The lower has failed @ 92,000 mi. I have all the goods needed for my repair. From experience around here, what kind of time am I looking at to complete this job today? Also, I have heard several bad things about the Dex-COOL antifreeze, and I have just recently had to replace my heater core due to corrosion, I was wondering if the aintifreeze has anything to due with these gaskets failing prematurely. Just a thought. (plastic-a$$ gaskets might have something to do with it) I have changed from the Dex-Cool to a universal anitfreeze. Wish me luck.

Probably take you about 4 hours. Takes me six, but I am very sloooow. Yeah, we think Dex is the devil.

Good luck! and it should be done within 4 or 5 hours, take your time and keep things clean.

Thanks fellas........I'm goin' in!

Here'* a process I wrote for a 2004 LeSabre L36, if you are interested. I am in the middle of doing this on the car even as I type

If this is your first time, budget a minimum of 8-10 hours.

(This process includes VC gasket replacement, so skip that if you wish)
(Also, you may not need to remove alternator, if it doesn't block access to any LIM bolts)

========================

Place front of vehicle on jack stands; chock rear wheels

Remove air dam
Remove rad cap
Detach lower coolant hose; catch drainage in clean bucket (rock car to get more)
Remove engine cover
Remove thermostat housing and thermostat
Flush block with hose until water runs clear
Reattach lower coolant hose
Replace air dam

Put vehicle down off jack stands

Disconnect battery
Remove spark plug wires and boot heat shields
Remove serpentine belt from alt (rotate breaker c-cwise to remove tension)
Remove alternator mounting bolts
Remove alternator output nut and electrical connector
Remove alternator
Disconnect MAP sensor harness from UIM
Disconnect IAT sensor harness from bellows
Remove airbox and bellows
Disconnect MAF, TPS and IAC sensor harnesses from TB
Disconnect coolant temperature sensor from LIM
Disconnect EGR harness
Remove vacuum lines from TB (and FPR?)
Remove EVAP solenoid from bracket; move solenoid assembly out of the way
Remove accessory and brake booster vacuum lines from UIM
Remove fuel rail nuts
Remove injector wire harnesses
Remove fuel rail and tie up out of the way
Remove exhaust crossover (or loosen and move out of way)

Remove CC and throttle cables from TB and bracket
Remove TB support bracket
Remove TB

Remove EGR heat shield
Move bundled harness(es) (IAT/MAF/TPS/IAC/EGR/injectors) out of the way
Remove UIM bolts; remove UIM

Remove alternator bracketing from LIM (as required to access rear valve cover)
Remove EVAP solenoid bracket
Remove EGR tube from LIM
Remove LIM bolts; remove LIM…coolant bypass elbow will break off

Stuff rags into all head intake ports
Place rag over lifter valley
Pick broken coolant elbow bit out of tensioner
Remove old LIM gaskets and side seals from block; scrape area, clean with solvent, and buff
(Now is a good time to inspect belt, hoses, and wiring harnesses)
(Also a good time to change plugs)
(Also a good time to change injector o-rings)
(Also a good time to degrease the rest of the block and tranny cover)

Soak LIM bolts in solvent
Examine LIM carefully for cracks and warpage
Remove ECT sensor from LIM
Pick broken coolant elbow bit out of LIM
Remove stovepipe (if replacing with Buttermore pipe or Dorman pipe)
Remove front coolant cap from LIM
Scrape away gunk from sealing surfaces, clean LIM with degreaser/solvent, and buff
Replace front coolant cap with new gasket (15 ft lb)
Replace ECT sensor with thread sealer (18 ft lb)
Replace stovepipe (if replacing)

Soak UIM bolts in solvent
Remove MAP sensor and PCV valve housing cover
Remove vacuum fitting
Remove runner insert; inspect for cracks/damage
Examine UIM carefully for cracks/breakage, especially in EGR area
Remove and discard main gasket, TB gasket, PCV o-rings, PCV valve
Clean UIM and runners with solvent/degreaser

Remove MAF sensor from TB
Clean out TB and MAF screen with carb cleaner and a toothbrush
Clean MAF filament with a q-tip and rubbing alcohol
Replace MAF in TB

Remove valve cover gaskets
Remove and discard old gaskets and grommets
Clean valve covers with solvent and degreaser
Replace valve covers with new gaskets and grommets (89 in lb)


Remove rags from valley and head ports
Place coolant bypass elbow into tensioner hole until seated (lube with anti-freeze if needed)
Lay new LIM gaskets and new end seals in place; dab RTV in corners
Lay down LIM, ensuring that bypass elbow seats fully in LIM and bolt holes and gaskets line up
Place bolts and hand tighten (use blue threadlocker)
Torque bolts, crosswise pattern center to ends (11 ft lb)
Replace EGR tube into LIM (use blue threadlocker) (21 ft lb)
Replace EVAP solenoid bracket (use blue threadlocker) (22 ft lb)
Replace alternator bracketing (use blue threadlocker) (22 ft lb)

Replace new PCV valve with o-rings, housing cover, and MAP sensor
Replace vacuum fitting
Replace new TB gasket
Insert runners
Replace new main gasket, ensuring J-tube hooked end is in PCV slot
Lay down UIM, ensuring EGR tube goes through hole in UIM
Place bolts and hand tighten (use blue threadlocker)
Torque bolts, crosswise pattern center to ends (89 in lb)
Reattach EGR heat shield (12 ft lb)

Replace TB on studs (use blue threadlocker on nuts; use red on rear nuts if studs are loose) (89 in lb)
Replace TB support bracket (blue threadlocker)
Torque nuts and bolts on TB and support bracket
Reattach CC and throttle cables to TB and bracket

Install new plugs, if changing (use anti-sieze compound) (20 ft lb)
Reattach exhaust crossover (use anti-sieze compound) (15 ft lb)
Bring fuel rail down and attach wires
Install fuel rail using new lower injector o-rings, ensuring injectors are well-seated in LIM
Replace fuel rail nuts and torque (89 ft lb)
Replace accessory and brake booster vacuum lines on UIM
Replace EVAP solenoid on bracket
Replace vacuum lines on TB and FPR
Reattach EGR harness
Reconnect temperature sensor on LIM
Reconnect MAF, TPS and IAC sensor harnesses on TB
Replace airbox and bellows
Reconnect IAT sensor harness
Reconnect MAP sensor harness on UIM
Make sure all harness wiring is properly re-loomed and re-anchored
Reattach alternator bolts (use anti-sieze) (37 ft lb)
Reattach alternator contact
Replace serpentine belt on alt (rotate c-cwise to remove tension)
Replace spark plug wires (use anti-moisture compound) with boot heat shields (use vaseline)
Reconnect battery (use anti-moisture compound)
Refill coolant
Replace thermostat with new seal and gasket; torque bolts (use blue threadlocker) (20 ft lb)
Replace new radiator cap

Remove drain bolt and drain oil pan; catch oil in clean bucket
Remove filter and catch oil
Replace filter
Replace drain bolt (use new gasket if available) (22 ft lb)
Refill oil

Start engine and allow to warm up; meanwhile:
Check for coolant leaks at:
Hoses, rad cap, bypass elbow, t-stat housing, LIM endcap, LIM gaskets, UIM gasket, TB gasket
Check for oil leaks at:
Filter and drain plug, LIM gaskets and LIM endcaps
Test for vacuum leaks: at all vacuum hoses and hose connections, and around MAP sensor
All vacuum hoses and connections, PCV housing, TB-UIM, UIM-LIM and LIM-head interfaces
Look for exhaust leaks at both ends of crossover pipe (if removed)
Check for CEL codes
Replace engine cover

Test drive, then check everything again

Did you get the APN UIM? Aluminum LIM gaskets?

If you lose the DEX, the plastic gaskets are fine. GM has been using them with green stuff for years, and they hold up well.

Very thorough procedure you did there. Way to go!

BTW, why would you have to remove the exhaust crossover?

That makes it easy to get to the bolt holding the TB support bracket to the LIM, and the two lower nuts holding the TB to the UIM. While not absolutely necessary (you can get them with a ratcheting wrench or an open-end wrench and alot of patience), it is the only way to be able to get a straight shot with a torque wrench to torque them properly.
PB Blaster is your best friend on that crossover.

P.*., I discovered while doing this yesterday that removing the rear valve cover on the 2004 would require removal of a PIA alternator bracket (or possibly even the entire pulley/bypass assembly):


All this was purely preventive maintenance for me, and my process was adapted from the 1998 FSM. Without the 2004 FSM in hand, I said screw it...I'll replace those VC gaskets someday if they actually start leaking.

BTW, turkaloo, getting back to you from this hi-jacking...how did it go?

Thanks. I'll try to remember that one.

Thanks for the write up, to bad I was away from the computer. It really wasen't that bad. It was time consuming, but not that bad. I used more plastic gaskets (Fel-Pro), my car has 94,000 on it, so if it makes it another 100,000 before they need replaced again, I can live with that. My brother helped me and we had about 7 hours into it. My upper looked like brand new but was replace anyway. The lower was pretty rough, mainly around the coolant ports. You could definatly tell where it had failed. I was a little disturbed with what I saw in the coolant ports, a rust colored goop/sludge in the heads. I cleaned it out the best I could, but man I'm glad I got the Dex outta there in favor for the green. It was no wonder why I've replace my heater core. If the next vehichle I own has Dex in it, it will be the first thing I change!!

Invested:

$90.00 for both gasket kits
7 hours of good times.