Fuel type/ Maintenace Questions

[BabushkinMechanic]

Hello,
Asking for some advice and assistance into inspecting our just bought Chevy Tahoe PPV 2011 5.3L from a local dealership.
I do have the old manual left in the glove box luckily but what are some lists of things I should inspect/Repair/drain-refill/ ect on these types of cars besides the basic oil and coolant level checks to get it to pristine condition once again before I start to apply any upgrades and before my wife starts driving it all over town, first time owning an SUV as well. Dealer replaced o2 sensors and said all fluids were flushed and replaced don't know how true his word is, back seats were replaced due to being torn up and don't know what else.
I replaced some cosmetics, ac works, got a new spotlight it was ripped off, transmission transitions into gears very smoothly, trans temp doesn't get above 170 due to upgraded PPV parts i can assume. Brakes do squeak every now and then. Will be jacking up the car tomorrow to make a nice long list of things to get or repair. I also have a pretty nice professional code scanner i can use to scan any undiagnosed codes or read engine ecm resets ect.

Another question concerning fuel I did not see it on this forum but it is a flex fuel vehicle and i want to know the fuel parameters according to the manual but would a prefer a second opinion on here, I have non ethanol 87 octane by my house and I always thought/researched/told ect non ethanol was way better due to it burning slower and not containing 10 percent (other) in the fuel it would help clean the fuel injectors/lines and just better overall given the right octane level? On that note what is the best octane to run and what other octanes can I run in it?

thanks.

 

[iamdub]

Hello,
Asking for some advice and assistance into inspecting our just bought Chevy Tahoe PPV 2011 5.3L from a local dealership.
I do have the old manual left in the glove box luckily but what are some lists of things I should inspect/Repair/drain-refill/ ect on these types of cars besides the basic oil and coolant level checks to get it to pristine condition once again before I start to apply any upgrades and before my wife starts driving it all over town, first time owning an SUV as well. Dealer replaced o2 sensors and said all fluids were flushed and replaced don't know how true his word is, back seats were replaced due to being torn up and don't know what else.
I replaced some cosmetics, ac works, got a new spotlight it was ripped off, transmission transitions into gears very smoothly, trans temp doesn't get above 170 due to upgraded PPV parts i can assume. Brakes do squeak every now and then. Will be jacking up the car tomorrow to make a nice long list of things to get or repair. I also have a pretty nice professional code scanner i can use to scan any undiagnosed codes or read engine ecm resets ect.

Unless they sucked/pumped it out, the rear diff cover would have to come off to drain the fluid. It should be taken off, anyway, to clean the metal off the guts and magnet. If that's recently been done, then it'd be obvious. Trans fluid and coolant is easy enough to check.

Another question concerning fuel I did not see it on this forum but it is a flex fuel vehicle and i want to know the fuel parameters according to the manual but would a prefer a second opinion on here, I have non ethanol 87 octane by my house and I always thought/researched/told ect non ethanol was way better due to it burning slower and not containing 10 percent (other) in the fuel it would help clean the fuel injectors/lines and just better overall given the right octane level? On that note what is the best octane to run and what other octanes can I run in it?

thanks.

Ethanol fuel is not the devil it has been made out to be. There are some engines in which it doesn't belong and some situations with compatible engines where it should be avoided. Technically, the LMG in your Tahoe is okay on 87 octane. I used to run it in mine until, one summer day, I mashed on the throttle and heard spark knock. I tried other stations (always top tier- Exxon, Chevron/Texaco, Sunoco and Valero) and got the same result. 89 octane made a notable reduction in the severity of the spark knock and 91-93 eliminated it altogether. This was when it was completely stock except for the Airaid MIT and AEM filter, neither of which would have any affect on the spark knock. So, I switched exclusively to high octane and enjoyed the power and MPG. If I wanted to save a few bucks, I'd run lower grades but only during cool weather. My assessment is you can run 87 if you want, just avoid high loads (hard throttle, etc.). I prefer the freedom to hoon at will.

E85 at the pump should yield a higher octane rating than 89 and possibly 91. So, if you're used to paying for 91-93, then the MPG penalty of E85 doesn't even touch the cost savings benefit.

If you wanna factor in the cleaning factors of E85, then the cost-to-benefit ration is even better.

No, E85 doesn't gum up your injectors. Quite the opposite, in fact.

Octane level doesn't have any bearing on cleaning properties. Marketing has many believing 87 is unfiltered crude oil and 93 is sanitary jet fuel.

Reserve the ethanol-free for powering your lawn equipment.

 

[bill1013]

It’s a good idea to find out what type/octane was used before you bought it and stick with that type/octane. I had a 1999 Tahoe, from Canada, and it used low octane fuel. At the time I only used hi-octane fuel and in a few months I had a total fuel system failure, spider, injectors and the 3 pumps in the tank, outside the tank and at the engine. I had it for 14 years. When I bought my 2012 Yukon the same thing happened, but only the spider this time. Now I stick to the 85 octane. No problems since then. Hope that helps. Aloha!

 

[Fless]

It’s a good idea to find out what type/octane was used before you bought it and stick with that type/octane. I had a 1999 Tahoe, from Canada, and it used low octane fuel. At the time I only used hi-octane fuel and in a few months I had a total fuel system failure, spider, injectors and the 3 pumps in the tank, outside the tank and at the engine. I had it for 14 years. When I bought my 2012 Yukon the same thing happened, but only the spider this time. Now I stick to the 85 octane. No problems since then. Hope that helps. Aloha!

A 2012 had spider injectors?

 

[solli5pack]

While your under the truck check around the oil pan for oil leaks. Very common on the older trucks and with AFM its extremely important to keep the oil topped off and fresh. Also probably a good idea to look into disabling AFM. Multiple threads on here discusses the topic.

 

[swathdiver]

Another question concerning fuel I did not see it on this forum but it is a flex fuel vehicle and i want to know the fuel parameters according to the manual but would a prefer a second opinion on here, I have non ethanol 87 octane by my house and I always thought/researched/told ect non ethanol was way better due to it burning slower and not containing 10 percent (other) in the fuel it would help clean the fuel injectors/lines and just better overall given the right octane level? On that note what is the best octane to run and what other octanes can I run in it?

thanks.

Ethanol is like running the engine on race gas, the motors love the stuff. They run smoother, cooler and accelerate and shift better after adjusting to a couple of tanks of it.

Ethanol was mandated by Congress to be added to gasoline back around 2005 or so. I believe this replaced MMT which are both used to reduce spark knock. While not great for food prices, it is better for the engines and the manufacturers have tuned the engines for it to maximize efficiency. It's better than ethanol free gas, you can see that with your scan tool.

 

[BabushkinMechanic]

Will be $500 out of pocket for fluid maintenance fluid/flush, brake fluid is black, trans fluid is overfilled been sitting for 2 days and is at hot mark when checked, trans pan looks like its never been dropped so filter never has been changed i have pics :0, oil is over filled by a quarter of an inch, power-steeking will be changed and rear differential, coolant is below max mark when i bought it so that's getting flushed. Will be doing all that over the next couple weeks between days, if anyone has good vids/tips on system fluid changes to point me to that would be great i know i saw some on here from researching.

 

[BabushkinMechanic]

Update: took a look under to drain the oil first, and seems the oil pan gasket is failing there is residual oil all along the seam of where the oil pan is bolted to. And and they over filled it by almost 2 quarts. Drained about 1 3/4 gal of oil into my measuring bucket. I do plan on replacing oil pan /gasket if need be but as of right now it was not coming out enough to be dripping just slowly but surely oozing out by the looks of it, will fill it back up with good oil and new filter at the right amount and will be checking after drives for seepage if that does seem to fix it. What would you guys recommend? thanks

Also any one have any idea what I can do with this console tray as in where I can buy the right one ect? It won’t sit in flush bc of some plastic cover thing underneath so I’m assuming they never installed the right tray. And don’t have key to the lock so any suggestions on replacing the lock as well?

 

[iamdub]

Update: took a look under to drain the oil first, and seems the oil pan gasket is failing there is residual oil all along the seam of where the oil pan is bolted to. And and they over filled it by almost 2 quarts. Drained about 1 3/4 gal of oil into my measuring bucket. I do plan on replacing oil pan /gasket if need be but as of right now it was not coming out enough to be dripping just slowly but surely oozing out by the looks of it, will fill it back up with good oil and new filter at the right amount and will be checking after drives for seepage if that does seem to fix it. What would you guys recommend? thanks

Not saying your oil pan gasket isn't (also?) leaking, but I'd first suspect that oil cooler bulkhead gasket as they are notorious for leaking. The oil can wick and/or be blown along the rails of the block and pan, making it appear the pan gasket is the source. Grab a few cans of cheap engine degreaser and brake parts cleaner from Walmart (Super Tech) and clean off all that sludge. Don't forget your safety goggles and/or face shield. Check it soon after some driving to see where the fresh oil is coming from. The oil cooler gasket is only like $15 and is a quick and easy replacement you can perform during the next oil change.

Also any one have any idea what I can do with this console tray as in where I can buy the right one ect? It won’t sit in flush bc of some plastic cover thing underneath so I’m assuming they never installed the right tray. And don’t have key to the lock so any suggestions on replacing the lock as well?

I'm not familiar enough with this to offer anything.

 

[petethepug]

To remedy an oil leak, clean off all the mess with a degreaser like simple green. No need to use anything harsh on the aluminum block.

Track where the clean oil comes from after the clean up and diagnose after that.

 

[BabushkinMechanic]

About to do coolant flush, manual says 18.3 quarts for mine. Most originals posts are showing 16 quarts for theirs, now which is it. It’s a PPV so is that bigger coolant capacity. Need to know for proper coolant mixture. I got close to 10 quarts out now.

 

[iamdub]

About to do coolant flush, manual says 18.3 quarts for mine. Most originals posts are showing 16 quarts for theirs, now which is it. It’s a PPV so is that bigger coolant capacity. Need to know for proper coolant mixture. I got close to 10 quarts out now.

I think mine calls for 17 quarts. That two quarts will make no difference at all. You could put 16 in it and pour another two quarts of coolant concentrate or two of distilled water and it'll still be close enough. It doesn't have to be precisely 50/50. Actually, I like to lean a little more towards straight water as it cools better. Freezing isn't much of a concern where I live. That 50/50 rule is generic for the entire country, for all climates.

If your OCD requires it to be right at 50/50, mix it in a third jug then pour it in as needed until full. Also, you'll never get all of the "old" stuff out so it's not gonna take the full specified capacity.

 

[BabushkinMechanic]

Updates: All fluids changed, have not ran it for 10 min and I look to see oil residue once again where I wiped it clean.


Seems it’s coming from the oil cooler gasket. I saw other threads talking about replacing it and changing the block of plate or something. Dont know if that’s the only place oil is leaking from, process of eliminating. It’s seems to run underneath the oil pan in the crack where it connects to the transmission. Pics below.

 

[iamdub]

Updates: All fluids changed, have not ran it for 10 min and I look to see oil residue once again where I wiped it clean.


Seems it’s coming from the oil cooler gasket. I saw other threads talking about replacing it and changing the block of plate or something. Dont know if that’s the only place oil is leaking from, process of eliminating. It’s seems to run underneath the oil pan in the crack where it connects to the transmission. Pics below.
View attachment 410428

Super common leak point. You don't have a block-off, you have the cooler installed. Models without the oil cooler will have a block-off. Each use their own gasket and are not interchangeable. Be sure you order the correct one. At least it's an easy repair! Replace it, hit the whole area again with a cleaner and let it drip dry. Check again after some driving. Be aware that some oil could be "baking out" of the pores in the block and pan and isn't an actual leak. It could weep or wick down and collect on lateral surfaces, appearing as a slight leak. It may take a few heating and cleaning cycles to get all the oil cleaned off, assuming there are no actual leaks.

 

[Geotrash]

Updates: All fluids changed, have not ran it for 10 min and I look to see oil residue once again where I wiped it clean.


Seems it’s coming from the oil cooler gasket. I saw other threads talking about replacing it and changing the block of plate or something. Dont know if that’s the only place oil is leaking from, process of eliminating. It’s seems to run underneath the oil pan in the crack where it connects to the transmission. Pics below.
View attachment 410428

And to add to Chris's post, which is great advice, is to use the OEM style gasket:

...instead of aftermarket designs:

The latter requires too much clamping force to seal. Gotta to be real careful with those bolts because they're small diameter, screwed into aluminum. Stripping one out will ruin your day. Ask me how I know.

 

[BabushkinMechanic]

And to add to Chris's post, which is great advice, is to use the OEM style gasket:

View attachment 410444

...instead of aftermarket designs:

View attachment 410445

The latter requires too much clamping force to seal. Gotta to be real careful with those bolts because they're small diameter, screwed into aluminum. Stripping one out will ruin your day. Ask me how I know.

Thanks, do you know torquing specs on these bolts ?

 

[Geotrash]

Thanks, do you know torquing specs on these bolts ?

106 *inch* pounds

 

[BabushkinMechanic]

Update: flushed tranny fluid new filter and gasket install. Noticed drive shaft links were covered in oil residue as well and is leaking somewhere somehow. Any pointers on whats causing this and how severe it is. The rubber boot seems dry and fine the u links are caked however.

 

[BabushkinMechanic]

Let’s see replaced oil pan gasket, oil cooler gasket, and oil pick up tube gasket o ring with upgraded flange kit using both bolt holes on pick up tube and well as all fluids changed oil changed 3 times in a month due to me forgetting put the drain plug back.

Well it’s runs but got some more stuff to fix based on test driving it.

Problem-
cold start oil is at 40 psi so that’s good there, then as it gets warmed up it drops and hangs around 18-19 in drive idling. in park the engine rpms are higher for some reason so oil psi is around 20. Engine rpms drop as well when the vehicle warms up.

Rough engine idling around 515 and dips sometimes to 480ish taking the oil pressure with getting as low as 16ish. It gets to 45 psi just fine with acceleration . But the idling is the main problem when it dips below 500 you can tell the difference in the vibration and the sound of the engine.

More info it’s a PPV so the trans temp never gets above 180 if that means anything but using my scan gauge I took pictures of pressures that might help. Seems something’s is off, any input maybe idle value change.