8.1L Intake Manifold Gasket change?

[jeff in co]

double check your heater hoses at the passenger side firewall. My 02 had a leak at one of those cheap plastic fittings, always smelt the coolant and could never see a leak because it was burning off on the exhaust.

Have you done the bearings yet? At 177K I'd be amazed if you haven't.

I'll check the heater hoses, that makes more sense, thanks.

I was thinking it was the front wheel hubs/bearings, too. I did change them out around 50k and 70k, so logic told me that they definitely could be due. I ordered up some new SKF front hubs and installed them both this weekend. I was assuming the truck was going to glide down the road but unfortunately, still there. Also have brand new tires. When I grabbed onto the original hubs, there wasn't much movement but I had already bought the new ones for $300, so went ahead and did them. Assumed with that amount of miles, there soon to be due.

Unfortunately, didn't fix it.

 

[skunked]

I have a weird sound like you describe (playing cards) that's dependent on speed. I replaced the front ring and pinion and the CV shafts and it's still there. I'm starting to wonder if it's the D-shaft, joints or t-case since they're stock.

 

[jeff in co]

When I get a moment (a few days), I'll pull the front driveshaft to see if anything changes. But I'm guessing that doesn't really turn in 2WD, so can it even be contributing?? I also grabbed my CV shafts and wondered....

I'll take it in for front end alignment (new tires), and I'll ask if they have any clues.

 

[skunked]

When I get a moment (a few days), I'll pull the front driveshaft to see if anything changes. But I'm guessing that doesn't really turn in 2WD, so can it even be contributing?? I also grabbed my CV shafts and wondered....

I'll take it in for front end alignment (new tires), and I'll ask if they have any clues.

I thought it turns all the time and when you activate 4wd the t-case locks the front output. FWIW my front CV shafts were still good at 250K+ miles but I had it all apart so I put new ones in. If the boots are sealed they're probably fine.

 

[jeff in co]

yea, boots looked fine when I looked at them, so that's encouraging. If the driveline is turning in 2WD, its worth pulling. Probably try over weekend....driving blazer now so nice to get it back from my daughter! We got her a new car so I can drive the blazer again!

 

[jeff in co]

double check your heater hoses at the passenger side firewall. My 02 had a leak at one of those cheap plastic fittings, always smelt the coolant and could never see a leak because it was burning off on the exhaust.

Have you done the bearings yet? At 177K I'd be amazed if you haven't.

OK, first of all, I did look a little closer at the heater hose connections. I'd have to agree with you on a potential leaking area. I see a little bit of wet drops and what appears to be some dried coolant possibly. I do see a few fresh drops sitting on the starter bolt, right on the bottom. And the starter is directly below the tee connection going into the front cab and hoses going to the rear of the truck. So that seems to make logical sense....thanks!

Now on the vibration. Got a front end alignment...it was really not very far off so good news. But, the mechanic couldn't feel it and when I drove it in initially, it wasn't really doing it. So bummer. I noticed it this morning driving into work, but going to the shop this afternoon....not so much. I'll keep trying.

I did look at the front driveline. Looks like a boot and possibly a slip into the t-case?? Other end on front differential just has normal ujoint straps. That will be my next idea, then maybe change the front diff and be sure there is no metal in the fluid.

It was nice to hear the mechanic say the truck is in amazing shape...especially with 177k on it! So that's good!

 

[skunked]

Hopefully that simple repair will solve the coolant leak.

The front driveline boot strap needs to be removed and then the driveline slides out of the t-case. After responding to this thread the other day I decided to order new front and rear u joints since I planned on having it down for some other work this weekend. I'm hoping this fixes the noise however with the miles this rig has they need to be changed anyway.

 

[jeff in co]

OK, update.

Got 2 new GM tees, and one new heater hose to the pump. Installed it all last night and looks good and tight so far. I did not replace the last special hose due to it's cost and availability, but will keep it on my list in the next month or so. It's the tri-hose combo pack. I might try to get a new connector and cut the existing tub for a fresh last connection in the meantime. So far....all dry!!

Secondly, took both driveshafts off. After pricing online, I could get 2x 1410x joints and 2x 795x joints for about $105.....plus me installing. Called local driveline shop with great reputation, $39 each...but then he said they would install for free. So for an extra $50 I don't have to hassle with them....worth it!

When I brought them in I told him about the vibration. He looked at my rear joint and said, "there's your vibration problem. One of the rears is going bad and not fully flexing all the way". Sweet! hopefully this is the fix!

 

[sweetk30]

When I brought them in I told him about the vibration. He looked at my rear joint and said, "there's your vibration problem. One of the rears is going bad and not fully flexing all the way". Sweet! hopefully this is the fix!

called it but wrong shaft . not saying it will fix the problem but i knew there was a bad joint some place .

 

[jeff in co]

I think that the two caps on the front driveshaft did not spin a full 360. They both only spun maybe 30 degrees total. Feeling a stop at each point....we'll see.

Also, strange but when I pulled my rear driveshaft, it said "made in China" on it. I bought the truck with 18k on it and was never replaced. Driveline guy said he hadn't seen one on a GM vehicle either but said that those looked to be factory ujoints. Did GM source some rear driveshafts from China??

 

[jeff in co]

Update....fixed vibration! Definitely was the rear u-joint going bad. 177k...it was due.

Decided to flush brake fluid, it was nasty. Everything went well until the back left caliper bleeder snapped off. So off I go to get a new rear caliper. Because I only got one bleeder to work, and second one snapped off, I checked the two front ones. Sure enough rusted tight too. But this time, took a torch to heat outside area a bit, wd40...and they move! Got both fronts to work again. So picked up one new caliper and 4 new bleeders, back up and running!

Got home after driving the entire day, see a little oil under transfer case. Looks like the output shaft is leaking. DANG! 2 steps forward, 1 step back! I think the driveline shop probably cleaned up the input shaft and now won't seal properly anymore. Next step, output shaft seal. Hopefully this is it for a while.....

 

[sweetk30]

if the rubber caps are gone off bleeder screws they will freeze up solid from rust . and i have got broken bleeders out before with the plug weld a nut trick like a broken bolt . and before i try them i take a air hammer with a button head and lightly rattle the area around the screw .

 

[jeff in co]

Yea, after I broke one off I went to the internet to see if there was some miracle idea on getting it out. Have seen the welding of a nut, etc. but I don't have a welder. Did see some videos with heat applied and that was the ticket. Glad I got away with one caliper rather than 4.

3 of the 4 bleeders actually had a rubber cap on them....but were still pretty stuck.

 

[jeff in co]

Just try to finish up this loop. I've been really fighting the input shaft leak to the rear driveshaft. After the new Spicer u-joints were installed, they painted the shaft and cleaned up the slip yoke.

I put it back in with the original seal...started to leak. Changed out seal with a new National seal. Re-install shaft.....still leaks.

So I go back to the driveline shop and see if they can suggest anything....because it did not leak before the new u-joints. He said that the factory joints can be off with the plastic inserts, so bring the shaft back in and he will check the balance. After his test, it was out of balance just a bit on both ends.

Re-install, still leaks!!

Scratching my head as to why, I bring it into the GM dealer. He said that the GM seal is different than aftermarket. After looking at it, the GM seal does have an extra set of lip seals inside so I was hopeful (the pink material in pic below). He also did say that perhaps the inner sleeve could be bad too, depending on miles. So I'm thinking I can install no problem...did it on the blazer. After staring at it, I really didn't feel like splitting the case to get that inner sleeve out....and then a potential for the case to leak afterwards.

Apparently, the dealer has a tool that can go in and remove the sleeve without splitting the case. Pretty cool tool but $500+ cost, I wasn't going to buy one. I asked how much to install new seal and sleeve, $160 labor with coupon. Way worth it to me and then if it leaks, it's on them to fix.

Conclusion, after 2 days of light driving, no leaks!! I hope this is the fix!!

Seal I used: GM 12547638

I don't know if I really needed the inner sleeve but figured I should do it just in case.

 

[mudmobeeler]

I did get some new KO's yesterday. So nice to have new tires!

View attachment 283112

Bumping a year old thread, what size tires and do you like the KO2s so far? Im looking at a 2004 3/4 ton 4x4 Suburban and it has some 20s with street tires. Looking at picking up a set of some H2 wheels from a buddy, have them powder coated and then throw some tires on them and sell the 20s. Truck is stock with no lift also so was thinking about a leveling kit at least. Im going to check out the front end but the steering wheel is off some so figured it needed an alignment anyways so might as well do a lift first.

 

[jeff in co]

I'm not positive because PO did the lift (of some sort). I see an extra leaf in back and I assume the front was cranked up just a bit on the torsion bars. Drives great to me and I really like it!

My truck also had 20" wheels......what's up with these 20" wheels anyways?!? And "P" rated tires. So good for a 3/4 ton truck!

My BFG's are 305/65r17's I believe.

First pic, 20" wheels (and bad fuel pump just after purchase.... )

Second, new wheels and tires.

 

[mudmobeeler]

Yeah I was thinking just a leveling kit and then either trying to add another leaf, adding either a factory block or a zero rate add a leaf from ORD, or a set of air bags for when towing. Or a combo of two or three of those. Just sticking with some good aggressive all terrains in/around the 33 inch size.

Yours looks good as its setting.

 

[jeff in co]

I like the back up just a slight more. Don't really prefer the raised front end and nothing in back. As soon as it's loaded up or towing, I hate the look of a squat in back with front up. Prefer it a level look when loaded up.

 

[mudmobeeler]

I like the back up just a slight more. Don't really prefer the raised front end and nothing in back. As soon as it's loaded up or towing, I hate the look of a squat in back with front up. Prefer it a level look when loaded up.

Yes, me too.