I just want to confirm, is the gasket for the UIM 89017554? On the GM parts website it'* called a Plenum gasket. I also found it on RockAuto as a set, MS95812. It appears this one comes with the Throttle Body gasket?

And also, after more looking on Rock Auto, they have the upper gasket separate, but they show a couple varieties. One is OEM and another is for the Dorman unit only. I had my UIM replaced over a year ago but I'm not certain which it is. Is there a way to determine what it was replaced with, or do I not need to worry about it?

I can't verify the part numbers, but I can confirm that the intake manifolds are also called plenums. (I had mine replaced last year.)

it "should" be the same as the OEM part. However it is possible the gasket is slightly different as the plenums are sometimes different.

What type of issue are you having, a vacuum leak?

Well, long story short I'm kicking myself because the upper puked in January '08 in the mechanic'* parking lot when I was having brakes done (great timing there), but he insisted I didn't need to worry about the lower. I had changed out the DEX when I bought it three years ago, so I thought maybe I would be safe on the lower so I agreed. This winter we had a couple weeks of temps around 0-10 degrees and it lost a couple inches of coolant. The oil has appeared fine, and I just see a little pooling of coolant on the front top of the LIM, and a little wetness on the sides. I've kept an eye on it, and it'* lost an inch or so of coolant since then. It'* interesting because I can check it over a month or more and it doesn't lose anything, and then a couple weeks later it will be down a quarter inch.

So I'm planning to try and tear it down in the next few weeks and hopefully also do the valve cover gaskets and plugs/wires. First I have two shot rear shocks I need to tackle.

I'll take a look at the upper for markings, but something is telling me it was the Dorman, but I can't remember for sure.

Oh..piece of cake. The gasket is reuable. It'* a rubber inlaid job that I've reused w/o issues.

OK cool! I haven't looked at the engine yet or delved into the process too much, but I assume I will still need to remove the UIM from the LIM when I tear it down?

What do you think I'm looking at for time to do the intake, valve covers and plugs/wires? Ten hours?

All depends on your skill and work ethic.

On an 96-99 you don't need to pull the accessory tensioner assembly or coil pack bracket. On the 2K plus you do pull the tensioner assemby. This adds a few minutes.

I can zip this out in 2 hours, with air tools for disassembly and a die grinder with gasket cleaning 3m pad on it. Takes all of the torture out of the job.

Give yourself 10 hours and you will probably finish in 5 hours.