qualityrockola
Member
I'd say 85% chance its the thermostat, 10% chance water pump, 5% chance headgasket. A thermostat costs what? $10-$15 max? give that a try first, and its easy to replace.
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overheating and I searched need advice
- Thread starter neodriftout
- Start date
neodriftout
Member
ok I think it is 99% chance it is the t-stat and here is why.
I did some research on the net today and found out that around 98 car manufacturers started bypassing the t-stat when it is cold and placing at at the lower radiator hose, the reasoning for it is so people who live in cold climates can A: warm the car up faster and B: get hot air out of the vents faster too. How it works it coolant is circulated from the block to the heater core bypassing the radiator all together until the t-stat opens (when the car is sufficiently warm) therefore heating and warming up faster. so if the t-stat is stuck closed coolant will only run from the heater to the engine and not get cooled UNTIL you turn on you heat activating the fan and subsequently cooling the coolant yet making you hot. This could also happen with the t-stat stuck open due to the coolant not staying in the radiator long enough for the temp to actually drop.
Reason why i think it is not the head gasket. If the head gasket where bad to the point it leak that bad I would think my coolant system would get over pressurized due to the leak and create boil over ( which didnt happen for the long ride i had with the heater on. Then there is the fact that the temps go down when the heater is on which probably would not happen if the gasket was bad
I cant wait till saturday so i can change the t-stat and put this thread to rest, with my luck however it will be the headgasket.
Does any of this make sense?
I did some research on the net today and found out that around 98 car manufacturers started bypassing the t-stat when it is cold and placing at at the lower radiator hose, the reasoning for it is so people who live in cold climates can A: warm the car up faster and B: get hot air out of the vents faster too. How it works it coolant is circulated from the block to the heater core bypassing the radiator all together until the t-stat opens (when the car is sufficiently warm) therefore heating and warming up faster. so if the t-stat is stuck closed coolant will only run from the heater to the engine and not get cooled UNTIL you turn on you heat activating the fan and subsequently cooling the coolant yet making you hot. This could also happen with the t-stat stuck open due to the coolant not staying in the radiator long enough for the temp to actually drop.
Reason why i think it is not the head gasket. If the head gasket where bad to the point it leak that bad I would think my coolant system would get over pressurized due to the leak and create boil over ( which didnt happen for the long ride i had with the heater on. Then there is the fact that the temps go down when the heater is on which probably would not happen if the gasket was bad
I cant wait till saturday so i can change the t-stat and put this thread to rest, with my luck however it will be the headgasket.
Does any of this make sense?
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- MP5T / 944
Hughes412 said:
Coolant flows to the heater core regardless of the position of the dial. There is no "Magic Water Valve" just the fan does not blow over it so no heat comes in until you ask for heat, then the air is diverted over the core and heats the car.
I'm thinking it's not the thermostat, but it is such an easy thing to check that it should be your first start.
Does this happen every time you drive?
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- MP5T / 944
The headgasket leak situation causes a pocket of "Air" to collect in the upper part of the water jacket. The head is the highest part of the engine, as you drive, some of the air will burp out and into the rest of the system, but most will stay there. It will get hotter and hotter until you basically have steam in the head, then it spikes and when you look down you say "OH s***"
neodriftout
Member
Yes water always flows through the heater core, the only thing that happens when you flip that switch is the fan for the heater turns on.
Soooo why would it be the head gasket? How would turning on a fan bleed are from the system while I am driving. Thats one magical fan, to be able to fix head gaskets almost instantly.
Just to make sure everyone heard this part a will repeat it.
The car drove perfect for 2 years in the florida heat until now. With the heater on I drove easily 15 minutes with NO PROBLEMS with out heater I could only drive about a mile before she got hot. Just for the hell of it when I was close to home I turned off the heat to see what would happen and the car got hot immediately so I turned the heat back on and it cooled down just as fast.
When I take out the t-stat should I take pics of th percedure and post them here? would that be helpful to anyone??
Soooo why would it be the head gasket? How would turning on a fan bleed are from the system while I am driving. Thats one magical fan, to be able to fix head gaskets almost instantly.
Just to make sure everyone heard this part a will repeat it.
The car drove perfect for 2 years in the florida heat until now. With the heater on I drove easily 15 minutes with NO PROBLEMS with out heater I could only drive about a mile before she got hot. Just for the hell of it when I was close to home I turned off the heat to see what would happen and the car got hot immediately so I turned the heat back on and it cooled down just as fast.
When I take out the t-stat should I take pics of th percedure and post them here? would that be helpful to anyone??
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- 2003 Black Mica MazdaSpeed Protege
My first guess would be thermostat, plus it's an easy check/fix.
Question - have you heard any of squealing that most waterpumps make on the way to their demise? Granted, not all of them do that, but it is usually a symptom of them going bad.
Question - have you heard any of squealing that most waterpumps make on the way to their demise? Granted, not all of them do that, but it is usually a symptom of them going bad.
Purrfectangel
Member
- :
- 2002 Protege 5
neodriftout said:
I heard it the first time and that's why I said waterpump and not thermo. It may have driven fine for two years but that's no reason to think it wouldn't be the pump.
So I'll ask again, how many km's on your rig, seriously, and when was the last time you had a timing belt change if you ever had one done? Because both are generally done at the same time.
My mom's 01 bug did the same thing as yours, was driving fine then one day started to overheat, she got maybe a km or two and had to pull over, she called me, I told her to blast the heater till she got it home and not to drive it anymore. Two different mechanics and the dealership said it was the oil pump because her oil light was coming on and I said no, waterpump, and I was right...she had no warning either..
By all means change your thermo first because it is the easiest and cheapest but I wouldn't be surprised if it doesn't fix the problem.
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neodriftout
Member
I just like to know what the problem is before I fix it so I tried to get as much info on this particular problem as I could, I dont like the "replace everything till it is fixed" route cuase it can get expensive as well as a waste of time.
So with what I know which is (There are no leaks in the system and for some reason the car runs fine when the heat is on)
So with that knowledge I did some reasearch and this is what I came up with.
Its not the water pump because turning the heat on wouldn't matter because you can have a million radiators and the biggest fans, it wont mean squat if your coolant isn't flowing.
So bad water pump = overheat all the time.
Blown head gasket = overheat no matter what.
stuck t-state means cold coolant doesnt reach the block however the water pump is moving coolant through the heater core back to the motor which doesnt cool the motor down UNTIL the heater fan comes off cooling the coolant transferring heat which cools the block down.
If anyone can explain to me why the water pumps works or flows with the heat on or why the the head gasket does not cause over heating with the heater on I am willing to here your hypothesis.
Dont get me wrong ANYTHING can happen and I can be wrong but a pray for t-stat
Saturday is the day I will take some pics and post them when all is said and done
So with what I know which is (There are no leaks in the system and for some reason the car runs fine when the heat is on)
So with that knowledge I did some reasearch and this is what I came up with.
Its not the water pump because turning the heat on wouldn't matter because you can have a million radiators and the biggest fans, it wont mean squat if your coolant isn't flowing.
So bad water pump = overheat all the time.
Blown head gasket = overheat no matter what.
stuck t-state means cold coolant doesnt reach the block however the water pump is moving coolant through the heater core back to the motor which doesnt cool the motor down UNTIL the heater fan comes off cooling the coolant transferring heat which cools the block down.
If anyone can explain to me why the water pumps works or flows with the heat on or why the the head gasket does not cause over heating with the heater on I am willing to here your hypothesis.
Dont get me wrong ANYTHING can happen and I can be wrong but a pray for t-stat
Saturday is the day I will take some pics and post them when all is said and done
qualityrockola
Member
that is sound reasoning and I agree with you. but as the devil's advocate perhaps the water pump is moving enough water to cool the car with the heater on, but not enough to cool with just the radiator. The heater core is enough to put it over the edge, so to speak. it could be the same story for a headgasket leak. the radiator might not have the umph to cool it down alone, but in conjuction with the heater, maybe it can.
neodriftout
Member
That is what I am worried about but we will see tomorrow
neodriftout
Member
Ok car is fixed and yes it was the t-stat. I was going to take pics but it was a straight foward deal that only took about 30 minuts to do.
It was four bolts total. I was going to take pics but there was nothing to really see. The t-stat looked fine but I guess looks can be deceiving,
The only thing i recommend is getting the factory part. The one I got from pep boys didnt come with the rubber seal around the thermostat, the old one was still usable so I reused it.
CASE CLOSED!!!!!
It was four bolts total. I was going to take pics but there was nothing to really see. The t-stat looked fine but I guess looks can be deceiving,
The only thing i recommend is getting the factory part. The one I got from pep boys didnt come with the rubber seal around the thermostat, the old one was still usable so I reused it.
CASE CLOSED!!!!!
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- MP5T / 944
Two bolts and 2 L of coolant to fix...
I had this same problem. The thermostat was bad. By running the heat, it allowed me to drive about 30-45 min to the mazda dealership. By the time I got there though, it was just about ready to blow. The coolant resevoir was bouncing around it was so hot.
I was on vacation in FL. It was a bummer to the vacation, but I got it fixed and went on my way.
I was on vacation in FL. It was a bummer to the vacation, but I got it fixed and went on my way.
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- 2003 Black Mica MazdaSpeed Protege
Yay for the cheap and easy fix!
I had this exact problem.. except I got stuck in inbetween texas an florida for a day or so trying to get it fixed.. there were no mechanics to be found, and I had no tools.. so 5-6 hours with the heater full blast got me back to florida and I fixed it there.
All that for a $7 part and about half an hour of trying to get to an annoyingly placed nut
Kyle
All that for a $7 part and about half an hour of trying to get to an annoyingly placed nut
Kyle
MazdaSpeed626
Member
- :
- Mazda 626 1998 5spd 2.0l FSDE
I don't know why anyone hasn't suggested this.....but have you checked to see if your cooling fan is switching on? You could have a bad relay/fan motor. I honestly don't think its the T-stat, cuz if it were stuck closed, it wouldn't only over heat when the car is sitting still....it would overheat when the car was moving too. If its stuck open, the car would never fully warm up to operating temp.
The reason i say this is cause didn't you say this is only happening when the car is sitting still? i.e. no air flowing through the radiator = (flame)
The reason i say this is cause didn't you say this is only happening when the car is sitting still? i.e. no air flowing through the radiator = (flame)
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- 03' silver dx
I have a question though. My car just started overheating today and it only overheated when I was driving. Like anytime I sat still at a light the temp gauge would go down. I luckily got home and checked under the hood and all I saw was a big leak like the coolant had bubbled out of the reservoir or something. Checked all the rubber tubing coming from the radiator and didn't see any leaks at all. Strangest part was when I shut the car off and watched the coolant reservoir go from full all the way down to empty. I refilled it and watched it for a few more minutes and it didn't go down anymore. I hope the problem with mine is only the thermostat too though.