Coolant boiling out overflow [Archive] - Forum


View Full Version : Coolant boiling out overflow

03-01-2006, 09:47 AM
Yesterday air temperature was near 80 degrees and I noticed my low coolant light come on and the temperature creeping up past the second notch past 200 when I was stuck in traffic. I got to a gas station and the reservoir was empty and apparently the coolant boiled out. Drove home with the heater on full blast and picked up a new reservior cap and a gallon of Dexcool along the way.

Replaced the cap, filled it up with dexcool and bled the system. I let it idle in the driveway for some time and watched it as the temperature creeped up to 3 ticks over 200 which is approximately 218 deggres from my estimate. At this point, the coolant began boiling again and shooting out the reservoir overflow tube.

Took it to a mechanic this morning and it didn't misbehave at all. On his scanner, the coolant never went over 200 degrees. Went ahead and drove into work and the temp never went over 1 tick the entire way.

I think I may have a intermittant cooling fan problem, but should the coolant be boiling out at only 3 ticks over 200 degrees? Seems to me like the system isn't getting pressurized properly. There are no external leaks and I've had it flushed, thermostat changed and LIM gaskets replaced about a year ago. Never have any high temperature problems when the car is moving fast.

Any ideas???

03-01-2006, 11:07 AM
FWIW - a pressurized system raises the boiling point, but given enough heat, the anti-freeze/water mixture will eventually boil. Might I suggest, as you have mentioned, that your cooling fan motors be checked. I had an incident in an older model that (unknown to me) the fans had a high and a low speed - my problem was that the fan/fans were not going into the high speed, thus it would overheat at low speeds or while idling yet would run at 'normal' temps while moving.
Hope this helps, good luck - be cautious of running the engine too long at higher temps, you're asking for engine problems down the road.

03-01-2006, 11:17 AM
Did you replace the relays to fix the problem or what? Yes, mine is a 2000 GT and I do believe that the fans are dual speed. At the mechanic, they were running on low speed but maybe occasionally they are not bumping up to high speed and then there is too much heat load and the coolant boils.

03-01-2006, 11:23 AM
If memory is correct, <g> - the mechanic changed the fan motors - I think he said that it was fortunate that the fan and fan motor were two different assemblies - for some models, it's all one piece - I don't recall a problem with any relays, but that's a reasonable component to check (shouldn't be difficult/expensive, and it would eliminate that as a cause)

03-01-2006, 12:31 PM
It was probably the cap.. happens

03-01-2006, 12:35 PM
Replacing the cap is the first thing I did.

03-18-2006, 11:41 PM
the same thing happened to my '01. i changed the cap and the thermostat. still the coolant would boil out the overflow tube. so i had the lower intake gasket replaced because i noticed it wet down there, and now its fine. i've been reading that a lot of the lower intake manifold gaskets were giving a lot of GA owners proplems.

03-19-2006, 06:16 AM
It was probably the cap.. happens

That's what happened to me. I didn't have the cap tightened all the way.

05-11-2006, 03:47 PM
Just thought i should ask yall for help...I got a '97 GAGT. I had to pull over 3 times today cuz the car overheated. started yesterday with this crap.The reservoir is not empty (duh), but wat happens is that the coolant is boiling up inside. As if it doesnt wanna go and cool the engine....believe it or not I just recently (thru the searching) found out about that messed up LIM gasket, can it be that? im guessing it is, it will be replaced no matter what but any other ideas? extremely frustrating pulling over waiting for the car to cool in this Miami weather and then it just overheats again in a few minutes.

05-11-2006, 04:05 PM
I would say you have a plugged radiator. My 78 Chrysler was boiling coolant out and it turned out it was a plugged radiator.

05-11-2006, 04:53 PM
^if ure talking to me, my radiator was flushed a few months ago...guess it wont hurt to do it again though.

05-11-2006, 05:00 PM
...just to car has been running idle for about 25 mins as i type this..its reading a little over 3/4 on the temp gauge...(yea i let it cool all the way down first) theres smoke coming out of the boiling like b4 though...this car is pissing me off!

05-12-2006, 07:42 AM
Sometimes a flush does not remove all of the deposits. You may also want to flush out the engine block as well.

Other than that, try testing your thermostat to see if it is opening correctly. Take it out and put it in some hot (180+ degree) water. Usually when the coolant boils over, it means there is a restriction somewhere in the system.

05-13-2006, 01:39 PM
thx for the help guys..i just got a new my car running idle right now, it started sucking in coolant as soon as i put it on so hopefully that was it..easy fix..ill test it on the road later......and yea the thermostat was next on my list if the cap didnt fix it so we'll see...thx again...

05-13-2006, 01:41 PM
don't forget to bleed it.

05-15-2006, 08:47 AM
hi all, is the DEXCOOL coolant red or orange in colour?

Last wk, after I drove my 2000 GA SE1 for 35mins and parked the car in the garage for 30 mins, I saw a big puddle of orange/red liquid on the floor. It was a very big puddle of liquid that stretches from my right tyre to the left tyre!

is this from the coolant? can the coolant vent out because of overheating? or can it be due to the cap not tightened? but i do not have the engine overheating and low coolant light coming on....
and also if the venting is due to untightened cap, how to explain this? I dont understand why a loose cap can cause the coolant to vent out from the tube... :)

can I cfm that this is not from the auto transmission fluid? I cant seem to chk the ATF fluid level...

sorry for sooo many qns.... I am just too afraid that during one of my road trips, my car is standed on the highway! :)
thnx alot guys!

05-17-2006, 04:27 AM
anyone can pls help?

05-17-2006, 10:39 PM
Sounds like you have a coolant leak. Dexcool is orange in color. ATF is red. As for where the leak is coming from could be anyone's guess. First place I would look is your radiator hoses. If they are dry then check the water pump. The internal seals in the pump are known to fail over time, causing it to leak from the bottom vent opening.

05-20-2006, 12:29 AM
i tightened my cap and pour in abt 1 gallon of tap water.
so far no problems....

can I jus leave it as it is, ie, diluted coolant, or do I need to flush the whole system and top with DEXCOOL??

09-11-2007, 09:53 PM
sorry to bring back an old thread, but i keep reading in threads that regard adding coolant to"bleed system", how do i do that in a 97. i think in the next gen after mine there was a bleeder screw, but i cant find one for mine, and i dont see one in my haynes. can anyone give me any ideas on how to blled, cause i think i have trapped air. so far the only way i see for me is to leave car running with cap off and heat on high and wait 10-5 minutes.

GA Nightmare
10-17-2008, 11:47 AM
Bringing back an old thread...

Anyway, i noticed that my low coolant light has been coming on AGAIN lately. Last time this happened so regularly, I had to replace the lower intake gasket @ 42,000 miles. My 1999 GAGT now has 118,000miles. I did noticed that the leaking of coolant has been coming from the overflow tank its self. I noticed two little cracks in the tanks, on the right side closest to the fender. I guess I'm buying myself a new overflow tank off eBay.

How do you check if the cooling fans are coming on correctly??

gagt Mechanic
10-17-2008, 03:37 PM
have your car on and wait for it to get warm. if you have a diag scanner, you can command them on, but this dosent always mean they work when they should. when you turn on your ac, your high speed fan should turn on.
If you have a cracked surge tank your eng may not reach the right temp to turn them on without boiling over. the cooling sys needs pressure, if you remember science class, liquid under pressure will have a higher boiling point than at atmospher. thats why race cars run raidiator caps with higher psi threshold. they can run hotter without boiling the coolant.