2JZ Radiator Flow?

[The Real Roadrunner]

1 are you sure the thermostat is in the right way.
2 are you bleeding the system properly
3 2750cfm, dude some dyno fans dont pull that much. maybe 275cfm
4 dont drive a car at 110deg your asking for BHG

pull your thermostat out completely and take it for a drive, if that doesn't fix it id be suprised.

you have diagnosed your own problem, if the lower tank is cold the rad is working, dont blame the fan cause obviously the lower tank is cold therefore its working.

so you OBVIOUSLY have a water flow problem.

cheers
linden

[sbyder]

Thermo fan pulls 2750cfm as per http://cgi.ebay.com.au/16-INCH-LOW-P...QQcmdZViewItem

Thermostat is in the correct way, ive triple checked that as well as testing it and it opens at 82 degrees like its meant to and opens all the way to 8-9mm at 100 degrees.

Im going to find a low temp thermostat today. If i cant, i'll drill this one out as i want to go to jamboree.

Cheers
Ben

[sbyder]

went everywhere and no one had a thermostat that would suit.

Just drilled out the thermostat with a 1/8th hole. See how that goes.

Cheers
Ben

[oldcorollas]

btw, what temp sensor/gauge?
is the body of the sensor grounded,ie, not sitting midway through the pipe with no electrical connection?

have you checked with another temp device what the actual temps are?

[sbyder]

Sensor is a greddy in-hose type. Its definately getting hot as any splashed coolant turns to steam when it hits around 100° C.

Drilled the hole, went for a drive and even though the temp actually stablised at around 90, it did climb up to 105 again once i got on boost, or increased the RPM.

I wish i could find a 70 degree thermostat. If anyone knows anywhere in brissy that stocks them please let me know.

Im going to remove the thermostat tomorrow just to see if the temp issue still happens. Do you guys recon it'd be safe to travel to jamboree (40 odd kms away) without a thermostat? Obviously id have to make sure temps stay around the 90° mark.


Ben

[allencr]

Has anything been done to this cooling system, any improvements other then direct replacements or any rearranged parts & rerouted hoses?
If the lower rad. doesn't get hot, it's not getting circulation from blockage, or no pump.
Obvious flow in top tank? Bypass hose warms up quickly?

Does this engine possibly have 2 differently rotating pumps for old & new belt setups, or a truck version?

I've been trying to think of what would happen with the water-pump trying to draw from the top tank/hose.

[oldcorollas]

Sensor is a greddy in-hose type.

so it is in th emiddle of the hose....

is there any electrical connection between the in-hose bit, and the engine blosk or the battery? or are you relying on the electrical connection through the coolant?

the temp sensor is a resistor between the gauge, and the battery -ve terminal.
the body of the temp sensor MUST be in electrical contact with the engine block.
(unless it is a 2 wire sensor with a dedicated earth wire?)
get a multimeter adn check there is almost zero resistance between the body of the sensor and the engine block..

if there is, then that resistance is being added to the temp measurement and you are not getting the right temp...

[Norbie]

Yep, I have an in-hose temp sensor and before I connected it to ground with a separate wire I was getting all sorts of weird readings.

[sbyder]

It is wired up exaclty how Greddy designed it. Using a loom. But its not temp sensor related. I can garantee it. It has been working for 9months (since i bought it) and its still working perfectly. If i turn the engine off at 105° carefully undo the radiator cap and after it has a hissie fit, i can use a normal temp gauge that reads about 98° which seems about right.

I also seriously doubt its the water pump though if it is im getting a warranty job done and they can install the fooker (newy installed in January). Im pulling the thermostat out now. If anyone has any comments on whether to run it without a thermostat, please let me know. I have a temp switch hooked up to the thermo's so they will only run when it hits 88°, so i should be fine. I cant see it overheating while normal driving without a thermostat. The only thing that might be a problem is the engine staying too cold. 20km of initial h'way driving should warm it up.

Cheers for all your help guys and i'll let you know how it goes.

Ben

[sbyder]

actually, i might just bastardise an old thermostat to provide some restriction so the flow isnt quick enough to get the engine hot.

[The Real Roadrunner]

so whats the point in buying a lower temp thermostat (68-70) if the one you have is working properly (according to you) and you still have 100+deg temps with a (82-85deg) stocker.

something else is obviously wrong, but considering you dont really care to listen i cant be bothered.

cheers
linden

[sbyder]

Linden, if you read, and read properly you would understand.

The issue was that when the HOT coolant from the top of radiator got to the thermostat the radiator had cooled it soo much that it would shut the thermostat, thus causing the coolant in the engine to get hotter and hotter.

Anywho... Ive ripped the guts out of an old thermstat and threw it in. Surprise surprise it now runs at around 82°. Cold start doesnt last long, about 2 minutes, then the coolant temp is up to 40°, go for a casual drive for 5 minutes and its up to 72°. Start giving it a bit, stop and then idle and the highest it got to was 90° then it came back down to 82° very quickly. Ive let it idle for 10 minutes and it stayed right at 82°. Drove at 70kph and it was 76° and stayed there. 100kph it dropped to 72°.

So from the anaylsis its simple. The thermostat i had was set to open too late in the temp range. I need to either find another low temp thermostat, 70° or similar, or leave the current set-up in place (which id rather not).

Anyway, im off to jamboree!

Big thanks to all that helped, oldcorollas, you are the man
Ben

[The Real Roadrunner]

1 you obviously dont know how a thermostat works.
2 why post if you know it all anyway
3 i do this shit every day and knew what the prob was as soon as i read it.
but hey youve figured out whats wrong so fix it your way.

[clubagreenie]

So from the anaylsis its simple. The thermostat i had was set to open too late in the temp range.

So the t/stat was opening late in the 82deg range instead of at the low end of 82?

I have a blitz cap, so my boiling/overheating point is a lot higher than stock. 115-120 i was told.

The pressure, not the brand is important here. What'd you pay to have blitz on it? bet it was more than $10- at super cheap for one rated to the same pressure and would do the same job.

You need to chill out a bit and realise that you're the one who asked for help. You had a problem, said everything is working ok, asked why it's hot then shot most everyone down in flames for their advice.

Whats the rating on a stock t/stat? Throw one in, if your rad is too efficient, NASCAR it, tape up ther lower section till you reach a compromise in running temp. In summer remove a bit of tape till you get it running normally. Or buy a cheaper radiator.

[sbyder]

wow, people can get bitchy quick...

I replied to peoples suggestions. I did not "shot most everyone down in flames". If you see a post of mine that is in response to someones suggestion that looks like im "shooting them down" then please fill me in as i dont recall writing it.

With the advise from oldcorollas and others we worked out what the issue was, thermostat. If I posted up what caused the problem and testing has proved it, why suggest something else?

As for the thermostat, its operational temp is 82°, if i buy a 68° thermostat, then obviously it will open sooner and thus resolve the problem.

It seems that some people reply without reading all the comments and then take offense when i respond. This is one of the reasons ive not bothered with this forum as of late. I remember the days when you could ask a question, people would respond, you'd have heaps of communication and no one would carry on about who is right or wrong as long as the issue gets resolved.

I appreciate all that have made suggestions and if you dont believe me, read my comments on most of my posts.

Mods, please lock this thread. Nothing else needs to be said.

Ben