Coolant overflow when engine turned off.
Discussion
Got home last night and around 30 seconds after switching off lots of steam from engine bay... nothing whilst on the move... and small puddle on floor.. flipped bonnet and seemed as though might be coming from the swirl tank... difficult to tell. Pressure cap is on swirl tank so is this nothing more than new pressure cap required and why would it only happen when the engine is turned off ?
Regards,
Mike
Regards,
Mike
Worms all over the shop ... 
You should never ever get water out of the top of the swirl tank. If you do, the cap isn't sealing. Most likely because the rubber seal has perished, or the cap has physically distorted (they're quite soft) and isn't clamping properly any more. It may also be because the sealing face at the top of the swirl tank is damaged or corroded.
As to why it happened after you switched off: if the engine is moderately hot when you switch off, the coolant temperature in the heads goes up sharply when you switch off. If the system isn't holding pressure, or the engine was *really* hot in the first place, this can be enough to boil the coolant in the heads and this will then blow water past the pressure cap. If the outer seal on the pressure cap is working properly this water goes into the header tank, if that overflows you get wet feet. If the outer seal on the pressure cap *isn't* working properly, you get a fountain of water/steam all over the engine/exhaust.
You should never ever get water out of the top of the swirl tank. If you do, the cap isn't sealing. Most likely because the rubber seal has perished, or the cap has physically distorted (they're quite soft) and isn't clamping properly any more. It may also be because the sealing face at the top of the swirl tank is damaged or corroded.
As to why it happened after you switched off: if the engine is moderately hot when you switch off, the coolant temperature in the heads goes up sharply when you switch off. If the system isn't holding pressure, or the engine was *really* hot in the first place, this can be enough to boil the coolant in the heads and this will then blow water past the pressure cap. If the outer seal on the pressure cap is working properly this water goes into the header tank, if that overflows you get wet feet. If the outer seal on the pressure cap *isn't* working properly, you get a fountain of water/steam all over the engine/exhaust.
Chaps, I am at the parental unit's house tinkering with my S2, which has been having cooling problems. I bought the correct(ish) cap (13lbs long throw from tvrcarparts.com), and fitted it to the swirl pot. Still no joy - I was thinking that I might need a water pump or radiator...
Symptoms were initially just like above; chucking water out after switching the engine off. Soon progressed to overheating quickly.
It turned out that the issue was the swirl and expansion tanks' design, and the way that the overflow pipes from the swirl tank were configured; this meant that the pressure cap was not sealing properly. So I swapped the caps; the blank cap's shape meant that it could form a tight seal on the swirl pot. The pressure cap sealed tight on the expansion tank (it wouldn't on the swirl pot). Result? Perfect running. I also filed the surfaces on the openings to both necks perfectly flat, and used a bit of vaseline when putting the caps back.
Without opening the whole 'where does the pressure cap go' debate, I reckon that the important thing is how best can you get a perfect seal. The swirl pot on my car (and I suspect others who use the same cap configuration as me) is simply too imperfect to allow a pressure cap to seal on the swirl pot. So, as GreenV8S says - make sure the system is sealing. That is the very first thing, it seems, that will cause the engine to rapidly overheat.
Good luck! Imagine my relief when I found my problem was so easily solved (touch wood - you never know with a TVR!). I hope yours can be as easily dealt with.
Harry.
Symptoms were initially just like above; chucking water out after switching the engine off. Soon progressed to overheating quickly.
It turned out that the issue was the swirl and expansion tanks' design, and the way that the overflow pipes from the swirl tank were configured; this meant that the pressure cap was not sealing properly. So I swapped the caps; the blank cap's shape meant that it could form a tight seal on the swirl pot. The pressure cap sealed tight on the expansion tank (it wouldn't on the swirl pot). Result? Perfect running. I also filed the surfaces on the openings to both necks perfectly flat, and used a bit of vaseline when putting the caps back.
Without opening the whole 'where does the pressure cap go' debate, I reckon that the important thing is how best can you get a perfect seal. The swirl pot on my car (and I suspect others who use the same cap configuration as me) is simply too imperfect to allow a pressure cap to seal on the swirl pot. So, as GreenV8S says - make sure the system is sealing. That is the very first thing, it seems, that will cause the engine to rapidly overheat.
Good luck! Imagine my relief when I found my problem was so easily solved (touch wood - you never know with a TVR!). I hope yours can be as easily dealt with.
Harry.
Oh, and I know it seems obvious, but move the jubilee clips on the hoses to the top of the swirl tank round so that they don't foul the cap. Even allowing the cap to ride up a millimetre or so by fouling on the clip will break the seal - eventual overheating due to lack of pressure.
>> Edited by Harry Flashman on Monday 13th June 15:02
>> Edited by Harry Flashman on Monday 13th June 15:02
Hello......and help! In an attempt not to create a whole new thread for a similar issue I'd like to use your collective brain power - I'm a new owner of an S3c which has identical symptons to the issue above EXCEPT the cooling fan seems to work intermittently and as a result occasionally overheats when sitting in traffic / getting home. No issue on the motorway because of air flow but stationary it creeps beyond 90 odd and soon bubbles away. I've seen the fan working with my own eyes but also have seen it overheat and the fan has never even kicked in. Any thoughts?
PS. Brilliant cars. Put off getting one for years and now gutted I did. Brilliant, brilliant, brilliant.
PS. Brilliant cars. Put off getting one for years and now gutted I did. Brilliant, brilliant, brilliant.
I had a similar issue on an S1 many years ago where the fan worked intermittently. It was the actual fan bearing which overheated jamming the fan. Once the bearing cooled the fan spun again for a while. When I tried spinning the fan by hand (ignition off, of course..!!) you could hear/feel a 'grinding'. Ended up getting a new fan.
Not sure if this is your problem but wirth a look.
R
Not sure if this is your problem but wirth a look.
R
Moggy - could simply be airlocks. If the system has air in it, the radiator pipe on which the fan otter switch is mounted may only intermittently get hot enough to trip the switch. First things first check that the wires between switch and fan are all good and connectors are clean and tight. Then top up the system while bleeding from the tap on top of the rad. If you still get the problem, time to think about fan bearings etc.
Mine overheated viciously on the way into London again.
The moral of the story? Once you have run system for a while after first filling, TOP UP AGAIN WITH THE ENGINE RUNNING IMMEDIATELY ONCE SYSTEM IS ALL WARM AND THERMOSTAT OPEN!
Don't do what I did - wander inside congratulating oneself on having sorted the cooling system and treat oneself to a cold beer in the garden, forgetting all about re-topping up the system. Muppet. Filled it up after the overheating incident in Richmond, worked fine through 45 minutes of traffic jams to Clapham afterwards.
>> Edited by Harry Flashman on Monday 13th June 15:03
Mine overheated viciously on the way into London again.
The moral of the story? Once you have run system for a while after first filling, TOP UP AGAIN WITH THE ENGINE RUNNING IMMEDIATELY ONCE SYSTEM IS ALL WARM AND THERMOSTAT OPEN!
Don't do what I did - wander inside congratulating oneself on having sorted the cooling system and treat oneself to a cold beer in the garden, forgetting all about re-topping up the system. Muppet. Filled it up after the overheating incident in Richmond, worked fine through 45 minutes of traffic jams to Clapham afterwards.
>> Edited by Harry Flashman on Monday 13th June 15:03
Cheers guys, will try bleeding......again.
Have now installed a fan overide which at least seems to do the trick and temp seems stable at below 90 in trafffic. Still had some bubbling when I got back last night and switched the engine off though (after the dreaded Sunday night M4 and crawl through london run, which is pretty extreme).
Have now installed a fan overide which at least seems to do the trick and temp seems stable at below 90 in trafffic. Still had some bubbling when I got back last night and switched the engine off though (after the dreaded Sunday night M4 and crawl through london run, which is pretty extreme).
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