Okay, I have the 87 4runner, 22re 5sp.
oversized (3 row) radiator, small 1/8" hole drilled in my t-stat, newer water pump, belts, hoses etc. runs perfect.
I recently had a shop do the r-134 conversion to my a/c. under normal driving conditions the temp stays normal with a/c on. yesterday i did some stop-and-go driving on a very hot day. my temp gauge read very hot- not overheating, but very hot. i shut off the a/c for awhile and it cooled down.
i went home checked everything and found no problems.

is there any way to make it run a little cooler? maybe put a t-stat in without a hole in it for summer and put the holy one back for winter?? electric fan??
any ideas?

thanks!

I live in OC and was out in your neck of the woods a few weeks ago (Anza Borrego) and it was 110. My '81 ran cool as a cucumber even in the sand, it's completely stock as far as the cooling is concerned. Bottom line is, something is wrong if you are getting that hot. Try adding some WaterWetter, it did wonders for my hot running streetbike. I've put it in all my vehicles just for GP. The hole in your t-stat shouldn't have a negative effect because it should be open all the way once the engine warms. Maybe it isn't? Maybe you need to burp your system? Idle with the front elevated, radiator cap off for 15 to 20 minutes. Make sure your fan is spinning when the AC is on. Maybe it is getting hot and crapping out when it's needed most.

Ok, this sounds like my old corvette... Check your Condensor. Make sure the fins are not all beat up and air passes through it easily. Maybe hose it off real well. on my corvette the condensor was so beat up it was starving the radiator of air. So I had to get a new condensor. Make sure theres nothing between the condensor and the radiator.. I found a whole page of a newspaper inbetween my corvette's condensor and rad. I think the toyotas come with a condensor fan that is a "pusher". Make sure that is working. On my 4runner the condensor fan was shot, so I removed it and the belt driven fan and put a Ford SHO electric fan on with a Flexalite fan controller box. no heating up problems... I run premixed 50/50 antifreez, 180* Tstat with a hole drilled in the flange to reduce cycling and incase of a Tstat failure it's better than nothing.

I tried running a 160 degree thermostat.The engine runs cooler but it might not be the right way for the engine sensors.I tried drilling my 180 thermostat and it runs a bit hotter than the 160.I checked the temperature with my infrared heat thermometer for a accurate reading and the reading was about 160 degree with the 160 thermostat and the drilled 180 at 165 degree.

Do you have an electric A/C condensor cooling fan? I had overheating probs aftre swapping to R134 as well, though I was using the R12 comp. It would only heat up on days above 98 with the A/C on, didn't matter if it was around town or on the highway. An A/C shop advised running a condensor fan, something about the R134 having a higher operating temp than the old R12. I decided to get rid of the R134 instead. I switched it out to Maxi Frig 12A, which runs at a less pressure than R134. Last summer I had no problem w/100+ days running A/C.

I see you mentioned 3 row radiator.....how new is it? I put my money on a marginal partially clogged radiator if it has real miles on it. 87 seems to be a popular year for clogged rads <img src="/forums/images/graemlins/kewl.gif" alt="" />

ps---got the factory shroud in place?

Have you checked the fan clutch recently?
- http://www.barneymc.com/toy_root/techneek/fan_clch.htm

It may not be locking up fully when hot. You could also refill it with a stiffer silicone oil:
- http://www.off-road.com/~estegall/tech/fanclutch/fanclutch.html

I suspect that the fan clutch is not locking up. If the clutch is working properly, you should be able to hear a noticeable increase in fan speed and noise once the engine temps begin to climb.

x3 on the fan clutch being shot. When the motor is hot you should hear the fan roaring and pulling lots of air through the radiator. If not time to replace it. One sign of a failed fan clutch is fluid on it. If the silcone fluid has leaked out then it is garbage.

rad is 3 years old same with fan clutch. no fluid leaking out. factory fan shroud in place. good flow with 50/50 mix.

no, i dont believe i have a condensor fan.... where can i get one of these??