Cooling system over-pressurizing?
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Cooling system over-pressurizing?
Sunday was a beautiful day and I decided to park my new daily driver and take the FC out for a spin. It's been about 3 weeks since I drove her last...
After about 10 minutes of driving, I noticed that my temps were almost at the halfway mark on the factory gauge...I turn around and go home without incident. Once I shut the car off, I opened the hood and noticed coolant coming from the overflow bottle and a lot of gurgling. The upper rad hose was also pretty hard and it seemed to have a lot of pressure. The top of the radiator was hot so I don't think there is a clog and while driving home I was able to get heat in the interior so I don't think the heater is clogged either.
The thermostat has maybe 800 miles on it and the motor has about 3500 miles on it. The next morning, I filled the car with coolant/water and pulled the EGI fuse to crank with the rad cap off. While cranking, no water spewed or gushed out of the thermostat housing where my rad cap goes (no cap on my radiator, this is how some FC cooling systems are designed).
I haven't played around with it since. Should I try taking the thermostat out and see what happens? I put another rad cap on - I had a spare. Now, as I said before, my rad cap goes on my thermostat housing. There is NO hose that connects that housing the the overflow bottle. The way my system works is that a hose runs from the top of the radiator to the overflow bottle. There is a pill/restrictor about an inch from the top of the rad in this line that you can feel and I believe this is how the system reaches pressure.
I was under the impression that modern thermostats only get stuck open, not closed. Any ideas?
After about 10 minutes of driving, I noticed that my temps were almost at the halfway mark on the factory gauge...I turn around and go home without incident. Once I shut the car off, I opened the hood and noticed coolant coming from the overflow bottle and a lot of gurgling. The upper rad hose was also pretty hard and it seemed to have a lot of pressure. The top of the radiator was hot so I don't think there is a clog and while driving home I was able to get heat in the interior so I don't think the heater is clogged either.
The thermostat has maybe 800 miles on it and the motor has about 3500 miles on it. The next morning, I filled the car with coolant/water and pulled the EGI fuse to crank with the rad cap off. While cranking, no water spewed or gushed out of the thermostat housing where my rad cap goes (no cap on my radiator, this is how some FC cooling systems are designed).
I haven't played around with it since. Should I try taking the thermostat out and see what happens? I put another rad cap on - I had a spare. Now, as I said before, my rad cap goes on my thermostat housing. There is NO hose that connects that housing the the overflow bottle. The way my system works is that a hose runs from the top of the radiator to the overflow bottle. There is a pill/restrictor about an inch from the top of the rad in this line that you can feel and I believe this is how the system reaches pressure.
I was under the impression that modern thermostats only get stuck open, not closed. Any ideas?
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Taking the thermostat out won't solve your problem, and could cause several others.
First, do a coolant system pressure test to make sure your engine isn't pushing exhaust into the system.
What's with the odd cooling configuration you have? There are many variations on stock, but that is not one of them. I would eliminate it and use a proper pressure cap before you troubleshoot further.
First, do a coolant system pressure test to make sure your engine isn't pushing exhaust into the system.
What's with the odd cooling configuration you have? There are many variations on stock, but that is not one of them. I would eliminate it and use a proper pressure cap before you troubleshoot further.
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Mine ('88 SE) has a non-sprung cap on the t'stat housing, and a regular, sprung- radiator cap on the rad. The overflow tube sits beneath the cap on the rad, and goes to the bottle. The cap on the t'stat housing is not a pressure-relief cap. (It has no spring underneath) It's just a cap. The cap on the radiator does all of the pressure releasing - That's why the overflow tube is there. That tube has got to be wherever the spring-loaded cap is, otherwise the overflow/reintake system won't work properly. Is that how your's is? It sounds like perhaps you've got the tube where the unsprung cap is. Have the two caps switched places? That would make a difference.
EDIT - I just reread and saw you have NO cap at all on the rad. You have to have that overflow tube under the sprung cap. Doesn't one of the setups come like that?
EDIT - I just reread and saw you have NO cap at all on the rad. You have to have that overflow tube under the sprung cap. Doesn't one of the setups come like that?
Last edited by nopistons; 04-12-05 at 02:27 PM.
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Originally Posted by Aaron Cake
Taking the thermostat out won't solve your problem, and could cause several others.
First, do a coolant system pressure test to make sure your engine isn't pushing exhaust into the system.
What's with the odd cooling configuration you have? There are many variations on stock, but that is not one of them. I would eliminate it and use a proper pressure cap before you troubleshoot further.
First, do a coolant system pressure test to make sure your engine isn't pushing exhaust into the system.
What's with the odd cooling configuration you have? There are many variations on stock, but that is not one of them. I would eliminate it and use a proper pressure cap before you troubleshoot further.
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That's a cooling config I have not seen on an FC. It certainly doesn't resemble any factory install. In this case, I would first suspect that check valve. Your car is demonstrating the symptoms of a bad pressure cap, so that valve would be the first place I would look.
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#8
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i had this same problem.... although i shouldnt advise it because its really dangerous... every time you drive the car open up the hood. then unscrew the bottom cap about 1/4 to 1/3 turn. just enough to hear girgling in the rad....this should allow excess press to release and you shold see some spray out the overflow tube...and continue to do this untill you stop having the problem.... and make sure you check to see that you have enough coolant in the over flow tank cuz on cool down it should suck some back up.
i have had success with this method anyways. seems like it might help! oh and if anyone objects to this idea please feel free to tell me im stupid and shouldnt do it because im always looking for new ideas
i have had success with this method anyways. seems like it might help! oh and if anyone objects to this idea please feel free to tell me im stupid and shouldnt do it because im always looking for new ideas
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Originally Posted by skatingsamurai
i had this same problem.... although i shouldnt advise it because its really dangerous... every time you drive the car open up the hood. then unscrew the bottom cap about 1/4 to 1/3 turn. just enough to hear girgling in the rad....this should allow excess press to release and you shold see some spray out the overflow tube...and continue to do this untill you stop having the problem.... and make sure you check to see that you have enough coolant in the over flow tank cuz on cool down it should suck some back up.
i have had success with this method anyways. seems like it might help! oh and if anyone objects to this idea please feel free to tell me im stupid and shouldnt do it because im always looking for new ideas
i have had success with this method anyways. seems like it might help! oh and if anyone objects to this idea please feel free to tell me im stupid and shouldnt do it because im always looking for new ideas
The one thing I DID notice during the drive is that my voltage was low - it wouldn't go above the 12 volt mark. After the drive when I let it idle it was down to 9-10 volts. It still idled and ran but the alternator wasn't charging the battery when I gave it some throttle.
Could this have something to do with what happened the other day since the same belt runs the water-pump? That wouldn't make sense. I've got a good spare alternator that I'll put in on Sat. and see what happens then.
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bump
So as I said earlier, after re-filling the system and replacing the sprung cap I had on the T-stat neck with the OEM un-sprung cap, the car seemed fine. It ran for about 10 minutes and idled for more than 5 minutes with good temps and pressure on the gauge.
While filling, I did squeeze the upper pipe with the bleed screw out to get rid of any air bubbles - could that have been my problem?
So as I said earlier, after re-filling the system and replacing the sprung cap I had on the T-stat neck with the OEM un-sprung cap, the car seemed fine. It ran for about 10 minutes and idled for more than 5 minutes with good temps and pressure on the gauge.
While filling, I did squeeze the upper pipe with the bleed screw out to get rid of any air bubbles - could that have been my problem?
Last edited by jon88se; 04-13-05 at 08:17 AM.
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Originally Posted by jon88se
That is def. not the right way to bleed air in the system Tonight I bled the system and filled it and put the OEM unsprung cap on the t-stat neck. I took her for a drive for 10 minutes and let it idle for 5 minutes. Temp was normal and there was no excess pressure, nor any leakage from the overflow.
The one thing I DID notice during the drive is that my voltage was low - it wouldn't go above the 12 volt mark. After the drive when I let it idle it was down to 9-10 volts. It still idled and ran but the alternator wasn't charging the battery when I gave it some throttle.
Could this have something to do with what happened the other day since the same belt runs the water-pump? That wouldn't make sense. I've got a good spare alternator that I'll put in on Sat. and see what happens then.
The one thing I DID notice during the drive is that my voltage was low - it wouldn't go above the 12 volt mark. After the drive when I let it idle it was down to 9-10 volts. It still idled and ran but the alternator wasn't charging the battery when I gave it some throttle.
Could this have something to do with what happened the other day since the same belt runs the water-pump? That wouldn't make sense. I've got a good spare alternator that I'll put in on Sat. and see what happens then.
Pete
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Thanks guys - as I said before, this setup has worked for years and years without incident. I'm wondering what could have caused my problem the other day that has now seemed to be fixed.
Could it have something to do with the fact that during last nights drive my alternator stopped charging? Air in the system?
Could it have something to do with the fact that during last nights drive my alternator stopped charging? Air in the system?
#13
If the belt is the problem, you'd see it when looking at it. It would have to be really quite loose (and would probably be squealing badly) to be not driving things properly. Poke at it. If it deflects more than half an inch or so on the long side, tighten it up. A slipping belt could definitely cause problems.
-=Russ=-
-=Russ=-
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Originally Posted by jon88se
My car has been this way since the day I bought it in 1997 - before and after the turbo swap without any problems. Here is a pic of the engine bay so you can get an idea of what I'm talking about:
That is EXACTLY like mine. It IS STOCK.
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Originally Posted by xtremeskier97
That is EXACTLY like mine. It IS STOCK.
And your radiator connects directly to the overflow bottle with a restrictor in that line, correct?
I just want to make sure we're talking about the same exact thing because I thought this setup was stock as well.
What year/model is your car?
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I've never seen that configuration before, and I've seen all the various factory configurations. If it's stock, then it's news to me.
Still, that "restrictor" is likely the problem. I assume that it is a check valve which serves the same purpose as a pressure cap.
Still, that "restrictor" is likely the problem. I assume that it is a check valve which serves the same purpose as a pressure cap.
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Originally Posted by Karack
you can see what i am talking about in this picture of my car.
notice the extra pressure cap assembly to the left of the coolant reservoir?
notice the extra pressure cap assembly to the left of the coolant reservoir?
I'll call mazda and get the t-stat housing with a pressure cap and overflow outlet and connect it correctly. I would need a t-stat housing from what year? Anyone know the part #?
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Originally Posted by jon88se
Ok, so you have ONE cap on the thermostat housing that is UNSPRUNG, correct?
And your radiator connects directly to the overflow bottle with a restrictor in that line, correct?
I just want to make sure we're talking about the same exact thing because I thought this setup was stock as well.
What year/model is your car?
And your radiator connects directly to the overflow bottle with a restrictor in that line, correct?
I just want to make sure we're talking about the same exact thing because I thought this setup was stock as well.
What year/model is your car?
Ill verify when I get home this evening and let you know, though I am almost POSITIVE that it is EXACTLY the same.