Grand Vitara overheating issues

[mewashoo]

Hi,

I have problem with my 2007 2.0 petrol Grand Vitara.

After 30-60 of driving it tends to either go hot or even overheat.
It's usually accompanied by cold air out of the blower.
Now, I had it checked by mechanic, he changed thermostat, pressure test it, did combustion sniff test. Flushed the coolant, bled it and found virtually no faults. Yet, problem still occurs. Now, I bled it myself on a hill and still nothing. I am suspecting a stubborn, will hidden air pocket, but I'm not sure.

I think it's more likely to occur when going downhill than up, but they might be my paranoia taking here.

Has anyone got any ideas, what could it be?

Kind regards
Miles

Ps. No sign of creamy residue in oil or oil in coolant.

[donkeychomp]

Is the radiator fan working? What's the rad itself like?

[maxaret]

As DC posted - Dodgy/clogged Radiator ?
Or perhaps a weak Water Pump ? - I don't know if the pumps give probs on this engine but they certainly do on other makes.

[mewashoo]

Is the radiator fan working? What's the rad itself like?

Radiator kicks in when it should add far as I can tell. Rad was tested and apparently it's fine, but my local friendly mechanic is fed up with me now, so is there anything I can check myself to see if it is actually okay?

[mewashoo]

As DC posted - Dodgy/clogged Radiator ?
Or perhaps a weak Water Pump ? - I don't know if the pumps give probs on this engine but they certainly do on other makes.

Sorry for posting to each of you separately. Not exactly sure how to use this forum on phone.

Is it something I could have a look at myself or garage? Thanks!

[donkeychomp]

First I'd try driving it without the thermostat and see if that keeps it cool. But even if it does we ain't exactly at the height of summer here so you may find that as the days get warmer, even sans thermostat, the truck might start to run hotter. Could be a water pump as stated. Could be a cracked block but I doubt it. Is it leaking any fluid at all? There are a fair few hoses and some are hard to access, you may have a leak without knowing it. Try no thermo, if that fails I'd fit a new pump.

[zook123]

Flush the heater matrix.

[ScottieJ]

Sounds like a headgasket to me. I had a 325 bmw that did a similar thing. Did all the usual checks but nothing showed like yours.

I would also check that the viscous coupling on the fan is working properly. Also don't always think that becasue a thermostat is new that its going to work ok, I have had dodgy new ones before.

[mewashoo]

Just tried cheapest one, new rad cap, nothing changed. I'll try an have a look taking thermostat out completely. Thanks for all the suggestions guys!