OVERHEATING FOR 9 MONTHS - Impossible diagnostic?

[Wolfgang]

Started overheating around February this year.

In the absence of anything to the contrary, I am assuming it was ok up to that time.

So what happened in February, or maybe January? Did you do ANYTHING to the car around that time?

I am wondering the same...

[KevGoat]

Sounds like the radiator guy didn't actually do anything, just gave some "advice". Most has been covered. My experiences with overheating have been mostly from pressure loss and once through a blockage. Usually pressure loss can be seen from evidence of coolant leakage somewhere like around hoses and other seals. Radiator cap can often lose pressure - or an incorrect pressure cap fitted. Head gasket. Tiny hole in radiator core (just a side comment on that one has anyone else ever use the old egg 'n pepper trick to seal the leak? ). Thought the rad guy would have done a pressure test.

Lack of flow from a worn water pump - even reduced flow will cause a problem. Blocked channels, though I've never had this. Blocked radiator core especially if tap water was used by previous owners.

I've been in situations in the past where I've removed the thermostat and run without one for months before replacing it and never had a problem.

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[Skifey]

Nah, garage didn't really look for a fault perse other than doing an CO2 test on the radiator looking for a blown head gasket. That came back negative for the third time running so no surprises there.

The ONLY thing I can possibly think of that may have changed around the time it started overheating was me removing the radiator cowl because it was plastic and it had broken in half. As to the ECU, it's running a Megasquirt of some variety, I'm not positive which version or variant so I'll check that and get back to yous shortly

[Red_Bullet]

Stick a timing light on it and check base timing.

[Red_Bullet]

Lean fuel mixture will also cause overheating. Trouble is this could be caused by a multitude of things.
Bad ECU tune, bad fuel pump, bad fuel filter, bad fuel pressure regulator, bad in injector.

Does the engine ping under load?

[Red_Bullet]

Another left field one, is it actually over heating or a bad temp sender saying that it's overheating? Temp sensor is cheap from Supercheap.

Also you don't have to totally replace the coolant each time you drain it, capture it in a clean container and reuse it, you'll spill some percentage of it but you will capture most of it.

[Magpie]

Confirm the temperature. Install a second sensor and or get a non contact temperature to confirm. In addition you can use adhesive temp strips and place them in strategic locations to record the max temps.

http://www.racerindustries.com.au/afawcs0161689/CATID=80/Temperature-Paint-and-Strips.html