Wonder if anyone has any ideas please.

A couple of months ago, the engine temp on my Impreza WRX 2001 started rising every few days, had the thermostat replaced by a local mechanic and everything has been fine up till today. My brother in law took the car round the block, didn't do anything ridiculous in it, but drove it harder than I normally do (and more than likely the hardest it's been driven since the thermostat was replaced that couple of months ago)

When I got into the car after him , I thought the temp seemed slightly higher than normal, but it was so minimal that I wasn't totally sure. Drove the 2 miles back to my house, no probs on the way. Got in the car about 5 hours later and had done appx 1 mile and noticed that although the engine had reached normal temp, there was no heat coming from the heaters despite them being on full. Another mile down the road, the heat suddenly came back but noticed that the engine temp had gone almost to the max mark. Swiftly turned round and came back home. Left the engine running on the drive and made the usual'oh my car's gone wrong' call to the brother in law and saw that the temp returned to normal whilst the car was idle, so took it to the end of the road to test it and as soon as I put my foot down, the temp started to rise again, so parked it on the drive. Got out the car and saw that the front grill was wet, so assuming all the coolant has come out again, like before when the thermostat was faulty.

Now, bearing in mind that the thermostat is max 2 months old and there have been no probs whatsoever until it was driven out of 'mum taking the kids to school' style this afternoon, is it possible at all that the new thermostat has packed up for some reason, or could it be something else altogether?

There was no smoke coming out the back of the car, the oil and water seem to be clear so I don't think it's a head gasket problem. The fans were on, so not that. I did think maybe an airlock, but given that the coolant was refilled 2 months ago by the mechanic when the thermostat was replaced, wouldn't an airlock have caused problems before now?

 

Have you checked to see if the radiator is warm from top to bottom and also removed the cap off the header tank to see if any of the water/coolant flows out when revved?

Tony

 

I haven't done a great deal so far, waiting till the morning when it's light again and I can see what's going on, but sitting here panicing about the school runs etc next week as it's their christmas plays etc. Oh the joys of mechanical failures on cars

I didn't feel any pipes, but did take the coolant lid off and it was empty, which I was expecting after seeing the dripping down the front of the car.

Had to laugh at your location by the way - being in Slough myself, I don't think I've ever used Slough and Heaven in the same sentence

 

Its a bit of a take on heaven and hell in slough just now but back up north next week which is heaven

Tony

 

Think the best thing is to wait till morning, refill with coolant and have a go at burping the system (god bless google !!) and then see what happens from there, then start feeling pipes etc if it starts overheating again.

Thanks for replying, and hope the journey back up North next week is fairly traffic free

 

i had the same problem and it turned out to be the radiator, but a couple of things explored before coming to that was the thermostat like you said and air locks in the system, i also think checking your header tank for very small holes/rust bubbles around the neck to where the cap goes on is a good idea as mine was letting air in there. also check your coolant hoses are all in perfect working order if all that fails it probably is the dreaded head gasket or another thermostat! hope this helps and good luck fella

 

Fortunately, I might be able to get my hands on a cheap, new radiator as my sisters father in law has a spare on sat around that he doesn't need anymore, so am going to get her to grovel and ask him if he'd fit that for me, and whilst I'm at it, I might as well throw another thermostat in at the same time - will hopefully save me a trip to Staines with an overheating engine if it's not the radiator or airlock.

Will check the header tank in the morning though like you mentioned, but from memory it's in good condition. All ideas and advice greatly appreciated though as I've not a clue about the mechanical side of cars at all

I'm a lass, not a fella !!

 

Had a similar type of problem on my 06 Hawkeye STI, and my engine is currently in peices on a garage floor due to head gasket failure.

 

subarus don't mix oil and water normally, if the head gasket goes it leaks combustion gas in to the cooling system which then creates an air lock around the top hose which stops the flow of water through the rad and the engine overheats. check for bubbles i the expansion bottle if theres any then the head gaskets are gone

 

Well, have spent all morning trying to get the thermostat out and can't get it to budge at all. Had help from my brother in law who took the 2 bolts out, but when it gets to taking the actual thermostat out, it wouldn't move at all.

Aren't the thermostats just push in, or are we being really stupid and there's a screw somewhere that we're missing, which is why we can't get it out ??

Thanks in advance for any help

 

the thermostat will just pull out but if its been forced in the wrong way it will make it hard to get out, see if theres is a little flappy pin at the top of the thermostat, if there is its in the right way, pull it hard and pop it out ( a screw driver may help), hope that helped,
phil.

 

Thanks for everyones advice. Thought I'd update this, just incase it helps someone else. Got the air out the system, but the temp still went up again and the coolant level kept dropping. Had a feel of the rad pipes and the top one was boiling hot and the bottom pipe was stone cold.

Had a word with my mechanic over the phone and he confirmed what my father in law said straight away, that the thermostat wasn't working (despite it being recently replaced, although it wasn't a Subaru thermostat so went out and got a genuine one this time)

The coolant loss was also down to a leak in the rad, so he's replaced the thermostat and put a new rad in. Was only done today, so fingers crossed it's sorted the problem and the temp behaves itself now.

 

Had the thermostat replaced in mine to see if it would fix the issue. No joy sadly - turned out to the head gasket :-(