I just found out the source of a coolant leak is the intake manifold gasket on our Lesabre. I was quoted "around $650" to do the repair (private shop). I plan on shopping around but does this sound about right (for the midwest)?

Labor is about 6.0 hours book time plus parts, see what the shop labor rate is.

After doing a good bit of research I think this is something I should be able to do myself. To date I've done the transmission filter, starter (twice - bad rebuilt starter 1st time), a water pump on a 93 Jeep GC, and the tine seals on a 1968 Troy-bilt tiller myself. I'm definately a mechanically inclined person, though sometimes intuition alone can't make up for the lack of experience.

Anyone who has done this care to offer any tips or precautions?

First things first..

You will need to go to the auto parts store

In the help section you will look for the coolant elbows DORMAN 47065
http://www.rockauto.com/catalog/moreinfo.php?pk=620228

Whatever you do make absolutely sure you get the Aluminum Lower intake gaskets for the 3800 Series II from GM... GM # 89017825

For the upper intake( if yours is more than a few years old ) I recommend replacing it weather it looks good or not..

Dorman will work for this and your local parts store should be able to get one for you... The new kits now include the reduced diameter EGR stove pipe/s to keep the stove pipe from touching the Nylon upper intake.. The upper intake kit will have the Throttle Body gasket already installed, as well includes the upper to lower gasket, so you should be set with that..

If there is anything wlse you want to know just ask..:)

I just found out the source of a coolant leak is the intake manifold gasket on our Lesabre. I was quoted "around $650" to do the repair (private shop). I plan on shopping around but does this sound about right (for the midwest)?

Was the DexCool ever replaced during the 8 years?

Is it leaking from the upper intake manifold gaskets at the LIM or throttle body or is it leaking from the EGR channel from deterioration due to heat?

The other leak is that it's leaking under the LIM at the gaskets there.

The car already has the reduced diameter EGR tube; those were installed starting in 1999 if I recall.

There are some guides posted around the internet as to the steps for replacing the upper and lower.

The leak was occuring in the vacinity of the throttle body (below) and after a second conversation with the mechanic he said he could do the replacement for $150. I was going to have them do it but the transmission decided to go before I could get it there. So, the folks who are doing the rebuild are going to install the upper manifold kit I ordered from autopartsdirecttoyou.com. For under $95 the kit comes with everything you need.

On a side note: I bought new tires and put new shocks/struts about two weeks ago and was having a very hard time getting the car to ride smooth. I had a vibration that mimicked out of balance tires but felt more broad (whole car) than one specific tire. The vibration was coming from the transmission/torque converter. The shop pulled a code that has something to do with "adjustment limit reached" on the engine's ability to compensate for transmission wear.