Is Your Gmt-900 Truck Or Suv Using Oil

[scogeb]

I've talked to my mechanic and the dealer's mechanic and my plan is to run 1,000 miles and see what the oil consumption is and then get the Range module and run another 1,000 miles and see what it is then. I'll post back with the results in a few months. Thanks!

[AzDragonLord]

I have just over 141K miles on my 2009 with AFM still on, and I had #7 plug foul on me a few months ago. I just topped off my oil using 1 qt after 3754 miles, which GM does not consider "excessive".

I'm outside the warranty period so I suppose I just have to live with it or replace it...but I'm not needing another payment right now. Not certain if the Range AFM Delete will help at this point.

[Jsdirt]

Mine is also long, long out of warranty. Only 91k on mine though. Cam bearings are going, plus started burning oil at 50k when pushed. I'm sure AFM issues are just around the corner ...

 

If I can nurse that engine along for another 5 years it'll be exempt - then I can drop a carbureted 502 in there. $6k for a new long block LS ... or $6k for a 502 - a no brainer for me. Problems solved!

 

(EDIT: Had to change AMF [bowling company that owned Harley, lol] to AFM - Active Fuel Management )

Edited September 26, 2017 by Jsdirt

[MaverickZ71]

Mine is also long, long out of warranty. Only 91k on mine though. Cam bearings are going, plus started burning oil at 50k when pushed. I'm sure AMF issues are just around the corner ...

 

If I can nurse that engine along for another 5 years it'll be exempt - then I can drop a carbureted 502 in there. $6k for a new long block LS ... or $6k for a 502 - a no brainer for me. Problems solved!

 

How can you tell cam bearings are going out?

[Jsdirt]

High levels of brass/copper and iron in oil analysis - given the history of the 5.3's of this vintage, it's pretty much a slam dunk.

Edited September 26, 2017 by Jsdirt

[dk1125]

2008 sierra 5.3 I have used mobile 1 since the day I got it. I bought it new with 8 miles on it. Iron block, 148,000 miles and I have to add a quart atleast every 1000 miles. No I haven't had the consumption rear gone yet.

[Colossus]

High levels of brass/copper and iron in oil analysis - given the history of the 5.3's of this vintage, it's pretty much a slam dunk.

I am not as up to date as I should be, I did not realize cam bearings were a common issue. Is there a cause for this? Just shitty design? Was the issue resolved later on prior to the 2014+ models?

[mookdoc6]

High levels of brass/copper and iron in oil analysis - given the history of the 5.3's of this vintage, it's pretty much a slam dunk.

 

 

This is a LS motor with "known" cam bearings problem? Never heard of that before? What is the Oil pressure at start up idle and hot idle etc, or 4K RPM's I am sure their is no problem with your cam or bearings...........

[Jsdirt]

Trust me - there is. It's a known issue in repair circles, maybe not the general public. The 5.3 in particular has shitty valve springs, AFM lifters, and oiling system. The failures are common and well known by any garage.

 

I've been watching my cold start-up oil pressure decline (albeit slowly) over the past couple of years, so that backs up my oil analysis findings. I'm running 10w-30, and on a 40° morning, the needle is now under 40 psi. Used to run way up around 60 or more. I've owned the truck since new, so I know exactly where that gauge is supposed to be, hot or cold.

 

Read this - keep in mind, this was 2009 when the issues were just starting to reveal themselves. This is just one post of hundreds across the net. Not hard to find: http://www.gm-trucks.com/forums/topic/96854-nbs-53-engine-failure/

Edited October 2, 2017 by Jsdirt

[mookdoc6]

Trust me - there is. It's a known issue in repair circles, maybe not the general public. The 5.3 in particular has shitty valve springs, AFM lifters, and oiling system. The failures are common and well known by any garage.

 

I've been watching my cold start-up oil pressure decline (albeit slowly) over the past couple of years, so that backs up my oil analysis findings. I'm running 10w-30, and on a 40° morning, the needle is now under 40 psi. Used to run way up around 60 or more. I've owned the truck since new, so I know exactly where that gauge is supposed to be, hot or cold.

 

Read this - keep in mind, this was 2009 when the issues were just starting to reveal themselves. This is just one post of hundreds across the net. Not hard to find: http://www.gm-trucks.com/forums/topic/96854-nbs-53-engine-failure/

 

 

OK, So out of those 6 pages 2qty are actual users with internal failures on that design? That engine I have never heard of "anybody roasting a Cam or Bearing, loosing a piston etc! Now consuming oil due to a couple of factors yes that was more common I will agree.......but I just certainly can't believe there is a 'Known worn cam/bearing issues" and as for the 40psi on cold start or under 40psi......Your absolutely JUST FINE I don't believe there is anything wrong with your Cam Bearings oil pressure is JUST FINE......

 

I am gonna need much information to convince me of major problems with the LS internals or overall architecture.....other than oil consumption or springs?

 

[Jsdirt]

You're going to have to join iATN and read the HUNDREDS of posts on this topic.

 

Just a quick Google search, "5.3 valve spring failure" or "5.3 cam bearing failure" will provide you with plenty of reading.

 

I appreciate you telling me my truck is just fine from across the net, without ever seeing, or hearing, or experiencing anything I have described or linked. You're one special human.

 

 

 

Oh, almost forgot .... care to explain my high levels of iron and copper in my oil samples running Amsoil Signature Series 10w-30? Did someone throw a pipe and an old penny in my engine?

Edited October 2, 2017 by Jsdirt

[Jsdirt]

[mookdoc6]

 

Thanks for posting didn't want to get you all angry over this although it seems it has? Anyway I am not seeing your High levels of CU wear or Iron wear or the Oil consumption for that matter......Your oil interval changes are lengthy enough to warrant "Make up Oil" Is this an FE block LS motor? What spin on oil filter are you using?

 

I still have really no worries about these readouts...........You have had no internal failures or valve train related problems? Yet, these model year engines have convinced yourself your having issues when a very ultra small fraction....I mean I have never even heard of 1qty person saying they have burned up the cam or bearings in those engines...not even 1qty person? Your oil pressure which is going to determine MORE than anything the disposition of the Cam shaft and bearings is Absolutely fine.

 

How much money do you want for this crappy truck? Because somebody will have an excellent maintenance free experience......

[Jsdirt]

It's not you - the whole experience of spending $30-LARGE and getting SHIT in return has me pretty pissed off.

 

I have read post after post from professional technicians from all over the country fixing broken valve springs, pitted cams, prematurely worn out cam bearings, stuck closed AFM lifters, broken valves, and the list goes on. Guess you'll just have to take my word for it. When my engine finally grenades (which will be years down the road, since I drive my well-built '86 Grand Marquis and '93 Volvo 940 when I'm not hauling, and leave the junk in the garage) you can bet I'll have detailed pictures and possibly video of the whole process.

 

GM HAD a great motor, then decided to cheap out on it starting in 2007. You don't see ANY of these types of valve train failures on '06 and prior. They happen, but are extremely rare. '07 up, they are pretty much guaranteed for the most part at anywhere from 91k in my case, up to 160k in other cases. Majority of the ones I saw posted were 110k-130k. Not what I would consider "high mileage".

 

My Grand Marquis has 246, xxx miles - original engine, original tranny, original rear end, and original fuel pump. Those days are long gone unfortunately.

[Cowpie]

Keep in mind, GM uses a LOT of copper in the form of brass, especially in cam bearings. High CU is not really that uncommon in GM engines. I have seen it in many engine oil analysis reports from relatively newer engines and ones that have racked up some serious miles and the engines are just fine. Only when there is corresponding elevated levels of tin and lead (the other components in cam and rod bearings) is that indicative of a problem. Elevated CU by itself may not mean much. Many sources from bearings I mentioned to oil coolers. And some oil additive packages will amplify CU leaching.

 

One of the big problems we as owners of cars and light trucks have, is that the OEM is not forthcoming with condemnation limits on wear metals in oil samples. We easily can get those for commercial equipment and heavy truck engines. Without knowing what the max limits on wear metals as established by the OEM itself, we are just wandering around in the dark, and probably over reacting to what some lab considers elevated wear metals. Many commercial engines do not reach max limits until FE counts get to 200 ppm. While 52 does seem disconcerting, it has to be factored along with other wear metal ppm to see if it is something to worry about. FE and CU are from totally different sources and elevated levels of each of them has little to do with each other. If I was seeing elevated levels of aluminum and chromium along with Iron, I might be concerned.

 

And without multiple UOA reports to track trend lines and patterns, it is a crap shoot to make a determination based on one oil sample.

 

On that report, TBN has gotten to the level I would change it out. Without doing a TAN analysis with TBN, the common practice in commercial industry circles is that when TBN reaches 1/3 of what it started at, it is time to get the oil out. TAN (total acid number) which rises over time, and TBN levels which deplete over time in addressing the acids, on average will meet at about 1/3 of the starting number for TBN. if the oil started with 10 TBN, then 3.3 TBN is all the lower I would let it go. If the oil started with 12 TBN like many of Amsoil's SS lineup, then the oil has dropped below 1/3, which would be 4 TBN. It is possible in that situation that acids are causing the elevated FE and CU. I said it is possible, not that it is a fact.

 

Will probably get some arguments against this, but there is tons of resources out there that will support my comments. So don't go shooting the messenger. Do your own research and find out.

Edited October 4, 2017 by Cowpie