Need help finding intake vacuum leak
 

After talking with justin when he took a look at my logs, he said I have a major intake vacuum leak, since my IAC is pretty much closed the entire time the motor is warmed up..

I checked the TB gasket, both sensors on top of the intake, plug for EGR, and all seemed fine. I couldnt feel anything around the brake booster or back of the motor where the line comes in.

Im thinking my next step is to pull the intake and re seal it. Any tricks to this? basically just unhook everything, 8 bolts that hold the intake down and go from there? Can I get new seals for it, or do I reuse what is on there?

I do have an oil leak from somewhere on the back of the motor, but im guessing that couldnt cause a vacuum leak anywhere right?

take some brake cleaner and spray around and youll find your leak..

Brake cleaner or some starting fluid with it idling. It'll show you exactly where the leak is ;)

thanks..That's what I figured..ill try it tonight n see what happens

Get new intake gaskets, they have the tendency to go bad.

found it today..one of the plugs on the pass side of the intake had a hole in it. it looks like something was broken off of it at one point..i put a screw in it and some rtv around it and now its good to go..do these plugs just pop off or what? where can i get a new one?

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also got my new engine cover on

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Don't forget your oil fill cap!!

Glade you found your vacuum leak, I have a smoke machine at work that works wonders with vacuum leaks, and evap leaks. pump the smoke into your intake sealing off anything that you dont want the smoke pooring out of and any small leak will show up like a red flag. they even have a smoke machine that presureizes the smoke your pumping in to help with FI intake leaks, turbo piping leaks, intercooler leaks. its a real nice tool.

lol you mean the rag that ive been using all summer since i lost my cap...ya i gotta snag one from my buddies house one of these days lol

what about finding an oil leak? I am leaking oil, about a half dollar size each night when im parked in the driveway...i cant tell where its coming from..they replaced my rear main seal when they did the trans, so maybe thats leaking again? its coming down and dripping from next to the drain plug on both sides, sides of the oil pan are covered as well as above the pan on both sides in the back..just annoying having to add oil here and there

I was going to suggest smoke testing it for a leak but someone beat me to it. Interesting place to find a vacuum leak but its sealed none the less.


Here is what I've found on the 4.8, 5.3,s and 6.0s as far as oil leaks go. The most common leak is the rear of the oil pan gasket. This seems to happen on 05+ engines the most although a handful of early 6 liters have a tendency to leak there too. A rear main leak isn't really all that common unless your bearings are wasted and by that point you'll know something is up. The other leak is the rear engine cover. I've seen some that were porous and the oil just leached through the casting and on some that oil was leaking out around the bolts due to a bad gasket. I put one on a 01 6 liter and got the timing cover, gasket, bolts and rear main already installed as an assembly for 66 bucks. You can't piece it all out for that. Put it on and no more leaks. The last leak is the oil pressure sender. Just because it works doesn't mean it doesn't leak.