I still really need help, so thanks for all I've gotten and will get. I didn't mention this earlier because I was waiting until I could get home and snap a few pics, but I noticed what looks like a missing bolt on the valve cover gasket. See pics here:

The pics are progressively zooming in







I hope you can see in the pics what bolt I'm talking about. And if I am correct, I would think this bolt would definitely hold in some sort of pressure, especially under heavy loads. Please let me know what y'all think. If that is a missing bolt, does anyone know what size and thread the bolt is that I need to get to replace it???

Thanks.

 

Thats the intake plenum

 

Looks like one of the bolts that holds the plenum on is missing. Look in the valley for that bole. Not sure if it will cause a boost leak or not. You are doing a good job looking for something wrong.

 

Thats a plenum bolt... Bad part is, if its leaking there, your going to have to remove the entire plenum and reseal it to get it to stop.

 

I'm not afraid of work. I am afraid of expense. I understand that this may not lead to what we would normally characterize as a "boost leak" but I would think that the greater the load that is placed on the motor, the more likely it is that the plenum would leak and cause a loss of power, right??????

For those who didn't see my other threads, I experienced a power loss and was only able to get 15psi of boost pulling my 14,0000lb 5th wheel. It also caused turbo surge at around 15psi, not the normal 23 or 24psi. Keep in mind that I was still able to easily get 23-24 psi of boost last night, unloaded, in the 80 daily driver tune of PHP (which is less aggressive I believe than DP's 80e). So, I am not getting a total loss of boost, just when under load.

 

With those numbers on the boost gauge i would just pull a another bolt out on the plenum and run up to Hdepot and grab a twin (grade8) and just reinstall. But use a different car to travel due to another bolt missing and you don't want to make it leak. Cheap repair. Good catch on that missing bolt..

You have an oil leak? Appears to have oil/fuel in the valley.

 

It isn't expensive to change those, you can do it for less than $60 using OEM stuff. To really be sure that is it you need before just spending money. Build a boost leak detector and see if you can find the leak though. Joe is right though, just replacing the bolt won't help you. If that is the issue I have what you need in stock.

 

Yeah, I noticed the oil, too. I haven't done the ccv mod, so was thinking the oil may be coming from this leaking plenum also????

I was going to build a boost leak detector, but would it show a leak there at the plenum? I have searched and searched for leaks at all the boots, at the intercooler, at the up-pipes, and this is the only thing I have found so far. My up-pipes are really clean, believe it or not.

 

Yes, it will show you a leak there as well.

 

Cool, well I will see about getting one built over the weekend then.

Clay, you should hope this turns out to be cheap because the repair is going to have to come from my exhaust fund.

 

Stick something in there, Some of those plenum bolts go right into the intake, so if there isn't a bolt there, it is blowing air out right through that hole and the seal will be fine. You might just have to stick a bolt in there and be done with it. Like I said check....

 

In addition to what Layson said, the gray sealant that holds the intake plenums to the block is some amazing stuff. You may not be leaking out of that area. Have you checked for split boots? I know you said you checked all your boots, but to see any type of leak they would need to be under pressure. Idling in the driveway is not considered pressurizing the system

 

That kinda makes me wonder, Did that bolt get removed to replace another one with someone not knowing what it was holding down...Orrrrr did it work its way lose and then what is the condition of the rest of them...Others lose? If so maybe the grey tub&tile is leaking in other places....

 

If the threads go all the way through, that would be a serious leak.
And yes to what Brandon is saying, that grey stuff will hold the plenum down without bolts.
I had to jack hammer the oil pan off of my old engine to inspect the insides. No way a simple pry bar was going to get it to remove!!

 

build a detector before you plug that hole and see if you can hear air coming out the hole.... that will tell you for sure that you have found your problem !!!