: Dex-cool or no?

Night Wolf
04-28-08, 04:36 AM
My mom is up visiting for a few days, I am going to be doing some maintenace/tune-up and brake work on their car. It's a '98 Park Ave with 88,360 miles (not supercharged :( ) 3800 Series II V6.

I figure it would be a good time to atleast drain/flush and refill the coolant...

Sticker on car says Dex-cool only... and I know it's controversal... but, should I keep the Dex-cool or flush it all out and put normal green stuff in it?

I know the two can't be mixed, but I remember reading if you really flush it out good, then you can change it over with no problems.

The coolant in the tank looks to be green though, and Dex-cool is normally green, although I know Prestone makes their new coolant which they say is compatible with all makes/colors of coolant... including Dex-cool, so maybe it was serviced with that in the past?

That coolant (which is the same stuff rebaged and sold under the Advance Auto Parts label for cheaper) is what I normally use in all my cars, so I guess it's a matter of... do I drain/flush it and fill with actual organge GM Dex-cool, or the Prestone all makes/colors coolant?

04-28-08, 06:26 AM
The biggest problem with Dex-cool is that since it has a high maintenance interval no one ever checks it.
It works fine if you keep the system full. If it gets low it does do some crazy stuff.
There is no reason not to re-use Dex-cool.
Don't believe everything you read.

GM's biggest issue with cooling systems isn't Dex-cool, its gaskets and other components that leak.
Don't believe everything you read.... except this! :lol:

Night Wolf
04-28-08, 07:34 AM
I looked at it again, the coolant in the recovery tank is green.

At Advance Auto, where I normally get my auto parts, they sell actual organge GM Dex-Cool, made by Prestone, then the all makes/colors coolant by Prestone as well which is green in color.

I'll drain it, flush it out with the garden hose then fill it up with the Prestone all makes/colors green stuff.... it's what I use in all my other cars, and its obvious it dosen't have the orange stuff in it now.... or any particular reason I should use the actual orange dex-cool?

04-28-08, 07:45 AM
It doesn't really matter, since there is green in it there would be no real advantage to using Dex.
Might as well go with whatever fits your budget.

04-28-08, 12:10 PM
I don't see any problem with it, just don't follow GM's recommendations for the "100,000 mile coolant flush". :histeric:

Keep it flushed every 30-50k and you'll be fine.

Night Wolf
04-28-08, 08:53 PM
Actually the sticker says 5yrs or 150k miles :)

Somebody has already changed it once, as they spliced in one of those flush kits in the heater hose... I already got the green Prestone all makes/colors stuff.

Didn't do much today... changed the air filter, PCV valve and seafoamed the crankcase, gas tank and then a 2nd bottle sucked in thru the intake via vacuum. I took the fuel filter out, but they gave me the wrong one, so new one will be at the store in the AM along with the cabin air filters.

I pulled the plugs, but they look pretty good, Autolite double platinum... plug wires have been changed too, car has 88k on it, so if they were changed at 50k, they have 35k on them? Really, I had the new plugs here, but couldn't justify putting them in as the old ones were really fine, so I returned them... maybe in another 20k I'll do them.

So tomorrow is finish the fuel filter, replace the cabin air filter, then the fun stuff, engine oil change, and drop the transmission pan, new filter, fill it back up add the trusty LubeGuard red, then drain/flush/refill the coolant.... then change front and rear brake pads.... should be good to go.

Oh, and the power seat, it's all the way down and when you move it up or down, motor just turns, so I am going to see whats going on with that, maybe pull the seat out.

But then tonight was a biggie... removed the spare tire cover to get the tire change jack (since my floor jack is supporting part of the house right now) and I was surprised to see water pooled up in the spare tire well... I looked at the trunk gasket and it looks fine... maybe a drain line? Anyone familer with these cars?

I drove it around a bit more... it's a really nice driving car... 3800 is great as always...plenty of power even in NA form. Has the GM feel that I pretty much gre up with... and the fuel mileage... I reset the avg fuel econ then drove about 10 miles "testing" and "diagnosing" them more after the seafoam was in to clean out the engine a bit.... and thru all that (driving thru town) it was averaging 23mpg.... quite amazing for such a car. The fuel info and gauge info is fun to play with tho, as well as having a tachometer.

Still though, I was happy to get back in the Town Car.... I dunno, I think I am finally getting used to that car, much like the '93 Coupe once felt like it was "me" the Town Car is now.... hard to say which is faster, I drove the Park Ave and was thinking to myself...wow, this is pretty fast.... then I get back in the Town Car and think to myself... nah.... this has got to be quicker.... who knows.... what I think I am getting at tho is that either car is a pleasure to drive, or own. I'll get a few pictures of it tomorrow.

04-28-08, 08:59 PM
Race 'em!!!!!

04-29-08, 02:11 AM
Dex Cool is alright, if you maintain it properly. I have had no problems with it. I change my radiator caps every year and always make sure I am not leaking.
Just make sure the last guy didn't mix the normal green gycol stuff with DEX cool, very bad. I don't even use the "mix with anything" crap.
I just get true Dex cool, unless it is for my truck then I go out of the way to get the normal green stuff.

04-29-08, 11:19 AM
I also say "don't believe everything you read" but I switched to the regular stuff too . I think Dex Cool was one of the major reasons why I had to replace the water pump .

05-01-08, 10:11 PM
Dex is actually easier on water pumps because there is no silicates to erode the seals.

05-02-08, 06:46 AM
One suspected issue with Dex-cool has been tap water.
Many municipal water supplies contain lots of minerals or other things that can react poorly to what is in the Dex.
I keep hearing GM is coming out with a pre-mixed Dex, which is more critical for some applications like the Hybrid truck.

If tap water gets used in a Hybrid the engine can "lose isolation" which would eventually cause the 300V system to shut off and the truck won't go.