Hello All

[OldRado]

I heard about this site from someone on GM-Trucks.com. That site has been a real help with keeping my truck going and sharing info. I have a 2000 Silverado Ext Cab Z-71 w/5.3. It has about 116K miles on it and I just got done replacing the head gaskets on it because I was using coolant. It had been using a slight amount of coolant for about 2 years but lately had gotten much worse. I discovered it was getting into the oil. When I pulled the head, the top of one head had a lot of black sludge among the valve springs and the under side of the driver's side valve cover was coated with a butterscotch colored slime from oil/water mix. I have been running Mobile 1 for about 30K and ran Castrol GTX before that. When I went to change the oil after the gasket change, I pulled the oil drain plug out and nothing came out! The sludge build up in the pan was so bad, I had to poke a screwdriver up there to get the oil to drain. Not sure where all the sludge came from, except from the water/oil mixing for a while. Hope it isn't the Mobile 1, I've heard all good things about that. I now have an extra 5.3 with about 50K miles on it on the engine stand to go in if I have more problems with mine.

Anyhow, that's my truck and where I'm at on it at the moment. Looking forward to more info and sharing tips!

[RedHeartbeat]

Welcome to the site. You're going to like it here. We're all about performance and do-it-yourself how-to.

[foggy]

you may want to put Sea-Foam in your oil, to get that motor flushed out.

[Jamest]

Mobil one doesn't sludge like that. unless the motor was getting extremely hot! I think it was a mixture of things.

Jamest

I heard about this site from someone on GM-Trucks.com. That site has been a real help with keeping my truck going and sharing info. I have a 2000 Silverado Ext Cab Z-71 w/5.3. It has about 116K miles on it and I just got done replacing the head gaskets on it because I was using coolant. It had been using a slight amount of coolant for about 2 years but lately had gotten much worse. I discovered it was getting into the oil. When I pulled the head, the top of one head had a lot of black sludge among the valve springs and the under side of the driver's side valve cover was coated with a butterscotch colored slime from oil/water mix. I have been running Mobile 1 for about 30K and ran Castrol GTX before that. When I went to change the oil after the gasket change, I pulled the oil drain plug out and nothing came out! The sludge build up in the pan was so bad, I had to poke a screwdriver up there to get the oil to drain. Not sure where all the sludge came from, except from the water/oil mixing for a while. Hope it isn't the Mobile 1, I've heard all good things about that. I now have an extra 5.3 with about 50K miles on it on the engine stand to go in if I have more problems with mine.

Anyhow, that's my truck and where I'm at on it at the moment. Looking forward to more info and sharing tips!

[OldRado]

Jamest,

I thought that too, but it has never gotten hot. I haven't done a compression check on it yet, may be getting lots of blow-by causing that.

[txarkitekt]

Welcome! Sounds like you have a slight problem on your hands... The culprit could be a number of things actually... Let me ask this: Has the problem gotten any better since you replaced the head gaskets? If not, there is a crack in one of the heads, which is allowing for the coolant to enter the oil stream. Mobil 1 should not do what you are describing... I would highly recommend that you go get a few bottles of Motor Flush from you local Vatozone or O'Reilly's and run a few bottles through your motor before the next oil change. Make sure to follow the label's directions. Once you have flushed out your motor completely, put in new oil. Run it for about 2k miles and change it again. If you are running into the same issue, then you either have a crack in one of your heads or in the block somewhere. I can almost say that the head that had the bad sludge buildup has a crack in it... If it was me, I would have replaced that head at that time... Good luck with your findings!