FYI: Plastic Part in Cooling System

I recently had a problem with my 1994 Park Avenue I thought I would share. While driving I had a low coolant light and gradual overheat. Turned out that a plastic fitting that connects a small cooling line between the water pump and the throttle body had sheared off level with the surface of the throttle body--a brittle fracture failure. The fitting is located behind the generator. It does not appear to be under stress so I don't know why it failed, apart from old age. I got remainder of the part out with a screw extractor and replaced the fitting and hose. The replacement fitting I got from the dealer ($20) is made of metal so I assume GM was seeing a high failure rate on the plastic version. If you have an older PA and are into proactive hose changes you might consider changing this plastic fitting as well--or enjoy an unscheduled hike as I did.

Do you have any idea how many threads about the bypass hose fitting we have on here? I can count 5 off the top of my head.

Anyhow, the part fails because the 195 degree coolant flowing along it all the time deteriorates the plastic.

Just for your info I replaced the same plastic fitting yesterday on my 94 Lesabre Luckily I saw it while I was replacing a 6 Mo. old rebuilt Alternator so it probably saved me a breakdown on the road, I never would have believed it was a plastic (Nylon/pvc ????) fitting, so who knows I may have pried on it changing the Alt. mine has 209,000 miles on it, So I guess its a lesson in the school of hard knocks on where and when to pry.
Also its a dealer item, takes 1 1/8 " box wrench to remove and cost me 13.13 + about 4.00 for the hose and clamps.
Rick

Rick,

Thanks for the reply. Glad you caught the bugger before it caught you. Congrats on getting 209K+ miles out of your LeSabre!

Tman or other,

A question/suggestion: Is there any place in the forum where premature/on-the-road failures are consolidated and listed? Given the number of these bypass hose fitting failures, it seems like we should be able to predict how long this part should/can last.

In my caveman opinion, the fitting failure mode is probably low-cycle fatigue from thermal stress. Probably proportional to mileage, but depends on the type of driving--e.g., highway miles would result in more miles per thermal cycle and a longer life. My fitting lasted 120K miles with probably 50% highway and 50% city miles.

For example, if the forum had 6 data points with fitting failures between 80K (I made that up) and 209K (Rick's) with an average of 120K (I made that up, too)--I think that would be useful data to collect and share. The raw data would be helpful; or maybe Weibull analysis is possible to provide a more scientific prediction of minimum expected service life.

Recalls and normal recommended maintenance cover most of the major issues, but it seems like this forum represents a lot of collective knowledge on unexpected problems. It would be nice to have a list of failures to watch for on a 3.8L motor with 100K, 150K, 200K, etc, miles. Sorry if such a list already exists and I am missing it (like I missed the other bypass hose fitting posts). I only have enough time to be a casual forum user, but try to contribute what I can.

Mike

Mike, we currently have no such thing, however, I have no time to devote to it, so if anyone wants to take the challenge, I'll be glad to post it as an important thread.

I had that plastic fitting break also, went to Sears Hardware and found a brass fitting, 5/8" barbed hose to 3/4" pipe thread. They had a clearance sale and the fitting cost me .99 Cents.

I need to do some proactive hose repairs. Believe it or not, I am still using the factory original radiator hoses on my 91 PA. I inspect them regularly and none have cracks or any bulges that would make me worry. I should probably go ahead and replace those... Is this plastic part present on earlier models?

The fitting broke on my '92 PA 3.8 with 106000 miles