Bnr34 Coolant Temp When Car Switched Off

[djvoodoo]

Hey SAU.

I have searched and did find a topic on water temps, but it's an old thread from 2009, so I just wanted to start a new one.

Details:

First time GTR owner, so still getting familiar with the RB26 donk

Had timing belt/water pump/ thermostat and coolant flush done when car was in compliance only a week ago.

On the weekend I went on a decent drive, about 35-40 mins, and the MFD temp sits on a constant 89-92 degrees under load and sitting in traffic. Oil temps are around 90-92 as well.

I went to fill up with some petrol, and after switching off the car for about 5 mins, and then switching the car back on, I noticed both the analogue temp gauge (needle went above half way) and MFD gauge jumped up to over 100 degrees. As soon as I start driving it goes back down to about 90 degrees within a min or 2.

After switching the car off, I can feel the top radiator hose boiling and a slight hiss from the radiator cap. Overflow bottle is fine and not bubbling. I haven’t seen/heard the front radiator fan switch on at all (what temp the fan is supposed to cut in?). Clutch fan spins as normal

No loss in coolant, and radiator is very clean, no gunk, very clear coolant and no rust/residue.

Should I be worried?

[GTSBoy]

It's not a massive problem. If I were to guess, I'd say that the cooling system hasn't been bled completely and you've got some dry spots up in the head that are getting hotter than the rest. Give another bleed, see how it goes.

[darksky34]

on my GTT the radiator fan is on as soon as the car is turned on - is this different for GTRs? Because OP has mentioned he hasn't heard the fan come on.

Or I'm mistaken and don't know fans from fans in my car

[GTSBoy]

That doesn't sound right. The engine fan is the cooling system fan. The electric fan out front if for the aircon and also comes on in severe over-temp conditions. If it is on at ignition-on, then something is borked.

[djvoodoo]

It's not a massive problem. If I were to guess, I'd say that the cooling system hasn't been bled completely and you've got some dry spots up in the head that are getting hotter than the rest. Give another bleed, see how it goes.

The bleed screw is a hex head bolt near the head correct?

[GTSBoy]

Yuh. I don't know if there are 2 of them on your car. There is one at each end of a Neo plenum.

Get the car warm enough for the thermostat to be open. Get a coolant funnel and gaffer tape it into your radiator cap opening if you can, so you can keep a head of coolant topped up in there and see what happens when you crack the bleeder. You want to see coolant immediately, but any little bubbles are an indication that there is at least some air in there.

Bleeding RBs properly is a bit of an artform. You need to vary revs, massage radiator hoses and so on. Sometimes it helps to have the front of the car elevated. And it is pointless trying if the thermostat is not wide open.

[darksky34]

http://www.skylinesaustralia.com/forums/topic/421184-rb25-neo-bleed-valve-for-cooling-system/

this is what they look like on the GTT

[Ben C34]

Coolant funnel is nice, or ghetto option like me, peice of old bike tube cut to about 300mm long stretched over filler neck.

[niZmO_Man]

I use a drink bottle and tape, usually sports drink, sometimes flavoured milk, whichever 'seals' the 'best' lol.

[XKLABA]

When you turn the car off the water stops circulating around the engine and heat soaks, as soon as you start the car it starts moving again, so as long as the temp comes back down when you start it it's fine

As for bleeding a GTR, its simple get the front end facing up a hill or on car ramps then top up radiator ( wait for it to cool down ) then remove that 10mm bolt, it's the only one with a copper washer , and wait for all the air to go and put bolt back in