'99 Yukon 5.7 intake gasket replacement

[dblott]

Hey Charlie,

My 1999 GMC Yukon 5.7, has a slight leak at the front intake manifold gasket. I got the Fel-Pro gasket kit. I borrowed a Haynes manual. Everytime I read the steps and am about to tackle the problem, I read about another step that refers to another section. Just getting to the manifold seems to be the hard part. A can of Bars Leak is looking better and better. Any better quick fixes? This is looking like a much better rainy day or ”later this winter” job. The thing that has me most concerned is the air conditioning. It works right now.
The book says to remove the bracket to get the AC pump out of the way. So I assume I can lift the pump and hoses (all still connected) up and towards the passenger side back corner of the engine compartment. It looks to me that if I take off the hood, I can easily tie the pump to a hook on the ceiling. Is there enough hose flex to do this or will I still have to discharge the air conditioning and disconnect hoses? I think I’ll be able to see the timing marks with the pump and bracket out of the way. Anything else I might need to know or tools I may need? Am I on the right track or over-complicating things?
Would getting a Chilton manual be a good investment? Haynes is probably adequate. Is Chilton better?
Parts guy says I don’t need a fuel line tool since his computer shows my year has female fittings for the fuel lines.

[-Ray-]

According to what I've been reading you can do this job in 6 to 8 hours. You don't disconnect the ac lines. Just position it out of your way.

[GRRRR8]

Having done a few hundred of these here are a few tips:

1. Make sure you use the new Fel-Pro rubberized metal gaskets. You wont be changing them again for a LONG time. Factory ones are plastic.
2. Remove 4 bolts from a/c compressor and flip it over to the left and set it in the air box.
3. Remove the 14 mm nuts and bolts from the a/c & p/s bracket. On the drivers side of the block there is a 14mm nut for the support bracket to the p/s, remove that. Now you can slide the whole bracket and pump forward on the studs. DO NOT REMOVE, just slide it forward so the intake will clear.
4. When removing the distributor: Remove the cap and see where rotor is facing. I usually make it face at 12 o'clock(firewall). Pull distributor straight up. You will see the rotor turning. When it stops make a mark on housing where it is pointing. You will also need to make a note of dist housing position. When you install: Hold housing in correct position, point rotor at mark made on housing and slide in block. Rotor should turn to same position as when you started.
5. Now that the distributor is out. disconnect fuel lines at rear of engine and carefully remove from top of intake(DONT LOSE YELLOW O-RINGS!)
6. You will need a scan tool to set dist. reference which is +/- 2 degrees
That is all the tricks the rest is basic.

Bars Leak will not seal a split plastic gasket.

They only pay about 4.8 hours to do and I can usually do one in about 3.

[G8GT721]

I just did this on my 96 1500, it's a bitch but it was also my first time. I think Ray is right with his estimate.


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[dblott]

Thanks for the help! I've got a couple more questions.
I haven't opened the gasket box yet, incase I found out it wasn't the right one. Does this kit sound right?
Fel-Pro PermaDryPlus MS 98000 T contains:
2-PremaDryPlus Intake Manifold,
1-#404 Fuel Rail o-ring, 1-#405 Fuel Rail o-ring,
1-dist mounting,
1- valve cover,
1-MB13-3098 Throttle body mounting,
1- MB 90269 Intake Manifold upper,
1- MB 90274 Fuel meter body,
1- RVT black(use as intake manifold end seals).
If I line up and mark the rotor and housing as you describe, this means I won't have to find #1 TDC? Will it run good enough to get it to a scan tool or can I rent one from a parts store? I imagine I can't see the timing mark very well to use a timing light with the p/s and airconditioning re-installed. Would finding TDC eliminate the need for a scan tool? Thanks ahead for your patience.

[-Ray-]

Charlie should he replace intake bolts if corroded?

[G8Smitty]

I've done this twice, so I have some pointers as a novice.

On the A/C Compressor, I lifted it vertically and then turned it over and it ended up way out of the way. It also didn't bend any hoses. It seemed to be perfect.

When I put mine together, I ended up breaking an intake bolt. DO NOT DO THIS! I hadn't made it to where it wanted the bolt torqued and it snapped. Because of the snapped bolt, I ended up taking off the heads which I then pulled the motor because it made it much easier to work on. These motors are very easy to pull, which led me to a rebuild and a cam swap while it was out. I really like these motors because they are so easy to work on.

Good luck!

[GRRRR8]

If the bolts are in bad shape replace them. They are reusable though, but use common sense if they look bad.

If you remove/install distributor it will run fun until you can get to a scan tool.
That gasket kit should be correct.

[dblott]

Thanks for the help you guys. I'm feeling alot more positive about this. I miss the old days when you could sit on the inside of the fender well. Guess I was smaller then too. All the extra stuff had me a little intimidated. So you think my wife would believe me if I broke a bolt and had to upgrade to performance stuff? I'd better not. I still want to put an exhaust on her G8GT first. Thanks again.
Hopefully just one more question. What size are the manifold bolts so I can borrow the right tap?

[-Ray-]

I wouldn't use a tap unless you are tapping iron. Best way is to use a stock bolt and cut a slot along the length of the threads. That will do a good job of cleaning the threads.

[dblott]

Thanks Ray. Makes sense. I'll have my wife get a couple from the dealer. Yukon's got 125K on it so probably at least a couple are bad. 45 min to town and back (in the G8), so I try to be prepared ahead of time.
I've got a Hypertech 3 programmer. Planning to set back to stock before I start tearing it down.

[dblott]

Hi Charlie,
I'm starting the removal/ replace this weekend. I think I've got everything, including camera, new radiator petcock, new bolts (wife got 8),& red high strength Thread Locker. I find a discrepancy with the torques between the Haynes and the fel-pro instructions. Book says 44 then 88 in/lbs, and the kit instructions say 50,100 then 132 in/lbs. The new bolts from GM should take this right? I'm glad my wife got all 8. I think the type of gasket is the reason for the higher torques but what is the amount of thread locker to use. Thin line on 1/2 the bolt or 1 drop on the 1st 2 or 3 threads? Somwhere in between? Brother-in-law said to use Blue instead of red as that is the part number 242(Locktite) that the book calls for.
Also the kit instructions say dry on all gaskets. The only place to use the RVT is to create the end seals. Book says to run the RVT 1/2" up the cyl.head. So, with the fp gaskets, would I go that far still then place the intake gaskets and press out the excess? (I know not to get any in the ports). What kind of time frame do I have between making the end seals and having to have the intake set and finger tight? Are there guide dowels already, or should I grind the heads off 4 of the old bolts to help guide it down before the intake gets close to the RVT? Would enough bolt stick out if its only just started if I just cut the heads off? Looks like the RVT tube is big enough for making the end seals, but not a re-do.

[GRRRR8]

Use the Fel-Pro specs for torquing the bolts. Do the 1/2 under the intake gasket with the sealer. There are no dowels. You could go get 2 bolts about 2 inches longer then what you have and cut the heads off to use as guides. Put 1 in the front corner and 1 in the opposite rear corner. Tighten all bolts from the center out.

[dblott]

Thanks for the advce guys. It went well and NO LEAKS!. I took about 8 hours spread over several evenings. I must have got the dist pretty close as it might run better now than it did before. Cheap oil change for tomorrow, then a good one before we go camping next weekend. Also will get the scan at the first of the week. When I pulled the Hypertech program, I found DTC- PO122 (throttle pos. sensor) and PO1122 (ignition control module or TBS out of range). Hopefully its just the TPS and not the computer. As good as it's running, it may be that unplugging/replugging the sensors may have solved the codes. I could reprogram the Hypertech and find out, but since I am going to have a scan done I don't want to keep loading and unloading the program. If the DTCs are caused by the computer failing, is there a good one that would upgrade what I have now (stock) to allow for more performance mods or tuning?

[-Ray-]

Good job, I hate having to do that work. Check your idle, is it correct? I would lean more on the TPS sensor going bad. My idle on my 5.3 will go high when the truck has been running for a while.

[dblott]

Hi Ray.
Actually, when warm, the idle is a little low. I figured that when I get the scan done and have the timing reset, I would try to get whoever does the work do a ”tune” also. I still have 2 shops I want to check with on prices. I checked with my GM dealer Friday so I have the high prices already I think. I didn’t get to talk to the tech I wanted to, so I didn’t get to ask about the tune. I was on my cell at work in the woods with a lowboy and my D8 behind me, so I didn’t have time to find out more than parts,scan and reset timing prices. I hope to find out that if my computer is okay, it could be tuned like the programer sets it and I wouldn’t need to use the HyperTech, (except as just a plug in code reader). Any thoughts?
Dale

[-Ray-]

Hey Dale,
Check http://www.gmfullsize.com/forum/
You may find a programmer for sale.

[dblott]

Thanks for the help! No leaks at all. Gave it a good test with a 400 mile trip and a little 4 wheeling up to 7000 feet!
The gasket replacement wasn't any trouble at all. The scan showed no problems either.
Dale