vinter98

Hello!

i hope anyone recognise this problem.

i have a 1995 4 runner 3vze who gets overheated.

i just changed my headgasket to mls type, and machined the heads and also pressure tested them. i also changed the waterpump and termostat.

the problem i have after this operation is that the engine gets overheated and boil......if i dismantle the termostat it works great and not boil over, but i donīt get so much heat in the vehicle (as it should be if the termostat was open)

i have tested if there is any exhausts in the cooling system, but none.
no water or oil in wrong system.

from the begining the engine was weak and was just running on 3 cyl, i didnīt have any problem with heating before.


any suggestions?

Chuck Manners

i had the same problem with my truck i tried replacing the thermastat several times flushing the cooling system too. heres what u should try when u notice the temp rising above normal running temp move ur temp. selector for the heater to the cold position. then after ur temp gos back down u can put ur heat back on. i dont know if this wil help u but give it a try and let me know if it works.

TNRabbit

Have you ever used any type of stop-leak product in the coolant? If so, your radiator is clogged up.

hairbear65

Assuming you put it back together correctly....You may have air pockets in the cooling system. You can jack the front of the truck up and the pockets should work there way out...or a quick drive before she heats up will also work....not sayin this is your problem, but I've seen a few of the HG jobs I've done act this way.

Good luck

hairbear65

Also...test the thermostat is a pot on the stove with a thermometer to confirm it is working properly...just cause it's new don't assume it works.

Th

bunkerhillbadas

Vinter98 here is something to think about on engine block is to take temp gun check around block when engine gets to normal op temp if hotter at corners of block there a threaded plug on engine block if so take it out back flush system this flushes water jacket ports if you have not allready done this you will get some increadible muk out of the block possible you have some clogging that normal flushing will not get rid I opened radiator hose and connected air to block port also, something to thow in the mix good luck

limon32

This sounds like a typical air lock problem. I would suggest searching on here on that topic, I know there are a couple good write ups...

bunkerhillbadas

would a air lock problem in a closed loop system be solved by jacking rig up giving high point for air to escape behind clogged water jacket yeh just keep jaking rig up rode that horse

limon32

I have no idea what you mean by that, but several threads on this site suggest parking up hill or similar, jacking the front isn't going to raise the front of the engine more than a few degrees which isn't going to accomplish anything.

Another common place air-locks cause problems on this engine is in the u shaped hose at the back of the engine near the temp sensors. Though that won't cause an overheating issue, it does provide another location to burp the system.

bunkerhillbadas

ok sooner or later that air lock will break free parked on a hill 1day maybe a week if it doesnt maybe the air is locked.

vinter98

now i have tried to get the air out from the water but with no sucess....
i will take the cylinderheads of and see whatīs wrong.

i know for fact that it isnīt any circulation and now when iīm driving in faster speed without termostat it get too hot sometimes. maybe there is a crack who opens when it gets really hot.

we will see, i will take it appart soon.

thanks for all suggestions and i will tell you what the problem was (hopfully)