Series 3 cooling system fun

finally got hot air going into the cab for the first time since I bought the car all those years ago

as the fan had never worked until I went through the electrics I just assumed that was why I got no heat since the heater valve was stuck in the open position. Sadly fixing the blower didn't solve the problem - I know its summer at the moment - got the engine warm but the heater matrix wasn't warm. took the heater valve off and it was just full of some white waxy gunk that I eventually scraped out with a wire coat hanger. Rinsed the valve through and it moves freely now and yay the heater works.

I did notice also that the cooling system doesn't seem to pressurise certainly not like my s1 does. fluid is obviously moving round looking through the rad cap and the rad gets hot. doesn't seem to lose water and there is no mayo in the oil filler cap. I have no idea whether it has always been like this.

its an s3 2.286 weasel.

cap seems to be rated at 10 lb's.

this isn't normal is it?.

No not normal does the cap have the rubber seal fitted.
Made this mistake with mine bought new cap assumed the seal was not required spent 12 months wondering where the water was going before someone told me to check for seal.

By weasel I assume you mean Diesel...

More the point, cap should be 9-10 pounds. The pressurization is definitely an issue - you need that to work. Cap is a good place to start, also check to make sure that it's seating properly on the filler neck - a bit of coloured gel or grease (clean it off after) applied to the cap seal - look for transfer to the seating surface and make sure it's doing what it should.

Be aware that this may point out leaks elsewhere...

yep its an n/a diesel.

cap seems fine, it doesn't boil over if you leave the cap off, my s1 chucks water out if the cap isn't on, (I had the same issue as you with the s1 Blackburn no seal on the cap, first cap I got was a 10lb one which caused other problems as it only needed a 4 lb one)

wonder if there is another blockage in the system somewhere stopping full circulation? it doesn't overheat although its only being run on the drive at the mo, hopefully going for mot in a week or two.

as I say it could have been like this all the time, certainly the heater valve has been blocked since I bought it.

I shall pull off some of the other hoses tomorrow and see what falls out.

Have you flushed out the heater matrix ? Doing that transformed my series three. I flushed with a hose pipe (be gentle with the pressure) I flushed both directions that is hose on each matrix pipe in turn, also did the same with the main radiator.

might give that a go divie, heater matrix does get real hot now but still if there was all that gunge in the valve there may be some in the matrix too. I did buy a new matrix a while back but it will probably be years before I get round to installing it

be best to make sure the system is clean first anyway