Re-installed my complete 216 rebuild about 8K back. All new hoses of course, new stat, flushed and pressure checked original radiator and heater core. I thought it made sense to upgrade to the latest GM technology and use the Dex-Cool that GM has been specifying for the last couple of decades. As I posted to a buddy this morning, BIG MISTAKE!!!! Been having little cooing system problems, like little radiator leaks, heater core leaks, hoses vulcanized to the fittings and this reddish brown sludge in the radiator. Just now spent a couple of hours reading all the bad reports from mechanics and radiator shops about Dex-Cool, and the class action law suits that are pending. I wish now that I would have done my ‘homework’ before choosing Dex-Cool over plain old green EG. The worst thing was the destruction of the pristine original fire wall Mariner Blue paint. The radiator was leaking a tiny bit at the top, just enough that the level only needed topping off once or twice a year. But….those few drops were enough that it was blowing back in a spray and the acid in the Dex-Cool etched itself into the original paint. Before being sprayed with Dex-Cool or early on: http://www.pbase.com/dennygraham/image/115111615/large Last stage at time of repair: http://www.pbase.com/dennygraham/image/160023893/large
Dex-Cool was not intended for use in vehicles with cast iron blocks/heads. It also seems that acids are formed if the system is not completely filled, with no air at all in the radiator. If the system ever overheats, acids are prone to develop due to the chemistry of the coolant at high temperature. Plain old green ethylene glycol is probably the best choice for cast iron engines with copper radiators. Aluminum block/aluminum radiator systems with puke tanks and high-pressure radiator caps that keep the air purged out is what Dex-Cool was designed to be used with, and it seems that idea was only partially successful. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Not claiming to be an expert here, just tryin’ to give a heads up to anyone that might be thinking about using this stuff in their classic truck. This is just the results that I’ve had with Dex-Cool. I do agree with your take 100% on going green Jerry and yes, one of the pro’s is that Dex-Cool is easy on aluminum parts. And though it may not, have been intended for, but by some executive order, was used in and recommended for all the GM engines since 1996. Not all parts on all GM vehicles came with aluminum engines, some cast iron and some plastics are still being used and vehicles are still delivered with the red juice installed. My 2014 5.3 liter V8 Silverado does have cast aluminum heads and a cast aluminum block but….with cast-in iron cylinder liners, so there’s still a lot of cast iron in contact with the Dex-Cool in many parts of the cooling system. http://prestone.com/enca/products/antifreeze_coolant/product_list
In my case, the extended life antifreeze, or OAT (organic acid technology) antifreeze seems to be where the blame lies for the etching of the cowl paint, the culprit I believe is from the acid, 2-ethylhexanoate in the compound. My ’50, 216 truck has not been run low on coolant, has not over heated, does not have a recovery tank and uses a sealed 4lb cap. It is, however rubber, brass and cast, if that’s a problem. So far the water pump seal hasn’t started to leak and I don’t have any plastic gaskets. However I am seeing some clotting even with the low mileage that the engine has on it, that being, under 10K miles. So, I will be getting’ out the Prestone flush tools and chems and gonna do some serious clean up before I put a new stat and green goop back in the new set up.
There are literally hundreds of complaints about the damage that’s been caused in some vehicles. There have also been class action suits filed against GM which they have settled, that to me is an admission of some guilt. Here’s one such just randomly grabbed off the net from a few years back: http://www.stuevesiegel.com/ssh/res...hed-in-gm/dex-cool-class-action-lawsuit/ There are also hundreds of testimonials online from radiator shops all across the country and ASE certified mechanics as to the problems encountered with Dex-Cool.
Yup, Dex-Cool is nasty stuff. Even for engines it was intended for, eats the gaskets. Lower intake leaks are common on GMs with Dex-Cool in them, especially the 3.8 V6.
OK, the wife's '97 Buick with the 3.8 V6 is going to get a change to Prestone. Dex Cool was specified in the owner's manual and I have added a 50/50 mix of that when needed. I use Prestone in the '48.
33 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
On the Buick, make absolutely sure to flush the system out to remove as much of the Dex-cool as you can. When Dex-Cool mixes with old school green antifreeze, nasty things can happen. At best, it'll just sludge up and make a slimy brown mess. At worst, and I have seen this happen, it'll set up link concrete in the cooling passages. If you do change it over, I would suggest using the "mix with any", which is the Chrysler spec HOAT, and is a greenish-gold in color. Much better than Dex-Cool, works fine in old school systems, too. I've been running that in mine without any problems at all.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
....it may get me in the end but right now the 2000 Silverado has over 282,000 on it and has never had anything but Dex-Cool along with the wife's 06 Buick. Now DG, why did you have to start this thread? I won't get any sleep tonight!!!!!!
I have Dexcool in my 96 truck I've owned since new, and also my 97 Blazer. Haven't had any problems, but I also service the systems regularly. I also believe in what Hotrod Lincoln says, air in the system, or mixed with green anti freeze will cause problems.
Brian 1955.2 3100 Truck The older I get the more dangerous I am!!!!!
Sorry about the rant Jim, thought you were aiming that at me, I see you were just pullin' Alvins jeber in fun, I apologize. I've deleted my original reply.
We have had a few guys here recently that are constantly shooting arrows into the threads just to satisfy their egos rather than adding constructive comments.
OK, the wife's '97 Buick with the 3.8 V6 is going to get a change to Prestone. Dex Cool was specified in the owner's manual and I have added a 50/50 mix of that when needed.
Wally, Dex cool is the least of the problems on that engine. If you have been adding coolant w/ no leak found they tend to melt the upper intake manifold around the ERG tube from the lower manifold (just behind the throttle body). ERG tube is too close to plastic, melts into coolant passages to throttle body & sucks coolant into intake. #01-06-01-007C: Engine Coolant Consumption or Coolant Leak (Inspect for Material Degradation/Replace Intake Manifolds) - (Sep 20, 2007) Subject: Engine Coolant Consumption or Coolant Leak (Inspect For Material Degradation/Replace Intake Manifolds)
also the lower intake gasket to heads is a plastic w/ rubber inserts. Coolant passages @ center of intake (not on ends like SBC) so may not see external coolant leak but leaking into crankcase. Newer gaskets have metal w/ rubber inserts, hold up better. great engines other those 2 items.
BC 1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc 1949 GMC 250 project in waiting 1960 C60 pasture art Retired GM dealer tech. 1980 - 2022
....it may get me in the end but right now the 2000 Silverado has over 282,000 on it and has never had anything but Dex-Cool along with the wife's 06 Buick. Now DG, why did you have to start this thread? I won't get any sleep tonight!!!!!!
Don't shove them in the ditch just yet Alvin. And don't worry, many of us DO recognize and appreciate witty sarcasm when we see it. Carl
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
Is that in any way related to this sort of complaint BC?
dg
That's a 3.1 / 3.4 they are working on. Intake gaskets have the same plastic issues but the 3.8 vin K (series II) have the upper intake issue as per the bulletin. G.M. redesigned the lower (aluminum) intake in mid 1999 w/ smaller EGR tube so there is a gap between the EGR tube & the plastic intake, seems to have fixed that issue. There are aftermarket repairs for the issue.
BC 1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc 1949 GMC 250 project in waiting 1960 C60 pasture art Retired GM dealer tech. 1980 - 2022
Sure was simple back in the day, getting way to complicated now. I don't envy you wrench twisters these days, way to much to go wrong, and way to hard to get at anything to work on it.
Just refilled my 216 with clear water to flush out the Dex-Cool and now the water outlet goose neck is oozing. Didn't have time before supper to pull it off and see what's happened to the gasket, did check the bolts and they were tight. That was all replace roughly 8k back with the engine rebuild. Dex-Cool???? Don't know yet, but it wouldn't surprise me.
I would think the easiest way to change the dex-cool out would be a good drain and flush then refill with Prestone all makes/models/colors. That way if there is a bit of diluted dex-cool left it would be further diluted.
Yup, Dex-Cool is nasty stuff. Even for engines it was intended for, eats the gaskets. Lower intake leaks are common on GMs with Dex-Cool in them, especially the 3.8 V6.
This is true. I've had to replace the intake gasket on 3 different occasions. I had to replace it twice on the same engine before I learned my lesson. I avoid it. Jon
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
Denny, when did you install Dexcool. It was designed for aluminum blocks, and it has been in litigation for at least 12 years and GM reached settlements in 2008 before their bankruptcy.
I have used Fleetguard 50/50 for over 15 years in everything and have had absolutely no problems with it. I buy it by the 55 gallon drum, but it is available in gallons.
