Hot Shot Secret vs Optilube

[Dean E]

New to the Duramax, have a 2022. What is the CP4?
As an additive to the fuel how much are you using and what brand?
Any preferences on DEF Fluid?
Thanks for your timek

As stated above the injection pump for the L5P is the Denso HP4. Before the L5P (your 6.6 2022 Duramax) came on the seen there was the LML series of Duramax. Those used the Bosch CP4 for the injection pump. This was a two piston design that would have worked fine in the old days before the introduction of ultra low sulfur diesel fuel but the process of removing the sulfur also stripped away much of the lubrication properties of the diesel fuel that the CP4 needed. Before the LML all the Duramaxes used the older CP3 which are pretty bullet proof and don't have the issues as the CP4 has. Matter of fact there have been some lawsuits against GM over the CP4s. Your Denso HP4 is a solid unit and does not require any additional lubrication.

Other than some occasional winter additives I don't use anything else. DEF, can't say, don't need it for my LMM. Dean

 

[MGKelly]

CP4 is the injection pump.

As for brand, take your pick. I'm partial to Hot Shots as my shop sells and uses it daily. Their dosing is 1oz/25gal for a "premium" dose and 2oz/25gal for a "performance" dose.

DEF fluid, in my eyes, is DEF fluid. I haven't seen any major differences in trucks running various brands but it may be a possibility in other areas across the country.

Bdsankey, Thanks, How often do you change the fuel filter? I have always thought it was important to keep the fuel clean. On my 1987 Ford, 6.9 I changed the fuel filter every second oil change, so (every 6,000 miles). Thanks again
What type of shop do you have?
We just retired, and hoping to visit all the states, and maybe try fishing in each one. I have read that Wisconsin has some great fishing.

 

[MGKelly]

As stated above the injection pump for the L5P is the Denso HP4. Before the L5P (your 6.6 2022 Duramax) came on the seen there was the LML series of Duramax. Those used the Bosch CP4 for the injection pump. This was a two piston design that would have worked fine in the old days before the introduction of ultra low sulfur diesel fuel but the process of removing the sulfur also stripped away much of the lubrication properties of the diesel fuel that the CP4 needed. Before the LML all the Duramaxes used the older CP3 which are pretty bullet proof and don't have the issues as the CP4 has. Matter of fact there have been some lawsuits against GM over the CP4s. Your Denso HP4 is a solid unit and does not require any additional lubrication.

Other than some occasional winter additives I don't use anything else. DEF, can't say, don't need it for my LMM. Dean

Thanks Dean for all the Clarification. I'm very glad I found this Forum.

 

[Chevy1925]

Bdsankey, Thanks, How often do you change the fuel filter? I have always thought it was important to keep the fuel clean. On my 1987 Ford, 6.9 I changed the fuel filter every second oil change, so (every 6,000 miles). Thanks again
What type of shop do you have?
We just retired, and hoping to visit all the states, and maybe try fishing in each one. I have read that Wisconsin has some great fishing.

you can continue to change the fuel filter at the same interval if you want. 10k miles is the general concensus though. Nice part is our fuel filters are back by the fuel tank and easier to change than the older years.

 

[Mickey D]

5 mpg from a lift pump and fuel additive?

Down hill. 🫣