Luckily, my 87 GT 5spd has never overheated. My friend's 87 GT automatic however seems to struggling to keep the engine temp down. My car has over 200k miles on it whereas his has less than 80k. Both have new radiators and water pumps.

With my scanner connected i can see that at idle his cooling fan comes on at 227*. I know that he has the correct waterpump but I noticed that his thermostat is a 180*. The A/C condensor is clean and the fins are open. All of the shroud material is intact. The thermostat and transmission seem to be the only differences between the two cars.

While driving in high temps, 95*+, both freeway and around town, his engine temp runs around 225* with the A/C on and radiator fan spinning . My 5spd car runs around 190*.

Is it normal for an automatic Fiero to run THAT much warmer than a 5spd Fiero?

They should run much closer to the same temperature if all else is equal. My guess would be that your friend's car has a restriction in the water pipes or tubing between the water pump and the radiator. He should look for crushed metal pipes along the underside of the rocker panels (common damage area from hydraulic lifts), or a collapsing rubber hose on the return side of the pump (passenger side). Other factors come into play as well such as the amount of crud built up in the engine block water jacket, ignition timing, exhaust restrictions, etc.

Agreed. I'm running a turbo with the auto and my temps are always ~195*.

Ah good thinking. I will raise the vehicle again and check out those tubes. I know that the timing is set and we had no reason to believe the block is plugged. Thanks for the tip.

See my cave, coolant section

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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 (It's also at the top and bottom of every forum page...)

Thanks Og! Unfortunately my Macbook wouldnt let me open past the main page. I'll have to work on that.

I crawled under this eve to check the pipes. The pipe on the right side has a very slight indent from a jack but it's not pinched..just a slight deformation that you almost cant see. The orig. hoses however are soft as marshmellows! I wonder if he's running too high a consentration of coolant...it's really green.

I once had a hose that had separated between the inner and outer layers that started to leak. It was very soft and mushy. The inner layer had also split such that it was able to partially block flow. Maybe yours is similar?

If the TCC is not engaging, the auto trans will generate a good bit of extra heat at speed.
Also if the TCC IS working but the trans is slipping due to a faulty torque converter or internal issues with the trans it can get hotter than normal.

Assuming that everything is in proper working condition with the cooling system, lines and fan, what you will observe at the temp gage will be opposite of what you might normally expect of the cooling system. When stopped , at idle, the temp will tend to go *down* and when accelerating or at constant speed the temp will go *up*.

This is obviously NOT a good situation as *conducted* heat from the trans will be raising engine temps as well as the heat added to the engine coolant by hotter than normal trans fluid at the radiator.

You *can* disconnect the auto trans fluid lines from the radiator and install a properly sized external trans cooler to the car, however while this will lower the *engine* coolant temperature appreciably, it only "masks" the still existing problem with the trans.
That problem must be addressed sooner or later.

YES, I know all of the above from unfortunate experience....

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[This message has been edited by randye (edited 08-29-2012).]

Got the hoses ordered. Thankfully, we know that the trans is currently working well tho we're waiting for the day that he gets off the freeway and the torque converter doesn't unlock! Gotta happen eventually!

I have a feeling that the coolant is all coolant, no water. I drew enough out to fill a mason jar and compared it to 100% coolant. There was no difference. I'm gonna see what happens after I replace the hoses and run a 50/50 mix.