Using Air-Con Causes Car To Run Hot

[ClareQuilty]

My old Ke-70 runs cool enough during normal weather, and there is no problem using air-conditioning in this kind of weather (though I never do as it isn't very hot out). I mostly drive the car at night anyway.

But during April and May I find it necessary to use the air-con, and alas during the day and particularly in urban stop-and-go traffic, using the air causes the car to run quite hot. Even out on the highway you can't use the air for more than about 30 minute before the temp starts to creep up. I've never overheated the car, but I usually have to turn off the air-con.

This air conditioning was no doubt added by the dealer back in the early 1980s rather than by the factory, so perhaps the cooling system was never quite adequate for it. Since that time the original owners replaced the original 1300cc engine with a new used 993cc engine, I suspect because of overheating it, though I don't know for sure.

I'm wondering if putting in a bigger radiator would be enough to solve this problem, or whether some other alterations would be necessary. I might consider it if a larger used radiator were very cheap - has anyone had occasion to install used radiators in Thailand on old Toyotas?

[VocalNeal]

Claire,

I can't say there should be but usually the is an additional fan that come on when the A/C is switched on or a relay that switches on the existing fan. Maybe you have an extra fan and it is not working or the extra relay is not working. Listen to see if a or the fan comes on when you switch on the A/C.

Heat transfer is based on the difference in temperature so if the outside temperature goes up the heat transfer drops so the coolant temperature has to rise to keep up as long as it doesn't go into the red it will be OK. If it goes from say 50% on the gauge to 75 -80% it is still OK.

You could have the radiator back flushed and some new coolant added if you are feeling flush (sic)

[transam]

Claire,

I can't say there should be but usually the is an additional fan that come on when the A/C is switched on or a relay that switches on the existing fan. Maybe you have an extra fan and it is not working or the extra relay is not working. Listen to see if a or the fan comes on when you switch on the A/C.

Heat transfer is based on the difference in temperature so if the outside temperature goes up the heat transfer drops so the coolant temperature has to rise to keep up as long as it doesn't go into the red it will be OK. If it goes from say 50% on the gauge to 75 -80% it is still OK.

You could have the radiator back flushed and some new coolant added if you are feeling flush (sic)

Correct, ''most'' rides fitted with aircon have an electric back up fan to service the condenser rad.

[Shurup]

As it's an older model, I bet there are no electric fans but perhaps just one common direct drive fan for both Rad and Condenser.

I would start with flushing (!! not just replacing the fluid) the cooling system.

Another possibility is, because it's a really small engine (1L), it didn't have a lot of power to start with and now it's getting older too (from 1980) so you have to push it harder to get the same out of it as it was 2 decades ago. Pushing harder will make it run hotter and the AC will add some load which maybe just enough to let it start overheating.

If you haven't done any tuning on it recently, take it to a mechanic, maybe the carb needs adjustments (running too lean can cause overheating), maybe the cylinders pressure aren't what they should be (shot compression rings), maybe the timing is out, maybe a bunch of other things... It could be as simple as a faulty waterpump...

How often do you floor it to lets say trying to keep your speed coming up a hill or even going straight on a freeway?

A little tuning wouldn't hurt and would be beneficial if you're planing to keep this car for a while.

If all of the above is done and it's still overheating, then the AC compressor may be on it's way, or/and the cooling system isn't efficient. Replacing a rad with a bigger one should help a bit.

P.S. Just thought about it - first thing you really have to do is to check your rad isn't plugged. Blast it with a pressurewasher to be sure. I do a lot of off-roading and you would be amused to see how many troubles a dirty rad can give you, even if it doesn't LOOK dirty!

[Naam]

i'm getting my coat and hat!

[Shurup]

i'm getting my coat and hat!

Must be that growth on your forehead!

[BSJ]

Not trying to be mean, but isn't it time you realised your not an old car person.....and you should be upgrading to something new.

Your current vehicle needs a tinkerer owner with a toolbox full of tools and a bit of mechanical knowledge.

[VocalNeal]

Not trying to be mean, but isn't it time you realised your not an old car person.....and you should be upgrading to something new.

Your current vehicle needs a tinkerer owner with a toolbox full of tools and a bit of mechanical knowledge.

I think he has a tinkerer just down the street. It is a lack of lets call it mechanical sympathy that is lacking.

I think it a bit arrogant to suggest that just because someone doesn't understand the inner workings of something that they shouldn't have one. How many people have air conditioning in their house , or own a computer or..or..and have no idea how or why they work.

You are suggesting that because his dog is old he should have it put down?

[BSJ]

Not trying to be mean, but isn't it time you realised your not an old car person.....and you should be upgrading to something new.

Your current vehicle needs a tinkerer owner with a toolbox full of tools and a bit of mechanical knowledge.

I think he has a tinkerer just down the street. It is a lack of lets call it mechanical sympathy that is lacking.

I think it a bit arrogant to suggest that just because someone doesn't understand the inner workings of something that they shouldn't have one. How many people have air conditioning in their house , or own a computer or..or..and have no idea how or why they work.

You are suggesting that because his dog is old he should have it put down?

"a bit arrogant" no, I don't do things in 'bits'.

It makes sense. If you have something that is continually giving problems why keep it? Get rid of the old one and get a new A/C, get a new computer, get a new dog.

But get the vet to put the dog to sleep. It's much quicker and cleaner than using an axe.

[VocalNeal]

"a bit arrogant" no, I don't do things in 'bits'.

I said a bit because you were not "trying"to be mean". If you don't do things in bits why where you only trying?

While your comment was well intended, if gets pleasure from buying older vehicles so be it. You may ignore his posts.

[ClareQuilty]

How often do you floor it to lets say trying to keep your speed coming up a hill or even going straight on a freeway?

No, I never floor the car, ever. All my life I've been one of those guys who drives like an egg is under the accelerator pedal.

In point of fact, the amazing thing is that if you're not in a hurry, the little one liter motor seems adequate to getting around - true, a lot of people pass me, but I pass some trucks and things no problem.

Not trying to be mean, but isn't it time you realised your not an old car person.....and you should be upgrading to something new.

New? Good lord man, the reason I have a 27 year old car is due to poverty - new is not an option.

And after all, compared to the average person (particularly in Thailand) I know quite a lot about cars and their mechanicals.

Edited April 20, 2012 by ClareQuilty