overheating already

[angeno]

So, after the winter that seemed it would never end it's just now starting to warm up here in the Northeast. Driving my VX this afternoon I exited the highway and was stopped at a traffic light with my A/C running and the ambient temperature in the upper 70s. All of a sudden I happen to notice my engine temp gauge creeping up to the H line. OH SHUZBUDT!, I say to myself, not again!!?

Seems I spent most of last summer running down every possible cause for engine overheating and remedying the problems one by one. New radiator, new hoses, new fan clutch, Mobil 1 synthetic, and so it went. I finally hoped/thought/prayed that I would have solved the problem. Apparently, not the case.

My VX is in remarkably pristine condition top to bottom (see attached photos), but it does have almost 150K on the clock. Maybe the engine is simply close to the end of its useful life? I'm frustrated. I do not want to stop driving my VX. Ever. But I also need to have a modicum of utility and reliability, yes even with the A/C on, and even in the heat of the summer.

Any thoughts / ideas would be sincerely welcomed. Thanks folks. :yesgray:http://www.vehicross.info/gallery/data/500/thumbs/photo-2.JPG (http://www.vehicross.info/gallery/showphoto.php?photo=22364)

[tom4bren]

It could be a slight leak in your head gasket. Check to make sure you don't have oil in your anti-freeze, anti-freeze in your oil, & also check to see if you have a slight fuel smell to your anti-freeze.

That's what the problem with Boy's Ebony ended up being & the only symptoms were the overheating issue after driving for about 15 min ... & the fuel smell in the radiator.

[Triathlete]

Did you change the thermostat? Also an overheating transmission will cause yourtemp to rise.

[vxcp]

Is the new fan / fan clutch the updated design?

[Y33TREKker]

Have you checked your coolant level in the radiator and made sure that the system is burped of any excess air pockets? Generally, the thermostat is located at about the highest level in the system of coolant passages, and if the coolant in the specific passage where the thermostat is located is a little low (meaning that it can in essence be percolating), it will read the higher coolant AND air temp and not the relatively lower temp if it were just coolant that was there.

Sometimes it's the simple stuff, and given how finicky our transmissions can be about having the proper fluid level, why should we expect that our coolant systems will be any different?

You could also always take a few manual temp readings using an infrared heat gun to see if the coolant is actually getting as hot as the temp gauge says it is.

[LittleBeast]

What type of radiator did you get?

[angeno]

Thanks, just checked. No dice. On to the next potential cause, I guess. <sigh>



It could be a slight leak in your head gasket. Check to make sure you don't have oil in your anti-freeze, anti-freeze in your oil, & also check to see if you have a slight fuel smell to your anti-freeze.

That's what the problem with Boy's Ebony ended up being & the only symptoms were the overheating issue after driving for about 15 min ... & the fuel smell in the radiator.

[angeno]

Did you change the thermostat? Also an overheating transmission will cause yourtemp to rise.

Thanks, changed the thermostat when I changed the radiator. Don't remember exactly the model #, but actually, got the idea from this forum and went with the recommended slightly higher efficiency one that "supposedly" offered enhanced cooling.

[angeno]

Thanks for the thoughtful suggest. But actually, here's how I know it's not that. When the VX starts overheating, usually the first sign is the fact that it's power is WAY DOWN meaning that it accelerates MUCH more slowly and only then do I notice that the temp gauge is creeping up toward the H line. So it's not just merely an erroneous temperature reading. The engine is definitely running too hot (when this happens). But all I have to do to make it go back to normal is turn off the A/C and just drive at a steady rate i.e. not under load for a while. Then the problem corrects itself.

But this is not the way I want to spend the rest of my natural life, by walking on egg shells so I don't cause my VX to overheat. That's why I thought perhaps that the engine might just be old and tired and in need of either a rebuild or replacement. Not possible?


Have you checked your coolant level in the radiator and made sure that the system is burped of any excess air pockets? Generally, the thermostat is located at about the highest level in the system of coolant passages, and if the coolant in the specific passage where the thermostat is located is a little low (meaning that it can in essence be percolating), it will read the higher coolant AND air temp and not the relatively lower temp if it were just coolant that was there.

Sometimes it's the simple stuff, and given how finicky our transmissions can be about having the proper fluid level, why should we expect that our coolant systems will be any different?

You could also always take a few manual temp readings using an infrared heat gun to see if the coolant is actually getting as hot as the temp gauge says it is.

[Triathlete]

Maybe your ac compressor is seizing up or has bad bearings putting extra strain on the engine?

[LittleBeast]

#1 - your radiator might be too small, I replaced with an aftermarket one and it was too small to do the job, went to a Ron Davis radiator and fixed the problem.

#2 - fan clutch, did you replace with a factory one? If so you needed new fan blades as well correct? If you still have the old fan, new aftermarket clutches are available and do a great job.

#3 - something on the belt like the A/C Compressor might be worn out, but it could also be the tensioner acting up with higher load from A/C unit as well.

[ohiovx]

Make sure the electric fan is working in front of the condenser. If your only getting hot sitting still or in traffic, it's not the radiator or cooling system. The fans are only needed when your going under about 30mph. If it goes down when you turn your ac off I bet the electric fan isn't working. The high side pressure in the system is getting WAY up there causing a lot of heat in front of the radiator& the mechanical fan is pulling that really hot air through the radiator. The high pressures also make the compressor work harder.

[LittleBeast]

Oh yeah I put an additional electric fan on the A/C condenser, it could be that your electric condenser fan is bad, this is a common occurance. Check your AC condenser electric fan, and I would add another one next to it.

[angeno]

Some terrific advice folks. Thanks so much! I'll follow up and keep you posted. :)

[eternal21]

Does it overheat only when the a/c is running?

[angeno]

Does it overheat only when the a/c is running?

Yes, this is correct. It only overheats when the A/C is on and usually when the VX is under load, such as after driving on the highway and sitting at a traffic light.

[eternal21]

So you can strike the thermostat, radiator, etc. I'm betting that the issue is w/the a/c compressor/bearing. Working through the same issue myself for the past 2 years. After upgrading everything in the coolant system (Ron Davis all alum racing radiator, thermo, tensioner pulley, Ron Davis dual 12" electric fans in custom shroud) + cutting a huge vent hole in the hood), the problem persists. The only thing I didn't do was the water pump, and others that have this issue *have* done the water pump and it still continues to overheat, so I don't think that is the issue. I've been reading some old posts recently about how others have had a similar issue, and after changing all of these things, still nothing. On a side note, my tensioner pulley shredded itself late last year, and I thought that this might have been the issue, but as 2 weekends ago showed, me, I was wrong *lol*.

Someone in one of the threads I bookmarked on my other computer mentioned the same issue, and the ac compressor being tested and drawing a heavier than normal load on the engine. I'll know more in about a week or so, as I'm going to have my A/C tested in the next couple days, and most likely have the compressor replaced. (Most likely will do the expansion valve and dryer while I'm at it, since the system will be open.) AC compressor is the only thing left that draws on the system when the AC is on. And like you, I could be sitting in 100 degree temp for an hour, and everything is just fine (which rules out heat soaking, too). As *soon* as the a/c comes on, in 5 mins, it wants to overheat. ONLY WHEN THE AC IS TURNED ON.

Interesting that we both have '99 Ebony VXs, too. You, sir, have excellent taste!