Ok i just bought a 93 GS300. Now i am no new to the 2jz engine but i am new to the GS model. Well when i bought this car a few days ago it overheated on and i checked it and all it seemed to be was the radiator cap. so i replaced it. ok i arrived home and i decided to check it again and when i pulled it off the damn thing was broken in half. so i bought another one and i decided to to do a tune up on it and i checked the cap again and it was broken in half. WTF this has never happend to me before. now i drove this car home from a 200 mile trip to pick it up it over heated on me because the fluid all came out of the filler neck where the cap goes. (60 miles into the trip) it hasnt overheated since but I've replaced the stupid cap three times. any idea what could be wrong and is there any where i can buy a powersteering pressure hose that isnt the dealer?

 

How do you break a cap in half? It sounds physically impossible.

 

Did the inside of the cap seperate form the top Housing.
Do you have an aftermarket Radiator ?
Have you checked to see if your fluid is even passing through the system?
IS the radiator Resivoir tank bubbleing when you turn the car off?
Does it stay cool when you are at Speed ?
Have you checked your OIL
If you answer we might be able to help more

 

It stays perfectly cool even with the ac on. It did seperate in half from the top housing. and it doesn't bubble after I turn it off. I don't think it has an after market radiator it looks stock. The caps work fine and doesnt leak or anything until i decide to take it off after the first time after buying it, thats when it seperates from the top housing. I did a block test and the fluid never turned yellow (to make sure there was no exhaust gases leaking into my cooling system). so I am stumped the only thing I can think of is that the neck where the cap mounts and screws on is worn, which would mean i need a new radiator. I also just did an oil change so it full on castrol synthetic and fluids are moving through the system when i did the block test you could clearly see the fluids moving (i had to remove 3 inches of fluid for the test )

 

flush all ur fluids

 

on a side note, my tem is normal, no overheating BUT after I turn the car off my reservoir bubbles and you can smell like if the car is overheating... any ideas on that one?

 

So i had all these symptoms as well. I got a replacement Clutchfor my fan, No aftermarket upgrade just the stock replacement and the problems of Bubbleing / Overheating went away after about 1 day of driving. the fan will still feel a little stiff if the clutch goes out so dont think that it is not worn out. If i were you guy's i would look for a Aftermarket electric fan or something that you can salvage that would increase the flow throught the radiator, I think someone on the CL Forum mentioned a electric Soarer Fan that was a little better.
The Broken Cap says that your system reached the point at where it blew the Cap apart ,this also happened to me with my replacement radiator cap for the new Radiator i got. I went to autozone and got the same Pressure of cap for the new radiator ( It was a square Cap and has not had any issues{i think it was for a ford** I can take a pic if you need.
The Bubble!!!
That damn bubbleing plagued me for about 6 months before i figured that the clutch was dead in my fan. This was fixed and the issue of overheating was curred.
The other Issue would be a Fractured or Blown Head gasket that is releasing Hot presurized air and steamed Radiator Fluid back through the system creating Vapor lock and the Bubble in your resivoir. a leakdown test will let you know if your f****d and need head work or new gasket.

 

please do. The way i figure it is that the caps i have been buying from the CST brand are really cheaply made atleast the ones for the GS. I was thinking of buying the Stant brand and seeing how they work, but my car isn't overheating as a matter of fact it runs fine.