I just replaced both headgaskets had heads surfaced, replaced water pump, thermostat, fan bracket, timing belt on a 91 toyota 4runner with a 3vze engine and now when I drive it starts to get hot and overheats. What could be causing this? I dont think its the radiator or cap I can see water flowing. I'm thinking about changing the thermostat again. Any help? The reason I replaced all this was because the head gasket blew and then it overheated and filled the exaust with antifreeze.

 

Did you do the work yourself? I've heard of quite a few cases where the HG's were put on wrong (upside down or on the wrong head), thus blocking the coolant flow.

 

Yes I did the work and I know for a fact that they were put on right I got the gasket set from engnbldr.

 

Ok, good. It's possible that your new t-stat is faulty. Before spending money on another one, just take it out and run the engine with no t-stat for a while and see what happens.

Is it running rough? If you didn't get the timing set right, it will overheat. You said that you had coolant in the exhaust, perhaps your cat is clogged with the stuff.

How 'bout your egr system. Did you make any modifcations to it? That system helps with engine temp.

The only other thing I can think of is a possible problem with your engine fan.

 

Its not running rough I can run the engine sitting in the driveway for 20 minutes at 2500rpm no problem the temp stays where it is supposed to but when I go down the road after 10 minutes it starts to get hot. I'm thinking the rad has restricted water flow or the kragen theromstat is faulty. All the coolent that was in the exaust is now gone it burnt up in a cloud of white smoke for 20minutes. Didnt mess with the egr. How do you tell if the fan is faulty?

 

It very well could be your radiator. My dads 97 454 suburban was getting hot when towing horses on back roads, and the tranny showed warm around town. The radiator looked good, but looks were deceiving. He had is changed and now his tranny never even shows warm unless he is at hwy speeds on a LONG hill, or has a trailer behind. Somethimes around town it warms up a little, but then right back to cold. His engine stays much cooler when towing also.

The other thing you might want to replace is the o2 sensor, they dont like getting wet.

 

Agreed, sounds like a radiator problem. But as CL suggested, check off the simple, cheap stuff first. See if you can borrow an infrared thermometer and see if you can find any inconsistant spots in the body of the radiator. Of course, check for mud or build up of leaves. Maybe try a reverse flush. Good luck.

 

It's likely the radiator isn't filled all the way. When I did my timing belt, same thing happened. I coul swear it was full because I could see the coolant flowing, but it wasn't. Is there coolant in the overflow? Try pouring more in until it overflows the rad cap. Also, could be air trapped in the system. I hear those "water wetter" additives help.

 

I just thought of another thing. If your mixture is greather than 50:50 coolant:water it doesnt dissipate heat as well as a 50:50 mix. If you think you have too much coolant add some distilled water to it and see if that might help.