Discussion
Took the S3 out for my first real long run on Saturday and broke down due to overheating in traffic in a huge queue getting back into Wales during the evening. I hadn't been pushing it hard, 2500-3000 revs up the M5 and over the bridge. It took 4 litres to top up after cooling down.
After reading the Steve Heath book I saw that the expansion tank and swirl chamber caps were the wrong way round. When I swapped them all I got was steam and coolant bubbling out of the top of the swirl tank. I looked more closely at the pressure cap and saw there was no rubber seal. Should there be?
I also suspect that I now have an air lock as the heater matrix pipes were cold with the heater set to full heat. They did get hot then cooled again and there is a lot of bubbling and gurgling in the expansion tank. The thermostat seems ok but I may replace it anyway.
As she runs ok when moving but still gets hot when idle I bypassed the cooling fan switch as per the advice from Steve Heath but it stayed immobile.
Also, I think I may drain and flush the system before refilling with coolant - does this sound like a good idea?
Thanks in advance for any advice,
SteveO
After reading the Steve Heath book I saw that the expansion tank and swirl chamber caps were the wrong way round. When I swapped them all I got was steam and coolant bubbling out of the top of the swirl tank. I looked more closely at the pressure cap and saw there was no rubber seal. Should there be?
I also suspect that I now have an air lock as the heater matrix pipes were cold with the heater set to full heat. They did get hot then cooled again and there is a lot of bubbling and gurgling in the expansion tank. The thermostat seems ok but I may replace it anyway.
As she runs ok when moving but still gets hot when idle I bypassed the cooling fan switch as per the advice from Steve Heath but it stayed immobile.
Also, I think I may drain and flush the system before refilling with coolant - does this sound like a good idea?
Thanks in advance for any advice,
SteveO
SteveOS3 said:
After reading the Steve Heath book I saw that the expansion tank and swirl chamber caps were the wrong way round. When I swapped them all I got was steam and coolant bubbling out of the top of the swirl tank. I looked more closely at the pressure cap and saw there was no rubber seal. Should there be?
If you do a search the pressure caps issue is a much discussed topic on this forum, what works for me may not be ok for someone else.On the swirl tank I have a 15lb pressure cap with a rubber seal and on the expansion tank I have a 13lb cap without a rubber seal, she never overheats no matter how hot it is or how long I am stuck in traffic and the fan works every time without an overide switch ! as I said before this is only what works best for me.
As for the air lock issue, try refilling the system and run up to temperature, then turn the engine off and open (carefully) the bleed valve on top of the radiator that should expel any air (and a bit of coolant) and hopefully go some way to solving your problems, Good luck.
Cheers.....Tony..
I recently had a problem with the Fan not working, it was nothing electrical it was simply partially seized, check it turns freely (very Freely) if not spray between the fan and the motor liberally with WD40 and turn the fan by hand about ten times, obviously with a cool engine and the ignition Off, the motor should free off quite quckly, mine now spins like a good un.
Worth a try, it may save you a lot of time checking relays and fuses.
Worth a try, it may save you a lot of time checking relays and fuses.
tozerman said:
SteveOS3 said:
On the swirl tank I have a 15lb pressure cap with a rubber seal and on the expansion tank I have a 13lb cap without a rubber seal, she never overheats no matter how hot it is or how long I am stuck in traffic and the fan works every time without an overide switch ! as I said before this is only what works best for me.
I think the cap on the Swirl tank should not be a pressure cap, it is simply a cap that seals the top opening only of the swirl tank, leaving the coolant to expand freely to the Expansion tank.Since learning this I have changed my outlook on the issue and now being aware of this fact have to agree with the theory of pressure cap on the Expansion tank, the one on the swirl pot simply acts like a screw on bottle top ( it does not seal off the vent to the expansion tank)The idea of the swirl pot is to release bubbles from the system and allow them to travel freely to the expansion chamber, or so I beleive.No doubt someone else will have a different opinion as this has been an emotive subject in the past. Edited by clarenceboddiger on Sunday 24th August 21:47
Hi Steve. Might be worth checking the relay in the passenger footwell 
. This happened to me about two years ago during London Thunder and took me ages to realise where the issue lay. The pressure cap on the expansion tank always worked for me but saying this is usually like opening a can of worms..... 
. This happened to me about two years ago during London Thunder and took me ages to realise where the issue lay. The pressure cap on the expansion tank always worked for me but saying this is usually like opening a can of worms..... 
Starting with the electrics, I took a quick peek at the fuses and it looked as if it was missing, but when I looked closer it seems to have melted and the slots filled up with crystalised plastic. This would explain the non-starting fan.
I'm not sure where to go from here. Any ideas would be gratefully received.
I'm not sure where to go from here. Any ideas would be gratefully received.
Probably not your primary cuase but you shouldn't have water bubbling out of the swirl tank (or expansion tank for that matter). It means the system isn't sealed therefore every time your engine gets hot it looses water from the cap and will inevitably suck air back in when its cooling down causing air in your system and poor cooling. I suppose ultimatley this is the job of the expansion tank.
The top of the swirl tank can sometimes become distorted making a bad seal. Your best bet is to make an extra washer from a bicyle inner tube that will get a better seal, also gently sand down the rim of tank if it is covered in gunk to aid sealing. As this is a relatively easy job start with this, but as Green V8s said get the fans sorted before you run here again.
The top of the swirl tank can sometimes become distorted making a bad seal. Your best bet is to make an extra washer from a bicyle inner tube that will get a better seal, also gently sand down the rim of tank if it is covered in gunk to aid sealing. As this is a relatively easy job start with this, but as Green V8s said get the fans sorted before you run here again.
As GreenV8S says, forget fannying around with swirl caps, pressure caps, gaskets, and all of that.
Primary cause is simple: the fan isn't working. It doesn't matter how good the rest of the system is, if the fan doesn't cut in then the system will boil in traffic. Water will come out of the swirl cap / expansion tank even if they are perfect. No fan = boily-boily. OK?
First step - put another fuse in. test fan. if it works, stop.
If not, then be methodical. Don't jump about like a fickle bee who can't make up his mind which flower looks the best. Diagnose. Disconnect the fan at the connector under the radiator. Connect one termonal to earth and the other to battery live with 2 bits of wire. If the fan works then your problem is in the rest of the wiring. If the fan STILL doesn't work then the fan itself is busted.
If the problem is in the rest of the wiring then isolate it. Short out the otter switch in the radiator hose. If that doesn't work then change the relay. If that doesn't get you the answer then you need to get even more methodical with a multimeter and find where the break in the feed or earth is.
ETA in case anybody missed it - get the fan working first. If it doesn't, everything else you try is a waste of time.
Primary cause is simple: the fan isn't working. It doesn't matter how good the rest of the system is, if the fan doesn't cut in then the system will boil in traffic. Water will come out of the swirl cap / expansion tank even if they are perfect. No fan = boily-boily. OK?
First step - put another fuse in. test fan. if it works, stop.
If not, then be methodical. Don't jump about like a fickle bee who can't make up his mind which flower looks the best. Diagnose. Disconnect the fan at the connector under the radiator. Connect one termonal to earth and the other to battery live with 2 bits of wire. If the fan works then your problem is in the rest of the wiring. If the fan STILL doesn't work then the fan itself is busted.
If the problem is in the rest of the wiring then isolate it. Short out the otter switch in the radiator hose. If that doesn't work then change the relay. If that doesn't get you the answer then you need to get even more methodical with a multimeter and find where the break in the feed or earth is.
ETA in case anybody missed it - get the fan working first. If it doesn't, everything else you try is a waste of time.
Edited by tvrgit on Monday 25th August 16:42
TVRGit, I wanted to try the fan fuse but found the slot in the fuseboard wont take the fuse because it looks like a previous fuse had melted in there.
I will try the fan to battery test just to prove the fan works or not then work backwards like you say. If it get to the fuseboard I'll have to see if anything can be done about the fouled slots for the fan fuse.
Many thanks to you all for the advice.
SteveO
I will try the fan to battery test just to prove the fan works or not then work backwards like you say. If it get to the fuseboard I'll have to see if anything can be done about the fouled slots for the fan fuse.
Many thanks to you all for the advice.
SteveO
page3 said:
Hi Steve, you were spotted by my bruv in law, hope you get your S sorted out, I am across in South Glam`with an S2 if you need a chat 
SteveOS3 said:
Thanks Steve, do you go to the S.Wales members meetings at Fairwater. I will try to get there this Thursday. If not I'll send you my details as I would appreciate a chat.
Cheers.
SteveO
I work away from home Steve so I`m only here at weekends. That might be changing soon though. I`m up for a chat though, no expert but may be able to help.Cheers.
SteveO
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