Vaccum leak detection methods

[Z28dryva]

My first post on this forum so let's make it a good one. 01 T/A with over 203k on it bone stock with a A4 to M6 computer flash. It whistles loudly when at idle with the A/C turned off and it just started recently. I'm having a hard time getting it to idle down between upshifts as well. Is there any specific tricks to looking for leaks without harming the plastic intake or aluminum block/heads? I don't want to end up cracking something by spraying cold brake cleaner on a hot engine so what would be an alternative way of checking for leaks? I do have access to an air compressor so I suppose I could do a boost leak test even though my engine is N/A but I'm open for any other suggestions if anyone has any. Thanks in advance for any tips.

[tatertot91]

Spraying some break cleaner to find a leak isn't such a bad thing, would really take a lot to damage anything under there. I'd inspect all the hoses leading to the intake carefully, look for cracks or tears. There are a few small hoses towards the rear passenger side of the intake manifold that are worth looking at.

[tatertot91]

Welcome to the site btw

[pajeff02]

The usual culprit is the PCV hose setup. It likes to disintegrate in the area just to the left of your throttle body (when looking at the engine from the front of the car). The hose setup runs around and behind the engine where it attaches to the driver side rocker cover. I would start by inspecting that.

[Z28dryva]

That was going to be my first move anyways before I take a trip to town to buy brake cleaner. I'll just unplug it and see if the whistle goes away before I waste a trip. I already had to re-do all the back hoses and had to put a metal T in the middle cuz of course the stock rubber Y had already rotted away when I got the car. I already bought the dealership replacement piece for my Camaro but it's too easy just to make one then waste money on all that. Thanks for the welcome and response guys. I should have this figured out within the hour

[Z28dryva]

Update: It seems the side of the PCV hose that actually houses the PCV valve had deteriorated badly. I never did stop the whistle by blocking it or unplugging it but I did get it to stop once I made a reliable leak proof replacement. I bought a piece of 3/8 emissions grade hose and crammed it into a piece of 5/8 hose and crammed my PCV valve into that and hose clamped the piece together in a way that can't be pulled apart. That should hold me till I get a GTO valley cover and route it there.

[pajeff02]

You can also fix it with an old spark plug boot. The different size ends of the boot usually accommodate the change in diameter fairly closely.

[tatertot91]

Good deal, just make sure you get the newer style ls6 valley cover, there are two part numbers

[Z28dryva]

Anybody ever try drilling a hole in the LS1 valley cover and putting in a grommet and PCV valve? I build industrial GM engines at work and we have hundreds of valves and grommets that are meant to go in the valve cover of a SBC but I could easily make one fit a hole I drilled in my own valley cover. Good idea or bad?

[tatertot91]

The ls6 valley cover has a built in PCV valve. In theory you could do it, but you'd still need the external PCV valve and i'd highly recommend the use of a quality catch can. You'd most likely get a lot of oil vapors without the baffle system found on the LS6 style kit.

[SuperSSguy]

Welcome to the site!

[Z28dryva]

Thanks SuperSS. I think I'll just buy the correct piece and call it good. They are cheap enough