87 Stock GT manual...
Burped the system per the Ogres Cave, all pipes/hoses get warm around entire car, coolant was flushed and filled this summer along with flushing the radiator to make sure it was not blocked, no play in water pump pulley, belt is tight (does not Squeak), fixed pegging temp gauge per Fierosails.com instructions, new fan relay (Fan only comes on if I turn on the AC even when gauge is in red???) new thermostat, Heater inside car blows out warm air. Like I said the fan never comes on unless I turn it on, and the coolant or the SES lights never come on. Car overheats within about 7-10 minutes.

My guess is its the Water Pump but if it was bad how come I get flow around the car and my heater works???
Please help I need to get this thing on the road.

The hose coming out of the thermostat housing and the top hose on the radiator should feel HOT not warm. You could have a flaky water pump or a crushed coolant pipe under the car. A quick way to check you pump is to pull out the thermostat (engine cold) and leave the cap off , then fire up the car. Water should come gushing out to the housing.

quote Originally posted by Phil: The hose coming out of the thermostat housing and the top hose on the radiator should feel HOT not warm. You could have a flaky water pump or a crushed coolant pipe under the car. A quick way to check you pump is to pull out the thermostat (engine cold) and leave the cap off , then fire up the car. Water should come gushing out to the housing.

Thanks Phil

The cooling pipes running under the car are all fine, I see no major issues there. I did your water pump test and coolant shot out of there pretty quick!
No water in oil from what I can tell but I think some coolant may be leaving the exhaust, not liquid but white gases. It could be steam cause it is 38 Degrees outside but I am not sure there. The car has 145,000 miles on it so it may just be getting worn.

Any other suggestions??

Could be a bad head gasket or intake gasket - letting coolant into the exhaust? If everything else is working correctly - that's my guess anyway.

The car runs fine and there is no oil in the coolant or vise versa. I put in a new temp gauge switch in but maybe I got a dud I will get a new one today or tomorrow. I just dont know why my SES light, Coolant Light, or rad fan wont come on. None of these things come on!?

As far as the fan goes.....did you change the fan temp. switch or just the relay? Did you test that the thermostat is opening fully (suspend it in a pot of hot water with a thermometer to check temp and see if it opens all the way)? Just because something is new doesn't mean it is working fine.

First time I ran it today I left the T-stat out and it took about 7-10 minutes to overheat. Now I just ran it again w/ the T-stat in and it overheated in about 4 minutes and this time the cooling pipes never got hot! WTF WTF. I am so confused.

double check the wiring with the temp gauge...
get an infrared thermometer.and check the temp right on the base of the thermostat housing
see if you get a different reading.
maybe the car is running really lean on fuel? just a suggestion.
but yeah find a cheap infrared themometer. they are actually pretty accurate.

I will try a couple more things including trying a new aftermarket meter gauge to see the real temp. I will also burp it again Saturday.

hows your timeing? if its wrong it can make the car run hot

quote Originally posted by FIER086: First time I ran it today I left the T-stat out and it took about 7-10 minutes to overheat. Now I just ran it again w/ the T-stat in and it overheated in about 4 minutes and this time the cooling pipes never got hot! WTF WTF. I am so confused.

Like Phil said, sounds like you might have a bad water pump, possibly with a plastic impeller. The problem with testing the water pump with no thermostat cap on is you do the test when the engine is cold. What happens when the engine is hot might be a different story.

Mine acted similar to yours - overheating but I had some heat from the heater. Engine hot, my radiator/hoses were cool even with the thermostat out. Pretty obvious for some reason the coolant wasn't circulating very well. My rad. fan would not turn on (except w/AC) & except for one time, no TEMP light. I checked my hoses/lines, all looked good so I removed the water pump. Sure enough, a plastic impeller. The problem is there's no easy way to know if yours has a plastic impeller, you have to remove the pump to find out. So check all your hoses (radiator & heater), metal lines, radiator & heater core not plugged, no coolant in the oil or anti-freeze smell at the exhaust, all air purged out of the cooling system. The heater core and hoses are important for proper cooling so don't overlook those. If it all looks good, I'd suspect the water pump.

Mike

[This message has been edited by Nosferatu187 (edited 11-29-2008).]

Also, how did you check your cooling tubes? Frequently they get bent upwards at the end causing the tube to collapse, but appear just fine to a visual inspection. You have to feel the tube to make sure it's round in cross-section and not collapsed.

The Fiero cooling system is really simple with just a few basic parts. The water pump is key to get sufficient flow. When operating normally it will idle all day long with the AC on in the hottest weather without overheating, and at any speeds over around 20 mph it will run at the thermostat temperature indefinitely without activating the fan. If you activate the fan by turning on the AC or defroster it will stay cool indefinitely.

JazzMan

quote Originally posted by JazzMan: Also, how did you check your cooling tubes? Frequently they get bent upwards at the end causing the tube to collapse, but appear just fine to a visual inspection. You have to feel the tube to make sure it's round in cross-section and not collapsed. The Fiero cooling system is really simple with just a few basic parts. The water pump is key to get sufficient flow. When operating normally it will idle all day long with the AC on in the hottest weather without overheating, and at any speeds over around 20 mph it will run at the thermostat temperature indefinitely without activating the fan. If you activate the fan by turning on the AC or defroster it will stay cool indefinitely. JazzMan

I have been doing this all at idle for fear of overheating so I have not really driven it. When I turn the fan on it really doesn't do a hole lotta good. With my other Fiero if it ever starts getting too hot for my liking I turn the fan on and POOF it lowers the temp. very fast. Not with my GT though. I will try burping it today.

Also I think my timing is okay, the car runs good (needs tune up) but I am not positive it isn't dead on.
Thanks to all who are helping, I just got this car back from getting a new tranny in so I am itching to get this car moving.

It'll run pretty cold without a thermostat. Put in a good thermostat and see what happens.

Mike

Today I bought a new 195 T-stat and installed it in the car. I let the car run for about 10 minutes to get it warm and the gauge actually moved to where it should be.

Q? With the T-stat closed (car warming up) my t-stat housing got hot but so did the entire passenger side of the system, the rest of the cars cooling system was still cool. Does this mean it didn't get hot enough to open the t-stat to start flow?

I'd guess you didn't run it long enough.

Engine warms up, thermostat opens, coolant flows up the driver's side into and through the radiator back down the passenger side to the water pump.

It will warm up "up-stream" a little before the thermostat opens.

I think you need to run it longer than ten minutes and watch the temp gauge, you'll know when the thermostat opens if you keep a hand on the coolant tube under the drivers side of the car while it idles.

Steve

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Where will the road take you today?

Some helpful links I've done
How to remove inner door panels, with pics.
How to remove outer door panels, with pics.
How to make rear coil-overs using factory struts, with pics.
How to remove rear bearing hubs, with pics.
How to modify the stock Fiero radio for MP3 players, with pics.
How to come up with the right coolant hoses for that engine swap...With Pics.
Basic Fiero electrical testing "How To" and equipment...with pics.

Just for reference you can also test the fan by removing the connector to the fan switch and connecting it to ground. The fan will run with the key on. The fan switch simply goes to ground when the proper temp is achieved, about 220* - 230* stock. Mine came one at 228* as reported by WinALDL thru the ECM temp sensor. Don't use thread sealer on the fan switch as it needs metal to metal contact to ground. Rodney Dickman sells a lower temp switch in the 200* - 210* range.

You can test your temp gauge by using Rodney's gauge test leads (or making your own). A crude test is to remove the connector and ground each side one at a time with the key ON. One side will light the overheat light. The other side will peg the gauge. This simply tells you if the gauge needle moves not if it's calibrated correctly.

You think your problem was the thermostat?

Thanks to all,

I think the problem is solved. I didn't want to run it longer for 10 min b/c the gauge was telling me it was overheating. Replaced the gauge and put in a good T-stat and now all is well. The fan should work w/ the new relay and switch on engine block, I will look into this more, maybe I need another NEW switch. Seems like I keep buying bunk gauges/sensors.

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'86 2m4- Auto, Daily Driver
'87 GT - 5spd, Project Car
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So now you'd better stop and rebuild all your ruins,
For peace and trust can win the day despite of all your losing