7 replies to this topic

[N/A_EJ22]

Hey guys,

After some ideas on what could be wrong with Dads GT foz.

Dad was driving it the other day and he was complaining that the cooling fans were on the entire drive once it got warm. I figured it was low on water and told him too keep an eye on the temperature. I drove it that night and same thing, fans on once it warmed up. Neither of us gave it a hard time either. Then I went to take off from some lights, normally, and then all of a sudden it lost a massive amount of power and dropped a cylinder. Pulled over immediately too see if anything had popped off. Nothing. Limped it home and it seemed to be running on 2 cylinders at idle but when I raised the rpm above 1500rpm it would smooth out as if it picked up a cylinder or two but this would only happen in neutral. Under any sort of load it all turns to shit again. After driving it in its poor state for around 15 minutes I noticed the temp started to fluctuate. It would rise a little bit when at a stand still but once I was doing some sort of speed it would drop but drop just below normal operating temperature. The car has just had a service around 1500-2000kms, always runs on premium and doesn't get a hard time since Dad drives it all the time.

Now I dont know if its two separate problems or one problem. When I did get a chance to check out the water level it had dried up the overflow tank and the header tank was pretty low. Does this sound like a head gasket has gone pop or a coil has died and the cooling system has issues?

Keen too hear what you guys think.

Cheers,

Ash.

[XXB4XX]

hmm.. sounds like you are in the sensor boat!

not sure which sensor it would be, either coolant temp or possibly one of the other 3 million sensors on these cars, but it's triggering it off as though the engine is over-heating..

Well thats what it sounds like to me.

If you are losing water, then do the obvious checks and look for the leak, it could be the heater box, AND it may also be an old-skool failure and just be the water-pump / thermostat.

Does the Foz have about 100k on the clock?

[N/A_EJ22]

Sensors, awesome. Atleast it isnt a TT.

Had a quick look for leaks. Nothing obvious, radiator is fair new and isnt cracked, all clamps are done up tight and nothing seems to be coming from them but i havnt checked the cross pipe etc yet.

Yeah its got 145ish on the clock. Bog stock too.

[RX25SE]

Ash,
Sounds a bit like a head gasket to me.
I would do a compression test and a cooling system pressure test.

If you do the cooling pressure test first, leave the tester on and maintain pressure while you pull the plugs out. Check the colouring of the plugs to see if they are the same as water will cause them to look a bit cleaner. Crank the engine with the plugs out (unplug power supply to coils) and see if coolant comes out the plug holes (this would only be for a really bad gasket leak) and then do the comp test.

The fact that the temp is moving, the fans are on and it's losing coolant point to a gasket IMO.

As Brenden suggested, check the sensors also. To accurately test the coolant sensor you need to remove it and check the change in resistance as it heats up so you will need a thermometer and a miltimeter.

[N/A_EJ22]

Thanks for the input RX25SE . Dad took it into the mechanics today. Turns out that it was running on 3 cause one of the leads going to a coil shat itself. He hasn't been told anything about the fans and coolant though so ill relay to him what you've said.

[RX25SE]

If it's running fine then maybe the fans are another fault (anything is better than a head gasket) such as a faulty coolant of fan sensor.
Im not sure if the fans are switched by the ECU using the coolant sensor, or if they have their own.

[XXB4XX]

or.. if the fans are still running i'd probably be more inclined to say it might be a faulty Relay,

[N/A_EJ22]

Ok awesome. Thanks for the tips guys. Ill check it out in a few days and let you know what I find.