I know BT has a lot of petrolheads who seem to know their stuff so I thought I'd ask your advice on a problem I've been having lately. I own a 2010 Astra 1.6 petrol, and recently I have been having an issue where the engine temp will start rising, and keep rising if I don't pull over and stop. Now it only does this if a) the engine has been running for quite some time (i.e. on long journeys or lots of little trips around town) AND b) I am in slow moving or stationary traffic. I could be driving down the motorway at 90mph all day and it will be fine, the problem only arises when I come to a slow crawl or stop for around 5-10 minutes or more. Also, I have discovered that putting the heater on full blast will keep it running at its normal stable temperature and even reduce the temperature from an overheating state. Obviously that is not really ideal in the current weather we've been having though. I've checked all the obvious things - the engine coolant is brimmed and it's only just had a full MOT and service with no faults found. At first the symptoms lead me to believe it was just a dodgy radiator fan but I've checked it a few times when the engine has started to overheat and the fan is running fine. Is there anything else that it might be that I can check? I don't really want to put it back in the garage and be charged an arm and a leg for labour costs if it's a simple fix. Even if it's just an idea of what the problem might be since if it could be serious I'll have to get it looked at straight away.
Is the coolant an anti-freeze/water mix or just water? There could be a blockage or leak in the coolant system. Check all hoses/caps etc are tight fitting and not leaking, if air gets in it can mess up the system. I would even use a screwdriver or whatever is required and check how tight the bolts etc are that are clamping the hoses. Do you get any drips on the road after you have driven the car? One slight fix if you are just going around town is to pop the bonnet and leave it on the catch, it will hold it slightly open and allow more air in but I wouldn't advise driving fast at all and it really is only a temporary 'get me home' solution.
Nope, no leaks underneath the car or in the engine bay, I've been keeping a close eye on that. The coolant is a mix of anti-freeze and water, but it has been topped up with water a couple of times. According to the car's service records the coolant has never been changed - it has done 96k miles so far, I don't know if this is normal or not? Is this easy to do? I'm sure I can find instructions online, just don't want to mess anything up and do more harm than good...
Find the top radiator hose, start the car and it should be cold to the touch. If the the thermostat opens (usually take a while 5/10mins) then you'll feel the hose flush warm as coolant floods ago the hose. If it floods warmth after a while means the thermostat is opening and it's fine. Have a look down the front of the rad for crap that is blocking airflow to the radiator, grass, plastic bags, etc I hate to say it, but it's most likely the water pump that's toast
Water pump on a 2010? Wow if true. Just to add to Burnout's technique, you're looking for a quick increase in temperature in the hose. In <20s it should be getting very hot (almost too hot to hold) if it's opening correctly. If it warms up slowly then the thermostat might be sticking half-open. Out of interest, how many miles has it done? Any warranty left? Could be worth dropping it in to Vauxhall if so.
Thanks for the advice guys, I'll have a go tomorrow morning and see what I can find out. It's done 96,000 so far which is a lot given its age (it was the old man's and he did 30k miles a year for work) but it has impeccable service history (every 20k miles at a main dealer). Vauxhall warranty runs to 100,000 miles IIRC so it would be however it only applies to the first owner of the car. Although my Dad was the first owner I am now down as the registered keeper so I don't think I would get away with having it covered under warranty.
Ah, could well be a duff water pump at that mileage. I think they have a plastic impeller, if a small piece has broken off the pressure at idle will be poor, leading to excessive heat build-up. A Google suggests the car will also be due for a cambelt change as well - the waterpump is likely to be driven off that, so it's belt, tensioners, pump etc all together.
Ok thanks. Is there any way to test for a broken water pump? Or will it just be a case of ruling out the other possibilities then having a garage take a look at it if I find nothing else wrong?
It's worth checking the thermostat, but if it's opening correctly, and there are no leaks, then that will be your culprit (assuming the car is running OK and using no water). The cambelt interval is 100k miles - you should seriously be thinking about changing it. If (and it's a big if) the belt does let go, if it's outside the recommended maintenance schedule you won't get any good-will from Vauxhall.
Could you take your dad with you to the Vauxhall dealer? Because if they use the term 'owner' the registered keeper and the owner do not have to be one and the same. So you could claim it's in your name for say insurance reasons but still owned by him, if that's the case https://www.askthe.police.uk/content/Q743.htm
If its got TOO much coolant in, it could be causing an air lock (this is what happened with mine) meaning that it wouldnt release the cold water round the engine till i revved when the temp bar was at max. ensure your coolant levels are between the min and max levels, and are not "brimming"
Cool thanks for that, sounds like it shouldn't be an issue then, the only problem would be if it turns out to be something that isn't covered by warranty, in which case it would just be cheaper to get fixed at an independent garage. It's definitely under the maximum level, and I was having the same problem before I topped it up when it was quite a bit lower, so I'm confident that's not the cause of it.
With it over heating you will lose a small amount of water/coolant, however... how low was it as you've said its been topped up a couple of times. run it up to temp and double check the fan kicks in... should come on around the 100 degrees mark, if it doesn't obviously turn it off sharpish and check these... 1) fuse - will be labelled on the fuse cover/lid. 2) disconnect the fan wiring and hook it up to the battery for a second to see if the fan spins ( make sure you cant get caught by the spinning fan!!) 3) wiring to the fan switch normally located in the radiator. hth...
If you've topped it up a couple of times, check how much coolant is draining. Sometimes it could be as simple as a leaky leaky radiator. Bar that it could be a radiator fan or parts of the hoses that are improperly secured.
I doubt it's a dead radiator as it would overheat everywhere, also you tend to loose a feck load of coolant when they go. A small pin hole might drip when cold, but when its hot it steam vents as the coolant system is low pressure ~1.1bar and that's enough to make a nice steam jet when it all goes wrong. Upside is it's easier to find. I suspect due to the shear mileage this astra has done in such a short time that the waterpump is toast. You could test it, but it's a little tricky. You would need to pull the coil packs to stop it starting, then pull the thermostat out which will get your feet wet. After removing ther thermostat, crank the engine over, it wont start but it'll spin the pump and you should get a surge of coolant make your feet even wetter, by this point all the coolant most likely will be in your shoes and your pets most likely dead due to drinking it. If you don't get a surge of coolant flooding the place when cranking the engine over either you've got no coolant left in there because you took too long removing the thermostat or the pump is toast. Also might I ask, when you say overheat, has it actually vented coolant/steam from the pressure relief cap on the header tank, or is it just pinning the needle into the red on the guage.
The fan comes on fine, that's definitely not the issue. There's no leaks whatsoever, the coolant level is the same as when I topped it up about a month ago. Nope, it just keeps going up until it hits the top of the temperature gauge and the warning alarm goes off, I've never had it release any steam or coolant. I also checked the thermostat earlier and it seems fine, the radiator hose goes hot after ~5 minutes. Not sure how long it took to go from cold to hot though, and I wouldn't say it was too hot to touch either (though I might not have had the engine running long enough). I guess it's probably time to phone around and see how much a new belt/water pump will cost me
With regards the warranty should have kept it in your dads name till it ran out The fact that when you are hammering along on the motorway and it is fine would suggest it isn't a pump failure to me.
