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Model specific boards => Golf mk4 => Topic started by: Napalm on 14 December 2025, 22:34

Title: ARL Boostleak whistle
Post by: Napalm on 14 December 2025, 22:34
Hello all,

I have recently bought a 2003 ARL pd150 mk4 golf, its got 200,000 miles on it and an issue i cannot seem to diagnose is a a turbo whistle/ boost leak, i've had it on ramps revving tf out of her feeling for the leak, and listening however i cant feel anything, and its not really loud without road resistance. Any help would be much appreciated. Hope ive done this right, new to Mk4's and the forum
Title: Re: ARL Boostleak whistle
Post by: Mr_Orange on 19 December 2025, 07:36
Any loss of power or just noise under load?
Title: Re: ARL Boostleak whistle
Post by: Napalm on 08 January 2026, 14:55
I dont know, i bought the car with the issue, however its top speed is only 121mph, factory its 137mph,
Update: ive had a smoke test done, reault was inconclusive, no smoke leaked out. Really stumped here guys
Title: Re: ARL Boostleak whistle
Post by: Napalm on 08 January 2026, 14:56
And yes only under load does it whistle, not on ramps
Title: Re: ARL Boostleak whistle
Post by: barrym381 on 08 January 2026, 17:20
I dont know, i bought the car with the issue, however its top speed is only 121mph, factory its 137mph,
Update: ive had a smoke test done, reault was inconclusive, no smoke leaked out. Really stumped here guys


137mph are you dreaming  :grin and any idiot doing that in an old mk4 deserves a slap
Title: Re: ARL Boostleak whistle
Post by: Napalm on 10 January 2026, 18:09
I dont know, i bought the car with the issue, however its top speed is only 121mph, factory its 137mph,
Update: ive had a smoke test done, reault was inconclusive, no smoke leaked out. Really stumped here guys


137mph are you dreaming  :grin and any idiot doing that in an old mk4 deserves a slap

Cheers for that mate, looking for advice on to stop the whistle when the turbo kicks in lol
Title: Re: ARL Boostleak whistle
Post by: bogwoppit on 11 January 2026, 10:10
Did the smoke test also pressurize the system?

If not, you need to try something like this, and then go around all the joints squirting soapy water on them to look for bubbling

https://www.youtube.com/watch?v=ijJNKXwxKco&t=202s