Overflowing Resevoir
 

About 2 years ago a new motor was put into my Supra (7mge) and since then noticed difficult starting no matter what time of day. Also I noticed white smoke on start up after installing an aftermarket exhaust. It's possible I had this white smoke problem before with the stock exhaust, but I notice it a whole lot more frequently now. Eversince summer began about two months ago I noticed that after driving home from work (15 min on Freeway) my car would immediately spit out hot coolant from the overflow resevoir tank after turning off the engine. The weather here has been around 90-100+ and my cars thermostat reads normal right below the middle mark. I recently changed the coolant temperature sensor and my oil. I didn't notice any milky residue in the oil then or now. I'm constantly filling up my resevoir tank to the full mark almost everyday (if I drive far). What could be causing this?

bad radiator cap...its not holding the pressure.

Either that or a BHG :dunno:

when mine did that i had a BHG. i had the exactly sympyoms your are describing. but im praying for your sake its just the radiator cap oe something else.

i had sum of the same symptoms AND DROVE WITH IT. turns out my water pump was trashed and it eventually ripped open my radiator. after i fixed this i also realized my thermostat was also to blame. try replacing these..then see. thermostat was like 4$ and the water pump was 45$

try a compression test first...itll tell you whether you have a bhg or not. if you do youll replace all that stuff as you do it. if not you can replace that stuff anyway

Alright thanks for the suggestions! Will try them out as soon as possible. Oh I forgot to mention. After the white smoke started becoming very noticeable, I checked around my exhaust manifold for any coolant leaks...and there was one right behind the water pump. I noticed coolant resting on the flat surfaces of the engine as well as wetness leading to or near the water pump. I'll check that again tomorrow because I had initially believed a faulty water pump or wp gasket was the reason for this. At that time my coolant wasn't overflowing out of the resevoir tank. Perhaps my problem has gotten worse since then.

OK overflowing problem solved. New radiator cap from Toyota did the trick.

awesome....thats the best thing that could have happened. im glad it wasnt a bhg. enjoy.

Its very commonly overlooked...I guess cause most people just see it as a stopper, but they have rated pressures for a reason.

Yeah it's surprising to me because I had the radiator and cap all changed brand new a few years ago. The rubber ring on the cap does have a damaged edge and I can see a lot of rubber residue on the spring. Again thanks!