Hi Every one, I'm after some help this is my first post....Ive just purchased a mk4 gti 2000 x reg. Its got 42000 full vw sh. my problem is when normal driving the temperature goes to 130'c but if i stop and leave it running it cools down to normal temp..ive replaced the thermostat thinking it might be that...the systems presureising but doesn't feel to have a lot of water in the top and bottom radiater hose. i was wondering if anyone has had thios problem or any one knows what could be wrong......thanks stu
Consider the usual suspects in this type of mk4 situation: -faulty water pump -If ok, check for faulty temp sender.
You'll have to visually inspect. Unfortunately, it's not 5min work. Its basically stripping the cambelt off, so now would be a good time to change the belt/other associated parts. Eliminate the sender first, then fear the worst. Of course, get it diagnosed properly first before starting.
yeh the fans are working its the 2.0 version...when you rev the engine the expansion tank bottle the cooloanrt rises until you let the revs off...the bottom hose stays cold until at normal operating temp. the old thermostat was solid so replaced with new one but to no avail,,, no difference. is there a specific way to bleed the system at all...
Oh ok, its the 2.0 In that case, its got more in common with the mk3 gti, so the above points aren't really relevant afaik.
water pump can still fail on 2.0 though! Take the return hose off to the header tank and hold the car at high revs, if there is little or no flow expect the water pump
today i spent about 4 hrs trying to sort it...i know its not the water pump cos when you rev it fluid comes out of the return hose.....ive took the new thermostat out and tried that it works fine no over heating apart from the heaters are cold....when thermostat is put back in it over heats when driving..on tickover it doesnt over heat its like a backwards fault. when temperature starts going high if you stop driving the gauge goes back down its a very bizarre sinario....lol
water pump! the impeller is probably cracked/damaged and not circulating as well as it should! all the later golfs and passats suffer with this, pumps about 40 & get genuine! budget in a cambelt and tensioner too as it all has to come off anyway as said
Thanks for that thread.....im still not sure its the pump though because when you rev the engine the return feed kicks water back...the higher the revs the more water it kicks out....so to me that says the water pump is working...but im not a mechanic lol no doubt i'm wrong...lol thanks again for your info....just wish i knew the fault before i start stripping it down...
I have been having problems with overheating on my MK4 Golf GTI. It's not the water pump as i fitted a new one with a metal impeller. I have replaced the thermostat and the engine coolant temp sensor. It goes over 90 and hits 100, by which time i turn the engine off. My fans were not coming on. I checked the fuse and found that ok and i did a power probe on both fans, low speed and high speed. Works great. Found that the fault was the cooling fan module under the battery. So i bought a new one. My problem now is, Both fans run at low speed continuously, even when the engine is cool and the ignition is switched off. Would i have a faulty cooling fan module, a faulty engine coolant temp sensor or can anyone think of what else the problem could be. It's driving me up the wall and it's stopping me from enjoying driving my Golf. Any help would gratefully appreciated.
Are you able to hook up to vcds, check for fault codes in the cooling module, and, and I’m not an expert but I think you can also manually trigger the fans via the laptop( it’s been a long time since I played with it, and not very deeply at that) you can plug your old module in to check also. is it a brand new module you fitted, and are the part numbers 100% matching?
