VJ RC51

You CAN NOT use the stock n/a radiator. I always ran my 1JZ with no thermostat, so it typically ran kinda cool, especially on the highway causing me to get bad fuel miledge. Well i put one in finally yesterday, runs fine, off boost. If you run on alot of boost it will overheat (not boil over, but boil into the tank). I had to pull the thermostat out this morning so i could drive it. Lesson learned: you can not use the stock n/a sc300 radiator, just doesn't cool enough when you get on boost and heat up the turbos (hot turbos = hotter water since they are water cooled). Koyo or aftermarket "stock" all metal supra TT rad is in the near future!

soardrft

iTrader: (8)

wow are you running 11psi or higher. i had my stock radiator on my last sc and it was fine at 12psi. maybe motor problems? just something worth looking into.

VJ RC51

Im running whatever PSI stock is, no boost gauge. The radiator is 1992 stock with 150k miles on it, tranny cooler built in being used (no additional cooler). Motor runs beautiful. I had a Jeep cherokee do the same thing in the past.. would run hot if you tow'd something or went 80mph on the highway with the AC on, radiator too small. A $110 replacement fixed that.

Maybe i just have a blocked rad..

EDIT: i dunno tho, my other stock sc300 with no overdrive will do the same dam thing if you go on the highway over 80mph.. Makes it run just a tad too warm, not enough cooling power with these things.

soardrft

iTrader: (8)

no boost guage? hmmm do u have a turbo timer? if not look at buying the blitz that has the boost guage on it. also how are your hoses? do a radiator flush. simple things before you invest and find out your investment was not worth it. good luck

VJ RC51

I run straight water with wetter, no antifreezzz. Its been flushed. All the hoses are new. The rad is old, has the famous leak or 2 and both the main top neck and overflow neck are broken and it looks like corrooded crap. Maybe its just not a swap issue, maybe its just my issue lol.

no boost gauge, no turbo timer. Its a bone stock swap, just looks pretty.

Kaiser

iTrader: (1)

MIne works just fine and I live in the desert. I haven't turned up the boost yet though.

soardrft

iTrader: (8)

cheap way to see what's wrong:
try stop leak.
put anti-freeeze.
if it looks messed up but a new radiator, but keep in mind the cheap was can help a great deal.

VJ RC51

Its weird cause it runs colddddddddd with no theromostat, so cold it goes into closed loop on the highway and it runs rich, but if i run it hard with a thermostat and idle it down, it will still boil into the overflow tank. If i drive it normally with the thermostat, its fine. Only when i get into alot of boost and shut the the engine down even if i idle it down, will it boil into the tank, with the thermostat in. Water is crystal clear, no oil or anything.. headgasket is fine. No water leaks anywhere except a drop or 2 around the neck sometimes

AME_VIP

iTrader: (2)

VJ good info there. But dude, get a boost gauge

VJ RC51

LOL why? I don't have a boost controller. i can put that $60 towards better things I figure if i blow a wastegate line, ill hit fuet cut

This info might be not accurate for brand new n/a radiators, but if yours is original and high mile like mine, its probably not going to work. Well works with no thermostat, but then u gotta worry about cold weather and the engine running crappy at highway speeds.

vipsoarer

id start looking else where for why its running odd. modern motors are meant to be run with a thermostat for a reason, or any one with one built into the block for that matter. it may be an old hot rodder trick (in actuality a myth). id diagnose whats wrong with it first before you start modifying how the system runs. my buddy doesnt run a t-stat but then again when you have a methanol burning catipillar turbo'd corvette that runs 6.5's id say you dont need one....

VJ RC51

What problem? Problem is my 13yo 150kmi stock radiator isnt cooling my 1jzgte. Its an old hotrodder trick also to pull out thermostat if you cant get enough cooling. There is no problem with the motor.

Gibenstein

Ok so your saying that off boost w/ thermostat you run fine but when you get into boost you start overheating ? But when you run w/o thermostat with boost you run fine ? How old is the thermostat ?

VJ RC51

Yep. Thermostat was brand new stant from autozone. Did it with the OEM one too, i thought it was bad and took it out and had none for over a month now. Ran fine when it was hot out, but now since its in the 50s, is causing me to go closed loop on the highway and i need to put something in there ASAP.

Gibenstein

You could try the TRD thermostat, it is supposed to open at lower temps (I believe it opens at 160) compared to OEM.