Hi,

I just bought an '89 Supra a couple months ago. The previous owner claimed to have flushed the cooling system. It runs completely fine around town and on the freeway UNTIL I reach stop and go traffic on the freeway. It then begins to overheat, and I have to blast the heater until I can get off (and in 90 degree California weather this is not pleasant!).

When I stop and open the hood after this, the coolant reservoir is jiggling like crazy and spews out coolant from a horizontal black tube that's on the top of it.

I am constantly checking to make sure the radiator and coolant reservoir are full, and I don't know what's causing this problem.

If anyone could suggest any and all possible causes, I would greatly appreciate it.

Thanks,

James

you are not going to like it
let me introduce you to the term "BHG"

it sure sounds like you have a blown head gasket "bhg"
welcome to the bhg club

rushing water sound in the dash when you first start up in morning ?

unfortunately ^ agreed

go to a mechanic you trust and get a block check done... this will tell you if you have exhaust gasses in your water... a compression check will also give you some tell tale signs...

or.. you could be really really lucky.. and have a blocked radiator or air in the system

well this might make you happy, you might want to try something as simple as changing your radiator cap. I had it this morning while delivering my newspapers same thing stop and go, and it started to overheat, i would quickly turn on the heater before it got to hot. So i figured the car runs same as always, its this humid weather that has changed, so maybe the cap is bad, and its not pressurizing the system to the point of get full cooling capability. So changed the cap, rode her up and down hills for awhile, then started to stop and go, stop and go through the neighborhoods by me, and then i just let her sit idling, cause once she started to heat up even after i turned the heat on, and she cooled down, once i turned the heater off and let it idle it would start to raise up, everything is great so far.

Yep, rushing water indeed in the morning, although I haven't had a clue where or why.

thanks guys for all the advice. I'll try the radiator cap first, then see if replaceing the whole thing helps.

What about the water pump? It's been suggested to me, so i'm just wondering if that's a potential cause too.

i wouldn't use after market stuff . costs a few extra bucks but atleast then you'll know if you used a toyota cap

is this a turbo or N/A ?
i've driven with a bhg for thousands of miles . just kept checking everything every morning an avoided heavy traffic .
even toyota told me i didn't have bhg at one point , i think they only really check compression and if that looks ok they write off the bhg idea. generally it's not like water comes gushing out
see here how thin the distance is from cylinder to water
http://www.ddmcse.com/turbo/images/bhg.JPG
you'll see the blown area this gasket had a special bite in the gasket to prevent gasket movement and it really did bite down and leave a pattern on the head and block

you also might want to look into your fan clutch too, if the clutch is not working when it is suppose to then this would also cause your car to over heat in stop and go traffic, my car is still overheating stop and go, i'm gonna change the clutch fan.