Overheating Issue - Toyota Nation Forum : Toyota Car and Truck Forums

Strum · 03-13-2010, 06:22 PM

1993 - 6 cyl.

I was sitting at a train crossing the other day and about three minutes into the wait I noticed the needle on the temp gage rising. I put the car in neutral and bumped up the rpm's a little and the needle went back down to normal running temp. I took my foot off the pedal and within a minute it started to rise again. Other than this problem, the car is running fine. If I stop at a traffic light the problem does not occur since it is usually no more than a minute at the light.

I searched some of the previous posts since overheating is not an uncommon problem, but couldn't find anything related to what I am experiencing. I'm hoping that it is just an issue with the thermostat. The car had a new radiator installed in July of last year.

I'll start with replacing the thermostat, but was wondering if there is anything else i should be looking at?

Thanks,

hill8570 · 03-13-2010, 07:43 PM

Real unlikely to be the thermostat. My money's on that hydraulic fan or the solenoid valve that routes fluid to the fan.

johnfrisco · 03-13-2010, 08:43 PM

Sounds like a problem with the Water Pump.

Strum · 03-13-2010, 08:44 PM

Quote:

Originally Posted by hill8570

Real unlikely to be the thermostat. My money's on that hydraulic fan or the solenoid valve that routes fluid to the fan.

Hmm, there's a thought. The fitting that connects to that hydraulic motor was leaking shortly after I had the radiator fixed. I replaced the seal, but had to double up the seal on one end to finally get it to stop leaking. Maybe it is leaking again - I'll check that out.

thanks,

Strum · 03-17-2010, 04:17 PM

Well, it is not the fan, it is working fine. I had no problems with the car since last Friday until tonight coming home from work. I was waiting on a truck that had the road blocked (about 2-3 minutes) I noticed as puling away that the temp was almost 1/4" from red lining. Unlike last Friday, it was difficult to get the temp to go back to normal. I attempted speeding up and it had a small effect on getting the temp back down. As I pulled in the drive, it was running between 1/2 and red line.

So is there a way of telling if it is the water pump or thermostat without a tear down and replacement?

rusty9 · 03-17-2010, 04:33 PM

what you described sounds like low coolant.

Nervous · 03-17-2010, 04:34 PM

Check the direction of fan(s) air flow. It might be reversed.
It could be water pump too, if it lost some of its blades and therefore works inefficiently especially when RPM is low. I don't know any way of checking this w/o taking it off.

Strum · 03-17-2010, 04:48 PM

I added what would amount to maybe 6 oz of coolant or less (a guess, not actually measured). I started up the car and when started it was midway between cold and running temp (almost mid point). After reaching running temp I let it run (in Park) for about 10 minutes. Stayed at running temp without any movement. I then put my foot on the gas and held it at about 1800 RPM and still maintained running temp.

Nervous, as far as the fan air flow, are you saying it could reverse itself or are you thinking incorrect installation? Another question and it may sound like a dumb one, but does the fan blow on the radiator or does it pull hot air from the radiator?

hill8570 · 03-17-2010, 05:12 PM

Quote:

Originally Posted by Strum

I added what would amount to maybe 6 oz of coolant or less (a guess, not actually measured). I started up the car and when started it was midway between cold and running temp (almost mid point). After reaching running temp I let it run (in Park) for about 10 minutes. Stayed at running temp without any movement. I then put my foot on the gas and held it at about 1800 RPM and still maintained running temp.

Nervous, as far as the fan air flow, are you saying it could reverse itself or are you thinking incorrect installation? Another question and it may sound like a dumb one, but does the fan blow on the radiator or does it pull hot air from the radiator?

"added maybe 6 oz", as in you added it through the radiator cap? How much coolant (if any) is in the reservoir?

Fan blows toward the engine (or sucks air through the radiator, depending on how you want look at it). Hard to reverse without messing with hoses.

Strum · 03-17-2010, 05:29 PM

Quote:

Originally Posted by hill8570

"added maybe 6 oz", as in you added it through the radiator cap? How much coolant (if any) is in the reservoir?

Fan blows toward the engine (or sucks air through the radiator, depending on how you want look at it). Hard to reverse without messing with hoses.

Added it to the reservoir (50/50) premix. When I got home the coolant was filling up the reservoir (not overflowing). When the engine had cooled down, the reservoir was essentially empty. I brought it up to the low line.

hill8570 · 03-17-2010, 05:33 PM

Quote:

Originally Posted by Strum

Added it to the reservoir (50/50) premix. When I got home the coolant was filling up the reservoir (not overflowing). When the engine had cooled down, the reservoir was essentially empty. I brought it up to the low line.

Wow -- that would seem to be really excessive "breathing". When's the last time you replaced your radiator caps? Are they OEM?

Strum · 03-17-2010, 05:48 PM

Quote:

Originally Posted by hill8570

Wow -- that would seem to be really excessive "breathing". When's the last time you replaced your radiator caps? Are they OEM?

Yes, OEM. When were they replaced - ??? I've had the car 7 years of which 3 years it was not on the road - got it back on the road in June of last year. Soooooooo, it has been a long time.

Edit: Thermostat was replaced in 1999 (previous owners records)

Strum · 03-17-2010, 07:24 PM

Took it out for a drive and then let it sit for a couple of minutes while in "drive", but had no issues.

Only difference from earlier is the outdoor temperature was 60 degrees earlier and it is 50 now.

johnfrisco · 03-17-2010, 07:40 PM

Quote:

Originally Posted by Strum

Took it out for a drive and then let it sit for a couple of minutes while in "drive", but had no issues.

Only difference from earlier is the outdoor temperature was 60 degrees earlier and it is 50 now.

You may have a camshaft oil leak messing with the water pump.

Nervous · 03-17-2010, 09:17 PM

Quote:

Originally Posted by Strum

Nervous, as far as the fan air flow, are you saying it could reverse itself or are you thinking incorrect installation? Another question and it may sound like a dumb one, but does the fan blow on the radiator or does it pull hot air from the radiator?

I am talking about incorrect installation. It should blow FROM the radiator TOWARD the engine. I had this problem, but with A/C fan, it blew ON the radiator (took hot air from engine and blew on rad

) Everything was fine if car moves, but once it stops A/C became crazy and basically stopped working (blew hot air). I figured this out after a couple years of ownership