GM Delco Cooling System Pellets

[JZRIV]

I know Dennis Manner always recommended dropping a couple of these pellets in the radiator in our old cars to prevent small nuisance cooling system leaks. Not that I question Denny's suggestion, just wondering if anyone here uses them what your experience was.

 

Thanks

[EmTee]

Do it -- they work!  My father had an 83 Eldorado with the HT4100 aluminum V8.  They were known 'leakers' and the GM answer was to use the seal tabs.  Fast-forward to about 2 years ago and I noticed a slow, but steady loss of coolant in my 2004 Silverado.  After being unable to locate any external leaks I started reading and discovered that I was apparently experiencing the dreaded LS head casting crack.  Sure enough, saw some 'cream' on the inside of the oil filler cap.  I bought a package just like the one shown above and in under 200 miles the leak stopped.  I have not added a drop of coolant since.  I did a couple of 'short' oil change cycles and once the oil came out clean (no chunks) I went back to my usual interval.  Now at 216,000 miles it's still smooth as silk and doesn't use any fluids.

 

Within the last year, my wife's 2006 PT Cruiser with 130K miles developed an intermittent leak.  Sometimes it would need a pint of coolant, then go weeks without needing any.  After about a year of this (and a gallon of antifreeze) I figured I'd give the seal tabs another try.  So I did -- and just as before, the leak stopped for good.  The best part is the active ingredient -- ginger root!  (You could probably eat them if you had a package in the glove box and got snowed-in somewhere for a few days!) 

Edited May 8, 2017 by EmTee (see edit history)

[PWB]

Take two of these and call me in the morning!

 

 

 

[dship]

Buick recommended that my previously owned '96 & '97 Riviera's and my currently owned '91 Reatta and '92 Riviera (all with the 3800 V6) receive a radiator flush every two years along with adding the cooling system seal tablets.  I've been using the tablets for many years.  Funny you bring this up as I had this conversation with Dennis at the BHA dinner in Allentown last year (we were seated at the same table).  He is kind of the guru of the 3800 V6. 

[1965rivgs]

I have used them many, many times but from a different source. I occasionally use these in fleet work to stop or slow down pesky coolant leaks which are very labor intensive to repair.

The issue with the 4100 Cadillacs was due to head gasket issues diluting the oil and causing huge problems. My mother-in-law had a new `82 DeVille which the dealer "fixed" with these pellets via a recall. The engine puked at 80K in spite of impeccable dealer maintenance and highway miles.

I suspect GM uses them to prevent the combination of a small coolant leak and an inattentive new car owner from producing engine warranty claims. Does this justify their use in a collector car with an attentive owner?

In some cases the "fix" is temporary as in an intake gasket which is grinded/torn due to movement of the block versus the manifold due to expansion and contraction. In more static circumstances the results will be longer term.

And any stop leak used in excessive quantity will plug small orifices which should not be blocked, like heater cores.

  Tom

[EmTee]

12 hours ago, 1965rivgs said:

And any stop leak used in excessive quantity will plug small orifices which should not be blocked, like heater cores.

 

Although I generally agree and do not normally recommend 'band-aid' repairs, I make an exception for these seal tabs.  Being 'OEM blessed' sets them apart from the other fly-by-night concoctions hawked on store shelves.  Also, if you look at these up close, they are actually a VERY fine powder that is pressed into a tablet.  In fact, generally one has to break them up into smaller chunks to get them through the radiator filler neck.  My point is that as long as there is sufficient flow through the core, I don't see these causing any restrictions on their own.  If there are mineral deposits significantly reducing flow, then I suppose the powder could see the situation as a 'leak'.  For prophylactic purposes I would probably only add 3 of these at a time.

[1965rivgs]

"If there are mineral deposits significantly reducing flow, then I suppose the powder could see the situation as a 'leak'.  For prophylactic purposes I would probably only add 3 of these at a time."

 

I agree...

  Tom Mooney