"Normal" overheating?

[Nomake Wan]

Today I went on a bit of a road trip to inland California where the temperatures are quite a bit higher than where I live. I was cruising along at about 75 when I noticed that the A/C wasn't blowing cold. My first thought was it lost charge, but then I remembered back on the road trip when we passed through Needles, CA the A/C shut off to save the engine.

Sure enough, my temp gauge was at about 75% high. Yikes. I backed off the throttle and cruised around 55 (much to the dismay of other drivers) to let the engine cool down.

After more driving and testing, I found that if the outside temperature is indicated as above 94 F, going above 2250 RPM causes the engine to gradually heat up past 50%. After 50% the A/C shuts off. If above 3000 RPMs the engine heats up more quickly, to where it was when I first noticed the problem.

At one point, outside temperature was indicated as 97. Not the highest I've seen (Needles was like 108 or so) but quite high. However, it perplexed me that Evos and RX-8s were going by like nothing was wrong. And didn't they drive the SVX through a desert? Isn't it supposed to be able to handle this sort of heat?

I did replace the radiator a while back. Along with it, the thermostat and water temperature sensor were replaced. Now, I did the water temp sensor myself... but my mechanic actually installed the radiator and supposedly replaced the thermostat. So I can't be positive how it was done.

Is this normal? Other cars seem to have little trouble doing 70+ in that heat... I'm wondering if there's something wrong with my cooling system, or at the very least something I could check...

Thanks for going along with my silliness.

[ensteele]

i have had my different SVXs going over that many RPMs and in that high heat without any problems. I don't know what the problem is, but it does not sound normal.

[nexus_7]

When it is supper hot here in chicago 100+ I dont have those issues. I would pull the radiator out and make sure it is clean, when I just did that with mine I found the bottom 3-4 inches was clogged with leaves and assorted other junk.

Just one mans idea.

Greg

[NiftySVX]

Sounds to me like a restricted or clogged radiator to me too. The car should be able to maintain temperature up to about 120 degrees or so, even higher if moving.

[Nomake Wan]

Thanks guys, will see if that's the case.

[kwren]

could be one of the 2 fan motors are not running to cool the radiator. if it heats up you could just stop and look to see if they are both running. They are supposed to be when the temp gets high. also that would make the air conditioner shut off because the high pressure side pressure will cut the compressor off when the pressure gets too high. Good luck.

[SSSVX]

Your coolant got lower? How does it look? Do you have bubble in the coolant reservoir? How does the engine oil look too?

Yes, if your temp gauge is 1/4 to H, stop and check, your both fans should run high speed at that moment.

Good luck.

[SVXdc]

Don't just go by the water level in the overflow reservoir — check the coolant level under the radiator cap (when the engine cools enough).

Check that the overflow hose is not clogged: Disconnect the end from the neck of the radiator, unthread it from under the radiator bracket, and drop the end of the hose below the level of the tank. The water/antifreeze should stream out freely (catch in a bucket if you want to re-use). Then you can overfill the tank a little and reattach the hose when the level drains back to the high mark.

[Nomake Wan]

The tank looks dirty or something, I can't seem to see inside it very well. But there are little drops of coolant on the cap of the tank.

Anyway, bad news. I was just out to get some late dinner and noticed that my car was overheating. It's only like 68 F outside. But whenever the car would go over about 2250 RPMs, the temp gauge would creep up. So there's definitely something wrong.

I'll get it all checked out this morning. Probably pull the radiator, clean it, then flush the whole system with new fluid, as well as check SVXdc's suggestion.

Grah, if it's not one thing...

[subarufamily]

i had a problem similar to this one on my xt-6 when driving across texas I found out i had a plugged / partially plugged radiator I would suggest that you get your radiator flushed/cleaned and make sure that both cooling fans are on with the a/c on. one fan is designed to run under normal heat load when you turn on the a/c the second one comes on for additional cooling as stated above make sure that BOTH fans are running under high heat, i live in the midwest summer days are easily 110 plus with humidity 70-100 % so it gets real hot and I have not had a problem with mine check / make sure that the thermostat was replaced properly and make sure that coolant is at least 50% antifreeze hope this help

[dcarrb]

Originally Posted by Nomake Wan

Is this normal?

Definitely not. My temp gauge actually reads a tick lower with the AC running, I figure because the cooling fans are doing their thing in earnest. August was blistering here, with many days in the high 90s to 100+, and I've had no problems. Stopped in traffic or at a drive-thru, I do keep one eye on that temp gauge.

I don't recall ever observing only one cooling fan running on my cars.

Before you go pulling the raidator, start by being sure the cooling system is properly filled. Top-off the radiator when cold, then fill the overflow reservoir. If the car still overheats you can probably rule-out low coolant as the cause. More likely, you're losing coolant due to overheating, not the other way around.

dcb

[Hocrest]

Originally Posted by dcarrb

I don't recall ever observing only one cooling fan running on my cars.

You're correct.
If working properly, both fans come on together. But they are 3-speed. Depending on Engine temp, AC, Vehicle Speed and other factors, the ECU runs them slow, med or fast.

If a car is overheating while moving it will not be because of the fans. Any consistent speed will move more air through the radiator than the fans can on their own.

[wawazat??]

Originally Posted by Nomake Wan

The tank looks dirty or something, I can't seem to see inside it very well.

Grah, if it's not one thing...

The dirty overflow tank is a bad sign. This can be a sign of a headgasket failure When mine failed, the tank was dirty and smelled terrible when the cap was removed. Same symptoms of random overheating regardless of temperature. I would recommend an exhaust gas in coolant test at a shop you trust. They can determine if there is a presence of combustion gasses in the coolant. If so, the headgasket (or gaskets) is probably blown

Figure $1500-$3000 for the job depending on the shop and whether they want to do the job or not.

[Nomake Wan]

.............

Yeah no, I don't have that kind of cash... if it ends up being the headgasket I'd be forced to sell the car...

I'll check it out...

[svxfiles]

Originally Posted by Nomake Wan

.............

Yeah no, I don't have that kind of cash... if it ends up being the headgasket I'd be forced to sell the car...

I'll check it out...

Or you could buy a used engine and install it for less.