I have discovered a slight coolant coolant leak (only seen with a pressure test) near the TB/UIM connection on my 1998 model 3.8 L36 with 67k mi . There a visible distortion at the TB/UIM connection . I haven't experience overheating or evidence of water in the oil. or leakage around the lower intake manifold . Green coolant has been used in the system since 2002 .

From what I have read here I need to replace the UIM and it is advisable to replace the LIM gaskets too ( I am pondering the latter) . I have seen this thread -

http://www.bonnevilleclub.com/forum/...=stovepipe+apn

and others about the aftermarket replacement upper intake manifolds and wondered which is now the one of choice and how to make sure it comes with the correctly sized "stovepipe" for my 1998 model engine .

Thanks

I recommend the APN. To find out why and to learn all you need to know to address this common problem, please take time to read this Techinfo article: http://www.bonnevilleclub.com/forum/...e=article&k=38

As mentioned in the link Bill gave above, the APN kit comes with stovepipes for both 98 & earlier (3/4") and 99+ (5/8")

I would not ponder about this. Replace the LIM gaskets. With 67K on the car it has a lot of life left in it. APN kit for me. Read the Tech info thread and go for it !

I thought some more about it and came to that conclusion before I read your reply .
I picked up the aluminum frame LIM gasket at the GM dealer today ( macthed prices with online+shipping) . I want do the job ASAP so I might be buying the Dorman UIM with the correct " stove pipe "from Advance Auto etc . unless the the APN UIM ships pretty fast ( how long do they take to ship ? ). I had planned to perform the work myself but found a reputable local shop who does many of these offer to do it for $ 260 labor which is very tempting .

BTW - I am confused about sealant to use on the LIM bolts - Loctie (which color ) or Loctite PTFE Sealant ( aka GM pipe sealant)mentioned here - http://www.grandamgt.com/forum/showthread.php?t=60868 ) ?

Thanks

Does the $260 quote for labor include doing the LIM gaskets? Does it include fluids (oil and coolant, etc.)?

The LIM bolts do not go into any water jackets, so Loctite / threadlocker is what you want. I recommend the blue "medium" strength oil-resistant type, like this:
http://www.permatex.com/products/aut...ocker_BLUE.htm

Make sure you pick up the package of plastic coolant elbows in the Dorman "Help" section of the auto parts store.

P.*., where are you located?

The Doorman intake comes with both size stovepipes in the kit. It also has a new PCV valve and UIM and TB gaskets. Its a complete kit. Thats whats on my car and that is what I put on my customers cars. Never had a problem

BTW- Do any of your know anything about those UIM * sold on Ebay for about $60 .Which ones , if any are are APN or Dorman and do they include the 2 sizes of "stove pipes" ? - http://search.ebay.com/3-8-upper-int...upperQ20intake


Thanks

agrezela -

That quote is for labor for both UIM and LIM . I will supply all majerials - gasket, UIM, coolant . This is in an Atlanta Ga suburb at a modest 35 year old neighborhood independent repair shop . Again ,it is very tempting .vs DIY .

The ad copy does NOT indicate that you will get the stovepipes with the e-bay kit. And at a price of $72 (including shipping), I would not expect them.

It is especially important with a 95-98 model that you use a reduced diameter stovepipe. Those older models put the hot, stock 3/4" stovepipe right up against the plastic. We know that the best way to repair these is to provide a heat shield in the EGR passage as APN does. And we know that the UIM will be slower to fail if there is an air gap between the hot pipe and the EGR bore. That air gap is provided by the stovepipes supplied in both the Dorman and the APN kits.

The Dorman kit is better than the e-bay kit because you will end up with an air gap around the stovepipe that protects the plastic. But the Dorman kit does NOT provide a metal heat shield, and the Dorman kit costs a LOT more. Usually Dormans sell for $150 or more locally.

If you choose the kit from e-bay, you will be getting a fix that is little better than what GM supplied new. But you will save $43 compared to the best fix you could do- the APN kit, which costs $115 including shipping. To me, it makes little sense to pay more for a Dorman kit to get less than the best repair.

So, the bottom line is: yes, you can save $43 by choosing the worst possible repair for the UIM. You will be putting the engine back in the condition it was sold by GM, with an inherent flaw that you could have rectified. When you sell the car, you can get more than your $43 back by explaining to the purchaser how you corrected that inherent flaw.

Compare the savings based on the total cost of the work you will be doing. The best fix will cost about $500 total vs $457. You will save 9% by choosing the worst instead of the best fix.

You will wait for shipping for a few days for the APN kit. Who knows how long it will take the e-bay kit to ship? If you are in a hurry, forget about saving money - you will pay more for a local off-the-shelf Dorman kit, and will still not get as good a repair as the APN.

Agreed with Bill.

Take the bus for a few days if you have to, but order the APN kit over any other
Many of us here have installed this kit, and can vouch for it'* quality and completeness.