1jz overheating..your thoughts?

[Cressid@]

Hey guys,

Single turbo conversion completed and i just converted the hydraulic waterpump to a 2jzgte item and i had some a 3mm aluminium tread plate sheet left over so i decided to make a flat aluminium shroud for my radiator and converted it to twin 12 “ thermofans with a thermoswitch in the bottom end tank of my radiator. the shroud is bascially a sheet of aluminium with two 12 inch holes cut out.

Now on sat nite was my first drive out. While driving to the city and back. I pulled over to fill up and noticed coolant leaking down. Popped the hood and i could feel the water boiling in the top radiator hose and the overflow bottle full and pissing out.

Scared the crap out of me so i quickly got some cable out and hard wired the fans in constantly to drive home. When I got home no more water coming out of the overflow bottle but the radiator was very hot.

The gauge in the car shows normal, my thermostat is new, the thermoswitch (85degrees – 80degrees) is working because i can hear the thermofans coming on and off.

Now ive come down to two conclusions, my twin 12 “ thermofans ( they are no name ebay items) even though are new are rubbish and are not drawing enough air and cooling the water down fast enough or maybe the shroud is acting like a heater and keeping the radiator hot.

What do you guys think?

[Valkyrie]

Is your car overheating at idle?

Is you car overheating ONLY above ~40km/h?

These questions will provide you with different things to check.

My car RA60/1JZ takes over 2 hours to bleed after a coolant change. Has yours been bleed correctly?

You are using Toyota red coolant?

[allencr]

i could feel the water boiling in the top radiator hose and the overflow bottle full and pissing out.
The gauge in the car shows normal
i can hear the thermofans coming on and off.

Blown head gasket.
Bad gauge.
Didn't top it off after initial fill & startup.

[Rhyno]

the shroud is bascially a sheet of aluminium with two 12 inch holes cut out.

Now on sat nite was my first drive out. While driving to the city and back. I pulled over to fill up and noticed coolant leaking down. Popped the hood and i could feel the water boiling in the top radiator hose and the overflow bottle full and pissing out.

The gauge in the car shows normal, my thermostat is new, the thermoswitch (85degrees – 80degrees) is working because i can hear the thermofans coming on and off.

What do you guys think?

Hey mate,

The shroud you have made would be limiting the effectiveness of your radiatior. Look at any standard set up and you will set that the cowl/shroud is designed so that all of the coil has air flowing over it. Also if you have a FMIC as well, then you have compounded the problem, as you are blocking the air flow before and after your radiatior. P.S. How does the AC work? Ok? Or N/A...

What are the ratings of the fans? Anything will help: Voltage, amps, watts etc etc

Was water coming from anywhere else? Just the overflow? How is the oil? Milky or black? You may have not blown your HG...

Kind Regards,

Ryan

[Cressid@]

yesterday i drive around abit say 30mins drive, mind you in western sydney yesterday it was hot as..but the fans were both still wired on constantly

it didnt overheat and i didnt see any water coming out of the overflow bottle.

when i filled her up i used red toyota coolant but only had a litre of coolant to water. i know its no way near enough but i wanted to see how she ran before buying a 4l pack. Just to make sure there are no leaks etc.
i fired her up for the first time after the conversion and let her sit with the radiator cap open, i saw alot of bubbles come up and waited till the thermostat open and i saw the coolant flowing. It wasnt overheating at idle.Ive been checking daily and kept topping it up

It was just on sat nite from the city home.

any ideas now?

[Bananaman]

Tested the thermostat?

[Rhyno]

Now on sat nite was my first drive out. While driving to the city and back. I pulled over to fill up and noticed coolant leaking down. Popped the hood and i could feel the water boiling in the top radiator hose and the overflow bottle full and pissing out.

What do you guys think?

So its only occuring under "spirted" driving conditions?

[Cressid@]

yeah thermostat is brand new and is working correctly. I didnt use the air cond much but tested it yesterday for abit and its not as cold as before.But remember im running the fans both constantly at the moment as im scared its going to overheat if i go back to the thermoswitch.

thats the only place water was coming out and i looked under the oil cap and no milky residue which i was happy to see

this is the thermofan i bought off ebay. it just says POWERFULL MOTOR @ 16OWATT haha


http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT

ryhno - it does have the jzx81 fmic and on sat nite..i wouldnt even call it even spirited driving..i seriously was just taking it easy

man im getting worried..maybe i should take the shroud i made off and just bolt the fan to the radiator?

[madmont]

this is the thermofan i bought off ebay. it just says POWERFULL MOTOR @ 16OWATT haha


http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT

I bought a couple of fans of him about 17 months ago . Were supposed to be 50mm thick . Not really strong either. Did not like it when I sent them back in disgust and gave him some negative rep. The ones I later got from Supercheap were far superior. Some people do not know how to use a rule to measure things

[Rhyno]

Sounds like you havent "popped" your motor so to speak...

It says 1650 cfm in the description...

Hmmn can you remove the 3mm plate, cable tie your fans (some how, just for a test) and go for a short drive around the block?

Im thinking the shroud/fan arrangement is blocking most of your flow especialy if it is affecting your AC as well...

If it works fine/ok, then that is your problem. Make a proper cowl, or just slap the fans on there, and it will work better than with the 3mm plate in place.

Best bet would be make a proper cowl/shroud.

Good luck,

Rhyno

[Cressid@]

okies just an update
i removed the aluminium shroud and just fitted the fans directly to the radiator and what do you know it seems to be better. Considering the fact there is now even less toyota coolant in there than before it seems better.I know tonight is quite cool but after a drive for about 20mins before the top radiator hose was actually very hard and hot. Now the top radiator hose is quite soft and seems better.

Ill monitor it over the next few days to see if it over flows in the overflow bottle and report back

thank you for everyones input,

im even considering putting the jzx81 shroud back on and installing a clutch fan. I feel more comfortable knowing that the harder i rev, the harder the fan will spin. At the the moment it relies on airflow from driving and only coming on when it hits a certain temperature.

if anyone is interested in a swap let me know...two pretty much brand new 12 inch fans for your jza80 clutch fan

[Cressid@]

Another quick question I forgot to ask. Is it bad for the engine it I just keep both thermofans running constantly?? Until I can find a clutch fan setup I'd rather be safe than sorry

[George]

Think that's ok, bet your thermostat don't even have to fully close to manage excessive heatsinking due to running fans.

[allencr]

Is it bad for the engine it I just keep both thermofans running constantly??

No, not at all, just bad for the longevity of the fans & will also shorten the life of the alt. a bit.
I'd never run them unless stuck in a traffic jam, then it is almost a necessity, or with an AC condenser that will always need air flow.

[midnight_purple_GA70]

just seeing this now... the "2jz-gte water pump you had lying around" was it brand new or 2nd hand?

i noticed a huge improvement in my cooling after i did a 100000km service and replaced the water pump... running thermo fans attached to the radiator

it used to get hot under spirited driving and low loads up hills...

always used fresh coolant and drained and flushed the system many times...

after 100000 service the car was not overheating even when just using water in the radiator during testing...

otherwise ide suggest getting some au falcon thermo fans... should be about 100 bucks from a wrecker complete with shroud...