Check your FAN clutch, I had a similar problem last summer. car would just over heat for no reason. checked everything and it ended up being the fan clutch, either rebuild it or replace it. I had mine rebuilt and it has worked fine ever since. good luck

 

Yeah, that's a typo -- my fault. I was definitely parked for 40 minutes after driving for 20 minutes.

I've got some bad news for you -- if that temp gauge goes into the red, you've already done major damage, usually in the form of a blown head gasket. To me, it's "starting" to over heat when the needle begins to creep upward from it's normal running temp. I'm not going to argue symantics with you -- you call it over heating where ever the heck you want.

Really? What does your temperature gauge measure? Mine actually moves up when the temps get hotter and drops when it gets cooler. You must have one 'o dem kUstIM gauges.

There's one reason that I'm continuing to debate this issue with you -- you're giving the original poster of this topic some bad, and potentially dangerous advice. He's over heating. If I'm wrong, and there really is no problem, he spends a few bucks to get it diagnosed to get some piece of mind. If you're wrong and he continues to drive around thinking it's "normal" for his vehicle to over heat in summer conditions while running the A/C in traffic you could cost him an engine, or worse -- his vehicle ends up becoming a Car-BQ.

Bottom line for this discussion between you and me -- I'm driving every day in the summer in more sever conditions than you'll see in 10 years of driving in the north east. My vehicle is two years older, and with 134,000 miles on it, I'm guessing I have more miles than you, too. I'm driving around every day in bumper-to-bumper traffic for at least 45 minutes with the A/C running full blast.

You're pulled over on the side of the road waiting for your ride to cool down and continuing the rest of your drive without A/C.

You lose.

Ed

 

Just thought I would toss my 2 cents worth in. I live in Houston, TX were we have BOTH high temps 95-100 deg and VERY high humidity 75-90% and you desert people are whining about 30 and 40%. I drive my 01 4Runner in bumper to bumper traffic for over an hour in the afternoon 5 times a week and I have never had my temp get over 210 (measured with an OBDII reader). Another often overlooked cause of overheating is debris in the fins of the condenser and radiator. Overtime I've found bugs get parts stuck in between the fins and its not very visible but does cut down on the heat dissipation of the radiator greatly. As far as idling I've sat in my 4Runner on an extra job several times for almost 8 hrs during the day with A/C on and never had a problem with overheating. The only time I have had a vehicle that overheated in the Houston climate and traffic was a Nissan and it was due to a clogged radiator.

 

TheFog, post some data from your ODBII.

 

4RUNR, I do not have ODBII on my old truck would you accept digital images from a watch and a laser thermometer?
I know that you a wrong, I also know any major auto manufacture would be out of their mind not to take a basic issue of cooling with or without ac on into consideration while engineering an auto. Well, I guess I could see some US auto manufactures doing that, but not my beloved Toyota.
I would also like to mention that your smugness about imperial data is annoying. There are multiple and critical mistakes in your methodology and analysis. However, I do not plan on arguing the merits of these tests as premise doesn't even pass common sense.

 

like someone posted above...FAN CLUTCH!! FAN CLUTCH!! FAN CLUTCH!!

Robinhood150, i think your problem is almost certainly the fan clutch. i had the exact same symptoms when i first bought my truck (used). (btw, if i turned on the heat full blast, it brought the temp back down to normal.) it was the fan clutch.

amir904, i would also bet that the fan clutch is your problem.

one way to test the fan clutch is to tie a piece of kite string to the fan and to the wall of your engine compartment. the string should be able to hold the fan from turning at idle when the engine is cold, but not when it is hot.

another test is just to listen to it. a properly working fan clutch (at least on a 22RE) makes a pretty loud whirring sound when engaged. you should hear that sound at idle once your engine gets hot (but not when your engine is cold).

here are a couple of links on testing and rebuilding the fan clutch:

http://www.barneymc.com/toy_root/techneek/fan_clch.htm

http://www.off-road.com/~estegall/te...fanclutch.html

(my fan clutch housing was kinda corroded, so i ended up buying a new one from toyota and then replacing the fluid in my old one and keeping it as a trail spare.)