cdem 0 Posted April 4, 2012 Had a problem with the corrado and I havnt got a clue what is causing it. Basically I drove about a kilometre down the road and the water temp was rising above 90 and oil rising aswell. The coolent level is fine as I checked this a few days back, the pipes to the rad and matrix were all hot too. The expansion tank was cold though and I was getting no heating in the car. No leaking pipes or matrix either. When I loosened the cap on the tank I had heating so thought great I'll visit my mum and have a cup of tea (thinking I had an air lock) when driving the 20miles home I had exactly the same problem, water sat just over 110 and oil at 110. Rad fan working fine aswell. Any idea what could be the cause? From reading around I think it could be a pressure valve but don't know where this is or what it looks like. Any help would be much appreciated Car is a 1991 1.8 16v Thanks Chris Quote Share this post Link to post Share on other sites
seanl82 23 Posted April 5, 2012 The pressure valves are on the in and out leg of the heater matrix pipework. If it had the recall, it will have one metal, and one plastic bypass valve, with a small hose running between the two. If your getting excessive pressure, it just bypasses the matrix, thus saving it from springing a leak and possibly scolding you inside the cab. Run the car up to warm from idle, with the expansion tank cap off. Massage the hoses whilst its warming up, including the bottom rad hose. Once at temp, rev up to around 2.5k for 30 seconds, then let it idle for 30 seconds. You should see it bubbling up at the top of the expansion tank if you have an airlock. If it starts boiling over, turn the engine off, leave to cool, and top up to max. Job done! Quote Share this post Link to post Share on other sites
cdem 0 Posted April 6, 2012 There is no air lock I've tried that. I've ran the car for A couple of months now aswell since I last had a coolent pipe off Quote Share this post Link to post Share on other sites
seanl82 23 Posted April 6, 2012 Not entirely sure then mate. Check your rad bottom hose to make sure it gets hot at 90 degs. If its siezed half shut it could cause problems, although its pretty rare for them to go like like, they usually get stuck open but its plausible I suppose. If your suspicious of your pressure valves, get them changed as well. I'd also be tempted to change your expansion tank cap if you still have the old black type. They are notorious for venting too soon or not at all, so if its not venting that could cause issues with high temps. Dunno how much the pressure valves are, but would imagine they're reasonably cheap. And stat and expansion cap are very inexpensive so worth a punt regardless. Hope this helps mate. Quote Share this post Link to post Share on other sites
cdem 0 Posted April 6, 2012 I've checked all the pipes when the cars at temp and they are all hot, with the cap on the pipes are rock solid. I've checked with vw and they stopped doing the valve 5yrs ago which is helpful and second hand they are £40 plus postage. It's better for me to get a mk3 matrix and get rid of the valve. I do have a blue cap so will change that over today Quote Share this post Link to post Share on other sites
