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Remind me, is it possible to replace the coolant elbows without having to do the full UIM / LIM teardown? If so, is there a 2000+ writeup just for that?

The replacement Dorman plastic is leaking, do the newer Dorman aluminum elbows seem less likely to re-fail?

And the 2000+ uses the two elbows, right?

I changed mine to the alum. ones when I did the LIM gaskets. IIRC, I'm pretty sure you can change the elbows by removing just the alternator mount/belt tensioner. Not sure though, it's been a while. I do recall going to Mr. Goodwrench to buy the O-rings rather than using the Dorman supplied ones. Probably an unnecessary precaution, but I feel better with the GM O-rings in there. Good luck.

Yes, you just have to remove the alternator and tensioner.

Two elbows, and yes, just the alternator and tensioner. It's a quick job for the most part. I think many suggest using RTV around the seals, and to scuff up the ports to clean them up a bit.

OK, gonna try to get to the aluminum elbows this weekend. Also going to replace valve cover gaskets with FEL-PRO as long as the alternator and bracket are coming off, I honestly can't remember whether or not I did them when I did the LIM/UIM years ago, but there's oil leaking somewhere from all around the top of the motor.

So let's hear more about RTV on the elbows. Who's in favor, who's against? And if in favor, how and where exactly are you applying it to the elbows?

I just used some "faucet grease" that is approved for butyl rubber, neoprene, etc. O-rings. I also installed a new tensioner and carefully polished it and the other bores with 0000 steel wool until they were very bright and smooth. So far, so good, knock wood.

I replaced the coolant elbow over 10 years ago and used Permatex Ultra Black and it is still tight.

Yep I have been using Permatex Ultra Black on radiator hos3es and o-rings for many years. I use a thin film of UB on the T-stat housing instead of a flat gasket. The stuff makes sealing better and makes removal of parts much easier.

Coolant will not dissolve Permatex Ultra Black.

i was cheap and put in palstics back in (not knowing they were a huge issue at the time) w/out any sealants or anything and its lasted 2 years and 20k miles already

Those that do it apply a bead on the part of the elbow that slides in before the o-ring, so the o-ring kinda squishes it in and holds it in place, and it helps seal the o-ring.

I will be the standout on not using gasket material on the elbows. I did a LIM gasket and elbow replacement last year on the 2005 Bonneville SLE. The elbows were leaking- but I went ahead and did the lower and upper LIMs so everthing would be rock solid.

When I pulled the tensioner the elbow came out with it. stuck to it. The permatex bonded to the tensioner, so I ended up needing to replace the tensionor. I used GM metal elbows. I sense the elbows may need the the ability to slightly move, and with permatex that may prevent that from happening.

I have had zero leaks and replaced the elbows the way it came from the factory- with the exception I used the updated metal elbow design.

I used black Rtv on the elbows in my car, and didn't use any rtv on dad's PAU. Both of ours have been in for quite a while, nearly 50k in mine and 30k in his. Neither of us have had any leaks at all. As long as you're using the metal elbows, you'll be fine either way. I think the main argument for rtv is based on one of the failure points for the plastic elbows. The o-rings tended to flatten over time and created a leak. The rtv would seal around that, so even if the o ring failed the rtv would still be sealing regardless. The new elbows I used had much better o rings than the plastic ones I used the first time, so I don't think they're an issue anymore.

Did get around to this weeknights last week.

First did a TB/MAF cleaning. Well, a MAF cleaning...brittle old MAF screen wanted to crack apart while trying to remove, so had little choice but the let the EGR-fouled TB stay pretty foul, or else the MAF screen would likely have gotten plugged up with oily gunk. Even though date code on UIM indicates it's original, I did confirm that there's a Buttermore pipe in there (thought so, but I lost my notes from years ago when I did LIM gaskets), could see no coolant puddles on the LIM, and the plastic around the UIM is as good as new. TB gasket was very compressed at bottom (around the coolant inlets, of course) so a new TB gasket was a must.

New spark plugs, it was due. Forgot how freakin' hard it is to get to the rear bank on the 2000+ Got more scars on my forearms than a hipster who woke up one day, realized all those tattoos were no longer cool and got them removed.

New VC gaskets; ones that were in there looked original...and very compressed. Hope this fixes the slow oil loss / dirty-ass engine compartment issue.

As for the old plastic elbows...lower elbow was cleanly broken on the smaller diameter side, right where it "thins" at the o-ring groove. I've done 5 or 6 elbow jobs now on various 3800 S2 cars, and as I recall this has been the failure mode in every case, the plastic broken at the o-ring groove on one or the other elbow. Certainly I expect aluminum elbows to avoid that!

(Thanks GM, another 10 cents per car for original aluminum elbows and these would have been far less of an issue, if at all. And don't even get me started on plastic LIM gaskets, and the failure to put a steel pipe in the UIM around the LIM...probably another $5 per car when originally designed and built and I bet 99.9% of these inevitable 3800 S2 coolant issues would never have happened. But here I am preaching to the choir!)

If elbows were all I was doing, this was a 2-hour job tops, and that's taking my sweet time. I did use blue RTV on the elbows, but probably I could have skipped it.

FWIW, if the honeycomb filter breaks, Rockauto has them, if you need to replace it at some point in time.

agrazela wrote:Forgot how freakin' hard it is to get to the rear bank on the 2000+ Got more scars on my forearms than a hipster who woke up one day, realized all those tattoos were no longer cool and got them removed.

Too funny!

Wish those rear plugs were a little easier to service.
My 01 had the original plugs and wires---whose boots had seized onto the plugs by 100K and 15 years of hot/cold cycles.

agrazela wrote:As for the old plastic elbows...lower elbow was cleanly broken on the smaller diameter side, right where it "thins" at the o-ring groove. I've done 5 or 6 elbow jobs now on various 3800 S2 cars, and as I recall this has been the failure mode in every case, the plastic broken at the o-ring groove on one or the other elbow. Certainly I expect aluminum elbows to avoid that!<br abp="759"><br abp="760">(Thanks GM, another 10 cents per car for original aluminum elbows and these would have been far less of an issue, if at all. And don't even get me started on plastic LIM gaskets, and the failure to put a steel pipe in the UIM around the LIM...probably another $5 per car when originally designed and built and I bet 99.9% of these inevitable 3800 S2 coolant issues would never have happened. But here I am preaching to the choir!)

Add to that the lack of zipties for the sunroof tubes and I'm with you 100% .
If I had bought my Bonnies new, I'd be pretty miffed at these things.
Thanks to all of the forum write-ups, and the fact that they're so comfortable, etc., I love these cars.