Coolant Recommedation

[Marc Haibeck]

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

[Dynomite]

Originally Posted by Marc Haibeck

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

The detailed information attached describes The three causes of LT5 Overheating and resulting Cylinder Head Gasket Failures which in itself is as important as using the wrong coolant making the overheating issues even more serious


Thanks Marc

[ZZZZZR1]

Marc


Thanks for posting this!!! This question comes up and most of us can't remember what exactly is safe to use



David

[efnfast]

Thanks Marc, doing coolant this weekend. Really nice to have confirmation of what to use from a trusted source.

[We Gone]

Great Info.

[Schrade]

Good info there Mr. H...

I would NEVER recommend GM Red coolant.

In 4 vehicles I've owned with the Dex-sludge, ALL 4 had the 'plug', including an '02 1-ton, bought new, which was my personal vehicle of my delivery fleet business. All were immaculately maintained by me, and the 1-ton stayed running. After 100k, about 14 months, it had the 'plug'.

I think GM lost a class action over this issue...

[Hog]

The orange Dexcool, will not tolerate any exposure to air, it will form an acidic sludge that will etch into cast iron heads. Dexcool is an OATs coolant (Organic Acid Technology).

Stick to the green coolant, but if you do, you must perform the coolant service at shorter intervals.

Anyone know if the orange Dexcool was the factory fill on the 1996 LT1 and LT4 Y-bodies? In the trucks it started with OBD2 in 1996.

ANother important thing is when you switch from the orange extended service interval Dexcool over to green Dexcool, be sure to flush all the orange out. BAd things happen when green and orange mix.

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Info on lawsuits

[I]GM Coolant Settlement Could Cost Hundreds of Millions
By Edward Niedermeyer
- 990 Views
The General has settled a class-action lawsuit claiming damages from its "Dexcool" coolant, agreeing to pay up to $800 each to customers who can prove damages. Plaintiff attorneys estimate that the final number of claims could top $20 million, a bill which would cost GM of hundreds of millions of dollars. "It could be multiple nine figures; it depends on how many people make the claim," co-counsel for the plaintiffs, Jack Brady tells the International Herald Tribune . "I think it could be a huge settlement." Of course, while the people who had to replace manifold gaskets and heater cores get between $50 and $800 for repairs, Mr Brady and his co-counsels will pocket up to $23 million in fees and $2.8 million for expenses. Still, if you own a GM vehicle with the 3.1-liter or 3.4-liter V6 engines for model years 1995 to 2003; the 3.8-liter V6 engines for model years 1995 to 2004; or the 4.3-liter V6 engines for model years 1995 through 2000 and have had to pay for coolant-related damages, you should check dexcoolsettlement.com to file a claim.



GM agrees to settle class-action lawsuits tied to engine coolant

The Associated PressPublished: March 26, 2008



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Info on the lawsuits
KANSAS CITY, Mo.: General Motors Corp. has agreed to settle a series of class-action lawsuits claiming a faulty engine coolant damaged thousands of customer vehicles.
Under the settlement, GM would reimburse class members between $50 and $800 for repairs linked to Dex-Cool, an orange coolant that GM included in cars and trucks beginning in 1995.
The total cost to GM will depend on the number of customers claiming damages, but the plaintiffs' attorneys estimate the settlement could cover up to 20 million initial and secondary buyers of GM vehicles that used Dex-Cool. They also say the price tag could reach the hundreds of millions of dollars.
A California state court gave preliminary approval to the settlement last week and a Missouri court plans to consider it Friday.
"We fought for about five years to recover monetary damages for people that would be meaningful and I think we achieved that," said San Francisco plaintiff attorney Eric Gibbs, who estimated most people spent between $600 and $900 for repairs. "The recovery for most of the people will be pretty good."
GM spokesman Tom Wilkinson said the company was not admitting any wrongdoing but is settling the case to cut down on legal bills.
"Our experience with Dex-Cool is that when the cooling system is kept full and properly maintained we haven't seen any problems," he said. "These kinds of things appear to be issues of low coolant, which isn't unusual with high-mileage vehicles, so we decided to agree to the settlement."[I]

[randy ransome]

My 91 ZR-1 has the Dex-cool in it. It was in there when I bought it. What procedure should I take to change over to the green?

I've read stories about air getting trapped in the system while refilling.

[Schrade]

I was able with all 4 GM's with Dex Red [Orange], to get the 'plug' out - IT FLUSHED FROM THE HEATER CORE EVERY TIME - with pressure from a garden hose. I'd put the hose to every coolant orifice I could find, and reversed from the other end when possible.

See if you can get feedback from Marc H on flushing LT5. Deference on alls' part here (save a few), goes to him...

There's a flow schematic recently posted here somewhere...

[WVZR-1]

Marc - it's certainly a "timely reminder" and appreciated