Not carb cleaner. Any cleaner designed and labelled to be 'intake safe' or 'sensor safe'. There are plenty on the shelf.

Hi Shawn

You will need spray cans that say Throttle Body cleaner on them. Several people have said not to use carb or brake cleaner, better to be safe than sorry.

First thing remove the Mass Air Flow sensor and place it in a clean container and refrain from touching or cleaning the wires on it. If you have a stock air filter the MAF should be spotless. Make this the last part to go back on the car it is pricey to replace.
On your Idle Air Control Valve it is best not to push or pull on the plunger. Just clean the tip and the shaft with cleaner and a toothbrush.
On my car the MAF, IAC, and the TPS all used different length screws. I was glad I marked them with paint pens before removing. I think your screws will require a special Torx bit to remove them.

The only thing that gave me trouble was the bolt holding the throttle body support bracket to the lower intake manifold. The bolt holding the bracket to the lower manifold would not budge with a 12-point wrench. Had to go to Sears and pick up a 6-point 5/16” wrench to break the bolt loose. Not sure if your car uses the 5/16” bolt head like my 96 does.

Good luck.

My mothers 99 LeSabre just started leaking, can see a small stain on the tranny, its not bad yet, so it looks like i have a project for when it warms up again.

I know everyone is holding their breath, so I thought I'd give you an update....

I'm not done yet...

Yes, I'm slow.... I can't help it... I'm an engineer....

Anyway, I'm pretty much done. I've got to clean up one more sensor, torque the upper to specs (89 in-lb), reinstall the fuel rail, and put the sensor back.... Thanks for the good idea about taking the sensors off first... I would have probably banged one up...

Throttle body cleaned up nicely...

So, here are some pictures of the job....

Here'* a snap of the Dexcool leak that started it all... I still don't know how I got such a large puddle (about a 1ft diameter) in the garage over such a small leak (you'll see soon). It must have puddled up somewhere in the transmission housing and came out when I stopped the car...


Here'* the before pict....


These boogers (sensors) made me have to run to Sears and buy some "Tamper Proof" Torx bits... The GM boys don't want you to "tamper" with these...


Here we are with the upper off... Do you see any signs of coolant? I don't...


Here'* a shot of the area that appeared to be leaking...


Here'* a shot comparing the Dorman upper and the old one... I don't see any warpage, but there was some kind of goo just below the upper gasket...


Comparison shot of the old upper and the Dorman....


Shots of the leakage area just to the right....



It took me a while to figure out those electrical connectors on the fuel rail... They looked too easy to snap...


Another shot of the goo/dexcool right next to the leak area....


Anyway, I'm almost finished... I couldn't take the cold anymore. I'm in Alabama, but it'* almost 25degF at night here now... Too much for this sensitive southern boy...

I"ll finish up tommorrow night (if it'* not too cold)....

Comments are appreciated.... I plan on changing the oil and filter (even though I didn't see signs of coolant).

One other question I had. I took the upper off with the Throttle Body attached (as one unit). I had planned on putting the upper back on by itself, but I noticed that I might have trouble putting the Throttle Body on later. There'* a black bracket to the TB that keeps me from having enough clearance. How did you guys do this? Did you take them off as one unit? Did you put them back on as one unit? I am putting mine back on as one unit. I've torqued the TB onto the upper to the torque specs (89 in-lb I think). I will then torque the upper down withg the TB attached.

Does this sound ok? At first, I thought I'd rather get the upper torqued down, but this bracket wouldn't allow me to put the TB on afterwards.... Maybe I'm trying to cut too many corners...

What do you guys think?

I can put up bigger picts if anyone wants them... I just didn't know if anyone was interested.... Probably stuff you've all seen before....

What ended up being the cause of the leak...cracked manifold? gasket failure?

My vote would be the gasket...

There was some kind of goo in the area of the coolant mating seals... It may be that the previous owner had used some kind of coolant sealant in the radiator (as the TSB suggests). Or, is it possible that this goo comes off of the gasket when it has finally bit the dust and failed/melted?

The leak wasn't severe, but I was real paranoid about getting coolant in the engine, so I went ahead and pulled the inlet cover.

I'm going to take a closer look at the gasket and inlet tonight to see if there was any signs of seal failure. The leak area was on the back/right portion of the inlet cover, right next to one of the coolant loop holes. The inlet cover didn't appear to be warped.

If you want to see close ups of any of these pictures. I have 5MP files (original size). I scaled all these down....

Silver SE, when I did my UIM,I bolted it down first and then attached the throttle body.For me ,alot easier to torque the throttle body that way.If the bracket you're referring to is a short support strut that mounts to the forward side of the throttle body---- at dissembly I loosened the throttle body end and bent the strut towards the radiator with the bottom still attached.After UIM and TB installation,bent the strut toward the throttle body and tapped it into place with a long screwdriver and small hammer before bolting it to TB.The goo probably was sealent installed by GM.It was common factory practice.The leak doesn't surprise me.Ichanged my UIM at 43,000 miles even though it wasn't bad yet but the coolant port gaskets to the throttle body were flattened almost level with the black plastic seal plate with very little compression left in them.It probably would have started leaking in the near future.The cover doesn't have to be warped,I think the heat(being near the egr tube) caused the gasket material to take a set and lose it'* "springiness".While you have the UIM off,check the bolt torque on the lower intake.I found those two so called "hidden " bolts (diagonally opposed in the corners) on the loose side.Also wouldn't hurt to use some locktite blue on the UIM and TB bolts.Good time to install some new injector o-rings as well.Also, if your mom'* 3800 has a leak,check the torque on the UIM bolts as I found some of mine a bit loose when starting the job.Good luck.

helikon,
Where would I get injector o-rings? Is that a dealer only part?

The dorman kit that I bought looks to already have some type of locking feature material on the fasteners. It'* red in color. But, good idea for those who don't buy the kit...

And yes, you were right about the strut. I could have rotated it. I torqued the TB to spec. Do you think the UIM will be ok to torque down with the TB already attached? I'm gonna' give it one pass at 22 in-lb, one pass at 44 in-lb, and a final to 88 in-lb....

Again, thanks for the added info...

Silver SE, you're right about the red threadlocker on the TB studs.Forgot about that.I used the locktite on the bolts that hold down the UIM.The injector orings I'd probably call around to auto parts stores first.I had to go to two different stores just to get 6 of them.Pep Boys had 4 and carquest had 2.Must not be a big demand for these or something (no NAPA in this town --unbelievable).I see no problem torquing the UIM down with the TB installed as long as you can get at all of the UIM bolts or have any interference from anything.It'* been a year so i don't remember all the details.I removed my TB first and cleaned it then installed the Dorman kit before installing the TB.I didn't change my oil because it was recently changed and there was no coolant loss and nothing got down into the oil while doing the job.This was a preemptive inspection and changeout.All it really needed was new UIM gaskets but decided to put the newUIM on while had it apart.It is supposed to be "improved".Other than the beefed up wall thickness at the cooling ports I couldn't see any difference.Good luck.