Overheating!!!
Discussion
So I get my S1 back on the road and it seems I have now entered into the dreaded overheating saga! Will be driving along temp sitting at 90 then will rise just below the red on the gauge , elec fan starts and brings it back down to 90. This seems to happen on a number of occasions whilst out driving, does not matter what speed either. Should the elec fan start a little earlier or is this normal.
I know this is a common problem, however is this rise in temp normal?
I can not think what would be the problem, I am sure there is no air in the coolant system, but who knows they are a nightmare.
Any thoughts ?
I know this is a common problem, however is this rise in temp normal?
I can not think what would be the problem, I am sure there is no air in the coolant system, but who knows they are a nightmare.
Any thoughts ?
I flushed the system last year and all seemed clear, I know the thermostat is operating as when stood in the garage with the car running when it gets to 90 degrees I can feel the pipe work in and out of the rad get hot ( thermostat opening) . The rad is possibly original, I'm not sure, but like I said flushed it last year and all seemed clear.?
If it's overheating when the car is moving, it's not a switch / fan problem - as stated above, the "ram air" effect should be enough at any reasonable speed.
I think that the system might be losing pressure somewhere - maybe only slightly and maybe not all the time, but enough to cause temperature to increase. I would check for even a tiny leak - hoses, radiator core, heater matrix. I would start with the radiator caps though - apart from an age-old argument about which way round the spring cap and fixed cap go (and the answer seems to be "it depends"), make sure that both are sealing properly.
I think that the system might be losing pressure somewhere - maybe only slightly and maybe not all the time, but enough to cause temperature to increase. I would check for even a tiny leak - hoses, radiator core, heater matrix. I would start with the radiator caps though - apart from an age-old argument about which way round the spring cap and fixed cap go (and the answer seems to be "it depends"), make sure that both are sealing properly.
CJD2005 said:
I flushed the system last year and all seemed clear, I know the thermostat is operating as when stood in the garage with the car running when it gets to 90 degrees I can feel the pipe work in and out of the rad get hot ( thermostat opening) . The rad is possibly original, I'm not sure, but like I said flushed it last year and all seemed clear.?
I would still try a change of stat given that they are cheap and its an easy change, it may be working but occasionally sticking, its the most likely cause of a random over temperature problem. Also, is the pump drive belt tight?rob.
When I first had the S, I had overheating issues, which turned out to be a massive air lock in the system. It appeared to be ok, with water levels up to the right place. The airlock I had was in the radiator. The garage that fitted it, put it in upside down with no way of bleeding air from the top of it. Are you sure it is not something as simple as an air lock. Even with everything good they are a PITA to bleed.
Stat or blocked radiator I reckon. Try (carefully) touching the rad in different places when hot, or better yet use an infra-red thermometer. If it has blocked areas you'll have cool spots.
The stat could also be sticky, and though it's opening enough to allow a transfer of heat when the car is sat idling, it might not be opening fully. Right old t
t to change though.
The stat could also be sticky, and though it's opening enough to allow a transfer of heat when the car is sat idling, it might not be opening fully. Right old t
t to change though.tvrgit said:
If it's overheating when the car is moving, it's not a switch / fan problem - as stated above, the "ram air" effect should be enough at any reasonable speed.
I think that the system might be losing pressure somewhere - maybe only slightly and maybe not all the time, but enough to cause temperature to increase. I would check for even a tiny leak - hoses, radiator core, heater matrix. I would start with the radiator caps though - apart from an age-old argument about which way round the spring cap and fixed cap go (and the answer seems to be "it depends"), make sure that both are sealing properly.
Losing pressure would have been my guessI think that the system might be losing pressure somewhere - maybe only slightly and maybe not all the time, but enough to cause temperature to increase. I would check for even a tiny leak - hoses, radiator core, heater matrix. I would start with the radiator caps though - apart from an age-old argument about which way round the spring cap and fixed cap go (and the answer seems to be "it depends"), make sure that both are sealing properly.
Thanks for all your advice, think its going to be drain down time again!!! Nightmare!!
I am pretty sure there is no leaks however not sure what goes on under that bonnet while driving?
Will maybe replace thermostat and pump at the same time (piece of mind). Will check caps..
At least I have time before the summer arrives, if we get one!
I am pretty sure there is no leaks however not sure what goes on under that bonnet while driving?
Will maybe replace thermostat and pump at the same time (piece of mind). Will check caps..
At least I have time before the summer arrives, if we get one!
The only reason the system is pressurised is to raise the boiling point of the coolant higher than the natural boiling point of water. If the system had a leak sufficient to drop the pressure (faulty pressure cap is the most common cause), all that would happen is that the car would overheat faster. It's not actually overheating or boiling over by the sound of it, it's just running hotter. That really has more to do with coolant flow and efficiency.
There's a chance it's taking air in somewhere, but not expelling any water, and if there's air in there that would explain it running hotter. I've had a car where the water pump took air in, but didn't leak water out. That said, if there was air in there you'd see the gauge fluctuate more too.
My guess is a coolant flow issue, and thermostat or blocked radiator is the most likely cause of that. Being a Cologne, you've also got a chance the engine has orange crustaceans growing everywhere inside it, blocking up various ports and channels.
There's a chance it's taking air in somewhere, but not expelling any water, and if there's air in there that would explain it running hotter. I've had a car where the water pump took air in, but didn't leak water out. That said, if there was air in there you'd see the gauge fluctuate more too.
My guess is a coolant flow issue, and thermostat or blocked radiator is the most likely cause of that. Being a Cologne, you've also got a chance the engine has orange crustaceans growing everywhere inside it, blocking up various ports and channels.
phillpot said:
Slight difference of opinion here 
my money is on an air lock
my money is on an air lock
They're easy, in theory. However, for a thermostat, they're located in a stupid place, so access isn't great. The main issue is the bolts and the housing, which like to corrode. Getting it all undone without breaking anything justifies a celebratory beverage!
Air lock? I reckon that's possible to, but then why would it suddenly take on air? Unless there's a tiny leak somewhere. Also, if it's got the bleed-off pipe from the rad to the swirl pot, it's very unlikely to keep an airlock for long.
Well I must admit that was going to be my first plan as I really do not want to change the pump and stat etc if I dont need to, I have just spent the winter doing brakes and general service, if i spend anymore time think my wife will start divorce proceedings!!
Will let you know how things go...
Will let you know how things go...
Just noticed the comment about the bleed off pipe from radiator to swirl pot. Mine does not do this?
I have a bleed off pipe from the radiator with a bung in the end, which you remove when you fill the system of course.
Could this be the problem...
I would have to get a new swirl pot as the connection pipe on the swirl pot has been crimped. (I just assumed this was normal)
Hmmmm thinking this could be one problem!
I have a bleed off pipe from the radiator with a bung in the end, which you remove when you fill the system of course.
Could this be the problem...
I would have to get a new swirl pot as the connection pipe on the swirl pot has been crimped. (I just assumed this was normal)
Hmmmm thinking this could be one problem!
I went to town on mine but the main things for me were:
1. fill the system well and burp it with the lid off the swirl pot until its free of air, a gentle rev with the swirl post cap off disturbs air in my experience
2. make sure the swirl pot is connected to a header tank to permit sufficient expansion and 'draw back' of coolant when cooling
3. to facilitate 2. you will need the right type of cap with a very good seal on the swirl pot so that it allows expansion and draws back coolant from the header tank.
i now run an alloy radiator - this overcools in all but very hot weather. i restrict the airflow through the grill to permit warming up in winter and spring.
pm if you want to chat it through
1. fill the system well and burp it with the lid off the swirl pot until its free of air, a gentle rev with the swirl post cap off disturbs air in my experience
2. make sure the swirl pot is connected to a header tank to permit sufficient expansion and 'draw back' of coolant when cooling
3. to facilitate 2. you will need the right type of cap with a very good seal on the swirl pot so that it allows expansion and draws back coolant from the header tank.
i now run an alloy radiator - this overcools in all but very hot weather. i restrict the airflow through the grill to permit warming up in winter and spring.
pm if you want to chat it through
CJD2005 said:
Just noticed the comment about the bleed off pipe from radiator to swirl pot. Mine does not do this?
I have a bleed off pipe from the radiator with a bung in the end, which you remove when you fill the system of course.
Could this be the problem...
I would have to get a new swirl pot as the connection pipe on the swirl pot has been crimped. (I just assumed this was normal)
Hmmmm thinking this could be one problem!
Some cars have it, some don't. The advantage of having the hose there is that the rad is constantly venting off any trapped air back to the swirl pot. If (like mine) you don't have the pipe, it means you have to vent the rad when bleeding it in (the bolt in the short pipe you described is just that) and then re-bleed the rad every now and then. They're pretty good on the whole though, as the radiator's not the highest component in the system.I have a bleed off pipe from the radiator with a bung in the end, which you remove when you fill the system of course.
Could this be the problem...
I would have to get a new swirl pot as the connection pipe on the swirl pot has been crimped. (I just assumed this was normal)
Hmmmm thinking this could be one problem!
So basically, it's not the problem if you've bled it recently. The rad itself could be clogged with silt and corrosion, however.
Kitchski said:
The only reason the system is pressurised is to raise the boiling point of the coolant higher than the natural boiling point of water. If the system had a leak sufficient to drop the pressure (faulty pressure cap is the most common cause), all that would happen is that the car would overheat faster. It's not actually overheating or boiling over by the sound of it, it's just running hotter. That really has more to do with coolant flow and efficiency.
There's a chance it's taking air in somewhere, but not expelling any water, and if there's air in there that would explain it running hotter. I've had a car where the water pump took air in, but didn't leak water out. That said, if there was air in there you'd see the gauge fluctuate more too.
My guess is a coolant flow issue, and thermostat or blocked radiator is the most likely cause of that. Being a Cologne, you've also got a chance the engine has orange crustaceans growing everywhere inside it, blocking up various ports and channels.
You might be right about the coolant flow issue, or about the thermostat. However if there is even a slight drop in pressure, then the boiling point of the water is raised - so the car runs hotter. It might not necessarily overheat to the point of boiling over, but it would still run at a higher temperature than if it was fully pressurised.There's a chance it's taking air in somewhere, but not expelling any water, and if there's air in there that would explain it running hotter. I've had a car where the water pump took air in, but didn't leak water out. That said, if there was air in there you'd see the gauge fluctuate more too.
My guess is a coolant flow issue, and thermostat or blocked radiator is the most likely cause of that. Being a Cologne, you've also got a chance the engine has orange crustaceans growing everywhere inside it, blocking up various ports and channels.
Until the leak gets worse, that is...
My car has overheated twice in the 12 years I have had it - it had an issue just after I bought it (on the way home from the seller) - I swapped the caps and that helped, but it was still a bit prone to getting hot. although not boiilng over - I fitted a fan over-ride switch so that I could switch the fan on when it started to get hotter, not leaving it to cut in when it was already hot, and that worked fine.
It was losing coolant, but very very slowly - I only had to top it up slightly, every couple of thousand miles or so. Later, I found a tiny, almost invisible leak in the radiator core under a pressure test. Recore, and all was well. I can't remember when I last used the over-ride switch.
The second time it overheated was when the connections at the fan itself corroded, and it boiled over big time, in the queue to get into a car show. Much hilarity ensued.
TOV!E said:
Just put in the evans waterless stuff, problem solved....
Mmmmmm, yes and no. By putting Evans in, you'd prevent it overheating and doing any damage (along with the numerous other benefits of it), but it wouldn't run cooler. If anything it'd run very slightly hotter.I speak as someone who runs EWC in his S1, and sells the stuff too
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