What's bust on my golf 1.8T?

PeterT · 12 Feb 2006 at 20:57

Hi, I have just driven 300 miles over the past 2 days in my Mk 4 Golf 1.8T and it has started making a noise that I hear more often from tuned up Subarus.
As I accelerate and then back off the accelerator to change up the gear box I can hear a fluttering noise from the engine area.
My son thinks it sounds racey but I am keen to know what has gone pop!
It has done this before, but about 4 years ago when it was still under warranty and I cannot remember what it was.
Any ideas??

Cheers, PeterT.

Dr House · 12 Feb 2006 at 21:08

Yes it’s the dump valve, if you feel a loss of power the diaphragm may had been damaged. Its worth replacing it with a piston based one, I think the I think the forge FMCL007P is the best one

PeterT · 12 Feb 2006 at 21:12

Thanks for the reply. Does the dump valve that you suggest woosh as you back off or is it silent? Also are there any issues when you don't fit the genuine VAG part?
Cheers, PeterT.

Dr House · 12 Feb 2006 at 22:30

My car makes a wooshing sound but sometimes I think that’s its more of a fluttering sound. I probably have the same problem as you, the only way to find out is to take it in the garage and they will pressure test it. The OEM part only costs around £20 if it needs to be replaces. I think you will find much more useful info at www.ttforum.co.uk

If your car is under warrantee i would go for a VAG part

Giddy · 12 Feb 2006 at 23:34

The forge is simply stronger and therefore better if you plan to remap your car. If you are running standard boost levels then the VAG part will be sufficient and a third of the price.

PeterT · 12 Feb 2006 at 23:37

Everything is standard at the moment, so it looks like it's time to get out the Haynes manual after a trip to Solihull VW in the morning.
Thanks for all your help, PeterT.

pinkaardvark · 13 Feb 2006 at 00:40

The 1.8T doesn't have a dump valve. It has a recirculating divertor valve. So no whoosh. But yes the fluttering could well be the diaphragm is shot on the original one. You'll find it's a black blastic pot with a big hose on the bottom and a smaller one on the side clipped near the back of the engine at the top on the passenger side. Can't miss it really.

I had the forge one on my 1.8T and although it's pretty being polished ally it makes no performance difference and isn't essential in anyway. So I'd tend to just get a new plastic one m8.

PeterT · 13 Feb 2006 at 07:49

Hi, I had a look for it last night and as you say pinkaardvark it is to the rear of the engine. Mine is held on with jubilee clips indicating that it has been changed before.

Cheers, PeterT.

Giddy · 13 Feb 2006 at 07:53

I wouldnt take it to Solihull VW, its a 5 minute job to fit yourself. There are numerous how-to's available on the net.

http://www.forgemotorsport.co.uk/valve.pdf

PeterT · 13 Feb 2006 at 19:06

Hi Giddy, I was only going to Solihull VW to buy the part and hopefully confirm that I was on the right track. A few years ago the same thing happened and I was hoping to get the service chap to look it up on screen. It appears that when they took over from Caledonia all existing data was wiped from the system so they had no records. Anyway I ordered the part and it will be here on Wednesday. As you say it will only be a 5 min job.
Thanks for your help, PeterT.