New 2007 Yukon XL Denali Owner looking for a service manual before tracking down oil leaks

Welcome from SoCal sleet. I went from 90’s vág (g60) to 06 YXL Denali to 02 6MT allroad and back to an 08 YXL Denali in the course of 15 years.

You got a good hit on the 07 Denali. It’s a 3-400k truck and predictable. Everything is just 3x as heavy and 3x safer too.

In a perfect world everything is easy and accessible on these AWD trucks. That is, as long as the trans is out.

If you can prolong a rear main seal, pan gasket, oil pump O ring, both front diff mounts, motor mounts, oil press sensor until the trans is out for its 100 or 200k major service everything is accessible without anything in the way.

You won’t be in there for another 100k miles.

The guy on Ebay that I've bought from was SeriousCTBuyer. The current AllDataDIY is so improved that I rarely use the pdfs anymore, it's easier to look things up on the computer since I keep it open all the time.

@sleet
youtube is your friend

Thank you for all the replies,

@swathdiver I ended up finding him and purchased a manual (he has a different username on ebay now) I guess they cracked down on him selling them there but based on what he sold me (for $15 I might add) it's an amazing manual and a ton of pdf's

It's probably not as good as a subscription service in quality but for me I think it will work really good.

The car was purchased locally from the dealer here in northern Utah. the original owner eventually sold it to one of their kids. The kids just upgraded to a newer Yukon XL and we got it from them. So we're the third owner but feel like we got it from the originals as it's always been local here and there's no major rust that I have been able to find. They even wanted a family photo in front of the car before we drove it off. We feel it was loved and cared for and hope it ends up being the case.

They guy did all his own work and replaced the front struts with something less expensive - he said it was going to be like $1,600 a side to replace them so he went with something that wasn't as fancy. Maybe someday I'll figure out what was in it originally and put it back in but for right now that's not the priority.

It has 218k and we got it for $7,000

We just out grew our 5 seat cars so this was one the wife wanted and we picked it up a few weeks ago. The plan is this will be the entire family vehicle and we'll drive the other 5 seaters for day to day driving when we're not all driving someplace together. So it's been sitting in the driveway until this past week when I figure I'd have some time now to get it running properly.

The previous owners had been running Mobil 1 High Mileage in it and said they changed it roughly ever 3-5k miles.

As I mentioned it has 218k on it so the miles are high to some people but I'm a sucker for doing my own work and trying to do things right. Two of my vw tdi's have over 400k on each and I'd drive them anywhere no questions asked. I do all my own work. The only thing I haven't tried to do is an alignment. but everything from timing belts / clutches / tire repairs I do myself at home. I don't have a lift yet but plan on getting one eventually. Realistically that's a few years down the road though.

I don't have a car payment and figure a part of what I'd spend on labor to get someone done can go towards my tool budget. The wife has agreed to far so I have nothing to complain about

Anyway I tried cleaning off the oil from the bottom and it was all over. Looking in the inspection hole for the transmission I didn't really see much inside, maybe some damp seepage that can from outside the bell housing. but I wasn't certain one way of the other.

I did think I could see some oil coming down an inside cornet on the block from the driver's valve cover so I figured valve covers would be the place to start, I also picked up an oil pressure sender so thought I might try that as well. then continue to clean from the top down and see how things and the oil leak stopped.

when I removed the coil pack bracket it came out easy with the air ratchet but the smaller 8mm bolts (that have the same torque spec as the coil pack bracket bolts) seemed more difficult than my 1/4 air ratches wanted to handle. So my guess is someone has been in there and tried to tighten those to hopefully "fix" a oil leak.

So I started with the easier side and pulled the driver's valve cover off yesterday and this is what things looked like. In your guys' opinion should a vehicle with synthetic oil it's whole life look this bad after 200k?




I run Mobil Turbo Diesel Truck in my vw's and the oil in those is black but things sure don't look like this bronze color. Maybe I've been living in a bubble and this is normal but I'm honestly not sure.

A couple other questions.

I'm thinking i should probably replace the pvc, possibly the plugs and wires, air and fuel filters and such.

I thought the pcv was pressed in the end of the driver's valve cover. However I can blow air though it (both in and out) isn't a pcv only supposed to be in a single direction? So should I replace this one? Do the hoses for it leak as well? - there seemed to be some seepage around the hose from the driver's side valve cover to the intake so maybe I should get a new hose?

What plugs do you guys reccomend? Rock Auto has a ton of options and in my diesel world I've never had to sort out what plugs are the right ones to use. I know NGK's are generally good for engines from Japan but this engine isn't fron Japan so I'm really not sure.

Rock auto has Copper/nickle, platimum, douple platinum, iridium, ruthenium. I mean I'd like good, but what's the good spot of quality (I don't want to put in cheap junk) end and where does being obsessive without any real benefit start?

Also, is there a good maintance schedule to follow? I look in the owners's manual and it shows some things to replace but @petethepug above mentioned transmission removal at 100k 200k I'm guessing I'm near that but I'm not seeing it mentioned in the owner's manual, so is there a different (I'd assume better) schedule I should be following?

Thanks for all the advice and welcome's

you guys are very nice!

-J

donjetman said:

@sleet
youtube is your friend

Click to expand...

yes I've been trying to sort of good and bad videos. Although this 6.2 seems to be a bit less common than the 5.3

I did see a post once in my searching a couple weeks back that you did with a huge list of parts / part number / cost you paid that you did to your Yukon. I'll have to find it again and bookmark it. I'll be referencing that in the future!

there's no real pvc valve like a check valve. the run full bore. there's a updated newer valve cover with a little better baffle but these engines really need a catch can installed. few good threads here about it. I have the newer style cover and my cheap 35$ Amazon catch can gets lots of oil in it.

the references to pulling the tranny is because in stock form the lock to cluch in the converter burns up and takes the rest of it with it. 100k to say 150k is pretty average. at 200k yours might have already been rebuilt once. either way there's a updated aftermarket converter with a better clutch and a tranny tune helps too.

pretty much oem parts for everything. but not Amazon/ebay. legit oem.

sounds like a clean truck with repairing. it afm is still active, even with 3k oil changes. it's probably a good idea to delete or at least disable it.

You got the golden ticket. That’s clean, clean for 200k. Next to no carbon build up. With these GM trucks the 2nd row, heated, 60/40, electric fold bench seat and captains chairs are interchangeable if you want a couch vs chairs.

Factory BT controlled through the steering wheel and uses the now defunct OnStar mic & OEM speakers & center dash display is a quick VCIM module swap out off eBay from an 09-14 truck for 20-$30 bucks.

Watch out for counterfeit parts. Oil press sensor especially. As difficult as they are to access you really only want to do the job 1x. I suspect my Indi diesel tech used a generic sensor and it died after 3 mo.

A dealer will still try to get you for $1.6k a side for new Autoride (z55) struts. The oem GM / BWI replacements are now $3h ea with a lifetime guarantee. When it comes time for bushings & bearings on the front end there’s good and better inexpensive OEM options. The link below shows parts needed for the AWD Denali’s brother or Escalade. Just swap the z55 struts for the z95 units. I really miss just looking up parts in EKTA emulators.

Aluminum / XFE NNBS Front Suspension Rebuild'
https://www.tahoeyukonforum.com/thr...-front-suspension-rebuild.146131/post-1855015

sleet said:

I'm thinking i should probably replace the pvc, possibly the plugs and wires, air and fuel filters and such.

Click to expand...

GM does show a PCV valve for your truck, none of mine have them, it's 12567915. Confirm this with your VIN.

Use OE plugs and wires, the computer system is designed to work around the resistance they provide, about 800 ohms, 41-162/19417055 plugs and 748UU/19351593 wires.

There is no fuel filter in these trucks. High capacity air filter is A3085C.

GMPartsGiant.com


With those two websites, you ought to be able to find just about anything you need for your new truck.

If anyone is looking for the real service manuals for their truck, do a Google search for a company in Detroit called Helm. I think their website is Helminc.com. They publish and sell the OEM manuals that the dealer would use. Along with owners manuals, etc. They are NOT cheap, but will save you a ton of money and time....

You can also look at Rockauto for GM parts plus a 5% off code.