: Dex or Age? Your Thoughts?



Ranger
10-02-10, 10:15 PM
The following is on my wife's '96 Bonneville with 170K on it. It started leaking coolant quickly and badly. I diagnosed it to be the plastic coolant heater bypass pipe pictured in the diagram below. I have also included pictures of the pipe as it was removed in 3 pieces (the O rings are off to the side). Both ends separated under the O rings and you can see the new pipe for comparison. They where not clean breaks and were not broken on removal. The obvious question now becomes was this a casualty of 14 years of heat/cool cycles or are the Dex-Cool nay sayers on to something?

RippyPartsDept
10-02-10, 11:02 PM
we replace them a bunch... i'd say age

Ranger
10-02-10, 11:07 PM
Yeah, the dealer I bought the part from said they replace a lot of them as well.

JimD
10-02-10, 11:08 PM
....The obvious question now becomes was this a casualty of 14 years of heat/cool cycles....That would be my "guess". Maybe the Buick engine group should have specified an aluminum part?

There is more than enough evidence that plastic composition parts cannot survive the heat/cool cycles and vibration forever. Radiator end tanks, reservoir containers and other non-metallic pieces will fail.


....or are the Dex-Cool nay sayers on to something?Not in my experience (with Northstar engines) and feeble mind .

RippyPartsDept
10-02-10, 11:10 PM
maybe something to do with it being a 90degree angle?

i've found that all engines with this part (3800s and maybe a few other) will need one eventually... usually

Ranger
10-02-10, 11:20 PM
I doubt the 90 had much to do with it as it was the ends that failed right at the O ring groove. At 14 years and 170K I guess I can't really complain except for the design. Sure seems to me they could have made it a little simpler. Had to remove the alternator and the tensioner. Still licking my wounds.

Submariner409
10-03-10, 09:36 AM
I doubt the 90 had much to do with it as it was the ends that failed right at the O ring groove. At 14 years and 170K I guess I can't really complain except for the design. Sure seems to me they could have made it a little simpler. Had to remove the alternator and the tensioner. Still licking my wounds.

"the o ring groove" looks like the culprit - not enough meat there.

...................if we're really honest about it, no matter how many different cars we've owned, the cooling systems have always had bugaboos, whether copper, brass, aluminum, silicone, rubber or plastic - or any composite thereof.

drewsdeville
10-03-10, 10:23 AM
^^^ yeah.

If the magical/supernatural Dex "ate" plastic, wouldn't all of the bottles on the shelf at the store leak?

The plastic heater hose T's on the 4.x's all break at some point, most with green coolant. Ford also has a similar fitting on the 4.6 panthers that always break. Dex has nothing to do with it.

johnny kannapo
10-03-10, 10:56 AM
170K & 14yrs logged, age & the weak point at the "O" ring groove are reasonable causes but you have to wonder if dex contributed to the degradation of the composite. The recent cooling system work I did I had a about 1/4 to 1/2 inch of diluted coolant mix in this dish washer pan for 2 to 3 weeks under the bench and when I went to dump it look what happened to the dish pan.

http://i826.photobucket.com/albums/zz183/billytheshoe/100_1599.jpg

I have used this pan for many hot oil changes and has always been flat on the bottom. I know this is a different typ of plastic but the Dexcool distorted the heck out of it.

http://i826.photobucket.com/albums/zz183/billytheshoe/100_1596.jpg

RippyPartsDept
10-03-10, 03:33 PM
dex does have some chemicals in it... not any plastic should be used...
that pan is obviously not made of the same plastics that are used on the parts in question