Few pics for you guys with Plenum issues

[luvmy03dts]

My 03 DTS was running like crap last week and I came online to see if you guys had similiar issues with codes P0171 P0174, and discovered that my plenum might be the issue. I purchased the plenum from my local Caddy Stealer for about $ 30 and got the intake gaskets for about $ 17 at Napa ( stealer wanted $ 7 a piece) I removed the fuel rails, intake etc and discovered the plenum had a huge crack on the bottom. I swapped it out put on the new intake gaskets and put her back together, the whole job took about an hour and a half and the car hasnt ran so good in the three months since ive owned it. Not bad for a certified shade tree tech. I attached pics might help you guy out there having the same issues

[Domino1968]

Good deal and nice car!

[Chuwee]

Nice work.

[bigmike750]

your pictures helped out alot I drove home with codes and after I was done no Codes YES!!! thanks for the pics. I had a tear about a QTR of the way around the Plenum

[submariner409]

luv........Posts like yours serve as a good example to other members. Nice work.

[CadillacSTS2003]

and a 1st post to boot
way to go and WELCOME!

[Logandiagnostic]

When mine did it, at first I thought I had some bad gas. Problem started just after leaving a gas station.

Anyway, spraying some carb cleaner around I could hear the leak at the plenum.

Ripped plenum, exactly like yours.

Mine was like $20 at the dealer. The intake gaskets can be reused if not damaged.


Logan Diagnostic LLC
www.ledfix.com
www.airbagcrash.com
www.logandieselusa.com

[Ranger]

How do these things develop rips like that?

[JimD]

Originally Posted by Ranger

How do these things develop rips like that?

It sure would be nice to hear from you-know-who on this issue. I don't think we had any reports of similar problems prior to the 2000 model year engine changes.

Material? Vendor? Design? Beats me.

[John Wicz]

My guess would be heat. Has me wondering if maybe I should do a little preventative maintenance and change it before it goes bad.........

[Ranger]

Jim,
Pre 2000's did not have the plenums. I think the TB was bolted directly to the manifold, which then brings up the question, why the change?

[JimD]

And you-know-who could provide the answer.

[Ranger]

Yeah, would be nice to hear from him. I tried to email him recently, but his email address was undeliverable and I don't have his personal address. Even if he was to come back, it would be under a different name and he would never divulge his identity again.

[submariner409]

There should be absolutely no movement between the TB flange and the intake manifold: they're both bolted to the same block, so that sort of rules out excessive flexing.

All the "plenum" problems with cracking appear to occur in the bottom 30 - 45 degrees of the bellows edge. Might this have something to do with a combination of fuel vapor (where from?), oil (PCV) vapor, and the fact that the bottom of the plenum bellows is a natural sump for holding liquid nasties? The GM fix might be as simple as a change to the ingredients used to mold the plenum in the first place, and a real hard look at the molding wall thickness in the break area.

Too bad you can't just clamp a piece of silicone intake hose in there........straight wall, impervious to fuel damage.

[Ranger]

Too bad you can't just clamp a piece of silicone intake hose in there........straight wall, impervious to fuel damage.

I see no reason why you couldn't.