2007 Tahoe/New member from sunny California/Looking for some advice

[Caligirl]

Disabling the AFM should be priority. Then monitor the oil. Not all of these consume oil through the PCV system, and I believe a large factor is the type of driving it is subjected to. Lots of high RPM/high load results in higher oil pressures and higher vacuum which could make the oil coming out of the rocker squirt farther and hit the ill-placed hole in the cover (if you still have the older one). The stronger airflow in the PCV system would vacate this oil and carry it to the intake manifold. I'd still strongly suggest adding a catch can. For its benefit, minimal expense and ease of installation, it's a no-brainer.

Shoot, thought I had a handle on the terms regarding this subject. What is this catch can of which you speak?

 

[wsteele]

Disabling the AFM should be priority. Then monitor the oil. Not all of these consume oil through the PCV system, and I believe a large factor is the type of driving it is subjected to. Lots of high RPM/high load results in higher oil pressures and higher vacuum which could make the oil coming out of the rocker squirt farther and hit the ill-placed hole in the cover (if you still have the older one). The stronger airflow in the PCV system would vacate this oil and carry it to the intake manifold. I'd still strongly suggest adding a catch can. For its benefit, minimal expense and ease of installation, it's a no-brainer.

I agree with this advice. My truck isn't using any appreciable oil between changes, but I went ahead and installed a catch can (air/oil separator), between the line that runs from the PCV to the intake manifold. Predictably, when I open it up, no oil flows out. But I consider it kind of a canary in the coal mine for knowing if the truck ever starts pumping oil. I think I probably bought the most expensive one I could have (Moroso) for like $150. It took about 15 minutes to install. You can find them for a lot less than what I paid. Just make sure if you get one, the top contains that pot scrubber material to help separate the oil from the air.

 

[swathdiver]

My observation is that my truck does not lose oil unless it is regularly spun past 3500 rpms. Now that my wife is driving it more frequently since I'm down for the count, it is using more oil and the gas mileage has plummeted! LOL She loves the sound of the LS motor she tells me!

I get 15 or so MPG and she's lucky to average 12 on pump gas. I don't lose any oil between changes and we have to add about a quart or so when she's behind the wheel for any length of time.

 

[iamdub]

My observation is that my truck does not lose oil unless it is regularly spun past 3500 rpms. Now that my wife is driving it more frequently since I'm down for the count, it is using more oil and the gas mileage has plummeted! LOL She loves the sound of the LS motor she tells me!

I get 15 or so MPG and she's lucky to average 12 on pump gas. I don't lose any oil between changes and we have to add about a quart or so when she's behind the wheel for any length of time.

I'm anxious to hit 205,000 so I can change my oil and see the contents of my catch can. Of course, this past 5,000 miles has included more WOT and 4,000+ RPM time than ever before. I did check my dipstick recently and it's maybe 1/2 a quart low. This is a marked improvement since the refresh. If I drove civilly for 5,000 miles, my oil level would probably stay ******* that "FULL" mark"

 

[Caligirl]

I'm anxious to hit 205,000 so I can change my oil and see the contents of my catch can. Of course, this past 5,000 miles has included more WOT and 4,000+ RPM time than ever before. I did check my dipstick recently and it's maybe 1/2 a quart low. This is a marked improvement since the refresh. If I drove civilly for 5,000 miles, my oil level would probably stay ******* that "FULL" mark"

So since you keep on throwing out terms that are new to me haha I had to look up what a catch can is...is this something that is easy to install and do you have to do any other prep or changes in order to install it?

I usually drive just a bit over the speed limit, and only time I really push the motor is passing or to get up a hill. I'll have to see what my rpms are with my normal driving.

So I can understand the priority- we should be disabling/deleting the AFM, replacing the cover shield (if not already done so), then the catch can?

If I'm not burning excessive oil, is the cover shield necessary, or is the cover shield necessary regardless of oil consumption? I can assume all day long that the updated shield is under the hood, but if it isn't, am I possibly doing silent damage or would that reflect in the oil consumption?

The last thing I want to do is nickel and dime just for prevention if the likelihood of these items being needed are low. I'd like to say if it's not broken don't fix it, but it sounds like with these AFM systems that may not be a good attitude.

Is it better to be proactive and spend a few hundred to take care of the cover shield and the catch can or do I wait to see if there are indicators that I need it?

 

[iamdub]

Shoot, thought I had a handle on the terms regarding this subject. What is this catch can of which you speak?

Something like this:

https://www.amazon.com/Tasan-Racing...b3fa4&pd_rd_wg=XC9Ta&pd_rd_i=B07KK81KMG&psc=1



You would just need to add one of these to it:

https://www.dollargeneral.com/produ...__Desktop___Ecomm_ROAS&12138401&gclsrc=aw.ds&


If you browse around Amazon for other catch cans, ignore the ones with a breather filter and with a dipstick. A breather would be vacuum leak on our engines and the dipstick is useless and just a potential leak point. When you get one, we can give you the details of where to put the stainless scrub pad. It's to increase the can's effectiveness.

I put this catch can on my brother's truck two years ago. I made a super simple bracket out of a piece of flat stock to locate it next to the alternator for easy access to drain it:

 

[iamdub]

So since you keep on throwing out terms that are new to me haha I had to look up what a catch can is...is this something that is easy to install and do you have to do any other prep or changes in order to install it?

I usually drive just a bit over the speed limit, and only time I really push the motor is passing or to get up a hill. I'll have to see what my rpms are with my normal driving.

So I can understand the priority- we should be disabling/deleting the AFM, replacing the cover shield (if not already done so), then the catch can?

If I'm not burning excessive oil, is the cover shield necessary, or is the cover shield necessary regardless of oil consumption? I can assume all day long that the updated shield is under the hood, but if it isn't, am I possibly doing silent damage or would that reflect in the oil consumption?

The last thing I want to do is nickel and dime just for prevention if the likelihood of these items being needed are low. I'd like to say if it's not broken don't fix it, but it sounds like with these AFM systems that may not be a good attitude.

Is it better to be proactive and spend a few hundred to take care of the cover shield and the catch can or do I wait to see if there are indicators that I need it?

LS engines have a strong flow of air in and out of their crankcase for the PCV (Positive Crankcase Ventilation) system. The PCV is routed back into the intake manifold. If the air flowing out of the crankcase contains oil, it ends up inside the intake manifold where it puddles up and eventually gets sucked into the cylinders and burned. The amount of oil in the PCV air varies by the condition of the engine (piston rings, mostly) and by how it's driven.

The routing of the PCV is that it comes out of the driver's side rocker cover, through a hose and into the top center of the intake manifold. The catch can is simply placed inline in this circuit. So, the routing would be out of the rocker cover and into the catch can, then out of the catch can and into the intake manifold. It's just an inline filter.

If you don't do a lot of high-load driving, then your engine will likely not pass much oil through the system. High load is not just hard throttle and high RPM, it's also moderate throttle and lower RPM, such as when going up an incline with just enough throttle to keep it moving but not downshift. This is also known as "lugging". The engine makes a deeper growl during this- I'm sure you've heard it. Having only 4 speeds to pick through, it'll happen more often than with a vehicle with more gears. It's fine for normal, everyday driving. But, a custom tune will improve these characteristics and make the vehicle more responsive. The factory programming is geared towards fuel economy and soft shifts at the expense of throttle response and trans life. Even the 6-speed transmissions benefit from better tuning.

If you wanted to prioritize these three mods, I'd order them as disabling AFM then/and installing a catch can. That's maybe $100 in worthy mods. The rocker cover isn't so pressing due to your civil driving and the catch can will make up for not having the updated cover in some aspects. The updated cover and the catch can both prevent the oil from ending up in your intake manifold, but the cover will keep it inside the engine. The catch can collects what makes it out of the engine and you drain it and dump it or, if it's clean, pour it right back into the engine. The cover is bumped down the list because it's kinda pricey at something like $60-$70, you have to remove your current cover to see if you even have it and you can kinda make up for it with the catch can if you don't have it. But, you should still have it to keep the oil inside the engine and rely on the catch can for just what makes it past that updated cover. At least it can wait, maybe until you find a deal on a used one or something. If you get bored one day and wanna take the 30 minutes to remove your rocker cover to check, it would also have the benefit of giving you a glimpse of the level of cleanliness of the inside of your engine.

All of these are the few small and cheap mods that were mentioned earlier that would go a long way in preventing damage/wear/failure. They're literally the "ounce of prevention" that's worth a pound of cure.

 

[Caligirl]

LS engines have a strong flow of air in and out of their crankcase for the PCV (Positive Crankcase Ventilation) system. The PCV is routed back into the intake manifold. If the air flowing out of the crankcase contains oil, it ends up inside the intake manifold where it puddles up and eventually gets sucked into the cylinders and burned. The amount of oil in the PCV air varies by the condition of the engine (piston rings, mostly) and by how it's driven.

The routing of the PCV is that it comes out of the driver's side rocker cover, through a hose and into the top center of the intake manifold. The catch can is simply placed inline in this circuit. So, the routing would be out of the rocker cover and into the catch can, then out of the catch can and into the intake manifold. It's just an inline filter.

If you don't do a lot of high-load driving, then your engine will likely not pass much oil through the system. High load is not just hard throttle and high RPM, it's also moderate throttle and lower RPM, such as when going up an incline with just enough throttle to keep it moving but not downshift. This is also known as "lugging". The engine makes a deeper growl during this- I'm sure you've heard it. Having only 4 speeds to pick through, it'll happen more often than with a vehicle with more gears. It's fine for normal, everyday driving. But, a custom tune will improve these characteristics and make the vehicle more responsive. The factory programming is geared towards fuel economy and soft shifts at the expense of throttle response and trans life. Even the 6-speed transmissions benefit from better tuning.

If you wanted to prioritize these three mods, I'd order them as disabling AFM then/and installing a catch can. That's maybe $100 in worthy mods. The rocker cover isn't so pressing due to your civil driving and the catch can will make up for not having the updated cover in some aspects. The updated cover and the catch can both prevent the oil from ending up in your intake manifold, but the cover will keep it inside the engine. The catch can collects what makes it out of the engine and you drain it and dump it or, if it's clean, pour it right back into the engine. The cover is bumped down the list because it's kinda pricey at something like $60-$70, you have to remove your current cover to see if you even have it and you can kinda make up for it with the catch can if you don't have it. But, you should still have it to keep the oil inside the engine and rely on the catch can for just what makes it past that updated cover. At least it can wait, maybe until you find a deal on a used one or something. If you get bored one day and wanna take the 30 minutes to remove your rocker cover to check, it would also have the benefit of giving you a glimpse of the level of cleanliness of the inside of your engine.

All of these are the few small and cheap mods that were mentioned earlier that would go a long way in preventing damage/wear/failure. They're literally the "ounce of prevention" that's worth a pound of cure.

So glad you all are so concise on explanations. I can tell my husband exactly what you'll are telling me and HE understands haha. Still a bit foreign to me, but I get the basic logic of it all. Just don't wanna toss too much at him all at once or he's gonna start hating on my new ride

 

[Millennium Falcon]

Welcome, from another Sierra Nevada dweller! As you've already decided, I was going to suggest you check your oil weekly for a while to see what your oil consumption is like. My parents have a '12 Yukon XL with the 5.3, and it can use no oil at all or quite a bit. We haven't figured out why it does at times and not at others, and the dealer has been no help on the matter.

My wife and I have owned Suburbans and now a Yukon XL Denali in model years from '89 to '09. For our latest vehicle, I looked for the 6.2L engine and the 2009 MY specifically. Our 2002 Suburban Z71, which we replaced with the Yukon, is an absolute dog going up hills. It has the 5.3/4L60/3.73 gear ratio combo and second gear is long and too high. We would require 2 miles of clear road (slight exaggeration) if we wanted to pass someone. It was great, otherwise. Now, with the Yukon, we just check for oncoming traffic, then engage the HyperDrive. We don't have to overthink it.

Some great things about the 2009 Yukon XL Denali are: 1) last year with NO AFM, 2) first year of 6-spd transmission, and 3) first year of 403 HP. This applies to the Cadillac Escalade, as well. Also, there is no part-time 4WD option for the Yukon Denalis and the Escalades in this series; they're both AWD. However, my mileage up and down the hill is the same as my parents' 2012 Yukon XL SLE with the 5.3L, AFM, and part-time 4WD. On the highway, they might beat my mileage by ~1 MPG.

I would just drive it for a while, and see how it does. If your happy with it, great. If not, there are other options within this vehicle series out there.

*Edit: May or may not be first year of 6-spd. I've found conflicting info re: that.

 

[donjetman]

6 speed was standard for the Denali starting in 2007