few tests like this, I plugged the rad fan back in. I just left it as is for insurance. I have a couple of new fans for replacement when it eventually dies.
sanderson231 DEC 11, 03:10 PM
I've twice had cars overheat that had been sitting a while. In both cases the problem was a stuck thermostat. Pull the thermostat, refill the coolant system and see if that solves the problem. If it does replace the thermostat.

------------------
formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged

Rhodesia1977 DEC 11, 03:55 PM

quote
Originally posted by sanderson231:

I've twice had cars overheat that had been sitting a while. In both cases the problem was a stuck thermostat. Pull the thermostat, refill the coolant system and see if that solves the problem. If it does replace the thermostat.




Sounds like a good idea. I will try it tomorrow. Thanks!
Patrick DEC 12, 12:54 AM

quote
Originally posted by Rhodesia1977:

I have a couple of new fans for replacement when it eventually dies.



Do you have a couple of replacements for the trunk blower as well? It's running whenever the rad fan is.
Dukesterpro DEC 14, 04:39 PM
It has been said, but it climbing to 220 and dropping instantly backdown, is a tell tale side of a failing themostat, you cant ask for a easier fix
theogre DEC 14, 07:07 PM
220°F Is Not overheating.

And very likely Nothing is wrong when the dash gauge is bouncing up/down.
Fiero has 2 or 3 times the coolant volume vs most front engines and takes a long time to = out the coolant system in cold weather.
In really cold weather may never even out the coolant system. Is why big trucks have covers to control air thru the radiator. (Many have hidden louvers that manual or automatic control rad air flow.)

See my Cave, Thermostat

But Stant is Gone and can't get the Super Stat that slows or stops temp bouncing.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 12-14-2022).]