My coworker friend's 92 4runner 3.0 just overheated this morning warming up b4 heading out the door.

We turned engine on for a few mins, then i heard the idle dropped to normal. I went in to turn on the hot defrost, but there was no heat coming out from the fan air the whole time we were scrapping ice off the windsheild. She went in again 2 mins later, seeing that the temp needle was at max hot! So we shut it right away.

Not knowing much about 3.0, I'm guess it's either stuck thermostat or maybe commonly known blown headgasket ? Expansion tank was filled w/ coolant to max during the process too.

ps, tomorrow i will check the coolant & oil.

Any suggestion?

I was thinking about the cjm's taco engine conversion today. If it's a blown headgasket, would it be worth-while to put in 1 of those engine vs fixing the headgasket? it's a mint 92 4runner w/ almost no rust, would be a shame to junk it...

It's your friend's dime, and would depend on how badly he needs to get it back on the road. Finding a complete 3.4 donor might take some time.

If doing the HG's, then remember I've posted a link for the TSB for torquing the 3.0 head bolts.

In the meanwhile, compression and leakdown will tell the story. Sparkplugs would be white with the presence of coolant.

Is the oil like a milkshake? Will do the same thing a 22R does; it's still water mixing with oil.

So, it turns out that the coolant was so low in the rad from yesterday that I couldn't even see coolant in it. (no wonder why it overheated!) I pourred the coolant in the expansion tank back to the rad, then started it up, it ran like normal w/ normal coolant temp, & heat from hot air too. I also heard the thermostat clicked & saw coolant moving as well.

So the question is why the coolant all went to the expansion tank to begin with...?

btw, maybe we should find out whether the toyota 3.0 headgasket recall (& the steering relay) is still on-going...

It sounds like the head gasket went, pressurized the cooling system and shot the coolant into the overflow.
The reason it was pegged hot was because the sensor was reading steam and not liquid... it probably didn't overheat.

And a 3.4 swap would be awesome!

Head gasket campaign has been over with for quite a long time. Don't know about the steering, unless that's a safety recall.

Never hurts to ask, but am pretty certain yer done with the HG campaign if it didn't go in for it in the first place.

I would agree that it didn't get overheated yesterday morning w/in those 2-3 mins idling. But it turned out it did overheated last september during a drive through keremeos. Bad enough that they had to put coolant in the rad to fill it up. Too bad they just bought it in august (luckily "only" for 2K), so not much history on that engine problem. Rad is in decent shape too.

We'll drive it as is now, & see if it'll happen again.

If the HG is bad, the cheapest route would be to drop in a used 3.0 if not capable/wanting to do the head work themselves.

A 3.4 swap would be nice, but given how cheap the 3rd gen Runners go for here in CA anyways(often sub $6k), it might not be worth doing to a stock Runner, unless they are going to get into wheeling.