| Ignorance is bliss for some as seen in these last few posts. I have
| had to change a radiator hose in over 20 years with low pressure
| Those high pressure caps are for those that may just run water or
| enough antifreeze to raise boil point of mixture against hot metal.
| Detroit tries to build idiot proof cars and the high pressure cap is
| part of that. Just like the Dexi problem. "Dexi" was a attempt to
| money by staying with 50/50 coolant with a mixed metal engine. When
| spread over millions of cars it adds up. Many have seen cooling
| problems for Dexi if it is not flushed from time to time but I have
| zero problems with Dexi because I run 60/40 or better with it. I
| a 2000 that I bought new that I have never flushed or replaced
| but I did increase it to about 70/30 when new. Coolant still looks
| new and radiator tank and even overflow bottle is still clean as
| You can run in the "box" with the herd or think outside of the "box"
| here. The choice is yours.
There are reasons why the pressure cap installed at the factory is
Let me state right now that I am NOT an expert and am replying only to
increase the general knowledge surrounding the original subject and to
lend my years of learned experience to the general discussion about
thermostats, pressure caps and Dexcool coolant.
First, the thermostat installed in G.M. engines are ALL 195 degree F
regardless of whether the engine is gasoline or diesel. Back in the
1970's, (I've been issuing G.M. parts since 1973), G.M. did offer a
180 degree thermostat for some applications but have not offered an
alternate for many years.
Federal emmission laws dictate the 195 degree thermostat based on
meeting emission control standards and how the engineers designed the
emissions systems to meet the federal emission laws. G.M. engines
must operate at 195 degrees F in order for all of the emission control
devices to funtion properly in order to meet federal emission control
To delay the water / coolant mixture from boiling off, it must be
under pressure as additional pressure raises the boiling point of the
coolant mixture. Pure water boils at 212 degrees when not under
pressure and that boiling point increases to 257 degrees when placed
under 17 lbs of pressure.
Dexcool is very corrosive in nature and using a mixture greater than
50/50 will increase (not decrease) the electrolysis process of the
different metals involved (iron, steel, aluminum, brass and copper).
I have serious doubts about the claims being made above as genuine and
completely truthful. Because Dexcool is corosive by its very design,
having a pristine cooling system without any maintenance (as claimed
above) leaves a big question mark in my mind as to the poster's real
Dexcool degradates both aluminum and solder (a tin / lead mixture) and
is the main cause of cooling system leaks when the 50/50 mixture
recommendation is not followed.
If there is an automotive engineer reading this thread, please expound
on my tiny bit of knowledge and correct any statement that is not
correct. My intention is not to mislead, but I may be misinformed or
may be skewering facts based upon my personal knowledge. All I have
is the years of experience listening to certified and master
technicians during the act of specifying parts for them to install to
An alternative to using Dexcool is the AMSOIL coolant which is
propylene glycol based. It is biodegradable, and, unlike Dexcool, has
a low toxicity. AMSOIL coolant has a recommended life of 250,000 when
used in automotive and light truck applications and 750,000 miles when
used in OTR applications.
To find out more about a Dexcool alternative, visit the link below:
Independent AMSOIL Dealer
Click to see the full signature.