this might be a stupid question... but how accurate is your temp gauge? ive heard of them being inaccurate as hell, i know mine is. with mine, it hangs out in the middle, when i jump on the gas to pass someone, it goes up to the overheating mark, then as soon as the rpms die down, it goes back to the middle. maybe thats your problem?

 

Not really sure how accurate it is. Would that cause it to overheat? Or would it just show a high temp? I know for a fact its overheating. But might be something to look into. Thanks

 

Well I had the EXACT same problem you do when I first bought my 88. I had the radiator flushed, rebuilt and re sealed, that seemed to fix the problem. Then it started happening again. So it turns out it was my heater core, it was leaking and that caused my coolant to disappear.

 

That too makes sense. Let me ask you this. While driving did you ever hear a gurggling sound behind the dash. Not constant just occasionally while driving? I have heard this quite a few times. Sounded sort of like a quite boiling or bubbling in the dash.

This trail and error is driving my wife nuts!!

I in fact am enjoying rebuilding this beauty slowly but surely.

 

you might have mentioned this somewhere but are you losing coolant. if you are constantly having to replace coolant but you can't see it leaking anywhere then its a head gasket problem. the factory gauge could have a bad sensor or something too. go to an auto parts store and buy a cheap aftermarket water temp gauge and that will give you a more accurate reading.

 

Yeah I had to constantly replace coolant. Does it neccassarily mean a HG?

 

Or it could just be leaking out somewhere, sometimes they tend to leak while you drive (under pressure) but then stop when you shut down. Get under the truck and look for drips while its hot or as it warms up. My Taurus has a leak (water pump gasket) while it warms up on a cold morning, but then stops.

 

OK time for a update.

Kinda wish now I had payed for shipping Still haven't gotten my radiator. My buddy is hung up at the coast and will not be able to get up here until next week but could be later than that. So I went a step further. I talked to a friend that works at a mechanic shop and he is picking up the old raidaitor to check it out for. If its not bad at least I can make a little money. If not then I will try to trouble shoot one more time then I guess I will bite the bullet at look to replacing the HG. I will keep you guys posted and I appreciate the support and information you guys have given me so far. You guys really know how to bring in a friend.

 

I have an 88 4-Runner (22Re Engine) and finally found the gurgling sound source. This is more evident when you initially turn on the heat (which lets the coolant go through the Heat Exchanger under the dash). In my vehicle,it was air in the system from one of the hoses under the EFI section. I took it in after about 2 months when I finally had a large coolant leak in that section (I had recently put in the 3 main new hoses). The mechanic fixed it and all is fine. He did say that there are several other hoses under this section which he would need to do a bigger job to get to - so, they will eventually go. Hope I am not too late in replying and this helps!