Greetings, and am new to the forum.

I have a 2001 Lesabre needing a replacement engine and came across what looks to be a '96-'99 Series 2 engine and transmission (the seller cannot verify year of donor vehicle). Judging by the engine cover, the engine definitely looks to be a '96-99 series II used in the previous model Lesabre -- and not the 00-05.

The engine and tranny had 81K mi at pullout per the seller. Assuming a '96-'99 donor engine and transmission, will I run into electronic or wiring harness issues if going with a Series 2 used in the previous platform of Lesabre? Just trying to do some research on compatibility before going any further.

Thanks for insights!

Depends on what trans is in it. There is a tag mounted on the side of the trans. If you can get a pic of it, that would help. Then there is the possibility of a different FD ratio.

Otherwise, 1995-2005 Series 2 engines are all the same. After 2005, they went to the Series 3 engine.


IMO, I would keep things simple and just swap out the engine. The engine should be a direct plug n play.

Why are you changing the engine?

Thank you for your reply: The '01 that I have has 220K on it. I did the intake with FelPro metal-based gaskets, aluminum elbows at about 160K and smaller EGR stovepipe. Recently, I noticed I was losing serious amounts of coolant and steam out the exhaust and it fouled out and will no longer start. I did not see any external leaks. The transmission is also original at 220K and I had already put a shift kit 1,2 in maybe 10K ago to stop the hard shifting overrride function when the shifts got a little slushy.

I haven't dug into the engine, but figured it'* getting coolant in the cylinders. I noticed it was low, and as soon as started pouring in the radiator while running, seconds later it started skipping and major steam out the exhaust.

I saw a craigslist engine/trans out of the '96-'99 with said to be 81K on both for 750, so I thought why not just swap out while I have the time. So, if I could get the seller to look for the tag on the transmission, that would help better solve the question of compatibility?

If it wasn't that long ago, you can remove all your spark plugs, crank the engine over and push all the coolant out. And just replace all the gaskets again. I've seen many of engines do this in here.

As far as the tag goes, I'll need a picture of yours too.

With the transmission in car, where would the tag be?

With 220K, if it were you would you lean more toward your suggestion of just taking plugs out, cranking over, and resealing upper and lower again? Other than time, I guess that'* a pretty cheap option. I've taken good care of it otherwise, do these typically have a fighting chance at 300K?

If it were me, I'd take the chance on that yes.

IMO, I'd still ****** that engine/trans combo. Rebuild them both when you have a few mins on a weekend. Spare engine is nice to have.

Got into it yesterday while waiting on shipped parts. Confirmed UIM manifold failure as the area around the EGR stovepipe was burned out.

Let me shift gears toward the repair: 5 years ago I did the upper and lower and bought the ATP manifold that has the metal sleeve insert and smaller stovepipe. However, when I torqued down the bolt on the corner (as others report in amazon reviews) the unit cracked. As a result, I would up using the smaller EGR stovepipe from the ATP kit in conjunction with a new GM composite plenum thinking that'* essentially the factory "fix" and design if the Dorman unit as well. However, when I took the throttle body off, the EGR stovepipe had dislodged and was laying back a few inches in the plenum and the stovepipe hole was burned up. I recall just tapping the stovepipe into the LIM when I did the repair 5 years ago. I'm concerned that it dislodged? It seems even if the plenum burned up around it that it should not have dislodged.

If this is a "for the last time" repair, should I use some type of epoxy when I insert the stovepipe into the LIM for this repair? It'* strange to me that it dislodged and was in the upper plenum.

Also, when I cranked over the engine with the plugs out, no coolant really came out of cylinders. I assume I burnt it all off right up until the time I got the No Start after the rough running. There is no noticeable coolant in the oil on the dipstick.

Thanks again for reading and for thoughts.

You can check under your oil cap for the milky goo.

Once all repairs are made, I suggest changing the oil and filter. Then rechecking the oil cap again after 500 or so miles.

From the sounds of it, the crack is what started everything. If you can, get your hands on a good digital inch pound torque wrench. Old style clicker torque wrenches aren't all that accurate at the lower end of the torque range.

I wasn't totally clear in the last post about the crack. The crack on the new ATP unit occurred on the outer corner where the PCV valve is just when I doing the final pass so I scrapped the ATP unit and got a new GM one but used the smaller ATP stovepipe with the GM unit. After 5 years the stovepipe became dislodged from the LIM during or before the burn through. But it burnt it pretty good and gunked up the throttle body. Will definitely change oil before running and then again. I'll check the oil cap.

Will check into a digital wrench and maybe see if a larger washer can go on the corner as I saw someone note in the amazon reviews. I remember that being a very bad feeling when I thought I was on the home stretch and that I heard that crack! I just figured the ATP wasn't made as strong as the GM. Never thought I'd be doing this job again but I guess it'* the upper that is the weak link after the OEM LIM gaskets are replaced.

Oh, ok. Those stovepipes usually sit in there pretty good. So, maybe some epoxy might work.