Dex-Cool: Good or Evil?
Thread Starter
Intermediate
Joined: Oct 2002
Posts: 29
Likes: 0
From: St. Louis MO
Dex-Cool: Good or Evil?
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
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
Burning Brakes
Joined: Feb 2000
Posts: 1,206
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From: USA USA
Cruise-In II Veteran
Re: Dex-Cool: Good or Evil? (aka_jsn1)
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
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
Race Director
Joined: Jan 2000
Posts: 16,487
Likes: 25
From: USA. Northern Virginia
Re: Dex-Cool: Good or Evil? (6spd.89)
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:
I'll report what I find :thumbs:
Larry :thumbs:
Burning Brakes
Joined: Oct 2002
Posts: 835
Likes: 3
From: Water Winter Wonderland
Re: Dex-Cool: Good or Evil? (aka_jsn1)
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.
Burning Brakes
Joined: Apr 2001
Posts: 994
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From: Jamison PA
Re: Dex-Cool: Good or Evil? (aka_jsn1)
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:
Le Mans Master
Joined: Mar 1999
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From: Fort Worth Texas
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Former Moderator
Cruise-In I-II-III Veteran
Re: Dex-Cool: Good or Evil? (Tony.96LT4)
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.
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.
Le Mans Master
Joined: Mar 1999
Posts: 9,659
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From: Fort Worth Texas
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Former Moderator
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Re: Dex-Cool: Good or Evil? (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:
http://home.flash.net/~reggy/TSB_Clean%20Coolant.pdf
You must do exactly as it says to clean the system out. Trust me!
:yesnod:
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Le Mans Master
Joined: Feb 1999
Posts: 5,381
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From: Pineville, Louisiana
Re: Dex-Cool: Good or Evil? (L98 DRIVER)
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?
Safety Car
Joined: Jul 2001
Posts: 3,524
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From: Pinellas Florida Misfit
Cruise-In III Veteran
Re: Dex-Cool: Good or Evil? (CowboyNVette)
I installed a 180 degree stat this time
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]
Le Mans Master
Joined: Feb 1999
Posts: 5,381
Likes: 0
From: Pineville, Louisiana
Re: Dex-Cool: Good or Evil? (Springer's LT4)
I installed a 180 degree stat this time
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]
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]
Pro
Joined: Aug 2000
Posts: 700
Likes: 1
From: Florida
Re: Dex-Cool: Good or Evil? (CowboyNVette)
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]
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]
Drifting
Joined: Jun 2001
Posts: 1,997
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From: Lake Ozark MO
Re: Dex-Cool: Good or Evil? (aka_jsn1)
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.
Le Mans Master
Joined: Feb 1999
Posts: 5,381
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From: Pineville, Louisiana
Re: Dex-Cool: Good or Evil? (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.
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]
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.
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]
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.
Pro
Joined: Aug 2000
Posts: 700
Likes: 1
From: Florida
Re: Dex-Cool: Good or Evil? (CowboyNVette)
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.
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.
Melting Slicks
Joined: Jan 2000
Posts: 3,418
Likes: 1
From: NW Chicago Suburbs
Re: Dex-Cool: Evil? (larryfs)
My 96 Impala had 5 clogged heater cores....
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.
Safety Car
Joined: May 2002
Posts: 4,010
Likes: 26
From: Somewhere nowhere
Re: Dex-Cool: Evil? (silver & red CE)
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.....
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.....
