99 4-Runner overheating in traffic jams only

[nina]

Please help.

My '99 4-Runner heats up (per gauge) only when I am stuck in traffic jams (stop and go) and it only seems to happen in hot Texas weather. During this time it also makes a loud clanking noise (A/C on) when I accelerate.

Radiator has been cleaned and checked and is all good.

Nothing is leaking from truck.

This does not happen during cold weather.

I had the same problem last year but back then the coolant would over flow out but that was corrected once my radiator was cleaned out.

Please help!

Nina

 

[JP4RNR]

You probably have a bad thermostat and or bad fan clutch. The fan clutch is supposed to engage in hot weather and usually operates when your traveling at low speeds to pull air through the radiator. At high speeds air is forced through the radiator and the fan clutch is disengaged. In real hot weather the fan clutch may stay on for brief periods even at high speed. If your thermostat is stuck open your engine will overheat in the summer and then not run warm enough in the winter

 

[wolfgang]

Please help.

During this time it also makes a loud clanking noise (A/C on) when I accelerate.

Nina

That sounds like your compressor might be freezing up or a bearing going bad in it. Do you have an electric auxiliary fan that comes on when AC is turned on to provide additional air flow thru the radiator? It or its thermostat could be bad. The clanking is not normal.

 

[sonoranrunner]

I have the exact same problem with my 99. just bought a new koyo radiator today, going to try to put it in this weekend to see if it solves the prob. previously a new therm and fan clutch was deemed ok. i also went with a seperate hayden tranny cooler. may or may not put it in series with the stock internal cooler. undecided.... any opinions out there?? ill post the results.

 

[sonoranrunner]

40-50% blockage in radiator and narrowly averted strawberry milkshake!!! Carefully dissected with a BFH!
New Koyo radiator installed in the nick of time!
110 degrees outside.... No worries inside!