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Was the AFM oil consumption problem ever really fixed?

OzAvy

Full Member
Joined
Feb 20, 2015
Messages
35
I have a 07 LTZ which sure enough developed the oil consumption problem at about 35K.

I had applied the fix by GM (fit new rocker cover and oil deflector) but the problem slowly came back.
Bought a Hypertech tuner to turn off AFM, only to sadly find that they do not offer this option for 07 models!  :oops:

So I studied the service manuals and worked out a way to turn off AFM myself. This seemed to stop the oil consumption even though a DTC is generated.

Now thinking whether I should change my Avalanche for a more powerful 6.0, 6-speed 2009 model, the last model year that a 6.0 was available.

Does anyone have any thoughts and/or oil consumption comments about the 09+ models?

Was the oil consumption problem ever completely fixed by GM?
 
The AFM oil issue was is primarily an issue for 07-08 model vehicles.  After that you really dont see it anymore..

You can defeat the AFM in your truck with a simple range module and not throw a code all the time..

Just google  Range AFM,,,And it will come up..  Tons of folks using them..   
 
Hey thanks  (y)  means that GM actually changed their design?

Yes, I've read about Range AFM disable......but I don't want to spend again as I still have the Hypertech and they say that they intend (some day) to change their software to include AFM disable for my truck.

Would the 6.0 2009 be a better option long term than my 5.3?

 
I personally have no experience with the 6.0..  I am sure its gonna use way more gas, but otherwise be about
the same.   Better towing etc..  If you find one that's not using oil now,, And lock out the AFM you should
be fine for a very long time....  Mine did not begin to use any oil till almost 240 K miles and that was with the AFM
working..    I think she would have run forever if I had disabled it... 
 
Does anyone who has made such a change i.e. 2007 5.3 to 2009 6.0 care to comment please. :help:
 
OzAvy said:
Does anyone who has made such a change i.e. 2007 5.3 to 2009 6.0 care to comment please. :help:

My 08' AV 5.3L with 105,000 mi. burns about 3/4 of a quart over 3500 miles. This has been steady since I bought it with 42,000.
Our 11' Tahoe 5.3L with 99,000 mi. doesn't burn a drop in the 4500 miles between oil changes.
 
Well, after all my efforts to clean out the oil contamination caused when my AFM was on, the other day I removed plug number 7 and the others on the same side and they all had oil which had gone through the threads to the sealing surface. This I think means that the rings are starting to fail again!  :E:

Has anyone out there had this problem and then changed rings and pistons and had a good result that lasted?  ???

 
OzAvy said:
Hey thanks  (y)  means that GM actually changed their design?

Yes, I've read about Range AFM disable......but I don't want to spend again as I still have the Hypertech and they say that they intend (some day) to change their software to include AFM disable for my truck.

Would the 6.0 2009 be a better option long term than my 5.3?

I'd be surprised if Hypertech would bother with such a change, if they haven't already.  I'd probably sell the Hypertech unit, and get a Diablsport Intune, so that you can have the improved tune as well as AFM disable.  I guess check with DS to ensure they allow AFM delete for all years, but pretty sure they do.

As for the 6.0L... there's no replacement for displacement.  :D  It would improve towing (if you need that).  Not sure how it does for fuel economy, but I have to imagine with a 6.0L/6 speed combo versus a 5.3/4 speed,  have to be almost identical.
 
I will probably pull the motor and get it honed with new pistons/rings. My current inclination is then, once the rings have bedded in, to maybe go with a Magnuson blower and change the axle ratio to 3.42.

Any thoughts?
 
OzAvy said:
Now thinking whether I should change my Avalanche for a more powerful 6.0, 6-speed 2009 model, the last model year that a 6.0 was available.

Kind of a great white buffalo.... might be tough to find. I'm sure it would be a better tow rig, if you can find one.
 
I have a buddy I work with that has an 11 model that burns a quart in less than 2000 miles. I told him he better get it check but he hasnt been concerned with it.
 
OzAvy said:
I will probably pull the motor and get it honed with new pistons/rings. My current inclination is then, once the rings have bedded in, to maybe go with a Magnuson blower and change the axle ratio to 3.42.

Any thoughts?

I think you will like it! 
 
Do you plan on leaving the AFM lifters in.
 
MS03 2500 said:
Do you plan on leaving the AFM lifters in.

I've only yet given a little thought about that as I'm not sure whether I would try AFM = ON once the piston to bore clearance and rings are good, or leave AFM off for good! So far I only sometimes get light tapping on startup.

But I don't know about the benefits of leaving the lifters out?
 
My only concern would be the collapsible lifter of the AFM, Summit racing sells the AFM Delete kits. Or maybe just change them to non AFM  lifter.

And yes enoniam knows quite a bit about the supercharger option.
 
MS03 2500 said:
My only concern would be the collapsible lifter of the AFM, Summit racing sells the AFM Delete kits. Or maybe just change them to non AFM   lifter.

And yes enoniam knows quite a bit about the supercharger option.


You can't just change the lifters, you definitely need one of the kits, plus a new camshaft.  This site has a decent explanation of what needs to change and why:  http://lt1swap.com/afm_delete.htm

If you changing the camshaft I would suggest a mild upgrade to improve powerband across the whole range.  A split pattern in the range of 205 to 210 on the intake (@.050"), lift over .500", and a lobe separation around 112 to 114 degrees.  Here's a good example http://www.briantooleyracing.com/truck-stage-i-cam.html, but Crane, Comp, and others also have them  in this range.  Throttle response, low rpm torque, and top end will all be improved, and it'll work with your stock torque convertor.  Keep in mind though, you will have to change valve springs as well.
 
I don't have any experience with the AFM engines but do have some with cams and one supercharger. I would be very tempted to get rid of the AFM and believe you would need to do more than just the lifters.

I would get a bit bigger cam than what Bigtrucklover recommended.  My last blower cam was 212 intake, 228 exhaust with 115 separation.  That was for a centrifugal supercharger but would probably wwork well with a magnuson as well but you may want to go to something like 224/230 with the magnuson since it won't need low end help.
 
Thank you gentlemen (x3) for your excellent help and suggestions  (y)

Because we are here in Australia and programming knowledge around is limited if at all, I will probably just change the cam to a standard non-AFM OEM and just use the program provided by Magnuson. One other thought I have is to get EFILive and be able to do it myself with a different cam, but I am not sure?

I'm sure I might need to ask your help again.....
 
OzAvy said:
Thank you gentlemen (x3) for your excellent help and suggestions  (y)

Because we are here in Australia and programming knowledge around is limited if at all, I will probably just change the cam to a standard non-AFM OEM and just use the program provided by Magnuson. One other thought I have is to get EFILive and be able to do it myself with a different cam, but I am not sure?

I'm sure I might need to ask your help again.

Holden has been selling vehicles with GM V8s for years.  Unless you're in an extremely remote area, I would be shocked if there wasn't a tuner near you. Guys over there love to hop up their Monaros.

You could easily get away without reprogramming if you keep the specs similar to what i listed.    Granted, it won't be optimized, but it'll still give you quite a boost.  But for gosh sakes, if you going to swap cams, don't put a factory one in.  The lack of valve overlap and lift really holds the engine back from its potential.  Oh, and when  you do upgrade the cam, raise the shift points to 6k to take even more advantage of it.
 
What part of Australia are you in?  Work may get me to Adelaide and from there north into the outback later this year.
 
Hey enoniam, we're in Melbourne, what have you got in mind?

Hear what you're saying Bigtrucklover, and I like it. Guess what I really mean to say is that often I'd want to do it myself and feel that all these places that can do programming for you here are ripping you off. I once was quoted some $1400 for a tune  (n) That's why also thinking about the EFILive package hoping the Magnuson software is not locked.

So I understand you, do you mean the truck would do a lot better with the modified cam even without the blower  ???



 
OzAvy said:
Hey enoniam, we're in Melbourne, what have you got in mind?

Hear what you're saying Bigtrucklover, and I like it. Guess what I really mean to say is that often I'd want to do it myself and feel that all these places that can do programming for you here are ripping you off. I once was quoted some $1400 for a tune  (n) That's why also thinking about the EFILive package hoping the Magnuson software is not locked.

So I understand you, do you mean the truck would do a lot better with the modified cam even without the blower  ???

Sorry, I missed the blower part, and was assuming naturally aspirated.  So yes, you'll see a big improvement over stock without the blower.  The torque curve will closely match the stock cam up to 2600rpm, and then pull away after that.  You can expect 25 to 35 rwhp on the top end power.

For blower, that cam will still be a huge improvement over stock, but it's not ideal.  Usually you want less valve overlap and much more duration on the exhaust side.  I'd target 115 to 117 degrees lobe separation, and have the exhaust at least 8 degrees more than the intake.

If you're not sure if the blower is in your future, I'd probably just go with the naturally aspirated camshaft .  If you are positive, then find a more blower compatible camshaft.  Keep in mind, you will lose low speed torque over the factory camshaft.

Also note, there are 3-bolt cams and 1-bolt cams.  Make sure you get the right one for your engine.  I believe the 07+ are all single bolt camshafts. There are also kits that will allow you to convert from 1 bolt to 3 bolt camshafts.
 
I've now got a lot of food for thought! Thanks all.

On top of this all I have found that the Magnuson needs to run on premium fuel. Could be a worry here in Australia!
 
OzAvy said:
Hey enoniam, we're in Melbourne, what have you got in mind?

I could tune it for you for the cost to me to license your vin, $100 US. I'm not going to be very close to Melbourne though.
 
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