Drove back to College this last weekend and lost most heat halfway home.
I also noticed when I would pull off the freeway and the temp guage skyrockets. I'd have to drive around at about 25 for a while and itd drop quickly back to average. When I pulled over after it hit normal temp the overflow bottle was full and overflowing and I could hear boiling in the radiator (engine off) and slight vibration at the cap to back up the boiling. I topped it off when I finally got home and when it cooled down it sucked the overflow bottle dry!?! I topped it off at the radiator and ran it to get any bubbles out and it kept bubbling for like 30 min. Am I looking at a head gasket issue with the bubbles?

 

Sounds like a head gasket.

 

Very likely the HG is going. Are you getting billowing clouds of steam out the exhaust as you are driving down the road?

If you have the 5vz-fe, here are two very good threads on re-building top end:
http://www.ultimateyota.com/index.ph...6&topic=2241.0
http://www.ultimateyota.com/index.ph...6&topic=7462.0

 

I agree with a possible head gasket going. The coolant is disappearing somewhere leaving the radiator mostly dry which is fine while you're at highway speeds but it will overheat when you stop. The constant bubbling you're getting out of the cap is more than likely exhaust gases. They will not always throw billowing clouds of steam out of the exhaust but if it does that is a good indication of head gasket trouble, it depends on how bad the leak is. At this point I would either buy a block tester, which will tell you if there are exhaust gases coming out of the radiator, or take it to a shop for diagnosis. I know you can get the block tester w/fluid at Napa, I got mine off the snap-on truck last year for about $60. Good luck to you!

 

Yea.... thats what I was afraid of. I do believe the boilovers of the overflow container have been caused by exhaust in the water. Is there any reason I can't wait till summer to tear into this? The overheating only happens if I park it directly off the freeway and it still gets 21 mpg on the highway so I may just use it till I get my summer job on. Save another overheat, will running it with a bad HG hurt anything?

 

With the overheating, you are likely going to warp the heads (possibly the block) or develop a crack in the heads if you keep driving it and letting it overheat. The additives in the coolant cause rapid bearing wear also.

It may be worth your time to call the local dealer with your VIN and see if there is any HG recall repair available to you.

 

have you tryed replaceing you rad cap. just a few bucks there might try it befor you just into head gaskets