Stupid Plenum replacement

99Classillac · #1 (**permalink**) 02-26-09, 07:08 PM

Okie doke, anyone on here got any thoughts on how hard it is to replace the plenum? I called Caddy dealer here in MD (Capital Cadillac, Greenbelt MD) and set up an appt for tuesday to look at my car. $125 just to look and $125 an hour to fix. I wanna do it myself but I am getting tired of fixing this car myself. I did the struts and stuff, but I don't feel like unbolting all that fun stuff by the manifold. What is the book hours on this repair? How much am I looking at?

submariner409 · #2 (**permalink**) 02-26-09, 07:32 PM

Greenbelt is a long way from Staten Island, home of Villa Marin Cadillac.

For a 2002 Seville, the intake manifold R&R is 2.5 hours, so add another .5 for the intake plenum, a $43 dealer-only part, and go from there.

DIY is a few hours, nothing magic, and the (dealer) plenum and a set of intake manifold gaskets.....get them from www.rockauto.com (expensive at the dealer).

99Classillac · #3 (**permalink**) 02-26-09, 08:38 PM

Oh I forgot my profile said Staten Island still. Lol. Yea I remember ole Villa Marin. I'm down in silver spring MD now. Scale from 1-10, how hard is it? I am mechanically inclined (I fixed Blackhawks for Army), I'm just gettin lazy thats all. All that fuel rail stuff and wires and what not. Too many screws and stuff to wanna even try it. I will if it'll save me $300 tho. 3 hours times $125 an hour plus $125 initial diagnostic. Screw that. Is there anyone with a write up on how to do this properly? I don't wanna start unscrewin stuff without knowin what I'm unscrewin

submariner409 · #4 (**permalink**) 02-26-09, 09:32 PM

Between here, Seville, and Northstar Performance there are enough threads on plenum replacement to fill a large telephone book. Use the Search tab up ^^^ in the blue bar and look for thread with "plenum", "intake manifold", etc.

On a 1 - 10 scale it's a 4. Just have the plenum, a new set of the proper year intake manifold gaskets, and some patience handy. Watch what you disconnect and replace it all.

If the $$$ isn't really a problem, take it to one of the local Cadillac dealers and have them do the job - then you have someone to bitch at if there's a glitch. I forget who's over there....was born and raised in Ch Ch right off the circle in MD.

99Classillac · #5 (**permalink**) 02-28-09, 10:05 PM

Where is Ch Ch? I took the airbox out today and took the IAC valve out today. I took throttle body cleaner and sprayed into the IAC hole and opened the butterfly and cleaned all in there. I put it all back together and it was running perfect all day! Then I go home and it starts to idle high again. It's not even idling till it shuts off, just really high. I shut it off and waited 5 minutes, then cut her on again and she is idling right again. I decided to unplug the IAC Valve and see how it runs without it plugged in. I wanna see if the IAC valve is at fault. I figured unplugging it while it is idling right will make the vavle stick in the correct position. Without any input, it won't move from its current setting. Also, I used to throw 2 codes, P0171 and P0174, both banks being lean. I cleared codes, now only bank 2 is running lean, P0174. Anyone think the O2 sensors might be bad? I was thinkin the bank 2 O2 sensor might be giving false readings, then again I would throw a bad O2 sensor code right? I looked at plenum, but it looks ok and I don't hear a vacuum sound coming outta there. I do hear a slight INITIAL hiss when I throttle the engine by hand under the hood. But the hiss is initial and then goes away. I think that is normal though. Anyone have any helpful input?

**Ranger** · #6 (**permalink**) 02-28-09, 10:20 PM

You are correct in that a bad O2 sensor should through a code. Don't rely on sight or sound for the plenum. The split usually occurs on the bottom where it is invisible. Spray some Brakleen around it and listen for an RPM increase.

99Classillac · #7 (**permalink**) 02-28-09, 10:37 PM

I'll try that in the AM. I really hope its not the plenum. Damn fuel lines and what not. Damn I just realized how lazy I am. I spent a year in Iraq fixin helo's. Don't feel like comin home to fix a caddy. Simple stuff, but I just don't wanna. I'd rather it be a IAC valve that is held in with 2 screws. I refuse to pay caddy dealer to replace plenum. I was contemplating it and even made a appointment, but man I like money too much.

**Ranger** · #8 (**permalink**) 02-28-09, 10:42 PM

I don't think a plenum is a bad job.

99Classillac · #9 (**permalink**) 02-28-09, 10:52 PM

Never had to do fuel line stuff. Special tools needed? I guess I'll be opening her up this week.

**Ranger** · #10 (**permalink**) 02-28-09, 10:54 PM

I think there is a special fuel line release tool, but if it is the same as the one I bought to work on a 3800, I ended up using pliers.

99Classillac · #11 (**permalink**) 02-28-09, 11:06 PM

What did you do about fuel pressure?

**Ranger** · #12 (**permalink**) 02-28-09, 11:08 PM

Bleed it off at the service port into a rag. Probably won't get more than an oz.

99Classillac · #13 (**permalink**) 02-28-09, 11:12 PM

Aww sweet. Thought it would be more than that. Guess that would be the difficult part of the repair. Everything else is bolts and what not. What is the official name for the gasket set. I know about the plenum and ordered that. I need the other gaskets, or whatever those little circle things are called.

**Ranger** · #14 (**permalink**) 02-28-09, 11:14 PM

I don't know. Haven't had to do one ..........yet.