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Just dropped off my truck at a local mechanic. The fellow has a good reputation and worked on the truck before. I hate letting someone else under the hood but this repair of the exhaust manifold gasket seems too difficult for me now, especially if a bolt breaks off in the head. That's the consolation I guess. Don't get old you young fellas and more importantly, don't let your wife's good cookin' add too much to your belt line!
That's my advantage, my wife doesn't cook.

Wait, that's not an advantage :(
 
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swathdiver

swathdiver

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swathdiver

swathdiver

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Truck is back home, the mechanic was great. The manifold's flange was warped (spilled oil on hot manifold?) so he had to resurface it and then discovered the #1 plug wire had fallen apart. Funny, it registered no misfires. The kids and I battled with it a few months ago, must have broken it. No broken bolts thankfully. Five Benjamins later and she's good as new.

Now we're going to order up the tie rods, sleeves and AC parts; cha ching, cha ching, cha ching...
 
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swathdiver

swathdiver

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We've been recording data for some time now and always glad when something new becomes apparent. Came across a post this year where it was said that the computer system has a high and low alcohol content tables and that running 50% alcohol is no different than running 80%. So I looked at our logs and it became apparent that this is so on the Sierra but with the Yukon it doesn't seem to matter between 40% and more. E70 includes fuel with an alcohol content of 51% or more to 70%.

Still trying to run more mixes with the Sierra at E15 levels, the Apple IOS phone was not talking to the Foseal OBD WIFI adapter so I bought a Foseal Bluetooth adapter and it works now. So I expect to be able to get more accurate data from the Sierra from now on. According to the data, the Sierra may get its best economy on E15 and maybe E50.

Appreciate any and all input.

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swathdiver

swathdiver

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Ok, back in May my daughters and I completed the front end overhaul on the Yukon. We replaced all the control arms and the strut assemblies with all GM OE or ACDelco Professional (when GM OE was not an option). If the original parts lasted 160K miles, these OE parts ought to as well. ACDelco Professional control arms are not the same, they have different GM part numbers and are the same as Moog's CK series.

Well, if you have a Yukon XL or Suburban with the plain Jane ZW7 Smooth Ride Suspension or want to convert to it, most if not all of these parts will be the same for you. My truck is a 2009 GMC Yukon XL, a 4x4 with the 5.3 LC9 engine.

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I could not find the GM OE rear springs anywhere so I had to go with the ACDelco Professional 45H2164. The struts and shocks have the same numbers on the box for GM and ACDelco. I did not need the Alignment Cam Guide Pins or the Alignment Caster/Camber Kit but did use the latter. Note, the nut in the kit is 1mm larger than the original. I forget the size now. Also not needed were the Suspension Control Arm Bolts. I was not sure that we would have to cut them off or not or have issues with the guide pins and didn't want to be waiting around for parts.

We had earlier replaced the sway bar end links so they were not ordered and the rear suspension has not been closely inspected yet, other than when I was down there a couple years ago and saw that the panhard bar was all rusty so why not.

Oh, to save a few bucks, I also opted to reuse the Strut Mounts and upon inspection, the rubber in them was still good and there was no play. Time will tell if I was penny wise or pound foolish. It is SOP to replace the Top Nut.

On another topic, we also replaced the Vapor Canister Vent Valve and the new style Vapor Canister Vent Solenoid Harness. My truck had the old style system originally and at some time it was replaced but the hose used was rubber and it was falling apart. The new hose is plastic and is literally shrink wrapped onto the Vent Valve. We replaced the Solenoid Harness as well. Usually, the P0442 code comes up towards the end of each tank of gas and so we'll soon see if this cures this long-term annoyance!

That's it for now. We're slowly replacing parts on the rear suspension and ordered up the parts to replace the tie rods on both trucks and the AC work. Oh, I bought a spare tire from a guy nearby and he threw in the old tire hoist kit. Came in handy as the ends on the extensions are worn and don't hold shape anymore after being squeezed in the vise long enough to lower the tire. The new ones have a round ring welded around them and voila, no more vise needed! Spare is identical to the other two that my truck originally came with Goodyear Wrangler HPs. One more and we'll have a set of 4.
 
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swathdiver

swathdiver

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The suspension overhaul is nearly complete now. My daughter and I replaced the rear panhard bar, rear springs with upper and lower insulators, jounce bumpers and the shocks. Somewhere along with finishing up the work it was noticed that the LR spring was out of place. So we put her back up on jack stands but the spring would not budge with moderate force. So then I disconnected the sway bar end link for a little more drop, not enough. Disconnected the shock and it dropped some more but I didn't have the strength with a pry bar even to get it to move. So I had Julia get me a ratchet strap and ran the strap through the crossmember over the spare tire and it moved right into place easy peasy. Put it all back together and torqued everything to spec. Forgot to torque the panhard bar on the suspension, oh well.

Test drive showed a noticeable improvement in ride, so much smoother than before. To me, the improvement in ride quality was greater than the front. It was dark and I was exhausted and could barely run the Tech-2 while my daughter drove.

In about a week, after the suspension has settled, we'll take new height measurements.

Rear Shocks took 21mm sockets and wrenches and are torqued to 84 foot pounds. Top and bottom. Watch those top AC lines and ABS connector on the passenger side.

Rear Sway Bar End Links took 18mm sockets or wrenches and was torqued to 45 foot pounds. Supposed to add 40 degrees but we didn't.

Panhard bar also took 21mm sockets and wrenches and was torqued to 74 foot pounds. Supposed to torque with the wheels on the ground. Note, the driver's side has a blind nut which drops out. The right side sway bar link has to be removed to gain access.

The AC Delco rear springs have 9 coils, my originals had 8.

The bump stops are friction fit.

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Note: The rear shocks are the same for both part numbers. The rear coil spring part numbers are not the same. I could no longer find GM OE coil springs and chose to run with ACDelco Professional.

Anyway, another purpose of the test drive was to check the Fuel Trims since the exhaust manifold gasket was replaced. The trims were quite high at idle before we left and as we drove I thought I could hear air swooshing into the motor and suspected that the intake system was loose. Pulled back up to the house, checked for leaks, none discovered, and then continued on our test run.

Fuel Trims were in the negative mid-teens at idle and negative 10 to 12 most of the time. Sometimes it got as low as minus 5 with Bank 2 always being higher than Bank 1 by about 2 points. I was too tired to think of setting up a graph and spraying water around the intake gaskets, we'll do that soon enough. AC Repair next.
 
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swathdiver

swathdiver

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When dropping the rear axle down to pull the springs, take the tires off and unclip the ABS wires from their 2 mounts on each side so as not to stretch them. The Lord had mercy on me!

Also keep an eye on the brake lines and differential vent in the center when doing this.
 
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