Overheating 180sx

[Equinox]

I've got a problem with my friend's 180SX.

After it is warm it only takes 3-4 full throttle runs to redline to get his water temp up to the 90s, and it takes ages to come back down. He used to drift it at Winton with no issues until one day when it just overheated on the track and has been doing it ever since.

Since that day, to try and fix it we have:

- Rebuilt head. Cleaned up the whole thing, port and polished the ports and installed new head gasket.

- Removed thermostat.

- Installed Alloy Radiator

- Installed Twin Thermos

- Bypassed heater core

- Changed Water Pump

- Flushed the whole system

And it still does it! Can anyone think of anything we've missed? One of our friends suggested that the water pump could be sucking the radiator hose closed at high rpm, but I've never heard of that happening before?

Car is running a T518Z, is an SR and is making around 240rwkw if it makes any difference.

Thanks,

Peter

Edited April 3, 2008 by Equinox

[meatwagon]

It should only suck the hose in if your radiator cap is stuffed. Have you done a cylinder leakage test on it?

[Equinox]

Got a new radiator cap with the new radiator. Could try another one though I guess. Pretty desperate for ideas at this stage...

What kind of test you mean? Leakdown test on the motor?

[sl33py]

Melbourne has a few mechanics doesn't it?

[-_-StRyDeR-_-]

you do have a thermostat back in there though now??

[Equinox]

you do have a thermostat back in there though now??

Nah. Would that effect how it cools at high rpm?

[-_-StRyDeR-_-]

well the water in the radiator mighten have enough time to cool down before its put back into the engine...

[Gtrgodzilla67]

LEAVE the thermostat Housing in thier and remove the centre of it as this allows it time to cool in the readitor instead of just pouring through HOT!!!

[acsplit]

possibly wayy too lean or rich causing all temps to rise?

[-_-StRyDeR-_-]

get the right temp thermostat and you dont have to "modify" it, it will work the way it should.

[tacker]

not to sure about your engine, but on the Rb26 if you remove the thermostat entirely then the water will bypass the block and just go straight out the outlet pipe as its only 100 mm apart. As most things it will take the path of least resistance and the rb26 has a 25 mm hole in the back of the themostat house which is connected the outlet pipe on the head.

[Cubes]

Shove a genuine thermostat back in and throw it on the dyno to check the afr's and ignition timing.

[Equinox]

Thanks guys. I'll try putting the thermostat back in and seeing how it goes.

Melbourne has a few mechanics doesn't it?

Would have to tow it there though. That's why I'm trying to work it out myself first.

[blind_elk]

The water pump may have spat some vanes off the impeller, so it doesn't circulate water properly.

[cpt_impossible]

Here is a writeup I did for NICO Club (US), maybe something in it will help.

OMG my RB is overheating

Oh, and the water pump sucking the line closed, that was my problem I believe. When I replaced the lower hose, which was soft with an OEM unit from tweakit, the overheating problem I had at constant higher RPM (Freeway) went away.

Edited April 4, 2008 by cpt_impossible

[Equinox]

Hmm some good info in that link.

I'll tell him to order a new thermostat and replace that hose and see how it goes.

Thanks for all the help.

[D_Stirls]

I'm pretty sure that an oil cooler will go a long way to fixing your heating problems. The thrust turbo's heat the oil up quite a bit as they are oil cooled and they run hotter than the equivalent water cooled BB turbos.

Do you have a SR with the factory heat exchanger on top of the oil filter or not? (some did some didn't) Even if it does they don't work very well.

I was having the same heating problems with my CA18 as i was getting oil temps around the 105 mark and water temps around 95 in general driving. As soon as i fitted an oil cooler i didn't get engine temps above the factory 82 degree's and the oil temps haven't been above 90 degrees

[Equinox]

Sorry. Should have mentioned the car has an oil cooler.