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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: oldblue76 on October 04, 2015, 07:40:17 pm

Title: Gunk under valve covers
Post by: oldblue76 on October 04, 2015, 07:40:17 pm

I recently obtained a 1976 Chevy K10. Its a 76 so it is not in perfect condition. I took off the valve covers a day or so ago to change the leaking gaskets. When I removed the cover I noticed there was a good amount of what looks like burnt oil on the heads. Is there a good procedure to clean the heads without removing the heads and why is the gunk there. Also is there something I can do to keep it from building up again. The motor runs struck except for what I believe is loose lifters/rockers.

Title: Re: Gunk under valve covers
Post by: rich weyand on October 04, 2015, 07:54:44 pm

Did it have a PCV valve hooked up on it?  Lots of people took them off.  If not, you will build up gunk in the oil system from blow-by not being evacuated.

Title: Re: Gunk under valve covers
Post by: oldblue76 on October 04, 2015, 08:04:17 pm

PCV Valve is still on the truck. Would cleaning the heads then replacing the PCV valve correct the issue?

Title: Re: Gunk under valve covers
Post by: enaberif on October 04, 2015, 09:02:16 pm

Quote from: oldblue76 on October 04, 2015, 08:04:17 pm

PCV Valve is still on the truck. Would cleaning the heads then replacing the PCV valve correct the issue?

Its normal for gunk to be under the valve covers especially if the motor is original and very little maintenance was ever done. You could run some seafoam through the engine but you have to be careful as that could cause more issues especially on a older engine.

Title: Re: Gunk under valve covers
Post by: rich weyand on October 04, 2015, 11:36:28 pm

Does the PCV valve rattle?  That's the test.  If it's good, it should rattle.  No rattle, it's stuck with gunk.

You could run some Seafoam through it, then follow it up with an oil change with a bottle of this.
http://www.amazon.com/ATP-AT-205-Re-Seal-Stops-Bottle/dp/B000NVW1LM

Title: Re: Gunk under valve covers
Post by: philo_beddoe on October 08, 2015, 01:13:24 pm

I have small drips from rear main seal, will that stuff work?  Can it cause harm?

Title: Re: Gunk under valve covers
Post by: fitz on October 08, 2015, 07:53:52 pm

I'd adjust the rockers & don't poke the bear.
Its a 39 year motor, that sludge may be holding it together.
I'd run it till it don't run no more.  When the time comes, drop in a $1500 GM crate motor.
Let Rick Weyand pick the cam.

Title: Re: Gunk under valve covers
Post by: VileZambonie on October 08, 2015, 07:58:16 pm

Get a bag of rags and a shop vac. Carefully break out and suck up what you can. If you drop pieces of sludge/carbon down into the pan it will plug up the pickup tube. As stated, this is caused by poor maintenance, lack of quality oil & filter changes.