Which antifreeze/coolant do you use?

[Bell Curve]

Originally Posted by 95ZR1#418

About a month ago I read a number of antifreeze threads and freaked out! Last year I had installed all new hoses, clamps, new 180 (& drilled out, as explained on ZR-1 FAQ) stat, & flushed the system. I then used distilled water, water wetter and 10% Prestone. So big mistake using Prestone (as I had read), it has taken a month but I will be receiving my GM antifreeze tomorrow via GM Direct. Then I will re-flush the system and make it 10% with the GM green stuff...I don't drive it in freezing weather & it stays in a heated garage.

So I think I have it right, finally...

Prestone doesnt make any type of the good stuff

[95ZR1#418]

Originally Posted by Bell Curve

Prestone doesnt make any type of the good stuff

The posts I read, everyone agreed that the Prestone is essentially Dex Cool.

[Hib Halverson]

Straight water + 1.5 bottles of Red Line Water Wetter changed every two-three years.

170° thermostat

Stock hoses

Fluidyne radiator

Lower fan on temps

[vilant]

I used Turbo Power. Was at Pepboys and meets GM 1825M specs.

[lfalzarano]

From an old post from Marc

Join Date: May 2007
Location: Addison IL
Posts: 195
Default Coolant Recommedation
The question often comes up about what is the best coolant for the LT5 engine. I recommend the OE style conventional green coolant. I have found that Dex-Cool causes swelling of the OE LT5 head gasket.

Since it is possible that organic corrosion inhibiter softens the head gasket material, coolant containing organic corrosion protection should not be used in the LT5 engine. The possible values of using organic corrosion protection are small. Dex-Cool claims extended service interval and possible longer water pump seal life. It is not worth taking even a small risk for those benefits since the consequences of head gasket damage are huge.

Use coolant that has the following characteristics:
- Labeled, “For older vehicles.”
- Coolant that is colored green
- Texaco UPC number 76568 12016
- Chevron UPC number 23968 10000
- GM specification 1825M coolant. The current pn is 12378560.
- AutoZone part number 540722. The UPC number is 52948 59081.
- Blue Mountain UPC number 74804 01858

The green coolant might not be available in a brand that you like. However the correct formulation is more important than the brand. Avoid “Universal” coolant. There is no need to compromise when the green coolant is available. Retailers like universal products because they reduce inventory costs, universal coolant is not the best for your LT5, the conventional green coolant is.

For detailed information about my observations of LT5 head gasket swelling see:

http://www.zr1specialist.com/HAT%20W...d%20gasket.htm



Sent from my iPhone using ZR-1 Net Registry

Some of the p/n have changed since 2007, since I went with the GM BrandImage1593791406.745911.jpg

[hiperf406]

I used the long life orange A/F for a few years then I read on ZR1 Forum that was a no-no
as it caused corrosion & was hard on heater cores. So I switched back to the approved green blend that GM recommended.

[Paul Workman]

Originally Posted by hiperf406

I used the long life orange A/F for a few years then I read on ZR1 Forum that was a no-no
as it caused corrosion & was hard on heater cores. So I switched back to the approved green blend that GM recommended.

Marc Haibeck wrote an article on this, some time back - on his web site. I defer to him/his article:

"My Recommendation
Since it is possible that the head gasket material is softened by organic corrosion inhibiter, coolant containing organic corrosion protection should not be used in the LT5 engine. The possible values of using organic corrosion protection are small. Dex-Cool claims extended service interval and possible longer water pump seal life. It is not worth taking even a small risk since the consequences of head gasket damage are huge."