Thermo Fan Issue VZ

[vzv8man]

Hi , have a 05 VZ SS sedan. About a week ago when we stopped we noticed the thermo fans were not turning off. Did this a couple of times over the next 4 days. Read about this on the web, and the usual culprit is the relays. I replaced both today from Holden. On the way home, the temp gauge was way higher than normal . It normally sits very low under a third. But on this short trip it was going up to the second marker. And moving even higher when we were stationary.

The relays were slightly different to the original. Still the same part number, but no brand name on them. The writing was a different direction to the originals, which meant i had a little fun fitting them, till i realised this.


Have had an aftermarket radiator and water pump fitted about 5000km ago, and new holden coolant. They were fitted because my warranty wouldnt allow me to use holden for the repairs.

Any ideas.

[Jag530G]

Pop the bonnet with the engine running after a bit of a drive and see if the the fans actually coming on when the engine temp is above about 92c. Both should come on low speed and then both should come on high speed at about 108c (which is roughly half way on the temp guage). I suspect one or both of your fans isn't coming on.

Cheers, Matthew

[vzv8man]

I hooked up an OBD device. The car got down to 93 degrees on the highway at 100km, with the a/c on. Got home and let it idle both fans were on, it slowly rose to 109 degrees whilst idling,with both fans on. Temp gauge half way between 1/3 mark and the next mark up.

[Micks]

I don't think your chasing a fan problem! As both are working!!

[vzv8man]

Fans are switching on when coolant temp reaches 98degrees whilst idling. I was just concerned because of the way the temp gauge rose after installed relays. Is it possible that ecu took a while to adjust because i took battery off whilst installing them?

[vzv8man]

What is a safe coolant temp?

[Micks]

Fans are switching on when coolant temp reaches 98degrees whilst idling. I was just concerned because of the way the temp gauge rose after installed relays. Is it possible that ecu took a while to adjust because i took battery off whilst installing them?

Is possible, best do all your testing with the A/C off as it will cycle the fans to low as default then switch them up to high in response to (HP) high pressure in a/c system
irrespective of engine temp!

[Radikl]

What was the outside temperature on the day and was the a/c on all the time when it hit 109?

Went through same issues with mine on the real hot days. Put new radiator in, changed fans etc. I was chasing ghosts!

[vzv8man]

Outside temp was probably 34 and yes a/c was on. To cut a story short found the coolant to be way down. I had only checked it a week before. Didnt expect it to be a problem as it has always been good. Topped it up with proper coolant and demineralised water. Will check it every day to see whats going on.

[vzv8man]

Just checked coolant again, and its way down again this morning after filling up last night and going for a short drive. There is nothing in the reservoir. There are no leaks on the cement underneath.?????

[Jag530G]

Just checked coolant again, and its way down again this morning after filling up last night and going for a short drive. There is nothing in the reservoir. There are no leaks on the cement underneath.?????

Then you might have had an air lock so top it up again and see how you go.

If there are no pools of coolant under the car, check the right hand chassis rail to see if you have a leaking heater tap, also check the carpet inside the car to see if your heater is leaking inside your cabin. Alternatively, do a compression test to see if you have a head gasket problem and coolant is leaking into a cylinder.

Cheers, Matthew

[vzv8man]

Think I just found the culprit. The main hose from the motor to the radiator has a worn hole in it, it is seeping. Looks like the pulley behind it has been rubbing on it.

[Micks]

Think I just found the culprit. The main hose from the motor to the radiator has a worn hole in it, it is seeping. Looks like the pulley behind it has been rubbing on it.

That will do it! a depletion of capacity!!!

[vzv8man]

And the reason for this is the silly bastards from the workshop fitted the hose back the front. One end has marked on it RAD and the other end ENG, well they are on the wrong way. It will be in at holden getting a new hose and coolant on tuesday. And the other mob will be being sent a bill.

[Micks]

Didn't think it was a "fan" issue!