: Dexcool/Peak coolant



lusen42
10-02-07, 07:42 AM
Hi
Its now a year since I changed coolant in my 99 STS 50000miles,
that time I used Dexcool.
Now I have drained most of it because of a alternator-bearing job.
When I went to bye Dexcool yesterday the shop showed me "Peak global
life time", they recomended it and said that they only use that brand now.
Do you guys think its a safe produkt or should I stick to Dexcool?
If I change to Peak could it be a problem if I still have a half gallon
one year old dexcool in the system.
/Swed

misfit6794
10-02-07, 09:22 AM
There's alot of info on this subject is you do a search on the forum. EVeryone here seems to have different opinions, here's mine. All the experiences I have had with dexcool (I've had several gm cars) have been negative. In both cars the coolant turned to mud after 20,000 miles. I switched to prestone (the kind for all makes and models) in those cars and in my northstar (after fixing my hg) with no negative effects, and the coolant didn't turn to mud. You can and should get ALL the dexcool out if you decide to switch. I recommend the prestone all make all model,and think dexcool is poison for the cooling system, but thats just me.

lusen42
10-02-07, 09:43 AM
Hi
I have searched for info of the specific PEAK coolant in this forum, but not
found anything. I like to follow GM recomendations and it seems like they
now recomend PEAK (in Sweden) instead of DEXCOOL so it would be nice to hear if some someone have any experiance (good or bad) of PEAK.
/Swed

Zorb750
10-03-07, 01:06 AM
It works fine.

It has a better anti-corrosion package than dex cool and a better pH value for aluminum engines. The lifetime thing comes from the design of the inhibitor package, though in my belief it hasn't been on the market long enough to make that claim.

dwight.j.carter
10-03-07, 07:12 PM
I am interested however I think this has been discussed before. I would gladly switch to it if they garauntee my head gaskets during that lifetime not to fail !

dwight.j.carter
10-03-07, 07:17 PM
Wow looks like it is an Ethelyne glycol base still. Ranger have a look and tell us what you think ? I just did my coolant in the spring and won't be doing it again for a while but like I said previously I would be willing to try it if they fix my car if it gets old and eats through the head gaskets.

Ranger
10-03-07, 07:59 PM
"A complete cooling system flush and fill is required. Follow vehicle's owner's manual for specified maintenance. For all limited warranty details, including maintenance requirements and claims processing information, please use our "contact us" form"

I'd be leary of any "Lifetime" coolant unless someone without a vested interest convinced me otherwise. Like GM perhaps.

Go to their site. http://www.peakantifreeze.com/peak_global_lifetime.html
Click on "Warranties" at the bottom. They only warranty radiator, heater core, thermostat & water pump and in no case shall they be liable for more than $1000.

Zorb750
10-04-07, 11:51 PM
Base is irrelevant. Ethylene glycol won't break down. It will still prevent freezing and boiling when it gets old.

Life is a function of the inhibitor package, and as I noted earlier, I don't quite believe it either. Seriously though, is changing every couple years too much to ask?

lusen42
10-05-07, 03:31 PM
Today I installed the alternator with new bearings and a new rotor.
The small bearing had rotated on the shaft of the old rotor so I had
to swap it.
I filled the system with PEAK and a can of "golden bar leak".
I hope this coolant is at least as good as dexcool.

Submariner409
10-05-07, 05:26 PM
I hope you diluted the PEAK to 60/40 or 50/50, whichever gets you to the lowest freeze point, probably around 60/40.

Ranger
10-05-07, 09:04 PM
a can of "golden bar leak".
I think you used the wrong stuff. You should use nothing other than Barsleaks tabs (HDC) or the powdered version (G12BP).

fubar569
10-05-07, 11:05 PM
I think you used the wrong stuff. You should use nothing other than Barsleaks tabs (HDC) or the powdered version (G12BP).

even my dealer had the gm tabs for under 5 bucks...i just got those and skipped all the crap...

Ranger
10-06-07, 10:45 AM
Just for clarification, the Barsleaks tabs and the dealer tabs are the exact same product.

Zorb750
10-07-07, 04:14 AM
I hope you diluted the PEAK to 60/40 or 50/50, whichever gets you to the lowest freeze point, probably around 60/40.

Lowest freeze point? I don't think so... you want the best compromise. Usually you want 50% mix because it is a good balance between carrying heat (more water is better) and freezing/boiling protection (more coolant is better). Will it be -30 degrees where you are?

MisterBlue
10-07-07, 08:30 AM
Oxygen sensors are VERY sensitive to silicone (it ruins them in short order). I figure the switch to Dexcool was probably prompted by the increased "leaking head gaskets" problem GM was experiencing. Ordinary (silicate-based) coolants can rapidly damage oxygen sensors if the coolant gets into the exhaust (which is highly likely). The Dexcool, containing no silicates, is far less likely to damage oxygen sensors.

Ranger
10-07-07, 12:11 PM
When a head gasket goes, the O2 sensors are the least of your problems. GM switch to Dex to make the cars more maintenance free, or at least stretch the intervals, which also adds a little safety factor for those who forget or tend to ignore the coolant change.

lusen42
10-07-07, 02:37 PM
ok I mixed peak 50/50 with water, the temp sometimes goes below -25 C.
About the can Bars leaks, it seems like that is how they sell barsleaks
here in Sweden, in us the same produkt is in a bottle with the text
"cooling system sealer and conditioner". I know that the tabs are recomended
but I belive that whats in this can fill the same purpose + some kind of lubrication that doesnt hurt the system.
(and i couldnt find any GM tabs here)
An interesting note is that the information on the can says that it only
protect against leaks for 12 months, is it possible that tabs are protecting
for a longer period?

Ranger
10-07-07, 05:00 PM
The tabs last as long as they are in the system. I am sure that is wrong stuff. The Barsleaks tabs will have a product code of HDC and the powdered version is G12BP on the package.

Submariner409
10-07-07, 07:35 PM
:xgrin: Zorb, read the first post. The car is in Sweden. It gets cold there. Look at the mix recommendations on a jug of DEX-COOL or Prestone alternative. Several ratios all supply adequate heat transfer from metal to coolant. There is a perfect mix, which is around 60/40 AF/water. Away from 50/50-60/40, freeze points change and so do pressurized boiling points.

Silicone, silica, silicates, silicon, and their other synthetic chemical alternatives are vastly different critters. Silicates are not silicones, and vice versa.

DEX-COOL is a trade name for a line of reduced-or-no silicate formulated ethylene glycol coolants which are designed to be mixed with clean water in ratios close to 50/50 for liquid cooled closed system mechanical application. It ain't rocket science. (We went from (GM) automatic transmission fluids labelled ATF, Type A, DEXRON(MERCON), II, III, V, and now VI.) When will we get DEX-COOL II?

parts68
10-09-07, 09:35 AM
When a head gasket goes, the O2 sensors are the least of your problems. GM switch to Dex to make the cars more maintenance free, or at least stretch the intervals, which also adds a little safety factor for those who forget or tend to ignore the coolant change.
Im beginning to have my doubts about Dexcool
On the left is 1 yr old mixed with distilled water
on the right is my 25K 4 yr old truck I bought new.
http://i42.photobucket.com/albums/e332/parts68/DCP_4078.jpg

Zorb750
10-10-07, 10:58 PM
Dexcool gets cloudy easily. You will be amazed by how acidic it gets though... That's one reason the 93-99 cadillac with dex cool has more head gasket problems than the 93-99 without it.

Ranger
10-10-07, 11:08 PM
Dex wasn't used till '96.

Zorb750
10-11-07, 02:37 AM
I know what years included what. Actually though, some early 1996 cars didn't have it.

I meant that pre 1996 cars switched to dex cool have a definitely higher incidence of failure than pre 1996 cars without it. Same goes for post cars that have been switched FROM dex cool. None of the shops I have any "connections" with seem to recall seeing a post 2000 car with anything but dex that they didn't install themselves. It should be worth noting that this acidity bit I wrote earlier doesn't apply to the Prestone Dex Cool Certified red stuff, just to GM's own.

lusen42
10-11-07, 06:43 AM
I have now driven the car a week with the Peak coolant and the "wrong"
bars leak produkt, and the last days its starting to running to cool. Its probably the termostat witch is stuck open or working slow.
From cold start the temp is increasing slow up to about 70 deg C.
I will change the termostat. But I am a little confused of how to do with
the coolant. I have to drain most of it when changing termostat, is it ok
to reefill it or should I buy more Peak and can I add more Bar leak??
I know its not good to overdose bar leak and I have a problem to know
how much of it that left in the system when I drain about 2/3 of it by the small alternator coolant tube.
/Sweed

Submariner409
10-11-07, 07:40 AM
Better find out from our resident Cad Techs who makes DEX-COOL before you diss Prestone. If you use an acid test strip in your acidic coolant, what is the Ph or acidity reading?

parts68
10-13-07, 08:56 AM
I believe its Havoline

LCLCLC
10-13-07, 05:19 PM
Dexcool has known problems when used in cast iron motors (non-alumium), and the coolant is allowed to become low in the system. Which exposes wet iron to air when stopped, which allows rust to form. This nasty looking bucket looks like rust to me.

Another problem I think happens, a system has the stop-leak 'pellets added multiple times, without a complete flush of the old coolant. When an overload of the stop leak occurs, Dexcool will look much darker and thicker. Don't overdo the pellets, flush the system well before adding new pellets.

If Dexcool is kept at the full mark, with the closed system completely full, which is how it is designed to operate, this will not happen.

If you have ever used 'green' antifreeze in a system, it will remain coating the system and changing back to Dexcool will not provide the long-life capabilities of Dexcool. In other words, in this case you should be draining the coolant every 2-3 years.

parts68
10-14-07, 09:12 AM
Dexcool has known problems when used in cast iron motors (non-alumium), and the coolant is allowed to become low in the system. Which exposes wet iron to air when stopped, which allows rust to form. This nasty looking bucket looks like rust to me.

Another problem I think happens, a system has the stop-leak 'pellets added multiple times, without a complete flush of the old coolant. When an overload of the stop leak occurs, Dexcool will look much darker and thicker. Don't overdo the pellets, flush the system well before adding new pellets.

If Dexcool is kept at the full mark, with the closed system completely full, which is how it is designed to operate, this will not happen.

If you have ever used 'green' antifreeze in a system, it will remain coating the system and changing back to Dexcool will not provide the long-life capabilities of Dexcool. In other words, in this case you should be draining the coolant every 2-3 years.



The brown stuff came out of my 4 year old truck,which I bought new,has never run low at the coolant tank.GM recommends change at 5/100
I changed at 4/24.Yes its an iron block and heads but air cant get in if it has always been above the add mark.
I never added stop leak or anything else to system before it was drained.

Ranger
10-14-07, 11:41 AM
That "brown stuff" may have been the cooling system supplement (sealant tabs).

parts68
10-14-07, 03:14 PM
That "brown stuff" may have been the cooling system supplement (sealant tabs).
Nope see the oranger(is that a word)stuff its one year old in Northstar with 2 large GM tablets.

JimD
10-14-07, 03:23 PM
If you still have a sample of the "rusty" coolant, do a test with a magnet. If nothing clings to the magnet, the discoloration can be almost certainly be attributed to tab material.

parts68
10-15-07, 08:49 PM
I dont know how many tabs the factory put in my truck but again the orange looking stuff
has 2 of the large GM tabs and its not yucky brown.
also I have found nothing that will cut this goo short of dynamite.

Submariner409
10-15-07, 09:06 PM
This is a brain-burner. The coolant in both my car and truck is clear yellow-orange. Car changed 3 weeks ago w/tabs. Truck OEM. No goo. Pull 12 oz. out of expansion tank with suction bulb, let settle in plastic container, no goo. Crack spigot at bottom of radiator: no goo.

Something's fishy.

parts68
10-16-07, 08:38 AM
I just had my truck in for warranty work(GMPP) and asked why I had some loss of coolant in tank
before I changed it(never went down to add mark but was close)and asked for them to check the intake
gaskets,which is a common leak area.Conclusion was no leaks...Still dont know why the yucky brown is there
other than aeration.My youngest worked at a GM dealership as tech and he saw alot of brown slimy Dexcool
if the radiator was run low and not purged of all air.