GT running hot

[pgackerman]

My 88 has been running hot.  Needle climbs above the 220 degree mark. 

I've replaced the thermostat with a 195 degree one from O'Reilly's, mostly because it's cheap and I couldn't find a 180 degree one.  Still runs hot.

The coolant up front is NOT hot.  Can touch the plastic container after a 20 minute drive.  The back smells like very hot car. 

What's the next step to check?

[The Art Doctor]

Feel the cooling pipes running front to rear along the rockers to see if one got crushed flat and to see if they are getting warm or not.  Putting it up on stands to do this is best but you can reach most of it lying on your back along side the car if it is not lowered too much.   

[pgackerman]

Didn't see/feel any crushed areas.  Both pipes were hot to the touch. 

[Fierofool]

Paul, it could be that your temp gauge sensor is going bad on you.  After driving it and being sure it's up to full operating temperature, park it, leave it running and wait for the radiator fan to come on.  Look to see what the temp gauge is indicating.  It shouldn't be more than about 230 or so when the fan kicks on.

I would suggest you get Rodney's 210 ON, 200 OFF fan switches.  That fixed the overheating issues on both my cars.  Keep the 195 thermostat so the engine stays in it's operating range and the ECM is getting the correct information to provide correct air/fuel mixture. 

http://rodneydickman.com/product_info.php?products_id=88

Edit:  When the car has been sitting all day or overnight, does the temp needle move to the bottom of the thermometer symbol with key OFF and to the 100 mark when the key is turned ON?  These would be the correct positions if the needle hasn't slipped on its pin. 

[pgackerman]

I'll check the fan the next time I drive it.

The temp needle is at the bottom of the thermometer symbol with the key OFF and at the 100 mark when the key is turned on.

[pgackerman]

Went for a drive this morning.  Warmed up nicely.  Went a bit above 220, then when back down to 220.  Exact midpoint on the thermostat.  Drove some more.  Needle didn't budge. Came home and fan was running.  Needle stayed straight down at 220.  Perfection.  Grrrrrr.....

Still don't trust the car.

[pgackerman]

Went for a longer drive.  Same thing.  Needle went a bit above 220 and stayed there.
Started cooling down while it was still running in the garage.

Suggestions?  Ideas?  Is 225 too hot as a cruising speed?

[The Art Doctor]

Try a laser thermometer to be sure of the temps you are reading.  Even a cooking one can be put between the radiator fins to check.   You can check at any point along the system looking for hot and cool spots.  Fiero's have been known to get air bubbles in the system when the radiator has been opened, possibly one occurred or moved to an undesirable spot. 

[Raydar]

Second the "air bubbles" idea.

Just for grins, try this...
Back the car up an incline. Try to get the rear as high as possible. A foot or so above the front should be enough. Do this with the engine cold.
Remove the thermostat. Put the cap back on.
Start the engine and run the revs up to around 1500-2000 or so. Just for a minute or so. 
Turn it off and check in the T-stat housing. Add coolant until it's full.
Repeat until it doesn't take any more coolant.
Reinstall the thermostat and give her a try.

Also check your radiator hoses at the front.
When the engine is warmed up and the coolant is circulating, the left hose should feel a little hotter than the right hose. Neither one should be cold.

I highly recommend the "210 on / 200 off" fan switch that Charlie mentioned earlier.  The stock switch doesn't kick on until 235.
Probably good for emissions and... some other government mandated silliness, but I don't think it's that good for your engine.

[pgackerman]

Jacked the car up and followed your procedure. Heard lots of gurgling, but coolant was still at the top of the T-stat housing when I checked.  Went for a drive and it felt great!  Still warmed up to 220, maybe a bit higher.  I'm going to order the "210 on / 200 off" fan switch Charlie mentioned earlier.

The radiator hoses were not cold.  The upper hose was hot, and the lower one was warm.

Side Note: 
 1) Filled the coolant up when the car first started running hot.  It was an inch or two below the Add line.  Filled it above the Add line. 
 2) Noticed dark, non-metallic dirt(?) in the reservoir when I filled it.  Not much.  Just noticed it was there. 

[pgackerman]

Try a laser thermometer to be sure of the temps you are reading.  Even a cooking one can be put between the radiator fins to check.   You can check at any point along the system looking for hot and cool spots.  Fiero's have been known to get air bubbles in the system when the radiator has been opened, possibly one occurred or moved to an undesirable spot.

HAven't convinced my wife to loan me her cooking thermometer.  Think she's afraid it might have the same fate my measuring tapes have when I lend her one.

[pgackerman]

Decided to swap fan switches with a spare 2.8 in my garage. Didn't help.  If anything, the car ran hotter.

Noticed the fan switch already in my Fiero looks a lot like the one on Rodney's page.  The fan switch from my spare had a much thinner base.

Can fan switches go bad? 

The radiator fan runs when the car gets hot.  I have the AC off.  Is there any other reason the radiator fan would run?  Basically, I'm wondering if the wires to the fan switch might be bad.

[Raydar]

I would imagine that fan switches could go bad.
But the only time the fan will come on is when the fan switch reaches it's temperature OR if the A/C (not defrost) is on.
If you want to try another test, unplug the connector from the switch on the receiver-dryer. (The canister in the front compartment with the A/C lines.)
Then turn your A/C on. With the connector unplugged, your compressor will not kick on, but the fan will (should?) stay on all the time.

Since it's been cool, and your A/C was acting up anyway, is it possible that you just aren't using it as much, and your engine temp is "doing its own thing", dependent on just the fan switch?

[Fierofool]

Both my cars would overheat when sitting in traffic until I installed Rodney's fan switch. Now, traffic isn't a problem even on the hottest days.  My gauges sut just to the left if straight down but prior to the switch Steve's method of using the ac function always worked.

[ron768]

When is the last time the radiator was cleaned out?