GM Truck Club
THE PREMIER CHEVY TRUCK & SUV FORUM
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Results 1 to 10 of 11

Thread: Bad Valve?

Hybrid View

  1. #1

    Default Bad Valve?

    Ok, I've got a 1999 Suburban with 181,000 miles on it. 350 Vortec. On Mon. it started pinging badly. I pulled a code that was #6 cylinder misfire. Replaced the cap, rotor and wires as they were all looking a little beat up. #6 spark plug was wet. I did a compression test on all cylinders. Got about 150 psi across the board, except for #6 and #4. They were both around 30-40 psi. I put a few squirts of oil in the cylinder and the compression stayed the same. So, I'm assuming the rings are fine(no blue smoke out of the exhaust), all I can think is that it's a carboned up valve or valves. I ran some Seafoam through it. Made lots of smoke but still had the rough idle, detonation and the same code. I may run a little more Seafoam through, but, looks like I'll be pulling the heads this weekend. What I'm thinking of doing is getting some new or rebuilt heads, an aluminum intake manifold, water pump and all the little things I come across. Am I barking up the right tree? Looking for some advice on where to go from here. Thanks

  2. #2
    Legend
    murdog94's Avatar
    Join Date
    Feb 2008
    Location
    Cloquet, Minnesota, United States
    Posts
    8,198
    Blog Entries
    12

    Default

    What are you looking to do? Are you looking for more power? and if you are looking for ease of use and design keeping the factory intake is just fine as well.. A little port matching etc might help some.. But if you arent going for a built motor I would just rebuild it fairly stock, and if you want more power i would build a new motor for it since the bottom end has so many miles on it. If you remain fairly stock 300K miles isnt uncommon for these motors.
    I guess the aluminum parts that you are looking to use really arent needed since the stock components are pretty good.
    I would go with a programmer a set of headers, and a cold air intake. and just clean everything and a good port matching otherwise id keep this motor stock..
    Last edited by murdog94; 07-02-2010 at 12:45 AM. Reason: Added some info
    Mike

    Currently

    1997 Chevy S-10 Blazer 4X4 with 330K miles and counting (Hunting rig).

    2009 Saturn Aura XE (wifes car)

    2011 F-150 Crew 4X4

    "Hold it to the floor till you see God.... Then Brake!!!!"

  3. #3
    Legend

    Join Date
    Feb 2008
    Location
    Red Wing, Minnesota, United States
    Posts
    3,386

    Default

    Identicle to what happened to my 99 it was a bad valve. for me they rebuild both heads but had I known what it was gonna really cost me to try and figure out the damn valves I would have just got a new motor and transferred the asseccories to the new motor
    99 K1500 Suburban LT "THE BEAST"
    Hypertech III, K&N, true dual
    285/75/16
    ___________________________
    Jason

  4. #4
    Legend
    murdog94's Avatar
    Join Date
    Feb 2008
    Location
    Cloquet, Minnesota, United States
    Posts
    8,198
    Blog Entries
    12

    Default

    Quote Originally Posted by vncj96 View Post
    Identicle to what happened to my 99 it was a bad valve. for me they rebuild both heads but had I known what it was gonna really cost me to try and figure out the damn valves I would have just got a new motor and transferred the asseccories to the new motor
    Good Point on that.. And then you have a new motor good for another 200K miles...

  5. #5
    Legend

    Join Date
    Jun 2006
    Location
    River Ridge Louisiana-4 miles W of New Orleans-didn't flood-water stopped 800 yards away.
    Posts
    1,613

    Default

    Good point.
    You can get a NEW GOODWRENCH from Pace Performance for $2250 delivered to your curbside.
    This is a new genuine GM motor not some BS aftermarket cheapo rebuild.
    One of the huge advantages GM trucks have is cheap ,readily available parts. It actually makes sense to keep them running for 20 years.

    It would cost 5X as much to by a Toyota or Nissan V-8 and 2x as much to get a Ford or Dodge V-8.
    1998 suburban-
    1/2 ton

    199500 miles
    River
    Ridge,LA

  6. #6

    Default

    X2 on the Goodwrench crate motor.

Similar Threads

  1. '93 with a 4L60E? no TV valve,
    By strantor in forum GM Powertrain
    Replies: 4
    Last: 08-27-2010, 03:19 AM
  2. EGR valve boogers
    By andrewh in forum Chevy Blazer Forum (GMC Jimmy)
    Replies: 3
    Last: 02-08-2010, 08:04 PM
  3. valve adjustment?
    By sparky09 in forum GM Powertrain
    Replies: 8
    Last: 02-18-2009, 09:05 AM
  4. Valve Problems?
    By mattyV in forum General Chevy & GM Tech Questions
    Replies: 4
    Last: 02-17-2009, 08:19 PM
  5. pcv valve?
    By chazawazzle in forum Chevy Suburban Forum (GMC Yukon XL)
    Replies: 2
    Last: 01-13-2009, 08:20 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •