How to identify a suspected boost leak

Geekazoid · 15 Aug 2013 at 14:49

Right guys my Saab 9-3 is seriously down on power and moves very slowly for the power it produces...

I can hear a slight hiss from the passengers window when on the boost... The boost gauge does move but the car is very sluggish I'm putting my money on boost leak but don't know what to look for or where to begin...

Should i take it to garage?... If it is a boost leak i want to change all the Inlet and IV hoses what's the cost of this procedure..

Phil W · 15 Aug 2013 at 17:51

Where in the UK are you? Various tuners offer boost leak checks for around £25 or so.

You can make your own kit up but to be honest its easier to get someone else already equipped to do it.

MatteH Oxford · 15 Aug 2013 at 19:16

Stick some car shampoo in a spray bottle and spray it over the pipes and intercooler, any leaks will make bubbles in the soap solution.

Clarkey · 15 Aug 2013 at 20:01

Going to be a big leak if you can hear it hissing. Best way is to add pressure and smoke to the intake and see where it comes out. Replacing all pipes will be pretty costy tbh.

LizardKing · 15 Aug 2013 at 20:44

MatteH Oxford said:
Stick some car shampoo in a spray bottle and spray it over the pipes and intercooler, any leaks will make bubbles in the soap solution.

This but stay away from the vacuum side!

Else block off your airfilter and blow smoke into a vac line. If you need pressure but dont have a compressor those pressure garden weed killer spray bottles do surprising well

Fuzz · 15 Aug 2013 at 21:05

Sit on the open bonnet and get someone to go for a drive.

Or go to a dyno where it can be loaded up in safety and pinpointed almost immediately

MatteH Oxford · 15 Aug 2013 at 23:33

LizardKing said:
This but stay away from the vacuum side!

Hardly anything will happen, the engine might bog down bit if it sucks in a tiny amount of water but it is hardly going to cause it to explode in flames or go hydraulic and chuck a rod. Unless the op uses a pressure washer. Vacuum side leaks will show up as bad positive fuel trim at idle, which gets better when the throttle is opened dropping the intake vacuum.

Smoke is good for leaks but I expect the op doesn't have access to a £1k smoke machine. The garden pump method might work with smoke from a cigar but I think it may be hard to get enough smoke in the intake to see where it's leaking from.

Sparky · 16 Aug 2013 at 08:45

If its pretty loud check the connections to the intercooler.