What did you do to your GMT today? [Part II]

Mike534x

Member
Apr 9, 2012
894
I'll have to give that a shot! If I can manage to use the same trick with the V8 I'd be happy as hell.

One thing I didn't see mentioned in past threads, but what was the biggest difference between the EV and thermal clutches aside from the EV robbing power away from the engine?
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
I've removed mine from the bottom after removing the unknown/useless plate that's bolted to the frame just under the lower hose.

There may be a little parasitic power loss due to the thermal but shouldn't be noticeable. Or it will just be noticeable because your old clutch was just freewheeling.

But you'll also enjoy that tune. Best bang for the money, especially on the V8.
 

Mike534x

Member
Apr 9, 2012
894
I've removed mine from the bottom after removing the unknown/useless plate that's bolted to the frame just under the lower hose.

There may be a little parasitic power loss due to the thermal but shouldn't be noticeable. Or it will just be noticeable because your old clutch was just freewheeling.

But you'll also enjoy that tune. Best bang for the money, especially on the V8.

It actually didn't occur to me to try it from the bottom... what is that plate for??? It seemed so out of place. I suppose it'll be interesting driving with a thermal based one, hopefully that actually blows air over the condenser at a stop....the old one sure as hell isn't even if the temps are staying within normal range.

Already is tuned! Though I couldn't remember what it was I had done to it lol. Waiting on Kelly to send me my tune sheet from 2017 so I can look it over and see what I chose. Might consider fully removing torque management though (I think it was dialed back 90%), and whatever else could be done to get a little more from it.
 
Mar 30, 2016
1,465
KSA
Been a busy week since I have ben back! Feels good to finally drive real vehicles again! The weekend I arrived went to the local junkyard pulled out some parts for the old mans Denali, and scored on a working head-unit as well!

I am still in the process of configuring new to me IPhone and getting used to transferring photos and all. Lots of pics coming hopefully very soon

Edit: They are here20220626_072043880_iOS.jpg

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Picked this up to replace the vent in the Denali. Been broken since we bought it almost 10 years ago!

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So this happened yesterday, my neighbor's wife rammed into the Yukon while parking, took out the taillight 😭. I loved these taillights, turn out they are very hard to find! 😞. But testament to GM build quality the bumper is untouched, just minor scratches which will buff out just fine! The neighbors car was in much worse condition with their hood bent in and front fascia gone
 
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TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,045
Brighton, CO
Thats the first Denali I have ever seen that didnt have tint... odd
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
Threw a can of R134 in the TB. Noticed today that the A/C wasn't cooling well and the compressor was cycling at idle. Could hear the low pressure switch clicking off and on. Didn't have time to properly diagnose it or check for a leak because we're leaving for the cottage in the morning. AFAIK, this is the first time it's needed a top up. Didn't see anything in the RCMP's service records about any A/C work. Not bad for a 15 yo truck.
 

smitty5150

Member
Nov 18, 2011
1,069
I bought the 245/70 nitto terra grappler when I was staying stock. Things changed and I got an 18 charger rt for travel, so I decided to install the 2" ready lift. I thought they'd look small, but I couldn't return them so I went ahead and did everything. Along with new ucas, ball joints, and 1.5" spacer....I don't think she looks too bad.
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Mike534x

Member
Apr 9, 2012
894
So for the last year or too, I've been contemplating what to do about the Envoy's 1st to 2nd shift being "harsh" for my taste. Despite the transgo kit being fantastic, I figured this was a product of the kit. I noticed during the summer of last year, that if you drove the truck for more then 30 mins or so and it was fully warmed up the idle became a bit "erratic". Similar to the I6's idling issue with a dirty TB and the A/C would be on. I could feel/hear the trucks idle constantly jump (thanks to the magnaflow :biggrin:) at a light/stop. Oddly enough, I thought it was the MAF sensor at first, but the readings from Torque were showing it performing within spec. Alright that's weird, and the TB was clean so it wasn't a carbon/gunk issue either. My spark plugs are a little foul, mostly from a seafoam treatment but otherwise have 30k on them. But the truck progressively felt more bogged down as the months went by and so did my fuel usage start to climb slowly. 02 sensors are new, as well as one of the cats.

After thinking back and forth for awhile, I said screw it. Ordered up a brand new DELPHI MAF sensor, installed it and yanked the PCM, ECM and TCM fuses and left it to sit for an hour. After driving around for a while.....problems fixed. 1st to 2nd shift is SMOOTH now, shes back to chirping tires from a dead stop and the idle is holding steady.

I hate that I waited so long, but couldn't believe it was a MAF issue despite it having normal readings.
 
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Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
I know. They're totally unrelated but the MAF will do that. Found that out when I forgot to plug the MAF once.
 

Mektek

Member
May 2, 2017
656
FL
remove the upper rad hose and go through the nightmare of bleeding the system.

It's not a big deal at all. Use a turkey baster or a large syringe with a tube attached to the front and insert it through the radiator cap opening and into the radiator hose as far as it goes. Then suck out as much coolant as you can - it should be around a quart. You can then disconnect the hose and very little coolant will be lost. After reconnecting the hose pour the coolant back. No bleeding needed.
 

flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
I wanted to change out the two front cab mounts on the '04 TB, but it rained this morning. I'll let things dry out (my 'garage' is the back patio) and do it tomorrow after church.
I did build this little gem:
001.JPG

This is an "extension" for my floor jack so it will lift the cab high enough to enable me to get the upper mount out of the frame. Nothing fancy, just an 18" length of 4x4 lag bolted to a 30" piece. I used the hole saw pictured and drilled down about 1/2", then used a wood chisel and chiseled out the hole. This is to help keep the wood on the floor jack. The saddle on my jack is just under 3' in diameter, so I used a 3" hole saw. Should work pretty well.
Speaking of cab/body mounts, does anyone know if the rear two mounts, back by the rear tire, are the same as the front mount up by the front tire? When I was shopping for new mounts, all I could find were front mounts, made by Dorman, part #924-041.
I checked the mounts on the wife's '06 TB and they are just finer than a frog hair split four ways.
 

Street

Member
Oct 2, 2021
21
Wilmington, DE
First - What a day !

Took the Envoy in the shop to change oil and front struts. New oil & filter, and strut change took about 1hr 45m (two of us). I think the hardest part was getting the old strut out of the fork. I should have changed those struts ages ago. Wow what a difference; and I gain an 1.5in in the front fender to ground distance. The Voy looks level (imagine that).

HOWEVER! That went all too well. Running errands and getting some work done, a quick trip to the Acme was a ride in hell. I pulled out of the parking lot, smelt a little oil burn smell; dismissed it as probably a drop on the exhaust from changing the filter (can you say ROYAL PAIN IN THE A**), even with the oil filter "socket". Anyway, I digress. Run a couple minutes down the road and the "Check Gauges" is blinking and chiming -- Oil Pressure = 0. WTH! Key off, coast to shoulder and pull the dipstick. Oil is on the stick, abet at the low mark, but showing. I'm confused. I restart the engine, oil pressure is good - to start, but within a minute, 0. key off. Scratch head. Poke head under truck. Oil is RUNNING out of the oil filter area.

Great, figure I've got a defective filter. Call the old man for a trailer ride back to his shop.

Get her on the lift, oil from the engine to the rear window - seriously, ON the window - and everywhere --- side note: she is not rusting this winter for sure. :tongue:
Alright, take off oil filter and examine it. Don't see any issues - hit Advanced Auto for another filter and a couple quarts synth oil. New filter on, refill with oil, all good?! NO. fire the engine and oil is still SPRAYING from the oil filter area. Crap.

Get out the big light, shine at oil filter mating surface, and start engine. Lo and behold, my only year+ old oil pressure sender is a fountain of oil, right through the electrical connector.

Hang head. Resign my wallet. $69.99 for an oil pressure sender -- holy cow! I managed to talk the guy down to $56 - but good grief.


So.
✅New struts
✅Oil & Filter Change
✅Oil Pressure Sender
✅Additional 3.5qts of oil.


That was a VERY expensive leak - Synthetic oil is great stuff, but not cheap. And I swear auto parts stores over price parts they know you're stuck on the side of the road without... grumble, grumble... at least I was aware that I lost oil pressure. I suppose some real damage could have been caused if I was running down the expressway and didn't notice it for a moment or two.


At least it rides better; no more sketchy roller coaster ride; and another winter without rust. (lol)
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
What brand switch failed?
 

Street

Member
Oct 2, 2021
21
Wilmington, DE
Good question, what was before I was keeping all the paperwork for the Voy; but I put in one from Advanced Auto with a limited lifetime warrantee - it was three letters starting with a B. And it was exact, even to the green paint mark on the side of the electrical housing.
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
I believe that would be BWD. Depending on where you look, they are associated to either Niehoff and/or Standard Motor Products (SMP).
 

Mike534x

Member
Apr 9, 2012
894
I know. They're totally unrelated but the MAF will do that. Found that out when I forgot to plug the MAF once.

It definitely surprised me finding this out, I seriously can't wrap my head around why GM decided that the trans line pressure needs to be "upped" when the MAF is disconnected/not running within spec. If this was a tactic to get people to take it into the stealership....then yeah I can see someone immediately jumping to that option.

Drove her around for awhile yesterday. Not a single idle or shift issue, even the A/C running isn't bogging her down at all which was the more noticeable improvement on top of it. Everything feels "right" power wise, I know its not a placebo effect just because she was never this responsive since buying her years ago. Amazon is also on backorder for the Delco Fan Clutch, so delivery is estimated to be between the 26th and 3rd of August.

Just replaced the passenger side low beam, and the driver side (started to dim considerably). I'm not sure if Philips is cheaping out on their HIR bulbs, but I only managed just two years out of them. I'm sure the DRL isn't helping longevity either, so I'm looking into doing the DRL killer or capacitor mod. Bought a set of Sylvania Xtravision's to see how well they hold up.

Though the mod itch has struck again, so now doing some research into the DDM HID Kit.
 

flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
Replaced the front cab mounts. Took a few pics, but they're still on the camera downstairs. I'll write more tomorrow after I replace the spark plugs on the wife's 06 TB 4.2. I'm flopped on the bed single finger typing this on my phone right now.
 

flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
OK, as promised I'm back to torment y'all some more!
I changed out the two front cab mounts on the '04 TB EXT yesterday. It really wasn't too bad of a job.
Here's what one of them looked like. The other side was in a similar condition:
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I used my homemade 4x4 jack extension to jack up the body after removing the bolts from the 3 body mounts on the side I was working on. I didn't do anything with the mount up at the front of the fender. On the other side I loosened the bolts until they were only in by a few threads, but didn't remove them. After jacking up the body until the front tire just barely left the ground, the old mount came right out!
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To install the new mount I found it necessary to use a pry bar between the mount bracket and body. While prying with one hand I was able to slip the new mount into place with the other.
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You may notice that I re-used the old bolt. That's because the bolt that Dorman includes with the mounts is 2 inches longer than the OEM bolt! This bolt goes into a captive nut underneath the floor pan, and 2 inches of extra length is going to cause problems, I gair-on-tee!
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All in all, it was a fairly simple job.
Today I replaced the spark plugs in the wife's '06 TB. I found that the coils are all AC/Delco, so that's good. The plugs were also AC/Delco, so that's good, too. Unfortunately, they weren't the RIGHT AC/Delco plugs! They were AC/Delco 41-981 plugs, which are platinum plugs. They should have been 41-103, which are iridium plugs. These 4.2 I6's are pretty picky about their plugs!
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Removal of the old plugs and install of the new (41-103) plugs was pretty uneventful. Whe removing the old I did the 'loosen the plug until you feel resistance, tighten it up again, loosen it until you feel resistance, tighten it up again, repeat, repeat, repeat until the plugs come out freely' routine. Better than having to fix or replace a cylinder head because the plug threads got all galled up!
Most of the plugs looked to be in fairly good shape, but #3 had a lot of oil on it, and #4 had some as well. I'm thinking that the oil got on the threads during the removal process. #1 is on the left, #6 on the right.
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This is what #3 spark plug hole looked like.
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We don't see any blue smoke while driving, so I'm guessing it's a valve cover gasket issue.
Oh, Pooh.
Eeyore.jpg

I'll tackle that job another day.
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
Those 41-981 were actually original and were replaced with 41-103 later on. My 07 had the 41-103 so we can guess when they switched.
 
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flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
That's interesting. When I was looking for plugs for my '04 TB I kept getting told that 41-103 were what I needed. I haven't checked, but I wonder if 41-981's are no longer made? I suppose these could have been the original plugs, but at 180,000 miles it's doubtful.
I checked on the cost of a valve cover and intake manifold gasket set, can get both for less than $40. But it's quite a job to do!
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
The 41-981 are no longer in production. Somebody confirmed it with ACDelco. Maybe yours were replaced just before they went out of production? Or maybe they are original. The 41-103 is now the ONLY plug that works correctly with these engines.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,045
Brighton, CO
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flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
Made another attempt today to get the fill plug out of the side of the rear differential on the wife's '06 TB. Used plenty of heat, tried to pound in a 3/8" pipe nipple extractor, used a long 1/2" breaker bar. Nada. Tried again using the 3/8" pipe plug socket. Nada.
Decided to take Tollkeeper's suggestion and use a rubber fill plug. I bought a Dorman #65293 3/4" plug from Autozone. The distance from the back of the large diameter to the front of interior sealing surface is right at 1/8" (.125"). The thickness of the cover is about .080", so there's a .045" difference. I'm thinking I'll drill a 3/4" hole and have a washer brazed to the back (inside) of the hole. That should seal things up tight.
I measured the distance from the bottom of the diff case to the center of the fill plug, and it was right about 6-1/2". I plan to use my 3lb. sledge hammer and the anvil area of my bench vise and make a flat spot in the cover. (I'll do that BEFORE I paint the cover!) I don't know how much clearance there is between the cover and the differential gears, so I got on RockAuto's web site (use promo code AF817821554108, from our sister site offroadTB.com, to save 5% between now and 10-7--22) and ordered a GM 8.6" diff cover, part #12479379, which I will install on her 8.0" differential. You can use an 8.6 cover on an 8.0, but you can't use an 8.0 cover on an 8.6 or you run the risk of rubbing ahole through the cover and getting lots of metal shavings in your differential. Not fun!
So that's what I did today. Tomorrow I hope to get the new struts and springs installed on my '04 TB EXT.
 

6716

Member
Jul 24, 2012
821
Saved myself a bunch of time and money by taking the truck to a new shop today, and got reminded how easy it is to jump to conclusions. The engine was getting louder and louder, especially under acceleration, and there was an odor of exhaust up front.

I was convinced the exhaust manifold was cracked or the gasket to the head was leaking. I didn't feel like doing this work myself this time since I don't have a garage right now and it would have been a lot of screwing around to let the engine cool down overnight at my buddy's garage, getting rides back and forth, probably snapping bolts, I mean it would have taken me three separate sessions I figure.

I brought it in and asked them to just go ahead and replace the manifold. They said, hey, we'll just make sure that is the issue.

Turns out the stud nuts connecting the manifold and the downpipe/cat section were loose. I must not have tightened to spec when I replaced the cat section a couple of years ago. They did a diagnosis, found the issue, tightened them up, they charged me the $80 diagnosis fee when they could have had a $700 repair if they had just done what I asked.

If I'd have had garage space, I'd have just dived in and done the repair.
 

aaserv

Member
Dec 1, 2019
408
N of Baton Rouge, La.
Since we're talking fan clutches AGAIN!! I thought Id update my latest experience. As i had posted a month or so ago I saw that Behr had been bought out by some other company. Rock Auto had their "Behr" fan clutch at a very reasonable price so I ordered it and had it installed all within about 4 days time. I said then that I didnt like the looks of it, it looks just like the $69 asian knock offs sold on Ebay...of which I have 2 sitting here that didnt work right out of box.
I hadnt really drove it much since changing it. Well yesterday around noon I decided to take it for a wash and run a few errands then make a lil trip 45 mins away......Well about 20 mins after I left the house I noticed Im solidly on about 211 Degs....thats higher than she normally runs but its 94 degs outside and the front and rear A/c is blasting so maybe???? Im just about to pull up to the carwash and shes closer to 218 Degs. Now Im worried. Run it thru the carwash and it drops on back down. But within a mile or 2 after leaving its climbing again.
Im also getting no "airplane roar" on initial start up and generally I think this new company is selling junk under the BEHR name... I kinda figured the price was to good to be true and it looks like it was....

Now I gotta worry about spending a mint on a real AC Delco and getting some knock off from them also.... This is 3 years now Im dealing with this SOB over heating and my patience is just about gone...
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,045
Brighton, CO
Could always get that clutch tuned out, and drop in a standard thermal clutch from the 08-09 trucks?
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
And other performance mods at the same time. Well worth it.
 
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Mar 30, 2016
1,465
KSA
Been a bit of a busy week. After getting the Head unit installed on my Dads Yukon, Got new taillights installed. He wanted to reuse the stock ones but I wouldn’t let him!

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Took it for Inspection. Passed with flying colors.

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We were planning to go to a hillstation this week. So oil change was due. Before I could go to get it done, check oil level light was on on the DIC. Checked the level it was below the first mark on the stick. Immediately topped up the oil and went to have the oil change done. Seems to be a leak in the valve cover gaskets. Will get that taken care of next week.

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The lights were changed back to stock halogens in my absence. Naturally changed the low beams to HIDs and high beams to LEDs on the Yukon. Also the rear seat belt was being obnoxious while driving down the road. Tightened the bolt and all is well now again. Enjoy the dry underneath of the Yukon. This is probably the best it has been ever since we purchased it! :biggrin:

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Trailblazer has been as faithful as a dog with its check engine light greeting me since my arrival. Will be checking the codes for that. My projector headlights were changed as the lens were pretty much gone and it wouldn’t pass the Vehicle Inspection. Stock headlights were installed with halogen bulbs which illuminate the roads like candles. Removed the projectors from my old headlights before I throw them away. Projector Foglamps is now on my list! Had some old liftgate glass struts in my parts bin thought I’d replace them. sadly they too are gone. Need to replace the liftgate and glass struts.

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Finally the dash bezel on my dads Yukon had many broken feet from being removed for installing the head unit. Fixed them to the best of my abilities and fitted the dash back together.
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Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
Dropped off the Sierra again at the body shop. No sooner that I'm back at home, they call me. I had given them the wrong key/fob. I gave them the one for the Caprice. :redface: Another drive over there for the exchange.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,045
Brighton, CO
I was going to say its probably a thermo fan, or a SAIS, but you have a 2009, so that cant be it.
 
Mar 30, 2016
1,465
KSA
Well been another busy week!

Switched my headlights and high beams for LEDs. Angled them to be evenly spread out and they turned out quite well.

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I plan on retrofitting my fogs with rejectors soon, so I will not be driving with my headlights a lot. They will just be for flashing lane hoggers whom we have a hellava lot of


Had a filament out n my taillight, changed the bulb on that. One of the torx screws wouldn’t open so I kinda just slid the bulb out and changed it.

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Saved some speed sensors from replaced wheel hubs. They were really hard to find for the Denali, so thought I would save these.

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Went for the trailblazers inspection. It failed! Apparently they changed the rules and now you can’t have leds or white lights on stock vehicles. Also they complained of the vehicle being smoky.

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Got my OBDII out and there were codes for EVAp leaks and Cylinder 3 Misfire. Will have to get that checked out. Also my AC works on all speeds except on 4. Will have to get into that as well.
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gmcman

Member
Dec 12, 2011
4,656
At 60 MPH, an hour and half from home...my water pump bearing failed....thought I threw a rod.

Was able to remove belt and limp to parking lot.....wife is bringing part.

Luckily I had most my tools with me to work on my buddies vehicle.... and a large crescent wrench with towing gear.

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gmcman

Member
Dec 12, 2011
4,656
Just finished a broken wire fix on the fan clutch harness.

When the water pump went, there was no warning...the fan was forced sideways and it stopped dead. The very loud knocking was the harmonic balancer bolts tearing up the fan blade jammed into the balancer.

Must have really cranked the harness as it was torn from the plastic shroud.

After I was back on the road, I had a CEL which was P0148.

Screenshot_20220724-020738_Gallery.jpg


95 deg ambient, pulling a trailer only about 1800 lbs gross, but in the hills at 60-70 MPH with the fan clutch on full tilt....was interesting.

Yellow wire was broken.

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Had to remove the plastic angle which mounts to the fan shroud, removed a section of wire and re-spliced.

New repair.

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Much better then buying a new fan clutch.

I'm not removing it twice in one weekend...lol.
 

flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
On the wife's '06 TB 4.2L, went from this:
TB Valve cover gasket start.jpeg

to this:
TB Valve cover gasket halfway.jpeg

Took about 7-1/2 hours, counting a trip to AutoZone for a tool I needed.
When I recently replaced the spark plugs, one of the coil boots was drenched in oil. 😡
Homey knows what that means. One of the gaskets in there is leaking. Today and tomorrow are only supposed to get into the 80's, so I took both days off to do this job. We probably won't get a couple of nice days like this until sometime in September, and I didn't want to let it go that long. Runs the risk of damaging the coil and causing misfires.
To get to that 10mm bolt at the bottom rear of the intake manifold I just spreadeagled across the top of the engine. Not real comfy up there, BTW.
We've also been trying to track down the cause of a gross leak in the emissions system. I don't have the exact code handy. I had bought a purge valve solenoid a while back, but just haven't had time to dig into the engine to install it. This is the perfect time! The old one is already off.
I noticed the timing chain between the two cam sprockets felt a bit loose. I measured the deflection and got right at 3/8". I've been trying to find a spec for that and have had absolutely no luck! The only thing the Haynes manual tells me is that for a V8 if the deflections is greater than 5/8" to replace the chain and sprockets. It's not that bad yet. Haynes also shows a top chain guide, but there's none on this engine. Rock Auto and AutoZone both list one for an '06, but nobody else does. I did fine one post on another forum where the guy said he bought one for his '07, but it didn't come with the bolts. Consultation with his dealership revealed that the '07 doesn't have the top guide. I'm assuming that deleting the top chain guide was one of the changes GM made for the later GMT 360's?
I have the valve cover and intake manifold cleaned up as well as I can, and have the new gaskets installed. The Fel-Pro valve cover kit came with new bolt grommets, so I replaced all those as well. Tomorrow is re-install day!
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
I wouldn't worry about the chain slack. The tensioner, which is oil pressure fed, will take it up. There is a ratchet system on it to hold the tension when pressure is low at idle or when shut down but doesn't hold it tight. The oil pressure will do that at higher RPM. It's only if you hear it flopping at idle you need to get in there. Been there.
 

flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
Thanks, Mooseman! We don't hear anything at idle, so it should be good! That's not a job these old bones would want to do anyway!
 

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