Funkster 0 Posted December 5, 2004 Hi everyone, bit of a ramble here, sorry... I'm having a bit of trouble with the cooling system on my '95M Corrado VR6. It warms up normally (at a guess, anyway) from cold and when it gets to 90°C it hangs there for a while. However, after driving a bit it will gently creep up to 95-100, even when just motoring along at 70 on the motorway, with 10°C ambient. Oil temp reads about 120 on the motorway so I don't think it's just a bad gauge. I haven't heard the cooling fans running yet, which is probably a big clue, but should the fans really be needed when cruising at 70? I did some searching on here (thanks to people who have posted about this in the past) and as a result tested out the fans - when bridging the wires in the radiator fan switch connector the fans come on at both speeds. So, this hints at a bad thermostat switch in the rad which seems like a great explanation - shouldn't be hard to get it sorted. However, I also bridged the wires in the yellow temp. sender connector with the ignition off, which caused the fans to come on at the slower speed - shouldn't this have happened when the coolant temp. got to 100? Surely both switches can't be broken? ) Finally, my auxiliary coolant pump seems to be both broken and leaking: http://homepage.ntlworld.com/oliver.stephenson/auxpump.jpg Is it possible to be leaking from the wet black bit in the photo? Apologies for poor focus. It doesn't make any noise with ignition on or with the yellow connector bridged (fan unplugged so I should've been able to hear it) and it seems to be dumping coolant out onto the mounts: http://homepage.ntlworld.com/oliver.stephenson/wetpatch1.jpg http://homepage.ntlworld.com/oliver.stephenson/wetpatch2.jpg So, I guess my question is am I just looking at several little niggly problems or is there something more fundamentally wrong here? Sorry about the huge post, normally I would lurk longer on a new forum before asking stuff like this, but I don't want to hurt the motor if it's a really serious problem, and I want to take the car back to the dealer tomorrow to get them to fix it - and make sure they fix the right bits! They replaced the radiator prior to my picking the car up 'cos they thought that was where the leak was. Many thanks for any advice, and my apologies if I've missed something identical in the search! -- Olly Quote Share this post Link to post Share on other sites
vr6storm 0 Posted December 6, 2004 yip deffo new aux coolant pump time.......as for the others if you can afford it.........just replace all the switches and coolant temp senders while getting the aux coolant pump done...........be as well budget for a coolant change too(G12+)............if you replace them one by one the law of sod or murphy will have you replacing them within weeks or months of each other anyway :wink: Quote Share this post Link to post Share on other sites
Funkster 0 Posted December 6, 2004 Is the coolant special? Due to the leak I've been topping up with 40/60 halfords antifreeze/water, which appears to be the same colour as what was in there before - blue. Have the garage used the wrong stuff? Muchas gracias, -- Olly Quote Share this post Link to post Share on other sites
Rpmayne 0 Posted December 6, 2004 The G12+ is pink and apparently better according to people on the forum so I just went along with that. I used halfords stuff in other cars with no problems though, don't really see the difference. Toyota recommend their coolant which is apparently special pre-mixed stuff and the bloke I get to do the head work says they're always the best preserved. Must be something in it. As it happens my auxillary pump is leaking like that too. £80+VAT from the stealer. Also seems to be leaking from around the top where the connector goes on. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted December 6, 2004 First things first - the "hangs at 90 for a while" tends to indicate that either your thermostat is opening a bit late, or you've got a dodgy reading on your temp gauge. Possibly the 'stat is getting sticky - should open at 80 degrees. The fans should NOT be needed when cruising along the motorway, and you shouldn't see more than about 90 degrees in the water then, either. It really sounds to me like you have a stuck thermostat. Does the radiator ever get warm? The temp sensors for the rad fans are in the rad, so if it never gets any hot water in it, there's your big clue... Quote Share this post Link to post Share on other sites
Funkster 0 Posted December 6, 2004 Interesting. The user manual has a line on the drawing showing 'normal' to be 90 so I assumed that that was the stat temperature. The top hose certainly gets hot, and when I tested the fans yesterday warm air was blown out despite the fact that I had allowed the car to cool down quite a lot. But if fans are never needed on the motorway then it certainly sounds like it's not opening fully. It's a shame there's no temp. gauge in the lower rad hose! I'll get the garage to change it anyway. Thanks, -- Olly Quote Share this post Link to post Share on other sites
dr_mat 0 Posted December 6, 2004 But if fans are never needed on the motorway then it certainly sounds like it's not opening fully. Not unless you're in that particularly weird part of the west midlands with a tropical climate, anyway... Quote Share this post Link to post Share on other sites
Funkster 0 Posted December 6, 2004 Not unless you're in that particularly weird part of the west midlands with a tropical climate, anyway... :oD Seems you're right on the money with the stat - I just drove it back to the dealer and the bottom rad hose was stone cold when I got there. Now I feel a bit daft for not checking it before, but never mind. The leak has also worsened, as it now seems to be coming out of the stat housing as well. Anyway, it's back with them now and they said they'd sort it out. Thanks for the advice and support! Cheers, -- Olly Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted December 6, 2004 Could have done it yourself in an hour and all the parts come to £30! Did a stat and housing change at the weekend on a fellow member's car..... but it turned out to be a faulty temp guage that gets as high as 70 and stops, LOL! I hope they don't sting you too much at the dealer.... it's not a difficult job.... even for them!! Quote Share this post Link to post Share on other sites
Funkster 0 Posted December 6, 2004 It will be free! Only just bought the car, and they said they'd sorted out all the cooling problems when I picked it up. Turned out not to be so! Not a VW dealer btw, just a general second hand car dealer. I probably wasn't very clear on that, sorry. If I was paying, I would certainly do it myself. Cheers, -- Olly Quote Share this post Link to post Share on other sites
crazymarcel 0 Posted December 6, 2004 Could have done it yourself in an hour and all the parts come to £30! Did a stat and housing change at the weekend on a fellow member's car..... but it turned out to be a faulty temp guage that gets as high as 70 and stops, LOL! I hope they don't sting you too much at the dealer.... it's not a difficult job.... even for them!! Yep cheers for that Kev, much appreciated, bit of a shit dint fix the problem, but least i know thats one less thing it could be and everything is working ok,(fans etc) looks like a dodgy gauge or if there is a sender for it somewhere. Quote Share this post Link to post Share on other sites
Funkster 0 Posted December 8, 2004 *sigh* Just picked the car up, the garage having said that they'd sorted the leak with a new jubilee clip and it was now holding steady on the 'stat with fans coming on and the aux. pump running. Went out on the dual carriageway and got it up to cruising speed, and sure as eggs is eggs it gradually crept up to just under 100. Got stuck in a queue getting off the dual carriageway and it was edging its way over 100 before I shut it down and let the heater take some energy out of the coolant. Once moving again, it dropped its temp almost straight away, to about 85, and then got back to 90 by the time I was home. Opened the bonnet and there's more pressure in the system now, and the bottom hose was at least warm (but not as hot as the top hose, which itself I could touch without major discomfort). And, IT'S STILL LEAKING! Not as much as before, but it seems to be seeping out from the hose that connects to the outlet of the aux. pump - where there's a join in the hose. Also, the aux does NOT seem to be running - unless they're so very quiet that I'll never be able to hear it? Are they really silent? I squeezed some hoses and couldn't feel or hear any coolant rushing round either. This is with the ignition on. I'll take it back first thing in the morning and give them another chance to sort it. Are thermostats readily available? I'm not too far from Stealth, will they have one in? p*ssed off, -- Olly Quote Share this post Link to post Share on other sites
dr_mat 0 Posted December 8, 2004 Aux coolant pump is very quiet, yes. Doesn't sound too bad, apart from the leak. Thermostats are easy to come by, yeah. Just a bit of a pain to swap, there's not a lot of room in there. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted December 8, 2004 BTW - don't worry too much about sitting with the fans on and the coolant at 100 degrees. VW knew this was going to happen, so it can handle it. Yes you get heat soak (inlet temp climbs rapidly), but all that kills is performance. Once you get moving again it should all cool down nicely. The only thing that is a concern is the climbing coolant temp while driving along. Oil temp should climb to over 100, that's perfectly normal, but the water temp shouldn't. Quote Share this post Link to post Share on other sites
Funkster 0 Posted December 8, 2004 Hokay, thanks for that - at least I'm not hurting anything in traffic. However, I'm pretty sure that the fans didn't come on while I was stationary - I turned the heater off and opened the window and I couldn't hear them. Presumably they'd be up to full blowing power by 100 degrees? Oil reached 114 at 85mph cruise today, just for reference. Cheers again, -- Olly Quote Share this post Link to post Share on other sites
dr_mat 0 Posted December 8, 2004 The fans should be cycling on and off anytime your coolant is above 85 degrees ish, plus after the engine is turned off for up to 15 minutes. You would know about it if the fans came on! They're a massive current draw! Quote Share this post Link to post Share on other sites
