Evening everyone. My emission warning lamp has come on again, and not sure what is causing it tbh. I recently replaced the engine breather hose with a VW one, pictured here (used from uk-mv's.net) - I noticed it was split in two when i cleaned the engine out, so replaced it with a VW part! But no warning lamps occured, and its since been better on MPG and running really well. It wasn't until we were driving back from the New Forest when it decided to come on. I lifted up the bonnet with the engine running, and there was quite alot of air escapping from the front of the manifold area. When this is pushed down it seems to stop, but when released it starts to let air out. Not sure if its that pipe or the ones below though, and what are they for. They don't look easy to replace either, as they are situated under the inlet manifold! Anyone ever had this happen to there MK4 1.8T? Any help would be great. Cheers
Just found this which seems to be helpful. So has anyone had this happen with there 1.8T? If so , was it hard to replace? Cheers
Clearly a vacuum leak as you have probably worked out. If you can`t get to the clip that holds the pipe on (where it`s probably leaking from) then you`ll need to get the manifold off to access it, which isn`t that difficult really.
Nice one Stu Was hoping it wouldn't be a manifold off job tbh. Its in such an awkward place Will try and see if its possible to fix without removing it first though. Cheers
Took the engine cover and lower cover off today to get a better look at what is leaking. Noticed a pipe which is situated on the left of the PCV Valve has a split in it!! Just wondering if anyone knows the part number for it... Cheers
Looks like an AUM (same as AUQ) yes split pipes are a big problem in that area. Engine light is probably "system running rich" or the like due to the boost leak/s. Watch you don't snap the dipstick tube (like i did) as they get brittle over time. MPG & running should improve if you get them all.
Cheers mate... Yep, its an AUM Im going to try and sort it soon, and look for any other ones which have gone. But looking at it today it seems thats the only one. Couldn't believe the state of the oil breather pipe pictured above. It was literally split in half. Has been sooo much better since i replaced it, but now ive got this! Been looking over on uk-mkiv's and it does seem to be quite a common problem. Found this link to - http://nomads.eurodiscussion.net/forum.htm Some great stuff there.
Those Y-pipes are well known for splitting. The one on the AUM I`ve put in the Mk2 had gone too, so got a new one off VW (not cheap! 25 IIRC), then realised I don`t actually need it, since I`ve ditched most of the vacuum system...
Its mad Stu. The prices are extortionate from VW, for the simplest of parts to. But i suppose as long as it sorts the problem out then its all good... How comes you have ditched most of the vacuum system then Stu?
Not needed on standalone management (Qpeng). I`ve removed the PCV and vac reservoir and all the related pipework.
find your local TPS (trape parts specilist) and buy the part from there, they are the dealier supplier so normally a couple of quid cheaper, or if you know some one with a garage get a cash trade account set up then parts are reeaaaalllly cheap!
Thats a goood idea tbh I do know someone with there own garage so would be an idea to ask him when im buying a few bits.
Oh i see I bet its really quick in the MK2. Well i managed to temporally fix the problem. Took the battery off for a while to remove the warning light on the dash, unbolted the metal plate to access the pipe and wrapped some rubber piping around it, and fastened it up with cable ties. Seems to have done the job for now, and isn't leaking any air. Drove to Surrey today, and its getting over 40mpg on the M25, best ive ever got tbh so its happy days
Lately the Mk4 has started hissing real badly, resulting in a real bad boost leak. So today i decided to fix the problem altogether. I bought a length of silicone hose to replace the perished one, which i had wrapped with rubber for the mean time... Its the pipe which runs along nearest the inlet manifold, which requires the metal plate to be removed to get to. I'd recommend checking them, as mine was in a real bad state. Hopefully MPG will be back to normal now.
