Hey guys

I have noticed lately that the temp. guage shows the needle sitting in the red zone after a few minutes of driving. If I kick it down to a lower gear, the temp drops to the lower temperature range, then slowly works its way back up.

Before it would generally just stay in the middle temp zone and it wouldn't vary hot and cold so much.

The thermostat is new, could it be my waterpump is going? If so, what is involved in getting a new one fitted?


Cheers!

I replaced my thermostat gasket and housing and mine still leaks. How hard is it to fit the hose running form the coolant bottle to the thermostat housing?

About 1 minute's work

i have a similar problem the temp rising and falling i was told the cooling system is to efficent nothing to worry about ive had the car 2 years no problems yet

was the problem there before you changed your thermostat? I found with thermostats dont change them if they work even if ts old.

I can't remember when it happened, but I think it jumps around more since I have changed the thermostat.

I get worried when it hangs around the red mark for too long...

When I rev it high, say taking off from the lights to get up to 100 or something, you can watch the temp. rise to the red zone.

So, I think the water isn't getting through fast enough to cool the engine.

Gday Lukieman, you can check your gauge by removing the wire going to the coolant temperature sensor (near the thermostat) and placing a known resistor between the plug and earth. This will make the gauge move when the ignition is on.

Don't know about an EA but for an EF the following numbers are true according to gregories manual. The sensor resistance at a given temp is as follows:
10C - 58.75 KOhm
20C - 37.30 KOhm
30C - 24.27 KOhm
40C - 16.15 KOhm
60C - 7.6 KOhm
80C - 3.84 KOhm
100C - 2.07 KOhm

(these should cost a couple of dollars at jaycar or d**k smith).

To check your thermostat, suspend it in some coolant/water over a heat source (BBQ/stove) and heat it up. Measure the temperature when the thermostat begins to open (approximately 89-93C) and when it is fully open (>7mm at 103-107C).

My experiance is for an EF, at 40C, 60C & 80C the needle should be indicating cold and at 100C it should be indicating normal (between A and M). With the EF you can also place the cluster into diagnostics mode and check the numeric value of the temperature - it should correspond to the temperature associated with the resistor vaule used.

This should give the best idea of what is going on. If the gauge and thermostat seem to work as expected, then it is most likelly a coolant flow or airflow problem.

In this case, check that there is no s**t infront of the aircon condenser and between the condenser and radiator. Get your system pressure tested (preferably when hot), and if that is OK try clutching straws and changing the water pump.

Good luck and let us know how is goes

Cheers.

PS: don't run the engine without a thermostat as theyare also used to throttle the water flow and keep water pressure within the block and stop/limit local boiling.