What did you do to your NBS GMT800 Tahoe/Yukon Today?

[ScottyBoy]

It's possible that all that sludge was already there in 2017, and it finally broke loose and fell into the oil pan with new oil and consistent oil change intervals.

Are you using high mileage oil? My understanding is the HM oil will contain detergents that will break up sludge and cause it to fall into the oil pan. If the PO only ever used conventional oil, and had extended oil change intervals, it could have caused the buildup you're seeing.

When did you purchase the truck, and how many miles have you put on it since you bought it? How many miles are on it now?

I purchased the truck in 2005 with 51k miles on it. Since then I have ALWAYS ran either Mobil1 full synthetic, or Amsoil XL series synthetic. No high mileage formulations. Longest I've ever gone was 7500 miles on an oil change, but when I saw how bad the oil looked I stopped doing that and changed it about every 5k miles ever since. It currently has 160k miles on it. I don't put a lot of miles on it, so a few times I've gone a year on the same oil because I didn't even put 5k miles on it. I wonder if sheer age of the oil is causing sludge?
Oh, and I've probably put about 40k miles on it since I last had this oil pan off in 2017. I also replaced the valve cover gaskets around the same time, and the top end of the engine appeared to be pretty clean.

 

[smcnair]

Got my oil pan dropped today and that sumbitch is FULL of sludge! Boy am I pissed. I COMPLETELY cleaned this pan out when I replaced the gasket and pickup tube in 2017. Since then I have changed the oil every 5,000 miles with Amsoil XL series oil and either a Mobil1 filter or a Wix XP filter. I'll admit though, the last 2 oil changes I used Mobil1 oil and then Walmart Supertech Full Synthetic for the last oil change. (about 3 months ago). In the bottom of the pan there is a THICK mud like sludge, and on the baffle, there is some hard caked up sludge that is flaking off in chunks kind of like rust. It also has a slight metallic color to it. Can anyone with more insight than me explain WTF is going on here?

It may be time...

BG Dynamic Engine Cleaner – BG Products, Inc.

As Step 1 of two, this potent cleaner thoroughly cleans the crankcase and the entire lubrication system.

www.bgprod.com

 

[Sam Harris]

Yours looks pretty level, did you just raise the torsion bars?

Yessir. Cranked keys, and upgraded to longer Bilstein 5100’s. She rides just great too. I thought I’d suffer a terrible ride after cranking the keys, but really can’t tell any difference.

 

[Sam Harris]

That Color has always been a favorite of mine. Damn good looking ride man. Whats the specs on the tire size???

Thanks man! It’s grown on me a lot..! Still think the Bermuda Blue is the best, but I definitely love this color as well. Tires are 285/60 18’s on 2015 Yukon wheels. Fit perfectly, no spacers, or trimming.

 

[Walchit]

I get my alignment on Nov 3rd I think. But it seemed to ride really nice after I got the rear sway bar back on. It was a little wobbly on the way out to the shop without it, lol. I got the 2" keys from RC too. I only got her up to about 60, but the rough country shocks seemed decent. I watched a video comparing the shorter Bilsteins with extenders, vs RC. And the guy liked the Bilsteins better. You could see that it was less bouncy with them then the rough country shocks. Maybe someday Bilsteins will make it on my to-do list.

Yessir. Cranked keys, and upgraded to longer Bilstein 5100’s. She rides just great too. I thought I’d suffer a terrible ride after cranking the keys, but really can’t tell any difference.

 

[Rocket Man]

I purchased the truck in 2005 with 51k miles on it. Since then I have ALWAYS ran either Mobil1 full synthetic, or Amsoil XL series synthetic. No high mileage formulations. Longest I've ever gone was 7500 miles on an oil change, but when I saw how bad the oil looked I stopped doing that and changed it about every 5k miles ever since. It currently has 160k miles on it. I don't put a lot of miles on it, so a few times I've gone a year on the same oil because I didn't even put 5k miles on it. I wonder if sheer age of the oil is causing sludge?
Oh, and I've probably put about 40k miles on it since I last had this oil pan off in 2017. I also replaced the valve cover gaskets around the same time, and the top end of the engine appeared to be pretty clean.

I change mine every 3k. M1 Synthetic, Wix filter. I have 175k on it and had the pan off at about 150k and no sludge present. I would at the very least up your oil OCI and probably should send in samples to Blackstone Labs for analysis on a regular basis. IMO 5k is way to far to go on oil especially if it had sludge prior.

 

[blueinkd]

Finally went to junk yard this weekend and got a replacement door sill. My old one had the weatherstripping hanging/ripped. They had several yukons/tahoes and I came across several sub boxes. I may go back for one next weekend.

 

[Tonyrodz]

Got my oil pan dropped today and that sumbitch is FULL of sludge! Boy am I pissed. I COMPLETELY cleaned this pan out when I replaced the gasket and pickup tube in 2017. Since then I have changed the oil every 5,000 miles with Amsoil XL series oil and either a Mobil1 filter or a Wix XP filter. I'll admit though, the last 2 oil changes I used Mobil1 oil and then Walmart Supertech Full Synthetic for the last oil change. (about 3 months ago). In the bottom of the pan there is a THICK mud like sludge, and on the baffle, there is some hard caked up sludge that is flaking off in chunks kind of like rust. It also has a slight metallic color to it. Can anyone with more insight than me explain WTF is going on here?

My Express van pan looked EXACTLY like yours. I bet it looks the same again.

 

[ScottyBoy]

It may be time...

BG Dynamic Engine Cleaner – BG Products, Inc.

As Step 1 of two, this potent cleaner thoroughly cleans the crankcase and the entire lubrication system.

www.bgprod.com

If anyone actually SOLD this stuff I would buy some. But the only places that do have BG products will not sell them. They will only perform service with BG products.

 

[ScottyBoy]

My Express van pan looked EXACTLY like yours. I bet it looks the same again.

Probably so, nothing would surprise me now after seeing this crap.
Here's what my pan looks like now after a few minutes of scrubbing it with some LA Awesome from Dollar Tree. That stuff is the ****. I'm not done with it though, I'm gonna give it at least one more scrub. I need to find my wire brush so I can get the spots in the corners that I missed.

 

[Rocket Man]

Probably so, nothing would surprise me now after seeing this crap.
Here's what my pan looks like now after a few minutes of scrubbing it with some LA Awesome from Dollar Tree. That stuff is the ****. I'm not done with it though, I'm gonna give it at least one more scrub. I need to find my wire brush so I can get the spots in the corners that I missed.
View attachment 353683View attachment 353684

What a difference !

 

[ScottyBoy]

What a difference !

Yep. And seriously, all I used was some LA Awesome, some hot water, and a stainless steel scrubbie. I did scoop out all the thick mud like sludge first though with my gloved hand.

BEFORE:

AFTER:

 

[ScottyBoy]

Also, the tool Gods blessed me today. I found a 10mm Snap-On mid length socket wedged between my oil pan and the wiring harness that run right alongside it. Must be from the transmission shop that worked on my truck a little over a year and a half ago, because I can't remember anyone else besides myself working on my truck in the last few years. If it was a USA made Craftsman, then I would assume it to be mine, lol Because that's what most of my sockets are. They are all from the 90's and early 2000's when Sears actually still had them made in USA.

 

[ivin74]

They didn’t fill at all or they didn’t raise the truck? If they filled until they feel solid (squeeze test) but didn’t raise it, either the ride height sensors aren’t telling it to raise it more or the compressor is bad.

They did not fill at all, the compressor tried filling them, then shut down right after.

 

[clandr1]

I purchased the truck in 2005 with 51k miles on it. Since then I have ALWAYS ran either Mobil1 full synthetic, or Amsoil XL series synthetic. No high mileage formulations. Longest I've ever gone was 7500 miles on an oil change, but when I saw how bad the oil looked I stopped doing that and changed it about every 5k miles ever since. It currently has 160k miles on it. I don't put a lot of miles on it, so a few times I've gone a year on the same oil because I didn't even put 5k miles on it. I wonder if sheer age of the oil is causing sludge?
Oh, and I've probably put about 40k miles on it since I last had this oil pan off in 2017. I also replaced the valve cover gaskets around the same time, and the top end of the engine appeared to be pretty clean.

That's very strange. I'm the original owner and have been running Mobil 1 High Mileage since around 75k miles, and I do not change the oil until the truck computer tells me to (generally 6-8k miles, depending on driving conditions). I've sent oil samples at least annually to Blackstone Labs since the truck had around 130k on it, and they've always come back looking good.

I dropped my pan and replaced my pickup tube o-ring in December 2017 when the truck had around 170,000 miles on it, and at that time it was sludge free.

I just can't figure out what's going on with yours - it seems the only difference is I've been using high mileage oil and you haven't, but I can't imagine it would cause sludge buildup like you're experiencing.

 

[clandr1]

I'm a day late, but yesterday I returned from a trip to San Antonio to visit the Riverwalk and Sea World with my wife and sons. It was around 650 miles round trip, about 5 hours each way. The truck cruised between 70-85 mph without any issues at all.

In fact, I rolled 232k on the trip. Guess I need to update my signature again...

 

[ScottyBoy]

I just thought about something. I installed a K&N air filter about 2yrs ago. I've been hearing mixed things about them. Now I'm wondering if maybe it "allows more dirt" to get into the engine, therefore creating more sludge? I dunno, just wondering about every possible scenario that could cause that crap to build up in my engine like that...........

 

[Walchit]

Probably so, nothing would surprise me now after seeing this crap.
Here's what my pan looks like now after a few minutes of scrubbing it with some LA Awesome from Dollar Tree. That stuff is the ****. I'm not done with it though, I'm gonna give it at least one more scrub. I need to find my wire brush so I can get the spots in the corners that I missed.
View attachment 353683View attachment 353684

Did you put that pan back on yet? I wish I would have changed the little oil level sensor when I had mine out. Because now I get a check oil level message sometimes.

 

[ScottyBoy]

Did you put that pan back on yet? I wish I would have changed the little oil level sensor when I had mine out. Because now I get a check oil level message sometimes.

No, I probably won't get it back together until this weekend. This is a multi day job for me. I still have to pull the timing cover and replaced the oil pump. Yeah, I could probably get away with just changing the pickup tube/screen but I already bought the new oil pump and timing cover gasket set. Plus my timing cover is leaking. So I may as well go ahead and change it all like I originally planned to. And yes I'm planning on replacing the oil level sensor as well, I already bought a new one as I was getting random "Check oil level" messages on my dash. But now I see with all that sludge and gunk in there, the sensor was just gummed up and sticking. So the sensor is most likely fine, but like l said I already bought the new sensor.

 

[clandr1]

I just thought about something. I installed a K&N air filter about 2yrs ago. I've been hearing mixed things about them. Now I'm wondering if maybe it "allows more dirt" to get into the engine, therefore creating more sludge? I dunno, just wondering about every possible scenario that could cause that crap to build up in my engine like that...........

I think there'd have to be a gaping hole in the filter to get enough dirt to cause that much sludge. I would recommend using a high mileage oil (I would suggest Mobil 1 brand since it's worked well for me) and see if your sludge issues continue. That's the only difference obvious to me between your sludge issue, and my lack of sludge.