Sudden overheating 87GT 5 speed (Page 1/1)
Daryl M JUN 16, 01:43 AM
My 87GT 5 speed overheated for the first time ever tonight. I live in Phoenix. I drove the car 35 freeway miles and parked for about an hour . No sign of a problem. Temp stayed at about 185-190 the whole way. After sitting for about an hour, I drove about 200 yards to a gas station to get gas. After getting gas, I drove about 2 blocks when I noticed the overheat light come on. The needle was pegged on hot so i pulled over and popped the rear hood. The car smelled hot. Did i mention i live in Phoenix where it was 112 degrees during the 30 min trip. By the time i let it sit for an hour, the outside temp was 105. What should i check first when i get the car home?
Patrick JUN 16, 01:59 AM

quote
Originally posted by Daryl M:

What should i check first when i get the car home?



Nothing. I'd let the car cool overnight.

Check obvious things first... like the coolant level in the reservoir. Remove the thermostat housing cap and check the coolant level in there as well. Make sure the rad fan is functional.
Kevin87FieroGT JUN 16, 10:47 AM
When was the water pump last replaced?
cvxjet JUN 16, 12:10 PM
A few things;
A) The (Replacement) water pumps that have a PLASTIC impeller can cause problems; The impeller expands more than the steel shaft and then the impeller won't turn. Only install a METAL impeller water pump!!!

B) Coolant level, obviously

C) Have you had the car lifted/jacked up recently? The coolant tubes can be crushed cutting off flow

D) The Fan temperature switch; Mine would only turn the fan on when I was pulling over due to overheating....I swapped in a 220* switch (Original is 237*) and problem solved- The fan comes on when the car is getting hot but otherwise stays off (A lower temp one will cause the fan to run ALL the time)
theogre JUN 16, 02:10 PM
Yup, check levels, crush pipes, etc...

Note: Even if T-stant seems to be good... Get Stant Superstant
See my Cave, Thermostat and rest of section.


quote
Originally posted by cvxjet:
A) The (Replacement) water pumps that have a PLASTIC impeller can cause problems; The impeller expands more than the steel shaft and then the impeller won't turn. Only install a METAL impeller water pump!!!

Even w/ "plastic" impeller, This is often a side effect not a root cause.
Metal impellers can have similar death from Cavitation cause flow problems or weak Rad Cap and more.
If you have problems w/ WP then look for crush pipes, plugged rad and/or heater core, etc, making flow restrictions.

Fiero Coolant System uses 2 to 4 times the coolant for most cars and that Mass have be driving thru it.
Even most V8 cars and trucks only use ~ 8 quarts vs Fiero 14+ quarts.
Anything restricting flow just makes problems worse and often WP dies.

Example: Radiator may look "ok" looking thru the fill port but other side can be full of crap blocking flow.
That's hopefully crap in the left tank... Often the tubes are block because of weak or no coolant product to stop that.
Heater core can have same problem.
True back flow flushing might help but often need to replace them when the tubes are plugged.

------------------
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

Daryl M JUN 16, 03:31 PM
I picked up the 87 Gt with the trailer and got it home. Overflow reservoir was empty. Took about 1/2 gallon of coolant to top off. Plus what I put in the reservoir. I drove the car for about 7 or 8 miles in the neighborhood. It's 104 outside right now, so it isn't really hot yet. Engine temp quickly leveled off at about 185-190 and stayed there. No sign of leaks, so I am wondering where the coolant went. I have never had any cooling problems with this car, but it is 34 years old at 95,000 miles.plan on letting it cool off, check levels, and go for a longer drive this afternoon when it is predicted to be 112 outside. I only drive the 87GT occasionally, 100 miles a month, so i haven't been checking coolant levels as much as i probably should. This will probably go down as operator error.
Mike in Sydney JUN 16, 07:22 PM
These are the things I'd look at :

1) When was the last time you checked / replaced the pressure cap on the radiator and thermostat housing?
2) Is the plastic reservoir cracked? If it is you could be losing coolant there.
3) What about the thermostat? I run a 160°F thermostat in mine.
4) Radiator fan switch OK? Does it switch on properly at the right temp? If not, does the fan come on when you turn the AC on?
5) Crushed coolant pipes
6) Water pump
Daryl M JUN 16, 08:08 PM
Went on another test run. After letting the car cool off, I went on another test drive. I first stopped off the coolant at the engine end. It took about a cup of coolant. The outside temp was 109. I drove about 10 miles at 50ish with starts and stops in my rural neighborhood. The engine temp quickly went to about 180 and stayed there. I'll watch it closely for leaks, temp, and coolant level, but I am comfortable in saying that the idiot in charge of maintenance let the coolant level get to low in Arizona in June. Yes , I'm the idiot.
Kevin87FieroGT JUN 19, 08:49 AM
If the coolant level should continue to go down with no indication of coolant leaking check your oil dip stick for discolored oil ( Carmel color, or the like) as you may have a blown head gasket. A compression test, or pressure test of radiator would help verify a bad head gasket.
Daryl M JUN 19, 06:52 PM
Drove to a car show today. 35 miles each way. Morning temp was about 80. Return at noon about 109. Engine temperature stayed below 200. No loss of coolant.