Hi,
I'm new to the forum and just bought a 95 4runner. It is a 3.0 automatic with 128,000 miles. I was used to driving an acura legend, so I am noticing a slight differance in power. It runs great, but when I'm in stop and go trafic or out wheeling and going slow, it starts to overheat. 95% of the time, the temp is dead center on the gauge and everything is fine, but the 5% of the time when it starts heating up is a pain. I can turn on the heater, and it cools down OK, especially if I can speed up to over 35mph. Another thing that it does is as soon as it starts heating up (I'm not talking about over heating, just the needle reading ANYTHING over 1/2 on the gauge, the A/C compressor and fan turn off. I live in Tucson AZ, and this will be a problem very soon. The coolant is fresh looking and full, I checked the fan clutch and it seems pretty tight. I figure it's not the thermostat, becuase usally the temp is regulated fine. I bought a new radiator, figuring it couldn't hurt, and it was only $129. I figure by the time I took off the old one to have it flow tested and flushed the system and put new red stuff in it, it would suck to have to do it again very soon if the old radiator was OK, then died in a year. Is there any thing else I should be looking for when I take the old radiator out? The timing belt and water pump were changed 15k ago. I just need this thing to run cool and keep me cold this summer. Any help would be really great.

 

do you have air in the system at all?

try parking on an incline so that your rad cap is the highest point of the motor. Take the cap off and let it run for awhile. You should see the coolant moving. as It goes down give it more coolant. It should burp out some air..That is what I did to mine when I could hear bubbles coming through my heater core and it fixed the problem.

 

If you're draining the system to replace the rad I would put in a new thermostat anyway, they're cheap and easy to replace at that point. Also make sure you give the engine and heater core a good flush while you're doing the job.

Overheating at low speeds could be from a water pump not pumping enough coolant, but if it's new that shouldn't be happening. Or a bad fan clutch not blowing enough air. If replacing the rad and thermostat and the flush don't fix the problem I would replace the fan clutch, or look into a Tauras fan swap.

 

all good ideas,but before spending any more money,take a regular garden hose & clean out the fins of the radiator & condensor,turn engine off spary from inside engine compartment out toward front grille,may have debris in it causing not to have enough air flow over radiator & condensor,if ac pressure gets to high compressor will shut off

 

Sounds like a air flow problem through the radiator at slow road speeds. Take a good look at the clutch fan. When the eng. is cold it should free wheel, when the eng. is fully warmed up it should engage and not free wheel very much.
The lack of air flow through the A/C condenser will increase the high side pressure to where a pressure switch will shut down the system as a safety measure.

 

Thanks for all the good input. I read about the Taurus Fan swap and liked the sound of that. Since I already have a new radiator I think I will do the following. Please let me know if I'm out of sequence or missining anything.
1. flush out cooling system
2. Remove old radiator
3. Check old hoses, replace if needed
3. Install fan and controller on new radiator
4. replace thermostat with 180* thermostat
5. fill up system with some water wetter and 70/30 water/coolant mix Toyota red
6. Park on incline and get all air out of system
7. Be happy it doesn't over heat any more
Am I missing anything?
Thanks

 

I would use 50/50 water/coolant, you'll get better corrosion protection