OK, lately i have been doing a lot of research into dex-cool issues. i must first say, that for many years i have always used, trusted, and stood behind dex-cool, but more specifically prestone "dex-cool", not the havoline dex-cool installed from the factory in gm,and some chrysler engines. i have not actually seen real hard research backing up that dex-cool is bad ans harmful from the get-go. 99% hear-say and speculation. i have, and continue to convert everything from my 86&90 toyotas, to my yamaha banshee, sno-go's, gen-1 firebirds, and all the gm-isuzu built engine cars and trucks i own....all with great, unparalleled results as far as longevity, and protection. i can also tell you, that the plastic gasket issue is not isolated to dex-cool era gaskets. i have replaced several deteriorated gaskets, basically looking identical to the ones posted in all 90's engines. the only difference with the engines running conventional coolants, is the white colored film deposit, rather than orange........the only difference.....i don't know why others have not come forward with this finding, because I'm sure it's not my own little world, that they all have come through my shop, and none others. perhaps, like i have before, everyone just chocks those up to overheating, and uses dex-cool as a scape-goat, on vehicles, which it was introduced from the factory. a prime example- my mother-in-laws' car, is a 91 buick century with a 3.1 bought new, and perfectly maintained by my (also life-long mechanic) father-in-law, and myself. it has always run on conventional coolant, and seen 4 water pumps, some thermostats, radiator hoses, radiator, etc, in a 180,000mile period, and still running like new, aside from the cooling system issues. i also bought a 95 sonoma with a blown head gasket and failing water pump, running conventional. now, i have also owned, and worked on/seen several "dex-cool era" vehicles, with 60-200k miles, and zero cooling system issues, save for 1....my 2001 tahoe ltautoride......and i know with 99% certainty why the water pump began to weep. the story is, that i bought this truck, and decided that i want to leave all maintenance to the lube center and .....trust.....them.....well, once i discovered the weeping pump, i decided to check the coolant condition my self, and boy, was i perturbed at what i found. the dex-cool had, indeed began to break-down. i went back over the service records and found, alarmingly, that the test results had randomly, but gradually, been logged as getting better over an 8 month period...[censored]??....it started at a point of borderline unacceptable, and soon due for service, to nearly new condition.......anyways, i digress.....the point of the matter- i believe the "issues" lie in the following conditions.
first- havoline lied to gm and chrystler, telling them what they wanted to hear from a marketing stand point- the coolant can actually last the average life-span of a vehicle, when, in reality, it had not been established to perform so, rather estimated. secondly, the big problem is lack of regular maintenance, and monitoring, as you should be doing with any coolant......all fluids, for that matter. sure, it may be possible to run the said life-span, in the right conditions, but you would simply be reckless not to check and make sure, at least every oil change.....
here is how i view it-
dex-cool (prestone, at least) is just about the best coolant you can use, with excellent lubrication, and the best cold-weather stability (aside from the exotic coolants, i.e. alcohol base) just like conventionals, it does break-down with use and heat. however, just as conventional will convert ph and eat away at your coolant system, so will dex-cool elc...adversely to this effect, the same as it is more effective than conventional, so is it more damaging when broke-down. i think that, years ago, gm could have saved tons of headache for both them, and consumers, simply by changing the stickers, and updating the owners manuals to follow my guidelines....
my advise, as it has been for years......
flush and fill (not just change) your dex-cool with prestone dex-cool and have it checked every oil change, and full tested yearly. change the coolant every 3 years, 4 at the most. even sooner if it shows signs of break-down.
well that's my long and short of it for now......thanx for reading
-Heath H-
