Random overheating in my VX

[Kieran263]

Hey guys,

I was going through the drive through at maccas the other night
and was stationary for maybe 4 minutes. I had my air con right up and out
of nowhere the temp gauge went right up and the car beeped at me.
I kinda pood my pants a little but I hung my arm out the window to check if I
could feel heaps of heat but it was only a little warmer than usual. Then the temp
gauge went back to normal.

What could the problem be? Its happened once before.

[torch]

Hey guys,

I was going through the drive through at maccas the other night
and was stationary for maybe 4 minutes. I had my air con right up and out
of nowhere the temp gauge went right up and the car beeped at me.
I kinda pood my pants a little but I hung my arm out the window to check if I
could feel heaps of heat but it was only a little warmer than usual. Then the temp
gauge went back to normal.

What could the problem be? Its happened once before.

the outside temp was warmer than normal, or the heat coming from under the car?
sounds like your electric fans failed to start up, then started returning the car to temperature. Another alternative is a thermostat that is sticky in operation.
Did you hear the fans going?

[Cameron P]

did you get a free big mac??

[])R@G()N]

Good chance your water pump is on its way out and dropping presser..

Check down the front of the engine for water leakage or signs of there was a water leak.

[PRAVX II S]

Does it only do it when the air-con is on?
Check that the fan is coming on.
When you turn the air con on the fan should be activated.
To quickly check if the fan is working put the car on reds and disconnect the coolant temp sensor. this tricks the fan into working.
Or could be the thermostat/waterpump.

[blueV8vl]

even air in the coolant given it bubble that would do it

[Jarrad]

even air in the coolant given it bubble that would do it

Yep thats what happened to me when I didn't bleed the system properly after a coolant flush.
I took it for a test drive and saw the temp gauge rising as I went up a hill, then fall as I came down it. I took it straight home, bled the system properly and it has been sweet ever since!!!

[Kieran263]

The fans were going, and it has only happened in the exact same circumstances. Through the same
maccas, air con right up, stationary for a while. Am definitely gonna check everything mentioned.
As always guys, champion effort, cheers.

[MR_VX]

it has only happened in the exact same circumstances. Through the same
maccas, air con right up, stationary for a while.

easy fix stop eating maccas

[Kieran263]

^^^ hahaha I'll pay that one!

[Brett_jjj]

Ive heard a few times lately about some cheap water pumps that have a problem with wearing away the fins on the pump impeller which then causes overheating. Some have only lasted 12 months or so.Its usually the bearings that go first on most pumps,but not with these ones.And to make things worse, its the sort of problem you wouldnt find unless you actually changed the pump.Worn pump impeller fins would also effect the coolant flow more at low revs or idling I would think.Could be why it overheated when sitting in the drive through.

[torch]

water pump? its possible, but dont see it going from not working to working suddenly, would expect just poor constant performancel. If fan operation is ok, leaning towards a thermostat problem.
Could as others have said be a air pocket or not enough gycol in the coolant which creates a vapor pocket when things warm up. Have you opened up the bleed screw near the thermostat cover when the motor is hot? If it bleeds coolant, all is good in that respect, if it splutters out a steamy mess, no good.

[])R@G()N]

water pump? its possible, but dont see it going from not working to working suddenly,.

They do if it drops water presser it will boil (135 kPa for V6 engine) it will go from normal temp to Hot in seconds, All you need is a little bit of movement in the bearing and it will loose presser though the weep hole.

The first thing I'd do is to check your radiator cap or replace it so you will know that it isn't loosing presser. Also check your radiator hoses for leaks\damage.

then remove your drive belt and see if there is any movement in the water pump's pulley if there is movement in the bearing you'll have to replace it.







Because its hard to see if there is any leak from the weep hole in the water pump and the water runs down the front of the engine
it easier to check to see if there is any water on the top of the sump (as in pic)
you should see it there or where its been when its dried (coolent or brown water stain)

[moose man]

My VX did exactly the same thing - gauge moved quickly to H and displayed HOT on the dash with the warning beep. A handfull of other lights turned on at the same time (low trac etc), then after about 3 seconds the gauge dropped back to normal temp as quickly as if i'd turned the key off. The cooling system checked out fine when checked later. From what I've read I think mine is evidence of the common ABS module failure. The gauge moved way too quickly for an actual overheat.

I don't know how to simulate the fault again, but am wondering if yours could be the same thing. Do you have ABS?

[Kieran263]

Yeh my exec has ABS. And the module is wrecked, airbag light on constantly, so that sounds like my problem to a tee.

[VX21]

mine was doing this, intermidantly overheating on the gauge and going to like 120 c and i took mine to my mates mr radiator shop and my thermostat was sticking on the sides causeing it to overhead plus i needed a coolant change. $20 for a new thermostat and literally 2min to get it out and it was fixed