Overheating 93 Camry

[AlaryicJude]

Hello,

I bought a used 1993 Camry wagon LE 4cyl about a year ago and a month or so after I bought it, it started having overheating issues when idling (after car was warmed up, mostly at stop lights or long waits to turn). I drove the car to Florida from North Carolina with no issues excpet a worsening of the same overheating problem when I got into town. A friend and I replaced my thermostat thinking that was the problem and it seemed fixed, for a little while, then the same issues popped up again when I got back home. I cannot remember if I always had the AC on. Knowing me I'm assuming it was mixed (sometimes the AC was on and sometimes my windows were down/no AC). Turning on the heater seemed to do nothing much in the way of getting the temperature to drop. Twice I reved the engine (with the brake on once and also once while in park) while idling and the temperature dropped drastically, though my dad told me not to continue to do this.

Today my boyfriend and I performed a radiator flush on my car and cleaned out a layer brown gunky film (almost like mud) from the middle of the reservoir. There was nothing else in the radiator fluid that looked suspicious or different. And the engine oil does not have any water in it (from what I can tell on the dipstick and the underside of the oil cap). My car does not blow white smoke upon start up, so considering all of this I'm not too worried about a blown head gasket *knock on wood*.

After we removed the initial radiator fluid, we filled the radiator and reservoir up with plain water and ran the engine for about ten mintues and the car got up to temperature and stayed put, but the cooling fans never came on. Later we ran the car filled with the radiator flush fluid and water and got the fans to come on after I turned the AC on about 5 minutes in. We left the AC on and continued to run the car for about 5 or 6 more minutes and when I checked the temp again it was at the red line for hot.

What is causing my car to now *not* overheat in plain idle but overheat with the AC on? Thanks in advance for any advice or help!

[KPARRIS-JONES]

Ok so a few things:

1. Does the Radiator fan kick (if at all) when the temperature gauge reads about half way?

2. When the engine comes off choke and settles down to idle, are all of the hoses hot and fairly hard to compress?

These engines run off a pressurised cooling system and all hoses including the heater hoses should be hot.

3. Does the heater work?

If the heater isn't kicking out hot air then you either have a blocked matrix or knackered Heater Valve. Remove the Valve and test it to see if it opens and closes properly, even if the lever moves the valve may not be moving inside. If it flows fine then you have a blocked Matrix and you will need to replace it.

4. Are there any leaks from anywhere else? Check the timing cover for the water pump.

A/C puts a little extra strain on the engine because it need to drive the compressor, the two systems shouldn't be linked.

Right now it sounds like you have faulty fan switches, so earth the fans and let them run all the time even at idle when you first start, I had to do this with my AE92 over heating.

I know how frustrating it is with the cooling system, but do your best to eliminate all of the variables. I have recently suffered water pump failure with similar problems. My AE92 kept overheating, the radiator then burst in my face. I replaced the radiator, and got it up to temperature and found my matrix was blocked, a few minutes later there was a leak from the timing cover (water pump) and it emptied the system on the garage floor. :censor:

Hope this helps,

KP

[AlaryicJude]

1. The fans do not seem to kick on at all unless the AC is also running, even when the car gets up to temp. As soon as I turn the AC on, the fans kick on.

2. I will check tomorrow morning.

3. The heater worked last winter just fine (thankfully). I will also check it tomorrow. *Note* I've been out of town (away from my car) on a job for 3-4 months this summer. I put fuel stabilzer in the full gas tank and disconnected the (almost new) Battery before I left town. When I came back, I reconnected the Battery and the thing started right up the first crank with almost no hesitation (I love Toyotas)!

4. There are no water leaks from anywhere I can tell. I do seem to have a slow oil leak and also a transmission fluid leak, but they are both rather slow, and not on my priority list right now.

If this is any help at all, I ran my car for about 15-20 minutes long before sunset (so still warm out) and just after a fresh oil change, with no AC, the temperature gague remained very steady in the middle and the fans did not kick on that I could hear (I had the hood closed).

Thanks for the advice, and I'll get back to you on the rest!

[KPARRIS-JONES]

The A/C will have it's own radiator and fan, so it sounds like your cooling fans don't work.

What you need to do is locate the Fan-Switch (it will be in a water junction), on the AE92 GTi the Fan Switch is in a water junction that rests on the gearbox which leads to the Pump and Heaters. When you find it, unplug it and turn on the ignition. The fans should kick in immediately and stay on no matter what the temperature. If they don't turn on, then your fans either aren't getting power or they are knackered.

Get back to me and tell me how it goes, I'll keep an eye on this thread for you. ;)

[AlaryicJude]

Alright, I just returned from driving the car around quite a bit and the AC seems to work just fine and the car does not overheat even at stop lights or stop signs or long waits to turn. The hoses all get hot and are hard to compress. But now the heater does not seem to be working. What is a matrix and how does it become blocked? I will check the heater valve tomorrow, as of right now I don't know what or where that is. Thanks for your help!

[AlaryicJude]

I just remembered something. The heater not working may be fuse related. I have a blown fuse somewhere as my clock and radio don't work and they previously did. My car has an aftermarket cigarette lighter/power adapter that was not installed correctly, one time when fumbling to put it back inside of the console (it doesn't fit correctly) it rubbed on something metal and created a small spark and that was when the clock went off and the radio stopped working. I will buy more fuses and check them tomorrow as well.

[KPARRIS-JONES]

No problem. I should have asked;

Is the heater control operated by a cable or is it electric? SO do you have a slider like this:

If so then check the cable too.

Best to check your fuses!

The heater matrix is a small radiator that runs off the engines heat from the cooling system, so when it gets up to temperature you turn on the heater and the Valve opens allowing the hot water to flow through the Matrix. The blower turns on to carry the heat through the vents to the cabin. Because it works off the cooling system it takes a while to get hot air when you first start in the morning. ;)

It can get blocked if you haven't kept up with coolant changes or the system somehow gets contaminated, or if you just leave it sitting which is what happened to me. You can try a system flush but it rarely works.