Lower plastic elbow leaking after replacement

12-04-2011, 02:47 PM
01 Lesabre

I replaced both plastic elbow connectors and after 2 months i noticed the lower one was leaking. So I disassembled everything again, put some silicone on the tensioner side, snugly fit the elbow into both the tensioner and the block and put everything back together. Before it was leaking from the tensioner side, now it's leaking a bit from the block side. I can move the elbow back and forth with my hand, so it does not look like it's as snug as it should be. What in the world can I do? I got the parts at Pep Boys, i believe they were Dorman.


12-04-2011, 02:53 PM
I have heard that the Dorman elbows have problems. You may want to go OEM on those.

Tech II
12-04-2011, 03:45 PM
I heard it was the o-rings, not the elbow.....

12-04-2011, 03:50 PM
So should i get OEM elbows or try the rings? Sucks that I wasted money on the Dorman (or what ever it was) elbows.

12-04-2011, 04:15 PM
We have discussed the leaking Dorman seals/o-rings before. No more than the parts cost, I would replace both elbows & o-rings with OEM parts. If you value your time, redo labor cost more than the parts, not counting the frustration factor of doing the job 2-3 times. Here is a diagram & parts list.

323 24503423 PIPE. Engine Coolant By-Pass. Heater.
PIPE,THERM BYPASS UPR(TO LWR INT MANIF.)(08.846). Required: 01For: C 3.8K(L36) (1999-2005) (1999 - 2005). For: H 3.8K(L36) (1999-1999) (1999 - 1999). $12.48
324 25537068 SEAL. Engine Coolant By-Pass. Heater. Throttle Body Coolant Supply. $1.42

341 12565082 PIPE. Engine Coolant By-Pass
PIPE,THERM BYPASS LWR. Required: 01For: C 3.8K(L36) (1999-2005) (1999 - 2005). For: H 3.8K(L36) (1999-1999) (1999 - 1999). $3.76

342 25537068 SEAL. Engine Coolant By-Pass. Heater. Throttle Body Coolant Supply. $1.42

343 24502846 SEAL. Engine Coolant By-Pass. Engine Fan Coolant.


12-04-2011, 04:17 PM
Guys, thanks!

HotZ28, too bad I did not see the discussion before (usually the dorman parts have always worked for me). Found these two GM parts on Ebay, they come with seals, do I have to get seals 324, 342 and 343 in addition to what's being sold here or is everything that I need is included?



12-04-2011, 04:40 PM
Everything you need is included with the elbows shown. Good luck, you are doing the right thing!

12-04-2011, 04:59 PM
HotZ28, thanks!

12-05-2011, 12:07 AM
Being the old Engineer that I am, not satisfied with hearsay, and in an effort to add a little clarity to the difference between the Dorman elbows/O-rings & OEM parts, I decided to go to my shop tonight, where I had a sample of both. It is obvious to me, that all parts are similar (very close) in dimensions. Actually, the Dorman O-ring measured .010 larger diameter than the OEM. When installed on the fittings, both had the same O.D. One thing I did notice, the OEM O-rings are much softer & flexible than the Dorman O-rings. Without knowing the exact nomenclature of the material used in both parts, I have to assume, the OEM O-rings are more forgiving to temperature fluctuations, than the Dorman O-rings. Most of the problems with the Dorman O-rings, are leaks experienced after the engine cools down (in cold temp) after being being driven at full temperature. Shown in the pics below, are some of the dimensions measured with a digital caliper to .000. BTW, I was not satisfied with only one measurement, so I took several of the same part & came up with identical measurements.

Dorman lower on left & OEM upper on right

OEM top elbow fitting ID

Dorman lower elbow fitting ID, which has the same O-ring as the upper elbow.

Dorman O-ring

OEM O-ring


12-05-2011, 01:30 AM
I love it!

Unfortunately, I followed advice elsewhere to use the Dorman elbow with a skim coat of RTV.:mad: If only this thread had appeared to me 6 months ago.

Well, when it does leak, I'll pull the tensioner, pull out the Dorman elbow, and soak the RTV with carb cleaner. I believe carb cleaner sufficiently softens RTV for proper cleaning.

Then I'll go OEM.

Tech II
12-05-2011, 01:26 PM
I NEVER used RTV on those o-rings......I just make sure the opening they slide into is clean, and I use petroleum jelly on the o-rings....never had a problem , but then again, I never used Dorman either...

02-22-2012, 12:45 PM
Do these elbows start to leak for a reason? Common problem. Thanks for the diagram as it appears I need to repair this on my 2002 LeSabre. It is leaking pretty good.

02-22-2012, 01:30 PM
How much coolant is going to run out during this repair? Do I need or want to drain some or have a pan ready to catch it?

02-22-2012, 09:36 PM
Anything below the radiator fill cap will drain to the level of the item removed, or lower. If you are doing this in a garage, it would be best to put a drain pan under the car.

02-22-2012, 10:37 PM
I saw someone said use vaseline to get the new O-ring in. Would something like plumbers grease be better? I dug around the bottom of the radiator and I don't feel a drain. Is there one and I just haven't found it yet? BTW thanks for all the help.

02-22-2012, 10:54 PM
The drain is on the back side, (drivers side) of the radiator plastic tank. Clean the inlet ports with mild sand paper & use either Vaseline, or silicone lubricate spray.

02-24-2012, 05:43 PM
Well I got the new elbows on and so far no leaks. They actually slid in very easy. Too easy I thought. Thanks for the tips.

05-10-2012, 04:12 AM
I saw someone said use vaseline to get the new O-ring in. Would something like plumbers grease be better?<snip>

Plumbers grease is essentially petroleum jelly (Vaseline). Most plumbers use it because it's a lot cheaper than Plumber's grease and it does the same job.

For applications like this one, I usually apply a thin coat of silicone under the O-ring, then a small bead ahead of it on the outer diameter radius which both lubricates it going in and perhaps helps seal it. All I know is that it seems to work quite well for me so long as the parts fit properly. Therein lies the rub- with a good fit you don't need any help; with a bad fit nothing will work for very long.


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