Temp Gauge Shoots Up to 'H'

Barossa Red AU3 · 01-02-2008, 12:48 PM

Gave the AU a squirt out the road today, and after about 4-5 seconds at half - full throttle i looked down at the temp gauge, Bugger Me it was all the way Over to 'H' and then the red temp warning light came on, WTF?

I backed of and the temp came down to normal in about 3-4 seconds and pulled over and stoped, expecting the thermo's to be roaring but they were only at normal speed. So i drove home and tryed again and sure enough about 4-5 seconds of decent throttle and gauge shot up realy quick.

When i got home i put the hand brake on and A/C and put it in gear and put the foot down and loaded it up, and the temp never moved of 'o' on the gauge, but i got the thermo's to kick in full speed after about 2 minutes.

Any Ideas???

**Whoosha** · 01-02-2008, 01:25 PM

Could be a bodgie thermostat ??

InfernoSR · 01-02-2008, 02:02 PM

When was the last time you serviced the cooling system?

Barossa Red AU3 · 01-02-2008, 04:13 PM

I flushed the cooling sytem with Nulon r40 and filled and drained it about 4 times with rainwater (with heater turned on)

Then used the nulon 100% coolant concentrate @ 50% strength 7.5 litres in all,
that was about a week ago and i held it at steady revs for about 10 Minutes to purge all the air out.

I also took the resovior off and cleaned it out so its nice and clear, and noticed that the small pipe that goes in which comes from the top of the thermostat housing, has a nice flow of coolant once the engine is at normal temp.

Next idea was the bottom hose which may have been collapsed with a few revs up.
Not that either because i got it up to temp then popped the hood and looked at the bottom hose as i wrap it out to the rev limiter but the hose was in fine shape.

This has got me stuffed at the moment!

p.s Car Loves revs and speed but it just not playing the game right now.

InfernoSR · 01-02-2008, 04:19 PM

Thermostate, pressure cap and sucking in hoses can be blamed there... so go through them 1 by 1...

Barossa Red AU3 · 01-02-2008, 04:30 PM

Thanks for the Help guys
I will have a good look at the thermostat and pressure cap and see what goes on.

Fairlane · 01-02-2008, 04:37 PM

Had a similiar problem on mine. Car would overheat if you stopped for too long. It started doing this suddenly. Anyhow after a but of investigating, it turned out only one of my thermofans was working (had to unbolt shoud from radiator and observe) and 1 fan is not enough to keep an AU cool.

New Thermofans for $130 and all was good again.

mattp · 01-02-2008, 09:02 PM

Once in a blue moon my car when I turn it on shoots up to H and beeps at me, then immediately drops back down to normal, I figure it must be a sensor or something, as it can't be too hot the second I start it? Any ideas? It's only done it once in the past year (replaced the thermostat, flushed the system), but still I'm curious as to what it was...

**Mechan1k** · 02-02-2008, 02:12 PM

If the fans aren't going to high speed ... you could have a bung relay (there's 3 that control fan speed depending on temperature and A/C Fan speed).

But go through the above items that were mentioned.
I had a bung thermo on the passenger side .. it was spinning ... but really slowly (I could stop it with my hand) ... I replaced the entire assembly though ... much easier.

I had my temp rise the other day ... but I had 850kg in the back of the ute ... on a LOOOONG hill ... on a hot day.

The is with a twin copper core ADRAD radiator in ... the high speed A/C relay mod (as soon as I turn A/C on fan speed 1 ... the thermos go straight to hi-speed) ... I have a relatively new water pump in ... new hoses ... new thermostat ... flushed system ... you name it ... evenything. It still gets a tad warm.

All i have to do is back off a bit and come straight back down to normal (right hand side of the "O"). It's mainly because I am working a loaded up ute in traffic with a lot of stop starting as well.

BOON250 · 02-02-2008, 09:14 PM

Quote:

Originally Posted by mattp

Once in a blue moon my car when I turn it on shoots up to H and beeps at me, then immediately drops back down to normal, I figure it must be a sensor or something, as it can't be too hot the second I start it? Any ideas? It's only done it once in the past year (replaced the thermostat, flushed the system), but still I'm curious as to what it was...

sorry to hijack thread but mine occasionally does this too. Start car after a drive and beep beep its on H but within a second of starting its back to O again where it sits religiously. weird.

:

**aussiblue** · 02-02-2008, 09:27 PM

Also check for crushed or damaged cat converters. Will glow red through the heat shield after a hot run at night.