Is my 2.5 V6 cooked?
 

I have had the thermostat replaced about two years ago as it was running too cold. It has been perfect ever since. That is until a few days ago.
Driving at highway speeds all was normal then as we slowed to a crawl for road works it started overheating.
Coolant was forcing its way out of the cap.
I topped it up with water and after about 15 minutes of driving it happened again. I got it towed home.

I have drained the system completely, added radiator flush and at idle it runs for twenty minuted until the temp gets too high and I have to shut it down.
I have flushed the system 3 times now.
It still overheats after 20 minutes at idle.

The fan works as it should.
I replaced the O rings in the cap with viton ones about four years ago and upon inspection they still seem perfect.

Could it be a failed water pump?
Could the cap be the problem?
Could the head gasket be the issue?
Could it be cooked???

Any advice gratefully accepted.

Argh.

Hi, thermostat Kaput perhaps appears to be common on the KV6 engine.

Replacing the thermostat I can do. I hope that's the issue.
I will wait for a few more ideas before I start on it though.

Thanks for the input. I really appreciate it.

Hi, yes could be a number of things like fan not running etc hope it's a simple fix for you. Post here

Hi Matthew.
How much coolant do you have in the coolant header tank, can you just about see the max mark looking into the tank?

Reason for the above question is if to much coolant in the header tank you will have no expansion, I would also change the coolant cap even though you have changed the O-rings sometime the cap can be faulty.

Then maybe look to the thermostat as the problem.

Ohh,yes!
Or there is some air pocket in the system?:shrug:
The cup has some pressure valve on it. If it is in fault this will uprise the pressure in the system as a result thrown up the liquid thru the small pipe.

What tests did you do?

TC

Hi Matthew,
Sorry to learn of your problem.
A friend speaks highly of the Ballarat based mechanic that has serviced their 75 for years.
Send me a PM if you would like his details.
Regards
Bruce.

Coolant leak.
Thermostat stuck
Fan not operating correctly
Radiator cap faulty.

These are the things that come to mind

If you are unlucky, head gasket failure.

Been through all this, Kaiser’s comments are correct.
You need to eliminate all those items.
Make sure the coolant in the tank is at the right level.
Undo the bleed screw in the top radiator hose,run the engine up to temp and see if air is coming out , replace bleed screw when water only is coming out.
Try the aircon test re activating the cooling fan.
If that’s all working you know if overheating is happening it’s either a faulty thermostat or somthing else .
I’d say the odds of it being a faulty water pump are slim as they usually die by leaking seals rather than the intervals seizing up.