jmuggali 0 Posted October 23, 2003 after reading all the posts about air locks etc. and changing the fan switch my c ('92) still boils over within about 15-20 mins of starting. It has been off the road for over a year, the original problem was a leaking pipe which was changed, 1st we checked the H/gas and all was fine, any new ideas? I'm new to the forum but been lurking for a while. Also anywhere recomended to take it to in the Cardiff area? Many thanks James. Quote Share this post Link to post Share on other sites
Guest Posted October 23, 2003 welcome mate, thats not good having ya C off the road for over year :shock: I'm sure someone will help ya out :D Thera Quote Share this post Link to post Share on other sites
Banana Man 0 Posted October 23, 2003 Have you changed the thermostat if it is stuck shut then the water will just be sitting in the engine and not running through the rad when its hot feel the bottom rad hose if it is still cold or luke warm then it is probably that, that is causing the problem! Welcome to the forum by the way!! :D Quote Share this post Link to post Share on other sites
jmuggali 0 Posted October 23, 2003 thanks, it's not good at all as I sold my wifes Volvo S40 for it! :? It has to get back on the road or it's going! Quote Share this post Link to post Share on other sites
paulg60 0 Posted October 25, 2003 i had this problem with mine it turned out to be the expansion tank cap the O ring was not seating properly therefor stopping the pressure relief valve in the cap from working. i also had same problem on a mk2 golf the pressure relief valve was stuck causing the same problem. might be worth getting a new cap for how much they cost. hope this helps Quote Share this post Link to post Share on other sites
exturbo2003 0 Posted October 26, 2003 i had this problem with mine it turned out to be the expansion tank cap the O ring was not seating properly therefor stopping the pressure relief valve in the cap from working. i also had same problem on a mk2 golf the pressure relief valve was stuck causing the same problem. might be worth getting a new cap for how much they cost. hope this helps yep agree a common problem with the caps,also wont let pressure build as the higher the pressure relief point the higher the boiling point, also what concentrate of anti freeze you using Quote Share this post Link to post Share on other sites
Supercharged 2 Posted October 26, 2003 Yes, the pressure needs to be there else the boiling point will be far lower than it should be! Quote Share this post Link to post Share on other sites
stevemac 0 Posted October 26, 2003 jmuggali Which pipe, exactly, was leaking ?? Had ANY engine work been carried out in the month or so prior to the start of your problem ?? Is the car definitely boiling up - or could you have a faulty temp sensor/wiring connection which would send a faulty reading to the dashboard gauge I would be changing the pressure cap & thermostat, if only to eliminate them from the possible causes. At the same time I would remove the top & bottom radiator hoses and run water through it to ensure it is not blocked. Then I would check the waterpump. Ensure that you drain & re-fill the system with the correct mix of VAG coolant and water. Quote Share this post Link to post Share on other sites
jmuggali 0 Posted October 27, 2003 Thanks for the help guy's, the leaking pipe was the plastic housing on the engine it's self which was changed without much hassle. The temp gauge has stoped working since this boiling problem! At the moment there is just water in it as the rad has been flushed etc.(It was really really dirty) When it does start to boil I can remove the cap with no pressure in the system so a quick trip to VW today to eliminate the expansion cap (fingers crossed!) Again thanks and I'll post the results later. James. Quote Share this post Link to post Share on other sites
Henny 0 Posted October 27, 2003 If this is the plastic bit on the FRONT of the engine that the top hose for the radiator comes from, then there's two sensors in it... The black one does your water temp gauge, the blue one does your ECU sensing. Check the wiring to the black sensor as this may have broken when it was swapped accross. If the wiring's OK, then you need a new sensor... It's a 2 minute job to do but make sure you replace the rubber O ring with a new one when you're doing it. If it was the plastic pipe on the SIDE of the head/engine then check this for leaks... I had one from VAG not long ago that was warped when I tried to fit it causing water leaks and lots of swearing... :lol: :mad: If there's no pressure even when the system is boiling and you remove the cap, then you've definately got a leak somewhere... Can you see where the coolant is leaking from? Quote Share this post Link to post Share on other sites
jmuggali 0 Posted October 28, 2003 Thanks for the help guys! after a new thermostat, fan switch etc. etc. it was a faulty expansion tank cap! best £5 I have spent, well happy :D No temp gauge as yet but at least we are running again! :D :D fingers crossed it lasts, all the best James Quote Share this post Link to post Share on other sites
stevemac 0 Posted October 28, 2003 Nice one - glad to see you got sorted m8 Quote Share this post Link to post Share on other sites
