I just came back from Mount Forest visiting my Parents and when I was just outside of Elmira, I noticed that my temp guage was rising. By the time I got home, it was just under 130*c, when I shut the car off, the coolant almost overflowed the overflow bottle. It never blew anything.The fan was running all the time. I have a 160* stat in the car and I never saw it raise above 100*. This was the longest run I've done with the humid weather. Most times I am just around town. I plan on flushing the rad, but does anyone have any thoughts as to what could have been the problem?

 

Hey Kev,

What is it -- a bad weekend in KW for f-bodies ? Have you tried draining the coolant and running water through to clear air pockets ?

Do you have en electric fan ? If so is it still working ?

RP.

 

It must be I will flush my rad hopefully this week. My electric fan is working. It is a continuosly running fan, even when I first start the car.
I hope you figure out your problem before too long...

 

Your fan may be on its last legs. I've gone through 3 fan motors already in the last 5 years. The design of these fans are not brushless. Having yours continuously run would run the brushes on the fan to the end quick. Good news is its pretty cheap for these fans but I wish someone would make a brushless design that is heavy duty as well. That's a tough combo these days with the kind of heat that flows around these fans. If it wasn't doing it in the previous days which were a lot hotter and humid than the last 2 days, then my bet is the fan motor is dying.

 

well i better not drive mine for the rest of the weekend

kev even with a 160 your fan should not run all the time. after about a min to get up to temp then it should come on not before.
on long runs you should also be cooler than stop and go driveing
the fan should not be the probleme if you were on the highway driving. it will not even be on at that speed. the computer will shut it down when your speed is over 40 for more than 15 seconds or so.

do you have coolant flowing in your system? is your water pump weak? when the engine is cold take the rad cap off. start the car and see if there is coolant flowing in you sys. it may take a min for your 160 to kick in and open up to let coolant flow in the rad.

 

I have a similar problem with my GTA, I just accept it, as long as it doesn't hit the red. I have a leak somewhere though... having a hard time finding it.

My fan is practically on all the time, because thats what the performance chip does.

Remind you though... my car reaches high temps when I am in stop and go traffic (ie. Clifton Hill in Niagara Falls). When there is air coming up from the air damn, while driving, I am fine.

 

Hey Kev,
Mine has been doing the same thing on these hot, hot days. It is like it is not not getting cool enough air forced into it. It only happens if I drive it on the highway over 110km. Stop and go it sits rock solid at 100 degrees which is the stat I just put in. Below 110 km on the highway it might get up to 110 degrees but no higher but if I start to push it it climbs up to 130 real quick. It is definitely heat related as one night when it was much cooler I took it out and ran it hard on the highway and had no problems. Let me know if changing the coolant and flushing the system works for yours.
thanks
Scott

 

just a thought, and since mine is being held on by the old trusty coat hanger at the moment, have you checked the air dam that scoops air up into the rad at speed to see if maybe you left it at a speed bump somewhere? i was lucky to catch mine before it came all the way off.

any of the other ideas strike me as something that would affect city driving too, not just highway.

my $.02

 

Maybe your thermostat is shot. that would explain the pressure in your overflow. All that hot fluid has got to go somewhere. Thats what mine was, just a damn thermostat.

 

Sounds like your thermostat is the problem.
If you replace it, try drilling a couple small hopes in the outter lip of the new one. This will give a little bit of continous flow and if the problem ever happens again, it'll relieve the pressure from the rad.

 

Thermostats are designed if they fail, to remain always open, thus you'd have a hard time keeping it warm.

I think I'm the only one who doesn't seem to have a heat problem during all these hot days probably just luck but I make it a point to flush the system every year too. It'll peak at 100 C in Toronto traffic (by far the worst) but as soon as I get it moving a bit drops to around 70-80C

Air pockets don't form from heat unless there's a leak in the system. How I figure out leaks is to do a cold high rpm gun on the throttle. Since the stat is closed under that time, the pressure in the system is great and where a leak is will rear its ugly head then and there. This won't work for underpulley users since the coolant pump is underdriven. For stock pulley setups it'll work. Just pray it isn't a head gasket or you see white smoke/coolant mixing with oil.

Keeping my car cool has cost me this while in my ownership:
a new radiator, a new heater core, 3 times replaced the fan, the oddball coolant flushes, a new air dam, and a manual fan switch(no point having the fan on on the highway I figure) At this moment, I know the seal on my coolant pump is a little old, but since putting in the underdrive pulley on my crank and tossing a bit of coolant seal into the mix, I've not had a problem with leaks. I've also gone in and tightened all hoses with a screwdriver to ensure it was ready for the summer. the switch from winter to summer always wreaks havoc on the hoses so a swap of a hose from time to time may be necessary. If a hose expands/contracts a lot when revving the engine (especially the pump to rad hose) then it should be replaced immediately.

Another thing is to keep in mind the mix you put into your car. Using distilled de-ionized water will increase the min/max levels of your coolant by a lot. I go with the 70/30 mix of coolant/distilled water as I recall gives you an upper limit of 143 C and -70C or something, check the back of the coolant you buy so you get the right numbers. These numbers are the boiling and freezing points of the coolant under 15/lbs of pressure I think. So even if you had a leak, at least the boiling point is high to keep it from boiling. Using a 50/50 mix with reg water puts it like 130C boiling point and with leak depending that'll drop to 110C which is not good and will boil.

 

I think, if everything works as we're told they are designed to, we'd never have any problems.
Thermostats have been sticking closed, since the beginning of time.
It's just a possibility.

 

Only the "FailSafe's" thermostats fail open, and thats even not 100% of the time.

 

I think I will pick up a new stat when I pick up some coolant at CT. I only put the 160* stat back in Feb. I guess I should check it first.I had the car out to Conestogo this morning to go golfing. It was normal then at about 10:00am and when I came home at 3:30pm it started to heat up again. Not too hot, it didn't fill up the overflow tank or anything. It got up to about 110-120*. I will let you know what happens tomorrow.

 

The simplest way to check if the stat is working ok without taking it out is to see if fluid is passing from the rad to the manifold. Just squeeze. If no coolant is flowing at that point, it takes awhile for that hose to heat up and will be pressurized, but when flowing can be hot enough to burn hand but will squeeze somewhat, so use a glove or towel when squeezing around the stat's temp. If it failed open (which all my stats have done since the dawn of my 88 camaro) then even before its heated up, should be easy to squeeze and feel the fluid flowing through.

 

If you're thermostat has failed outright in the closed position- you would overheat in a matter of minutes- and I mean overheat to the point of blowing the rad hose off or the overflow bottle overflowing all over the engine compartment.

A few years ago I had a stuck thermostat in a 305ci Buick (i.e. a lot more open front grill area than any f-body)- middle of January and -20* weather- 15 minutes at 100km/h on highway- major problem overheating...

I would bet on air deflector or fan shroud issues, a clog in the system somewhere (when was the last time you flushed everything?), or a waterpump going bad. Anything else is pretty much irrelevant- as already mentioned, at highway speeds the fan doesn't need to operate to keep things cool.

 

Well I took the cap off and ran the engine to see if the coolant was flowing through the system. I ran it for about 5 minutes and nothing happened. The coolant was right at the top of the rad. I drove to Crappy Tire and back. After letting the car sit for awhile, I opened up the rad cap, and the coolant was down. I replaced the stat with a new one and ran the car again. I could see the coolant going through the cores. I drove to work and the temp stayed at about 90-95*. Hopefully that was the problem. I will flush the system when I change my manifold, no use having to buy coolant twice in one week( hopefully)