Hello There,

I've tried everything. Jacking up the rear for air pockets, new thermostat, new fan switch. Can a bad water pump cause the engine to overheat? What I'm asking is even if the water pump is not leaking, can the pump somehow cause the flow of water to not have enough power to push the coolant through the radiator so it can go back to the thermostat housing? I don't think that the water is making it back up to the thermostat housing so it can get into the enginge. The truth is with the thermostat housing cap off, after all air bubbles are out, there is not any flow of water making it back to the thermostat housing coming from the radiator. One last question. Is the water supposed to leave the radiator from the bottom hose or top hose, and is it supposed to come back through the top side of the thermostat housing, or is it supposed to leave the top side of the thermostat housing? There is flow, but how do I know know if there is supposed to be more or not, because there is pressure when the engine gets hot.

Can anyone please help me, I am really stumped. I need anyone's help.

I am new to this site, why do I get a couple of answers right after I post a question, and then no one else answers ever again?

Does anyone have a diagram of the which way the coolant circulates throught the car?

Thank You Very Much to all who have tried to help so far. 87 V6 2.8 Liter Original Engine

Tony

I am editing this question after I received a couple of answers. I don't know how to thank the people who answered by contacting them directly.

The radiator was staying cold in the beginning when the engine was overheating, but water was circulating throught it. Even the resivior was staying cold and even over flowed from the cap, but it was cold water. After I shut off the engine and a few hours when everything has cooled off, the resivior is almost completely out of water. I put my hand all over the radiator and it was always cold, like the water was going in and out of it, but not through the fins. Now after alot of flushing and alot of burping, the radiator gets hot like it's supposed to, and the water is circulating through the whole car, but whan it overheats, and I shut off the engine, the radiator instantly gets cold again. Thanks for everyone's replys, but what else can be wrong? There are no collapsed hoses, no crushed pipes, and all this started overnight. It didn't happen slowly. One day all ok, and the next overheating problems. Please help!

Does anyone have the diagram of the cooling system that shows the circulation direction through out the whole car? Also how do I do a radiator flush?

Thanks Again!

Tony

Edited again

It takes about 5 minutes from completely cold for the engine light and the needle to go into the red. Right now I'm even running the engine without the thermostat. I noticed when the the engine gets really hot and the coolant tank starts to overflow out the top, not only is the water in the coolant tank cold, but the radiator instantly gets cold. The radiator is really warm, but as soon as the tank starts to overflow, the radiator instantly gets cold also. I think the water starts to flow backwards when I turn off the engine after the coolant tank starts to over flow. After about a few hours, when I open the rear cap, There is water in the thermostat housing if I turn off the engine in time before the coolant tank starts to overflow. Maybe this will help someone answer my questions.

Again thanks for all your help. I feel that I'm getting closer with all your help. Please keep it up!

Tony

THANK YOU EVERYONE WHO TRIED TO HELP!

MY CAR IS BACK TO NORMAL. -------------------------- IT WAS THE WATER PUMP---------------------------------------- I HAD THE OLD ONE WITH THE PLASTIC INTERNAL PARTS. I NOW PUT THE NEW ONE IN WITH METAL INTERNAL PARTS AND MY CAR IS RUNNING FINE. MY METAL HOSES UNDER THE CAR ARE A LITTLE BENT, BUT THAT DOESN'T HAVE ANY EFFECT ON THE OVERHEATING PROBLEM. LIFTING THE REAR, ALSO DOESN'T HAVE TO BE DONE. JUST CHANGE THE WATER PUMP, AND FILL WITH COOLANT. LET IT RUN FOR A WHILE, LET IT COOL OFF, AND TOP OFF WITH COOLANT AT THE THERMOSTAT HOUSING. THATS IT!!!!!!!!!!!!!!!!!!!!!!!


THANKS AGAIN


TONY

[This message has been edited by TonyMony (edited 08-30-2007).]

I have heard of some 2.8L waterpumps with a plastic impeller, and those ones have a problem of having the impeller fall off. Which could be your problem, all you have pumping the water is a little shaft spinning around, which will do nothing.

The coolant goes from the waterpump, through the engine, to the thermostat housing, across the front of the engine through a pipe external of the engine, then down the drivers side of the car, into the top of the radiator, then back out the bottom of the radiator, down the passenger side of the car, and back into the waterpump.

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84 Fiero Sport Coupe #1192 :: 86 Fiero Base Coupe Quad 4 HO :: 1998 Dodge Neon EX 2Dr 2.0L DOHC Auto

[This message has been edited by befarrer (edited 08-06-2007).]

Yes- the water pump can fail.

Some other items you can check :
Is the thermostat installed, try removing to test if it stuck shut, would block coolant flow.
Check the coolant pipes, sometimes the the pipes get crushed, blocking coolant flow. (check pipe by front and rear wheels)
If the hoses are old, a hose could be collapsing.
Raditor could be blocked, can test by flushing.

Does the radiator get warm or hot, would tell you how much coolant is getting to the radiator (Be careful around fan as it could startup).

Have you check the belt that drives the water pump? If it is loose and slipping that can cause it to over heat.

The radiator was staying cold in the beginning when the engine was overheating, but water was circulating throught it. Even the resivior was staying cold and even over flowed from the cap, but it was cold water. After I shut off the engine and a few hours when everything has cooled off, the resivior is almost completely out of water. I put my hand all over the radiator and it was always cold, like the water was going in and out of it, but not through the fins. Now after alot of flushing and alot of burping, the radiator gets hot like it's supposed to, and the water is circulating through the whole car, but whan it overheats, and I shut off the engine, the radiator instantly gets cold again. Thanks for everyone's replys, but what else can be wrong? There are no collapsed hoses, no crushed pipes, and all this started overnight. It didn't happen slowly. One day all ok, and the next overheating problems. Please help!

Does anyone have the diagram of the cooling system that shows the circulation direction throught the whole car?

Thanks Again!

Tony

Are you hearing any air coming out while you are burping?????
Is the Temp gauge going all the way to the red real fast or just slowing climbing???

If it jumps to the red then its more than likely an air pocket..
With the rear higher I remove thermostat and cap fill the system then very slowly open the radiator cap and hold when I start to hear air escaping...repeat till no air is heard then refill.

If the waterpump has a plastic impeller it can cycle water when cool. When it warms up the impeller slips under pressure and does not cycle the water correctly (not fast enough) causing it to over heat.
I would drain the system, change the waterpump making sure the replacement has a metal impeller, Then re-fill the system by raising the rear of the rear of the car and removing the front radiator cap, Fill from the rear. Once it starts to overflow, replace the front cap and continue filling from the rear. Once it is full run the engine at idle for a few seconds with the cap off. It should bubble a little then settle down. Turn off the engine top off the system, Fill up the overflow tank up front, install thermostat and cap. Then drive the car untill it warms up (20minutes or so) and then turn it off. Let it cool down (4-5 hours) remove rear cap. If the coolant level is still near the top, all is good. If it is not, raise rear, top off. Then unless there is a leak somewhere, all should be fine.

Thanks to everyone so far for all your help. Anyway, it takes about 5 minutes from completely cold for the engine light and the needle to go into the red. Right now I'm even running the engine without the thermostat. I noticed when the the engine gets really hot and the coolant tank starts to overflow out the top, not only is the water in the coolant tank cold, but the radiator instantly gets cold. The radiator is really warm, but as soon as the tank starts to overflow, the radiator instantly gets cold also. I think the water starts to flow backwards when I turn off the engine after the coolant tank starts to over flow. After about a few hours, when I open the rear cap, There is water in the thermostat housing if I turn off the engine in time before the coolant tank starts to overflow. Maybe this will help someone answer my questions.

Again thanks for all your help. I feel that I'm getting closer with all your help. Please keep it up!

Tony

Tony,

Sounds I had the same overheating problem.

Turned out to be the water pump. Mine wasn't leaking at all.

This path will show pic's of the water pump install on my Formula

https://www.fiero.nl/forum/Forum2/HTML/081914.html

Good Luck

PS, Make sure you have the right radiator cap - Slant has the wrong number listed. (We need a non-vented cap)

I'm surprised no one's mentioned the trick on how to keep track of all the different screws on the 2.8 WP.

Here's the deal..
(1) Take a cardboard box a little bigger than the pump itself and completely trace the pump gasket onto the box, HOLES AND ALL. I usually use the box the pump came in for the tracing.
(2) Punch out the screw holes you've traced on the cardboard.
(3) As you remove the screws from the actual pump, put them in the coresponding holes on the tracing.

This way, you know EXACTLY where each screw goes. The first time I changed a WP, I put all the screws in a cup and spent HOURS figuring out whch screw went where. The tracing idea eliminates all that confusion. Good Luck.

[This message has been edited by Doni Hagan (edited 08-06-2007).]

But to somewhat answer your question.
The main flow starting at the thermo housing.
Coolant flows out the thermo housing down the pipe to the drivers side, up to the radiator on the left, acroos to the right side, back to the engine, into the hose on the timing cover into the pump, out the pump into and thru the block and back to the stat.

The stat blocks the coolant outflow from the engine to the radiator.

For the heater, if you have the small pipe on the water pump, that is the return of water from the heater. The flow to the heater comes off before the stat.


And there is no way for coolant to flow thru the main system unless it flows thru the radiator. There is no way it can by pass the radiator other than the heater lines.

[This message has been edited by Dodgerunner (edited 08-06-2007).]

Thanks! You are a real big help. Do you think that not having enough flow because of a bad water pump is the reason within 5 minutes, the over heating engine lights all go on? Also why does cold shoot out the top of the coolant container when it starts to over heat, and when this happens, the radiator gets cold instantly while this is happening and right when I shut off the engine? I tried to rate a positive for you, but it said that I had to be a member for at least 30 days! Thank you so very much. I hope it is not the water pump, but I did burp it with the rear jacked up, and even with the thermostat out it seems that the problem is still the same. Thanks Again!

But to somewhat answer your question.
The main flow starting at the thermo housing.
Coolant flows out the thermo housing down the pipe to the drivers side, up to the radiator on the left, acroos to the right side, back to the engine, into the hose on the timing cover into the pump, out the pump into and thru the block and back to the stat.

The stat blocks the coolant outflow from the engine to the radiator.

For the heater, if you have the small pipe on the water pump, that is the return of water from the heater. The flow to the heater comes off before the stat.


And there is no way for coolant to flow thru the main system unless it flows thru the radiator. There is no way it can by pass the radiator other than the heater lines.

[/QUOTE]

yes a bad pump will do that.
mine did exactly that, 5 min of sitting to overheat.
the pump had a plastic impeller. if you held the shaft, you could spin the impeelar on the shaft with your pinky.

quote Originally posted by TonyMony: There is water in the thermostat housing if I turn off the engine in time before the coolant tank starts to overflow. Maybe this will help someone answer my questions. Tony

I did answer your question and provided a repair procedure.
See my previous post.

As stated by many your waterpump is bad.

Think your going to have to bite the bullet and change that pump.
Also check you have the right cap on the radiator. If someone changed it they might have got the wrong cap since the parts books list the wrong cap for Fieros.
Check the cave at the top of the site for info on the right cap.

[This message has been edited by Dodgerunner (edited 08-07-2007).]