2JZ over heating problems help please??

[dirtyJZ]

Any ideas apprecitated

Ok I have a overheating problem with my stock 2JZ-GTE that has taken me 2 months and i cannot sort out. had a few mechanics and the tunners do not know why either.

Motor was sposed to be a runner ended up having a blown head gasket do not know the history of it. Importer was a wanker and send me a head gasket and bolts and told me to fix myself. It is stock besides the usuals exhaust fmic g3 link wide band o2 sensor etc.. It can be driven around town and on the open road and not overheatd with a 52mm 3 core radiator. The standard radiator gets up to 95degrees in these conditions.
under boost 10psi the temp sky rockets and you have to back off and let it cool down takes about 2minutes to get it to 100-110degrees with the big radiator in, had two huge fans (tuners fans) on the dyno and could only do two power runs then we took it off.

Now i had the head crack tested checked for straightness machined etc.. i overhauld it on top of that as well while it was off. The block was straight replaced heeadgasket and no more water in the oil. So far ive driven it about 1000kms

What ive checked....

Headgasket was identical and had all holes pressed out etc...
Does not loose water
It does not blow water into the overflow when getting hot etc... (shouldnt be exhaust gasses in the coolent)
Radiator is not blocked
It is not leaning out
Do not think it is a air lock driven the car nearly 1000kms now and it bubbled out over flow a little bit as i did not bleed cooling system properly first time, when it first got warm then stooped. Then took it for a drive
Pretty sure it not radiator cap tried 3.
Pressure tested cooling system
Brand new Thermostate and it does open at 84 Degrees
What pump genuine toyota 5000kms old off my 1JZ bearings are good and impellor has not rubbed etc.. pretty sure it cannot move back to lose efficiency
The timing is correct, and doesnt miss or anything stupid. all new belt etc..
Prettys sure it not ecu temp sensor as water temp gauge reads same and fluke thermography gun reads within a degree of the temp in radiator.
No cylinders as best i can see with gun are hotter than others.
1huge Fan on front and small on back both on and running in right directions.
Heater core is not blocked and the non return works. Turnning on the heater does not drop temp mind you mkiii supra heaters are shit. Heater plumed in or by passed doesn't change anything
All the coolent lines are clean around block as checked when i put on.
No kinked lines
Using coolent not water as well

I have flushed out the cooling system as i noticted it had a bit of sludge in it after realising the head gasket was blown, drove it only 3km didnt even get hot at that stage (didnt thrash it) heaps of brown merky water came out, and water was discusting and left the hose running through it for a hour ( I know this will not remove sludge if there is some at bottom of the water galleries) Used nulon cooling system flush as well cheap but heaps brown merky water came out.

I havn't removed the thermostate was going to do it this w.e as i have pulled it down again to check everything for a third time so cambelt etc.. water pump off etc...

Posted this on a few fourms
Sorry this is so long but i think this is everything any help very frustrated and just want to go to the track again :s help

Josh

 

[thedave925]

You are aware the purpose of coolant is to regulate the boiling and freezing points of the water that the coolant is diluting?
Water is about the best medium for heat transfer, whereas coolant by itself doesn't do a very good job.
50/50 water to coolant mix is good.
Zerex G-05 coolant is good if you can't get the red toyota coolant.
Throw in 2 bottles of redline's WaterWetter for bubble prevention under boost.

Other things to look into is how fresh the catalytic converter is, and the color of the spark plugs.
BTW, what weight oil are you running?

You don't have a dead bird restricting airflow to the radiator right??? Them things can do a number :] lol

 

[dirtyJZ]

Cheers for the responce mate and yes fully understand that about coolent but coolent is also good as it doesnt turn into wet steam as fast as water does, coolent is always a 50/50 mix when i mix it for that car not a 2/3 and 1/3 and is prestone anti-freeze. The thing is it does not bubble/ boil enough to come out the radiator cap when under boost, and the radiator (relief valve) appears to be fine as it has relieved before with this motor due to air locks (i think as i did not bleed the cooling system initally) the first time and then stop and i have swapped with a few as well.
Oil is a 15w 40 castrol oil neverhad any probs before and has always been real good to me. Spark plugs got replaced straight after dyno as they were shot and no cat do not need that in this country. Haha if it was a dead bird i would be stocked then i could fix it

Will go price up redlines stuff as there oil is amazing and might be better for in the long run.

 

[Spaniard]

Oil at 15w-40 is stupid. Check out the lubrication section here on SM for proper oil for your 2JZ. 15w-40 is too thick. Also, tuner fans? Really? Whats the CFM flow rate. If it's below 3400 cfm then thats your problem right there. Stock fan flow's 3400 cfm.

 

[Jostar]

Or you might be lifting the head,,,,, My friend had that problem, Car ran great without boost, as soon as it started boosting the temps skyrocketed....

 

[89turbotoy]

I am on board with the fans what cfm? and also agree you shouldn't run 15w-40 oil