: STS4 Oil Change Revisited



Zig28
02-26-07, 04:53 PM
After reading all of the oil change tips, I went out to do the first oil change on my '06 STS4 3.6L V6. Not sure if they've changed the design with the AWD version, but none of the photos or tips seemed to help.

First of all, there's no way I can reach under the engine without the car on ramps. Then, looking under the engine, there are two drain plugs. There's a 13mm plug, not located pointing down, but pointing towards the front of the car, in the front of the bottom of the engine casting. This plug does not have a gasket or washer under it. I don't think this is the oil drain plug, because it would have a gasket, no?

There's a hex Allen bolt towards the back of the engine, facing the ground, on the bottom of what looks like it might be a finned oil pan. This is about a 10mm Allen bolt and it does have a gasket/washer under it, so it looks to me like the oil drain plug. The transmission pan is in back of the engine, and it also has its own drain plug.

I messed around for about 1/2 hour trying to figure out what to do but gave up. I tried lowering the car off the ramps but there's no way I can fit under there and reach either plug.

Can anyone help and confirm which plug is the engine oil drain plug for a 2006 STS4 with the 3.6L V6?
Thanks,
Ziggy.

Jesda
03-02-07, 02:18 AM
Bump!

STS2002
03-02-07, 09:40 AM
After reading all of the oil change tips, I went out to do the first oil change on my '06 STS4 3.6L V6. Not sure if they've changed the design with the AWD version, but none of the photos or tips seemed to help.

First of all, there's no way I can reach under the engine without the car on ramps. Then, looking under the engine, there are two drain plugs. There's a 13mm plug, not located pointing down, but pointing towards the front of the car, in the front of the bottom of the engine casting. This plug does not have a gasket or washer under it. I don't think this is the oil drain plug, because it would have a gasket, no?

There's a hex Allen bolt towards the back of the engine, facing the ground, on the bottom of what looks like it might be a finned oil pan. This is about a 10mm Allen bolt and it does have a gasket/washer under it, so it looks to me like the oil drain plug. The transmission pan is in back of the engine, and it also has its own drain plug.

I messed around for about 1/2 hour trying to figure out what to do but gave up. I tried lowering the car off the ramps but there's no way I can fit under there and reach either plug.

Can anyone help and confirm which plug is the engine oil drain plug for a 2006 STS4 with the 3.6L V6?
Thanks,
Ziggy.

Ok..i have changed the oil on the V8 AWD and the drain plug was on the side of the pan. It did not have a gasket or washer....in fact i have never seen a gasket or washer on any drain plug from other cars. I would bet that the one pointing towards the front of the car without the washer and gasket is the one you want. :)

Zig28
03-03-07, 04:57 AM
Thanks STS2002 -- I think I'll give it a try today. It's interesting to note that no one I've talked to seems to know what the other hex drain plug is for. I guess I'll ask the Caddy dealer next time I'm down there.

Ziggy.

Zig28
03-03-07, 04:58 PM
I finally figured this out. The oil drain plug on the STS4 3.6L V6 is the 13mm hex nut towards the front of the engine. It does not have a gasket. I had to jack the car up and remove the right front tire to access the plug. After that, it was easy.

The 17" wheel lug nuts use a 19mm or 3/4" 6 point socket with 1/2" drive. One of the lugs is the locking lug nut, so you'll need the special McGard lug nut key they give you with the car, it should be in the trunk. The lug nuts came off nice and easy -- loosen them up first before you jack up the car, then remove them in a cross pattern.

The dealer who rotated the tires on the car before (the STS4 has all the same size 17" wheels and tires and is the only one that Caddy recommends rotation) did a good job of not over-torquing the nuts. The wheel lug nuts on the 17" STS4 wheels take 100 ft. lbs., according to the owner's manual. Tighten them in a cross pattern, I used 3 steps to get them up to 100 ft. lbs., using a cross pattern each time.

The oil drain plug is 13mm hex. I used a 12 point box wrench to unscrew it. It was pretty tight, so I had to maneuver on my back in front of the car and reach in to get enough muscle behind it. I don't think I can reach it unless the car is jacked up.

I drained the oil and lowered the car on the jack until it was level as the oil was draining. I placed two ramps under the side of the car for safety. It drained about 5.5 quarts, so there's about 1/2 quart in there somewhere that didn't come out.

You'll need a 24mm socket to unscrew the oil filter housing. This is the easy part -- so much easier than any other car I've worked on. The dealer who had done the first oil change had the thing screwed on with like 100 ft. lbs. of torque, which is ridiculous. There's no need for lots of torque here -- the housing top sits on it vertically and doesn't support anything, so a snug fit is fine, although I'm sure there's a torque spec for this somewhere.

The filter cartridge comes out with the top. Make sure you securely push the new filter on to the top and don't put the filter in to the housing first. Make sure the filter fits like it should into the top part of the housing that you remove -- important! Then place the filter with the top of the housing back on and screw it down.

I've attached some photos. By the way, the oil filter I bought is a CarQuest (Wix) 84090. It cost me $7.21 at the local auto parts store. That's 4 bucks less than the oil filter for my lawn tractor I bought at the same time!

Hope this helps someone, the search function on this forum leaves a lot to be desired and I know there was another post with this info and photos but after searching for like 1/2 hour I couldn't find it, so I figured I'd add my own and hopefully it will help someone.
Ziggy.

zapconj
09-05-11, 04:44 PM
I know this is an old thread but i wanted to say thank you for the info. I changed the oil on my wife's 2007 STS4 today and it was a breeze!

Thanks for the great thread.