2002 WRX, minor engine mods including air intake, 3" straight exhaust system, stage 2 mapped. Had the car for 3 years so know it's normal running well. Car has an STi rad which it has been happy with for a while.

Symptons, car suddenly ran hot 3 days ago after months of steady temp so called AA out at the time. Pressure test inconclusive (their words) but imo they didn't do a proper test anyway so it would be inconclusive lol. Drove fine with normal running since then until today when car reached hot within a short distance. I had checked water prior to journey start too. Water within res and rad and overflow about 3/4's full (as per AA recommendations).

Anyway, no smoke, oil clean and no burnt smell, no mixing of oil and water in either area and no apparent massive leakage of water either. Top pipe has collapsed or vacuumed. No apparent loss of performance before the AA visit and it overheating again today. (not that I have ragged it but I do travel 60 miles a day to work) Totally perplexed.

 

Checked the thermostat? Is the rad fan working?

 

Rad fan working - yes

Checked thermostat - no, is there an easy way to do it or can a garage check it for me? but..... if thermostat gone would I have a consistent overheat rather than my seemingly overheat one day, work fine for 3 then overheat again?

 

The collapsed hose sounds like you might have a blockage somewhere, try sticking the heater on full bore, but i'd drop the fluid and change the thermostat and give the system a good flush with a hose pipe, don't want water issues heading into winter.

And head gasket means engine out.

 

funny you should mention heater as it jogged a memory.... when she overheats the heater doesnt blow hot. Rest of time heater seems fine.

And yes, I had realised head gasket equals engine out and lots of $$$

 

If you haven't already, check under the front bumper for a build up of leaves and crud at the bottom of your radiator and a/c condenser matrixes. I've had a rad rot through because of leaf build up. Take care when clearing out as the matrixes are easily damaged.

 

if heater blows cold means no water in system of thermostat no workin..dont drive it

 

Thank you, I won't. Garage tomorrow for my baby

I did start her earlier though, pre checked water levels, topped her up then let her run for a while. Watched temp. Noted no hot air in cabin and she got hot and then suddenly, hot air through blowers and temp dropped?

Still thermostat do you think?

 

if u run the car with heater on full blast itll drop the temp guage and if its been hot air then theres water in the system..pull the thermostat off and change it...straight forward enough job and should be sound with a new one...give the system a good flush while ur at it...pull bottom radiator hose off then pleny water through the top..refit hose fill up then empty again..should take out any crap thats in there and the water will be clear..good luck bud