Associate
- Joined
- 29 May 2003
- Posts
- 2,038
- Location
- Cambridge
Be gentle with me ... I don't normally venture into 'Motors' as my knowledge of things in that area could be written on a postage stamp 
The temperature guage in my wife's Rover shot up on a short trip recently - on checking the coolant tank, I found it was empty
Thinking that was the root of the problem, we bought some pre-mixed coolant and topped it up. Started up and went for a short run on the road that runs around the circumference of the village - somewhere between a quarter and 1 mile at a guess - the temp. guage sat at its normal level until about 3/4 of the way round and shot up like before. Didn't go right off the scale, but was way higher than it should have been.
As we pulled into our street, it dropped back down to normal level again and stayed there. We did three more laps of the village and the needle never budged from the normal - including a couple of minutes sat in queuing traffic - so we guessed there had just been an airlock in the system or such like. The heating control on the dash was set to max heat and we had hot air coming out the vents. We parked up outside the house and popped the bonnet, only to find the coolant bottle empty again ... no obvious signs of leaks - none of the hoses appear perished and the jubilee clips look almost brand new.
Phoned a mechanic friend and he said that it was either the thermostat or head gasket. He got me to check under the oil filler cap for sludge (none found), for water on the dipstick (again none) and got me to refill the coolant tank and run the engine with the cap off and look for bubbles - ran the engine for 5 minutes and none were seen. He reckoned that confirmed thermostat trouble and got me to run the engine for a further ten minutes with the coolant cap off, which he said would help clear any air that was in the system.
While this was going on I was looking for bubbles in the coolant and checking the needle on the dash - the needle didn't budge from its normal level. After about 8-9 minutes we were getting coolant coming back in through what he said was the overflow pipe near the top of the tank and also the odd bubble coming up from the pipe at the bottom of the tank. At that point I turned the engine off as the coolant had expanded dangerously near the top of the tank - I had expected this from reading the Haynes manual but it happened quicker than I had expected - wasn't in time to prevent an overspill from the neck of the bottle though.
I described all this to him as it was happening over the mobile and after telling me not to panic, he then got me to just turn the key enough to get the interior heating system running - he reckoned the air coming out of the vents should have been red-hot at that point - in reality I would have said it was more like luke-warm - certainly cooler than we had been getting while happily going round the block earlier.
He's fixed a problem with the compression on my wife's previous Corsa that a local garage was going to charge a small fortune for, so I trust his judgement, but as with all things, a second opinion never hurts. From the way I've described it, what does it sound like to you peeps? Thermostat or head gasket?
The temperature guage in my wife's Rover shot up on a short trip recently - on checking the coolant tank, I found it was empty
Thinking that was the root of the problem, we bought some pre-mixed coolant and topped it up. Started up and went for a short run on the road that runs around the circumference of the village - somewhere between a quarter and 1 mile at a guess - the temp. guage sat at its normal level until about 3/4 of the way round and shot up like before. Didn't go right off the scale, but was way higher than it should have been.
As we pulled into our street, it dropped back down to normal level again and stayed there. We did three more laps of the village and the needle never budged from the normal - including a couple of minutes sat in queuing traffic - so we guessed there had just been an airlock in the system or such like. The heating control on the dash was set to max heat and we had hot air coming out the vents. We parked up outside the house and popped the bonnet, only to find the coolant bottle empty again ... no obvious signs of leaks - none of the hoses appear perished and the jubilee clips look almost brand new.
Phoned a mechanic friend and he said that it was either the thermostat or head gasket. He got me to check under the oil filler cap for sludge (none found), for water on the dipstick (again none) and got me to refill the coolant tank and run the engine with the cap off and look for bubbles - ran the engine for 5 minutes and none were seen. He reckoned that confirmed thermostat trouble and got me to run the engine for a further ten minutes with the coolant cap off, which he said would help clear any air that was in the system.
While this was going on I was looking for bubbles in the coolant and checking the needle on the dash - the needle didn't budge from its normal level. After about 8-9 minutes we were getting coolant coming back in through what he said was the overflow pipe near the top of the tank and also the odd bubble coming up from the pipe at the bottom of the tank. At that point I turned the engine off as the coolant had expanded dangerously near the top of the tank - I had expected this from reading the Haynes manual but it happened quicker than I had expected - wasn't in time to prevent an overspill from the neck of the bottle though.
I described all this to him as it was happening over the mobile and after telling me not to panic, he then got me to just turn the key enough to get the interior heating system running - he reckoned the air coming out of the vents should have been red-hot at that point - in reality I would have said it was more like luke-warm - certainly cooler than we had been getting while happily going round the block earlier.
He's fixed a problem with the compression on my wife's previous Corsa that a local garage was going to charge a small fortune for, so I trust his judgement, but as with all things, a second opinion never hurts. From the way I've described it, what does it sound like to you peeps? Thermostat or head gasket?
