ok so when i start my engine and let it run for like 20-30sec then shut it off and open the thermo housing there is a layer of white foam sitting on to of the coolant what do this mean?

You are low in coolant. There shouldn't be air (foam is air mixed with water) in the cooling system.

ive purged the cooling system all is good there i guess i should also mention that once warmed up the cooling system starts to over heat and does not cool efficiantly and the engine starts to over heat

quote Originally posted by drebinpk: ive purged the cooling system all is good there i guess i should also mention that once warmed up the cooling system starts to over heat and does not cool efficiantly and the engine starts to over heat

How did you purge the system? The Fiero is fairly finicky when it comes to getting all the air out. Does it overheat even with no thermostat installed?

i purged it by running for 20sec then topping off and doing this till couldnt add any more and yes it still overheats without thermo

Does the radiator hose/radiator itself get warm?

yes all the hoses and radiator get warm

Does the radiator fan come on when the engine gets hot? If you turn on the A/C does the radiator fan come on?

Edit: be careful if you can see the hose swelling up, do not want to be near that if it breaks.

[This message has been edited by Xanth (edited 01-22-2011).]

the fan comes on at just over 220

A leaky head gasket would cause low coolant and air in the coolant, yes. It would also cause the cylinder(s) it's leaking into to run lean, which would result in the ECM trying to dump more fuel into the engine. You would also have white smoke out of the exhaust.

Are you sure you have coolant circulating? Perhaps the impeller in your water pump is broken?

Even with no water pump / impeller broken etc, the heat will sometimes make it look like coolant is circulating (but not enough obviously). Just thought I'd throw that out there if you've checked all of the obvious items. (The impeller in the big block Olds Water pumps have a habit of breaking so I thought I'd mention it. I've gone through them quite a number of times.

Also, When you are bleeding the system is the car level? (I often raise and lower the front of the car to make sure all the air is out).

With the my V8, I have a cap on the thermostat housing on the engine so I also raise the rear of the car. You'd be amazed how little air it takes around the water pump impeller or somewhere else in the system that can stop the flow of coolant.

Doby is correct, A leaky head gasket can cause the cooling system to pressurize as well. If you have one (or can borrow) one of those radiator pressure test caps, you can see if you have substantially over 15-16lbs of pressure with the system closed.

You can also see if your auto parts store or radiator shop carries those "test strips" that you dip into the coolant. They change colors if they detect hydrocarbons (Exhaust gasses) and let you know if your cooling system is pressurizing from cylinder pressure.

[This message has been edited by 3084me (edited 01-22-2011).]

May also want to try topping the system off by removing the thermostat and putting the cap back on and running it with the radiator cap off, check the level in the radiator then. If you have ful fluid you may want to then next check into a new radiator cap. Id start with those things before going at the pump you will be able to tell if its flowing enough too when you have the cap off.

If the system is full, coolant would come pouring out the radiator cap when it is opened. The fill point in the rear is higher than the rad cap. That is one of the important parts of filling the Fiero system.

[This message has been edited by Xanth (edited 01-24-2011).]

coolant is deff flowing i have new water pump and new radiator also ive burped the cooling system without the thermo in so i know its full and just replaced head gasket to see if that fixed it and well no change so im starting to think the only thing jeft it could be is warped block/head or cracked head.....
oh and there is a tad bit of white smoke that comes out tailpipe

quote Originally posted by dobey: A leaky head gasket would cause low coolant and air in the coolant, yes. It would also cause the cylinder(s) it's leaking into to run lean, which would result in the ECM trying to dump more fuel into the engine. You would also have white smoke out of the exhaust.

Ill also go with this.

quote Originally posted by rogergarrison: Ill also go with this.

I third that.

also once the car warms up there is a slight miss that wasnt there before

quote Originally posted by drebinpk: also once the car warms up there is a slight miss that wasnt there before

Pull your spark plugs. Are any of them super clean and white-ish?

they all look pretty normal

Sounds like a head gasket. Here is how to find out. You need an air compressor and a compression tester with air hose coupling. With a cold engine (but warm place to work, cuz it will take a while) remove all spark plugs. Now remove coolant cap closest to the engine. One cylinder at a time, screw in the compression tester and hook up air supply. Be careful when hooking up air because the engine might rotate a little. Turn the engine by hand until the valves shut on that cylinder. Look for air bubbles comming out of the coolant cap opening. There should be no air. Repeat on all cylinders or until you find air, then you can stop because the head(s) have to come off.

This tests the combustion chamber for leaks into the cooling system. So if you find air, the only two causes could be a bad head gasket or a cracked head. Usually it's the gasket, but either way the head has to come off.

If the plugs are all correctly worn, and you aren't seeing white smoke out the exhaust, then you are probably lucky enough to only have a problem with low coolant (even if it's too much water and not enough antifreeze). Check the coolant tubes for kinks too, as they commonly get crushed, if you've had any work done at a shop lately. Sounds like it's just low and boiling when you get near normal operating temp.

quote Originally posted by FTfiero: May also want to try topping the system off by removing the thermostat and putting the cap back on and running it with the radiator cap off, check the level in the radiator then. If you have ful fluid you may want to then next check into a new radiator cap. Id start with those things before going at the pump you will be able to tell if its flowing enough too when you have the cap off.

This is highly incorrect. the front radiator will overflow from the cap point when it is filled properly. the rear cap by the engine is the correct fill point. you also need to park on a steep incline or put the rear up on jack stands to properly purge the cooling system of air.

The ogre has a perfect HOW TO about this in the cave, scroll to the top of the page you are on right now, look at the black bar at the top and click on where it says "OGRES CAVE"

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quote Originally posted by drebinpk: coolant is deff flowing i have new water pump and new radiator also ive burped the cooling system without the thermo in so i know its full and just replaced head gasket to see if that fixed it and well no change so im starting to think the only thing jeft it could be is warped block/head or cracked head..... oh and there is a tad bit of white smoke that comes out tailpipe

Def sounds like your on the right track!! Have you checked the oil to see if its getting mayonaise looking?

Cracked head