Since there doesn't seem to be any good step by step DIY's with pictures floating around I thought I'd make one.
Have you noticed coolant leaking from the passenger side of the engine compartment but the waterpump doesn't appear to be leaking? Welcome to the wonderful joys of the 3800 coolant elbow failure. The lower elbow is part of the bracket on the 97's so there is technically only one elbow, all other years have 2. Sometimes these pesky little pipes will crack and leak at alarming rates and other times they will leak from their orings making it sometimes difficult to spot where exactly a leak is coming from. But don't worry and don't pay a shop 200 dollars to fix the problem, we've got you covered.
This DIY is also 9/10 of the way to a drive belt tensioner replacement and also an alternator replacement, and is a good start to the inevitable LIM gasket job which I may make a DIY for since it looks like it's on the list of things that need done
I did this on a 04 GT so Series II guys the sizes of a bolt or 2 may be slightly different and for S/C guys I obviously didn't have the additional belt to show, sorry. So let's get started.
What you'll need:
-About an hour of your time. I took 45 minutes, taking pictures along the way, but some work faster, some work slower.
-New Coolant Elbows: Dorman HELP! P/N 47065 (4 bucks at any local auto parts store) or 47065HP for the new aluminum ones. You can also get the arguable better OEM ones but I don't remember the P/N, sorry.
-Roughly 2 gallons of coolant (so 1 gallon concentrated + a gallon of distilled water or 2 gallons of 50/50 premixed). If you need to do a coolant flush now is the perfect time to do so since the radiator and most of the engine will be emptied by doing this. And remember DON'T MIX COOLANTS!!!! If you still have Dexcool either refill with Dex or completely flush it before adding a different kind.
-Optional 20mm socket (for drain cock, on older Wbodies it's just a wingnut type thing you can do by hand)
-A catch pan for the coolant. Be kind to mother earth and dispose of used coolant properly.
-As with all engine bay repairs it's best to disconnect the negative terminal of the battery and allow the engine to cool off.
-Jack the front of the car up and support it with jack stands.
-Locate, loosen, and slide open the drain cock on the lower drivers side of the radiator (on this it was a 20mm plastic plug but on others it's just a wingnut style that you can do by hand just be careful not to break the plastic since it may be brittle). Make sure to put a catch pan underneath the drain spot.
In the event that the drain cock is broken, removing the lower radiator hose will also do the trick.
-Remove the engine cover (if not in trash can) by turn the filler neck counter clockwise and removing.
-Remove the overflow reservoir which is held in by 2 10mm fasteners. (97-98 get out easy on this step).
-If you have an L67 or L32 supercharged 3800, remove the supercharge belt by rotating the tensioner with a 15mm socket.
-Remove the drive belt by rotating the tensioner counter clockwise with a 15mm socket
-Remove the alternator support bracket by removing the 15mm nut and 10mm bolt. Supercharged engines have different rear brackets from what is shown but will still need to be removed if they are preventing the removal of the alternator. Series II engines have an additional support bracket in front of the alternator which will also need to be removed.
Picture of front support which is held in with 2 15mm nuts
-Remove the 3 15mm alternator bolts. Again 97's are slightly different here so their bolt locations aren't represented in these pictures.
-Set the alternator off to the side.
-Remove the 3 15mm driver belt tensioner bolts. One is hidden on the lower part of the bracket but the wrench is on it to show you the location in this picture.
-Remove the drive belt tensioner by pulling it towards the passenger side of the vehicle.
-Take note that your LIM gaskets are leaking and will need to be replaced very soon.
-Remove the old elbows. Occasionally they will break even if you're careful, just make sure not to lose the pieces inside the bracket or LIM.
-Clean the bore surface of any corrosion or plastic/rubber debris. A nonscratch type pad works fine for this.
-Lubricate the new elbow orings with coolant or sealant and firmly but gently insert them into the tensioner bracket ensuring to prevent the orings from binding or tearing. Coolant has worked fine for me in the past but others have had to use RTV sealant.
-Install the drive belt tensioner while aligning and again firmly and gently walking the elbows into place. Tigthening the 3 15mm bolts in sequence helps to ensure that the elbows both go evenly and straight.
-Tighten the 3 15mm tensioner bolts to 37lb-ft and check the fit of the elbows. You may have to push them in just slightly more.
-Install the alternator and tigthen all 3 15mm bolts to 37lb-ft.
-Install the alternator support bracket and tighten all bolts to 37lb-ft, this applies for all the different styles of brackets front and rear.
-Install drive belt.
-Install supercharge belt if applicable.
-Install coolant overflow reservoir and tigthen the 10mm nuts.
-Tighten radiator drain cock or install lower radiator hose.
-Remove jack stands and lower vehicle.
-Reconnect negative terminal of the battery.
-Open the thermostat air bleeder valve, this will allow for faster filling of the radiator and will be used for the system bleeding shortly.
-Add coolant to radiator filler neck and add some to the overflow reservoir as well.
-Start the engine and turn the heat to full blast. Wait for it to get up to NOT (normal operating temperature) at which point the thermostat will open and you'll begin to notice bubbles coming out from the bleeder valve. Leave the valve open until a steady stream of coolant flows out then close the valve but be careful to not over tighten it because it will break very easily.
-Take the car for a drive and check for leaks.
-Pat yourself on the back and enjoy a tasty beverage.
As always, I'm open to any comments, questions, or concerns so just let me know