aka_jsn1

I just had a chat with a friend of mine who's hearin all kinds of bad things about dex-cool engine coolant. He has a friend who had dex-cool gum up the radiator, pump, block, you-name-it, on his new(er) camaro; and he's also heard that GM dealers are dumping the dex-cool and replacing it with the good-ole green stuff when cars come in for service under warranty.

Can anyone confirm the evils of Dex-Cool coolant? Since my manual says 'ownly use dex-cool' and I just replaced all the coolant with Dex-Cool a month ago, I'm hesitant to flush the system and switch to the green right now... But I'd also rather not replace my water pump again.

????

jsn

69mako

I flush my system every other year and add Dex-Cool....I never have had a problem with it :cheers:

Hope that helps, Larry :steering:

6spd89

I think it stinks!!!! Had it in my 97 ext. cab.Injectors went bad along with intake
gasket. Upon removing intake the rear water passages were almost completely blocked off with some kind of crud!!!! I flushed it out for at least an hour,until it ran clear. I also had heard the dealers were changing back to the green stuff. Its been green now for a year and no probs. By the way, the thermostat was corroded as well and replaced it w/ a new one. My .02
No war intended here,just stating what my truck looked like.
Matt

69mako

After the first of the year I will see what my intake manifold's water passages look like when I take off the intake to change out the gaskets.

I'll report what I find :thumbs:
Larry :thumbs:

ELEVENS

Check the archives for some good threads. Basically, stick with what the car came with originally. And avoid cross-mixing and all costs, even though the Dex-Cool jug says that you can. If you want to switch, make sure you drain every last bit - radiator & both sides of the block, then flush well. Some claim mixing the coolants will cause gelling problems. There are also reports that Dex-Cool isn't as efficient at transferring heat (cooling). Maybe a coolant expert can jump in here.

Tony.96LT4

Switched mine over to the green stuff after warranty ran out. This was on the advice of the mechanic at my Chevy dealer. I had no problems before but had good information that the Dex-Cool was not good for the heater core. I haven't seen any difference in cooling but I do have a little more piece of mind. :crazy:

Marcho Polo

Dex-Cool when not maintained properly will clog up heater cores. If your coolant level drops too low, the air in the system acts as a catalyst and the dex-cool begins to gum up.

I had this problem on my '99 Jimmy and saw the GM TSB's on this. Took me all day to flush with a special powdered flush and then neutralizer. Yes, going Green is one alternative, but as long as you keep an eye on the level, dex-cool will be fine.

Marcho Polo

oh, and here's the TSB: (Adobe Acrobat required)


http://home.flash.net/~reggy/TSB_Clean%20Coolant.pdf


You must do exactly as it says to clean the system out. Trust me!


:yesnod:

L98 DRIVER

my .02
wife's 98 Buick has 125000m on dex-cool, no problems :yesnod:

CowboyNVette

I'm just wondering if that may be the problem with my cooling system. I have a 96 that has the original coolant in it. except for changing it yesterday. In the past I would add coolant when needed but only when it was needed. Now lately my cooling system has been running a little above normal, 197 = normal 205 = little above normal, so I had the shop change out the lower radiator hose and the thermostat. I installed a 180 degree stat this time. On the way home from the shop my temp got up to 195 and stayed there. I know the fans don't run when you are on the highway at highway speed so why did my temp go up to 195? Wouldn't it seem to run around 185 or so?

Springer's LT4

The original T-stat was a 180 in an LT car. Mine with a 160 in it runs 173-175 on the highway.


Both my 95 and my 96 have had no problems with using Dex-cool.


[Modified by Springer's LT4, 8:21 AM 12/17/2002]

CowboyNVette

Well I be damn I thought I was lowering the thermostat temp :mad But I wasn't thinking at the time I was at the parts counter :lol: Then there was something wrong with my old stat then cause I was running 203 - 205 lately...now I am running 196 - 197.....I would change the stat out again but I hate to drain the damn coolant again. :smash:

larryfs

My 96 Impala had 5 clogged heater cores.
my 96 LT4 vette seems ok....

93LT1

Cowboy
I just replace my thermostat. In the past I was running at 172-174 during highway speeds and slowly but surely it was at 190-200.
Here's a good test. Just heat up some water and verify it's at 160 (used my meat thermometer) and see if the thermostat fully opens. I tested the new unit and it fully opened at 160. Tested the older unit and it began opening up at about 190 and never fully opened.
Hank
By the way, it took me 20-30 min to replace the thermostat. It's really easy.


[Modified by 93LT1, 10:32 PM 12/17/2002]

Dan Parker '96

No problems on my '96 Vette. Original Dex Cool just drained out for impending rebuild. It tested to below zero and all my heating/cooling works just fine at 104K. Always maintained level though.... and there was little of that. I'll see how much gunk comes out after the flush. Not expecting excessive amounts.

CowboyNVette

Mine was normally running at 196-197 degrees on the highway with the stock thermostat but lately has been creaping up to 204-205 degrees even in cold weather. I then went a bought a new thermostat ( thanks to everyone here on the forum) and I thought I bought a lower temp model. But, being absent minded when i was at the parts store I got a 180 degree stat which is stock. :cuss I could not replace it last weekend as planned so I took it to a local shop and had them to replace it for me. After replacing mine it started running 195-196 again, which had me puzzled at first till someone here on the forum pointed out that it was a stock stat... :lol: Now I am releaved that my car is running correctly again.
I wish I had asked for the old thermostat so I could have seen what was wrong with it. It would have been nice to see if it was broken, stuck or just wore out.

Can you change the thermostat without lowering the coolant level? I know I can in my moms pontiac but I am not sure in this reverse flow vette.

93LT1

Can you change the thermostat without lowering the coolant level? I know I can in my moms pontiac but I am not sure in this reverse flow vette

No. There's a platic screw plug in the radiator. Just slightly open it and let some fluid drain out. About 3/4 of a gal. I used my oil pan to capture the fluid.
No mess what so ever.

silver & red CE

This is because the dealer kept putting those clay pellets in after they replaced the core, how dumb can they be? Replacing the heater core because it's clogged with clay makes no sense and doesn't fix the root cause of the problem. The clay pellets will clog the Implala's heater core. My Impala needed a new radiator under warrenty, soon after my heater core clogged. I had to flush my cooling system 3-4 times, but I finally got all the clay crude out. I've replaced the radiator a second time but still have my original heater core.

Eric
Running Dexcool in both my 96 Vette and my 96 Impala, no issues because I do all my own work and don't use those clay pellets.

larryfs

dealers can be pretty dumb. the problem is even the service manual. I'm changing the waterpump in my 95 GMC van. the FACTORY SERVICE MANUAL says to use the clay tablets after a water pump change, or premature waterpump failure can occur. can you believe that hogwash.

after 5 heater cores and a waterpump in my impala, they still refused to flush the system. I figure by the 5th heater core, all the clay stuff was filtered out. who knows, it's been good for 2 years now.....