coolant question

[louisgtp]

im new to these forums and im a new owner of a 98 gtp, i hope you guys can help. i just checked my coolant and it was dark like almost black. it says dex cool only so is this normal for dex cool. the car runs fine it dont overheat.

[blueguy]

Welcome to dex-sludge.

And owning a non-touched GP.

Might run good, doesn't mean it is right though, I suggest a full flush at a place that has a vacuum system to get all of that crap out of your car, then re-fill with some regular green or yellow stuff.

[louisgtp]

Thanks

[BillBoost37]

May also be that someone added some green to the dex. It'll turn dark and ugly when that is done.

[kyrebel]

What most people dont under stand isthat.dex-cool which gm advertises as a lifetime coolant is severly corrosive to aluminum there for to continue touse dex-cool is only asking for problems another thing that many dont know is that when the dex-cool is mixed with conventional green as mentioned by billboost it does gel and if the temperature reaches cold enough of a temperature that gel will freeze ultimatley seizing the motor

[SlowNA06]

What most people dont under stand isthat.dex-cool which gm advertises as a lifetime coolant is severly corrosive to aluminum there for to continue touse dex-cool is only asking for problems another thing that many dont know is that when the dex-cool is mixed with conventional green as mentioned by billboost it does gel and if the temperature reaches cold enough of a temperature that gel will freeze ultimatley seizing the motor

Dexcool in no way interacts with aluminum.

[sseilmnop]

Severely corrosive to aluminum????
Dex-cool is mixed with conventional green .... it does gel????
gel will freeze ultimatley seizing the motor?????

Never heard of any of these.

What I've heard.
Dexcool cool will slime up if left in motor over 5ish years.
Dexcool may help deteriorated lower intake plastic gaskets.
Dexcool can block flow in radiators or heater cores when it turns to slime.

[blueguy]

Dexcool sludge isn't a MYTH by any means.

It causes problems because people neglect their cars, hence it gunking up, getting hot, melting LIM gaskets, and coolant puking into the rotating assembly chucking motors.

If you were to get updated Aluminum Lower Intake gaskets, flush and vacuum the radiator with Dexcool every year or two...I'd bet you wouldn't have any issue...ever.

It's called maintenence...people need to learn it, that's all. Friggen' lazies.

[sseilmnop]

GM recommends service at 5 years or 150,000 miles I bought my 03 Bonneville before it was 5 years old and less 150,000 miles and it was already slimed. The glycol based antifreeze never had this problem. If you look on Wikipedia gm had problems with LIM gaskets on 3.1, 3.4 , 3.8 etc all attributed to dexcool. There have been several lawsuits and gm has settled them.

DEX-COOL specifically has caused controversy. Litigation has linked it with intake manifold gasket failures in General Motors' (GM's) 3.1L and 3.4L engines, and with other failures in 3.8L and 4.3L engines. Class action lawsuits were registered in several states, and in Canada, to address some of these claims. The first of these to reach a decision was in Missouri where a settlement was announced early in December 2007.[17] Late in March 2008, GM agreed to compensate complainants in the remaining 49 states.[18] GM (Motors Liquidation Company) filed for bankruptcy in 2009, which tied up the outstanding claims until a court determines who gets paid.[19]

According to the DEX-COOL manufacturer, "mixing a 'green' [non-OAT] coolant with DEX-COOL reduces the batch's change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine."[20] DEX-COOL antifreeze uses two inhibitors: sebacate and 2-EHA (2-ethylhexanoic acid), the latter which works well with the hard water found in the US, but is a plasticizer which can cause gaskets to leak.[13]

According to internal GM documents,[citation needed] the ultimate culprit appears to be operating vehicles for long periods of time with low coolant levels. The low coolant is caused by pressure caps that fail in the open position. (The new caps and recovery bottles were introduced at the same time as DEX-COOL). This exposes hot engine components to air and vapors, causing corrosion and contamination of the coolant with iron oxide particles, which in turn can aggravate the pressure cap problem as contamination holds the caps open permanently.[21]

Honda and Toyota's new extended life coolant use OAT with sebacate but without the 2-EHA. Some added phosphates provide protection while the OAT builds up.[13] Honda specifically excludes 2-EHA from their formulas.

Typically OAT antifreeze contains an orange dye to differentiate it from the conventional glycol-based coolants (green or yellow). Some of the newer OAT coolants claim to be compatible with all types of OAT and glycol-based coolants; these are typically green or yellow in color (for a table of colors, see [12])