Anyone Still Having Oil Consumption Problems On The Afm 5.3

tightline07 · July 8, 2011

I was wondering if anyone has actually had this problem fixed on their truck because mine keeps using it. Been to the dealer 3 times... 1) oil consumption test 2) new lifters and valve cover on drivers side 3) AFM shield. Now its been roughly 1600 miles ago and im a qt low again. Goin back today to see what they say about it. It seems to not have gotten any better through everything that they have done....

tightline07 · July 10, 2011

Well i went to the dealer on friday and they looked at it and topped it off. They told me to keep an eye on it till my next oil change is due and if it isnt any better then they are gonna have to put in new rings or a new motor...

VVT · July 10, 2011

AFM sucks

cariveau · July 10, 2011

I had the deflector installed first... didn't help. Then they replaced all the piston rings. They say that is the issue. It has only been 600 miles and I haven't seen any oil lose, of course they over filled it by a good 1/2 quart... It took about 25k miles before I got to this point! Don't let up on them. Ryan

Zembonez · July 11, 2011

One of the mods here is using a quart every 900 miles in his. I won't name him, but if he wants to speak up he will.

AzDragonLord · July 11, 2011

After two years and 30k miles, I've never had the oil consumption issue...Knock on wood!

Z45 · July 11, 2011

Talked with a friend who is SM at GMC dealer just last week on this subject. New engine is far down the road right now. They will install new rings and pistons before that ever happens. He said they did one and so far things are looking better. He said the GM service advisors have their hands tied on what they can do, they have to follow what GM wants them to do and replacing the engine is not one of the options they have at the moment. That's a decision the area service rep makes and as you can imagine, they are not going to make any snap decisions along those lines soon.

tightline07 · July 11, 2011

I wonder if new rings will really fix the problem... I dont see why they dont just put a new motor in. I would think it would be better on GM because of the labor and time it takes to put in rings. Im no mechanic but i just figured it would be easier and less time consuming and maybe cost less to put one in..

VVT · July 11, 2011

The 5.3L is a superb engine there is no need to replace it with a new one simply because the add on AFM is junk. There are many vendors who sell an AFM delete kit for around 300 bucks and once its gone your engine is as good as any other 5.3L out there. Granted if you oil consumption problems have escalated to the point of piston rings caking into the pistons then you will need to have fresh pistons installed but there is nothing "wrong" with the rest of the engine and you wont gain anything from having a brand new complete engine assembly installed.

But if you ask me the AFM delete should be done to all of them. It only gives you max 1mpg better mileage anyways so its no big loss to ditch it. The downside is you can pretty much kiss your engine warranty good bye but meh... as I see it these engines ( without AFM ) seldom if ever fail anyways so its not a big risk. Anyways Thunder Racing sells a complete AFM delete kit for anyone interested in doing so

mkelly · July 11, 2011

Maybe I'm missing out on something, but why do people associate oil consumption with the AFM system.

If changing piston rings solves the problem then it is a problem with the rings, not the AFM system. Its entirely possible that GM got a bad batch of oil rings, or they were installed incorrectly. AFM has nothing to do with the piston rings.

I will admit that I dont know evertything about the AFM system, but I dont see how it could be responsible for oil consumption issues. From my understanding a failure of the AFM system would only lead to a dead cylinder, not oil consumption.

VVT · July 11, 2011

AFM uses craptastic collapsible lifters to deactivate the cylinders in conjunction with PCM controlled ign/fuel cut. For whatever reason the system requires quite a bit more oil pressure than a non AFM engine. The oil squirts out of and all around the engine so badly its literally SOAKS the cyl and theoretically the bottom of the pistons with too much oil to drain properly so the rings cannot handle swiping off the excess and the oil burns and cakes the rings into the piston resulting in a loss of compression masked by oil sealed artificial compression whcih results in more oil consumption and on and on. Some think its the bypass valve blowing the excess into the bottom of the piston thats causing these problems but a baffle install doesnt seem to remedy this in all cases. I think its just too high pressure and not all engines are "exact" in terms of tolerances so the ones that are ever so slightly looser squirt oil out in the loose places and its just a downward spiral

Oh yeah... Change your oil pump too when you delete AFM

tightline07 · July 11, 2011

Oh yeah... Change your oil pump too when you delete AFM

Im game for gettin rid of the afm when the warranty is out but not till then... why change the oil pump though?

VVT · July 11, 2011

The AFM pump is a higher pressure and possibly the root of all the oil squirting on the pistons issue. New pump is around 80 bones through GM parts direct

jimbrown1 · July 12, 2011

Blackbear tune the AFM out!

Z45 · July 12, 2011

Lots of its has to do with the oil being used also. If the oil cannot take the heat it cooks more easily onto the pistons and rings escalating the oil consumption because the rings on not sealing. Petroleum oils only have to meet <15% volatility to pass API tests. Most are in the 12-14% which means that after one hour of the test, up to 15% of the oil is allowed to boil off and still meet the specifications. One the other hand, many high end synthetic oils have a volatility of much less than 10% and even 6% in not uncommon.

Check out this page, http://www.pqiamerica.com/testresults3a.html

Go down and look at Volatility

NOACK Volatility

ASTM D5800 - 08 Standard Test Method for Evaporation Loss of Lubricating Oils by the NOACK Method

NOACK volatility determines the evaporative loss of engine oils. This test is important because the operating temperatures of an engine will typically drive off the lighter ends of a lubricant while in service. This effectively results in pushing the viscosity of the lubricant to a more viscous level (up) and, as a result, fuel economy goes down due to an increase in parasitic load.

The evaporation loss is of particular importance in engine lubrication. Where high temperatures occur, portions of an oil can evaporate. Evaporation may contribute to oil consumption in an engine and can lead to a change in the properties of an oil.