Exhaust leak

[AlaskaTy]

I'm fighting a couple different problems right now. First is I have an exhaust leak coming off the bottom of my passenger side exhaust manifold (at least that's what I think: the spark plugs were all covered in carbon everywhere that was exposed.) I can hear it ticking, but I couldn't feel a leak when I put my hand in there. I'm assuming I'll have to replace that gasket, any tips that will let me do it in one day? (it's my dd)

Second is that I put in a vortec BOV (plumbed to the front manifold vac source) and it's LEAKING bad. The instruction sheet says not to put the adjuster screw in any farther...well, I put it in 95% of the way and it's a lot better but still leaks. Could my exhaust leak have something to do with the poor performance of the BOV?? I'm gonna be away from my truck for a week, so when I get back I want to get it running right. Thanks.

 

[AlaskaTy]

What's the minimum you can take off to change the passenger side exhaust manifold gasket? Can I get away with just removing the upper IC?

 

[Tydriver]

I'm betting there is a crack in that manifold. From the factory there was/is no gasket between the head and the manifold.

Its common for the passenger side manifolds to crack on these trucks, the added weight of the turbo seems to be enough to cause problems with more than one of these on our trucks. I was fortunate enough to find a replacement so they ARE out there but inspect that area and see if you dont have a crack. I didnt see mine until I pulled the manifold off. I had the same symptoms you mention.

 

[VermontTy]

I didn't see mine either. This is where it cracked, and was repaired.

 

[Tydriver]

Same place as mine was leaking.. I have seen a few others do same thing. I am betting thats the weak spot !

 

[AlaskaTy]

Thanks guys. I'll check that out when I get back to my truck. Would a crack up by the front plug spray carbon all over all three plugs? And the top of the manifold looks clean/ no carbon deposit.

 

[ghettosled]

make sure the source you have the vacuum line connected to is a positive manifold source so it forces the spring closed when in boost.. if you have the line plumbed after a check valve or something the pressure in the intake pipe will blow open the spring/valve.

 

[AlaskaTy]

make sure the source you have the vacuum line connected to is a positive manifold source so it forces the spring closed when in boost.. if you have the line plumbed after a check valve or something the pressure in the intake pipe will blow open the spring/valve.

I have it plumbed into my front manifold exhaust line...about an inch or two off the manifold so there's definitely no check valve before it. It's leaking pretty bad and I dont' have much adjuster screw left to play with. When it was all the way out it was basically an open system.

 

[ghettosled]

are you trying to use the blow off valve as a wastegate or something? If thats the case there's your problem. The BOV should be installed on the turbo-ic pipe anywhere post turbo, pre throttle body. There should be a vacuum line that goes to the top of the bov as well.

 

[AlaskaTy]

are you trying to use the blow off valve as a wastegate or something? If thats the case there's your problem. The BOV should be installed on the turbo-ic pipe anywhere post turbo, pre throttle body. There should be a vacuum line that goes to the top of the bov as well.

It's the whole setup I bought off you (BOV, stainless turbo -> IC hose w/flange) so it's between the tb and the turbo. The BOV has the vac line coming off and t-ing into the front manifold vac source before any check valves. When you've installed the vortec BOVs have you had to massively adjust the spring spring via the adjuster screw?

 

[ghettosled]

ok you had me confused when you said "I have it plumbed into my front manifold exhaust line".

I have never had to make much of an adjustment at all on the vortecs.. Hook up a boost gauge to the line and see if it is getting boost.

 

[AlaskaTy]

ok you had me confused when you said "I have it plumbed into my front manifold exhaust line".

I have never had to make much of an adjustment at all on the vortecs.. Hook up a boost gauge to the line and see if it is getting boost.

I'll do that when I get back, but my in cab boost gauge is reading boost (more than datamaster is saying that I'm getting). Should I hook the boost gauge to the new vac line I plumbed in (BOV to front manifold)?

 

[ghettosled]

yeh because it sounds like the source you are feeding the bov with is not making positive pressure. Just rig your gauge up temporarily to confirm in fact positive pressure is being fed from that vacuum line going to the bov.

 

[AlaskaTy]

sounds good...but this is my second vac source I've tried (the one under the TB being the first).