1998 leSabre
I discovered my GM replacement UIM at 75K mi now is leaking--sweet smell from exhaust after sitting hot with pressure on the radiator and it even had a stumble when I started it to move it into the garage last night like a wet plug. Oil is clear. Has been losing coolant off and on for months--probably when sitting hot and under pressure.

Which brand should I put on? I checked NAPA and they have Belkamp made by Motormite at $139 and Pepboys have Dorman at $199.
Which ones have the enlarged EGR tube?
And I'm open to suggestions. Cost is actually no object-just don't want to overspend.

How easy is it to pull the injectors out. Last time I worked on the top end of a motor it had a carburetor on it! :grin.

Any tips I should know about/ I have read lots of posts here and the techinfo. Any gasket sealers needed?

yay! i get to say it all first.

Get the APN kit. its about $115 with shipping, comes with new reduced-diameter stovepipes and a plenum gasket

http://www.bonnevilleclub.com/forum/...e=article&k=38

while you're in there, you'll want to pull the LIM gaskets and replace them with the newer aluminum framed gaskets from GM. They are almost guaranteed to fail. and when you refill coolant, make sure it isn't dex-cool.

i've found injectors are easy to remove. disconnect them from the harness, then disconnect (IIRC) the 3-4 nuts holding the fuel rail on, and the injectors should pull right out of the LIM with the fuel rail

Does the Dorman have a reduced size EGR pipe with it that has to be installed? What about the Mightymite?

Do either of these have more clearance between the EGR pipe and the plastic?

It'* interesting that the Dorman and Motormite intakes are different prices. They're the same company.

The Dorman (and therefore I'd assume the Motormite) intakes have the reduced diameter stovepipes. They do not (last we heard) have the metal shield in the upper for the extra protection.

If you decide on one of these, at least check with Bill Buttermore regarding a sleeve. The APN is strongly suggested as the best solution.

What am I looking for in the UIM if I ever get it off to indicate the leak was occuring there.

If the leak was in the lower intake gasket, that would have coolant showing up in the oil wouldn't it? I really don't want to mess with the lower and the o-rings on the plastic tube to the heater if I can avoid it.

The UIM fails in the EGR bore usually where the heat is greatest near the bottom of the hole. Probe the plastic there aggressively with a sharp instrument to see how the plastic has softened from exposure to heat.

The LIM does not necessarily put coolant into the crankcase when it fails. A small leak into one of the intake ports could be pumped out the exhaust with very little making it into the crankcase. Please do not consider doing only the UIM without pulling the LIM and installing the aluminum frame gaskets. By the time you have the UIM off, you have done 80% of the work in getting the LIM off. That plastic elbow is another failure waiting to happen. The UIM may not be your problem, anyway. It is just as likely the coolant is leaking through a failed LIM gasket.

Buy the APN kit. It is cheaper and better.

Nothing to be apprehensive about. We are here to help.

Get the APN, I did, and its not too tough to install.
Plus, you get the upper and TB gaskets as well.
Use the good quality lower gaskets and youre home free.

Dont forget to use the techinfo right here, it was a huge help!!!

Injectors should come out without too much problem, just take your time and dont force anything. A little WD-40 helps them pop out.

I used a drop of clean oil to get them in easier. New o-rings are tricky!!
Vaseline also works great, I hear.


Good luck!!
Bob

There is an "ancient" Fram oil filter commercial whose slogan fits here. A mechanic holding up the oil filter saying "you can pay me now", and then pointing to rebuilding an engine "..or you can pay me later."

Both of the items that you want to avoid will fail, sooner or later. Worse case, taking your engine with them - especially the LIM gasket failure. As you're most of the way there already, take care of the problem areas before they become a real problem.

I got the injectors out.

I am having trouble getting the crossover pipe off at the right side toward the driver. I can't find a way to hold the taps and turn the studs. I'm going to try to get at the lower tap on the throttle body mount from the front behind the bracket that'* close to it.

If I do the lower as recommended, is there a need for sealant at the ends? I recall someone posting a picture of sealant--not just the gasket itself.

If you are attempting to take the crossover off to remove the bracket that connects to the side of the throttle body, that is not necessary. Just give it a good whack to the side to get it out of the way. Remember it when you put the throttle body back on before you tighten the TB or it won't line up properly.

Sealant (I'd recommend the high temperature copper RTV) goes in corners of the end gaskets, where the meet the LIM gasket. Put a good dollop there. Some has gone as far as to seal the entire end gasket with it.