Chevy Avalanche Fan Club Forum

Avalanche Owners Zone => Chevrolet Avalanche Problems, Questions & Answers => Problems: Engine => Topic started by: RCBearings on 04/16/18 07:52 AM

Title: P0307 and sucking oil
Post by: RCBearings on 04/16/18 07:52 AM
2004 Avalanche 1500 with 240k on her.  Was towing my 26ft travel trailer from Colorado to Austin, TX a couple weeks ago.  Just outside Killeen, I got a check engine light.  Took it to Oreilly and had them read the code.  P0307, Cylinder 7 misfire.  So, I did the cheap thing and hoped.  Replaced the coil, wire and plug.  The plug I took out looked like a lump of coal.  That didn't fix the rough idle or clear the CEL.  Engine temps and oil pressure were still good, so I finished my tow to the RV park and check oil level warning came on.  It was 5 qts low!  Had put in 1qt at Oreilly.  Took it to dealer in Rockdale.  They said 0 compression in Cyl 7 and 90 in Cyl 2.

I know I need a new engine and dealer quoted $7300 installed.  I have been reading up on these engines and came across the 4 corner steam kit.  Seems under hard loads, #7 can overheat causing the ring gap to go to 0 and breaking lands on the piston.  I was flogging her pretty hard so maybe that's the case.

Anything else I should look for?
Title: Re: P0307 and sucking oil
Post by: ygmn on 04/17/18 04:11 AM
Did anyone check head gasket?
could be that simple.
Title: Re: P0307 and sucking oil
Post by: RCBearings on 05/21/18 02:09 PM
Oh well, got a Silverado engine for $450 with 170k on it and had the engine swapped.  All in all cost about $1200.  Avalance back in business.  Silverado engine soesn't seem to have the power.  Same year 5.3l. Guy who swapped it out said he would text me when he tore it down.