Water Temp Continually Increasing When Highway Driving Upto 120c

[full_stick]

Hi guys,

I've got an R34GTR and recently had my clutch replaced since the clutch replacement or recently after I've noticed my daily driving temps have significanlty increased. To keep temp level at close to 100 I have the car in sixth gear and 2000rpm anything over this will cause water temps to increase. I live in northern aus so its hot all day everday but this was never a problem before. Even a spirited drive wouldn't bring the the tempts upto 100, maybe close 95 or 96 before I'd slow it down and go back to normal driving to bring the temp down.

For some reason my overflow bottle didn't have a lid/cap so I bought one yesterday and it was $16.30 for a milk carton lid from Nissan, so I put it on and filled it with coolant.

Prior to this I'd flushed the radiator by removing the bottom rad hose putting a hose in the top of the rad and just idling the car which did absolutely nothing, mind you at that time the overflow tank was empty and and there was no lid on it.

I can drive normally and the car doesn't go up to ridiculous temps but it still goes quite high like into the 90's in no time at all, so I'm always keeping an eye on temps, keeping revs low etc.

My next thought was to check the thermostat is stuck closed or partially closed. I thought this was changed in service I did about 20K ago, along with the water pump, did 100k service very early.

Thoughts???

[blind_elk]

Possible causes:

1. Blocked radiator.

2. Stuffed water pump.

3. Stuffed thermostat.

[R33 Eddy]

Possible causes:

1. Blocked radiator.

2. Stuffed water pump.

3. Stuffed thermostat.

4. faulty temp sensor

[Messiah]

5. faulty rad cap or a pressure leak somewhere. had it myself once... replaced everything including the thermostat,no joy... did the cap in the end and presto.

As for the thermostat, pull it off and drop it in a jug of hot water. if it opens its ok... if not then its buggered.

[Hanaldo]

Sounds like an airlock to me...

[jiffo]

Prior to this I'd flushed the radiator by removing the bottom rad hose putting a hose in the top of the rad and just idling the car which did absolutely nothing.

Not sure what you were trying to achieve there. To flush the radiator, remove it and take it to a radiator works. They'll give you an indication of its condition and cooling capacity.

After you did this flush, did you re-fill and bleed all the air from your cooling system?

[full_stick]

In regard to faulty temp sensor, standard R34 gauge reads a degree or two higher than the power fc and from what I've read they use different sensors?? So don't think this is the case. Also steaming coolant sort of tells me that the high reading is correct lol jokes on me lol.

[full_stick]

Not sure what you were trying to achieve there. To flush the radiator, remove it and take it to a radiator works. They'll give you an indication of its condition and cooling capacity.

After you did this flush, did you re-fill and bleed all the air from your cooling system?

I'm far from a mechanic mate just thought I'd replace the fluid in there and run some water through it after I'd let it drain to see if I could flush some of the shit out. Just trying to do a few things myself in an attempt to learn a few things and save a few bucks cos I'm broke and can't afford a new radiator.

[KiwiRS4T]

I'm far from a mechanic mate just thought I'd replace the fluid in there and run some water through it after I'd let it drain to see if I could flush some of the shit out. Just trying to do a few things myself in an attempt to learn a few things and save a few bucks cos I'm broke and can't afford a new radiator.

Flushing is unlikely to clean out a blocked radiator. Try the cheap fix (test or replace your thermostat if you have to go to the trouble of pulling it out) but if that doesn't fix it

new radiator = $300

cooked engine = $$$$$$$$$$

[Cowboy1600]

Same thing happened to me.

Radiator was blocked to f**k.

Only way to fix it is to replace it. There are some traders on here with really good deals on radiators.

[lachlanw]

my money is on not bleeding the air out

tell us exactly how you filled it back up with coolant or water

[Hanaldo]

+1 ^

After you tried to flush the system did you bleed it? Try this:

Jack up the front of the car, or park on a fairly steep hill, so that your radiator is the highest point of your car. Then get a 2l coke bottle and cut it in half, and stick it in your radiator cap. Fill the coke bottle about half way with coolant or distilled water, and now just run your car. Continue to top up the water in the coke bottle if need be. Just let it run for awhile to let any air in the system escape.

Give that a go and see what it does, won't hurt anyway, as long as you use distilled water.

[paulr33]

do both guages match

ie does digital readout on the MFD and the stock guage both show mega high temp

ie, is it a sensor issue, or is it really 120+ deg water temp

[full_stick]

my money is on not bleeding the air out

tell us exactly how you filled it back up with coolant or water

To be honest your probably right I don't know how to bleed out the air. So all I did was basically drain all the fluid by removing the bottom hose of radiator, put a hose in the top of the radiator in an attempt to flush shit out while car was idling, reconnected hose, turned car off, filled radiator with coolant, then let idle again and attempted to put more fluid in but thinking that the bubbles would come out once car was idling but this really didn't happen and I couldn't really fit any more fluid in???

So thats what I did. Please tell me what I should have done... I love doing this stuff myself but there's just so much to learn....

[full_stick]

OFF TOPIC: Just a quick note, I should still have the old working thermostat (if the current one is broken gonna test this weekend) but my mechanic who did the service on it taxed it and never returned, I'm going to go get it back!!! Scamming mechanic charged my friend for a turbo that he didn't even put on his car, still had the stock one on it after the engine rebuild. Also blew one of my turbo's while doin the 100 000km service the bastard....

[full_stick]

<br />do both guages match<br /><br />ie does digital readout on the MFD and the stock guage both show mega high temp<br />ie, is it a sensor issue, or is it really 120+ deg water temp<br />

Both gauges the digital and the one on the dash show mega high temps including some steam to verify, so definitely not a sensor problem...

Edited July 30, 2010 by full_stick

[dkbcleaner]

OFF TOPIC: Just a quick note, I should still have the old working thermostat (if the current one is broken gonna test this weekend) but my mechanic who did the service on it taxed it and never returned, I'm going to go get it back!!! Scamming mechanic charged my friend for a turbo that he didn't even put on his car, still had the stock one on it after the engine rebuild. Also blew one of my turbo's while doin the 100 000km service the bastard....

Mate am I reading this right??? DO NOT take your car back to this mechanic! And how the hell do you blow a turbo doing a service??

[dkbcleaner]

And yeah I also had a similar problem to you. I bought a new thermostat and a nice fat just jap radiator. Problem solved and now water temps are always low even out on the track.

[full_stick]

So I've properly bled the radiator as instructed, and checked thermostat is working and still no difference so I guess its either, radiator cap highly unlikely, water pump or radiator now...

[Cowboy1600]

Radiator.