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Primrose Winter Klenz ID 5757 - Premium Diesel Additive - An Ongoing Review


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Mike submitted a new resource:

Primrose Winter Klenz ID 5757 - Premium Diesel Additive - An Ongoing Review - An ongoing review of Winter Klenz ID 5757, and winter diesel fuel additive by Primrose.

As I mentioned in another thread, it's time for winter to show it's ugly face again, and for those what face gelling/icing concerns, it's time to start combating the issue again.

Beginning with my next fuel up which will be this evening, I will begin adding Primrose Winter Klenz ID 5757 to the fuel.

I will be running this product from October through March, longer if weather requires it. During the warm months, I plan to transition to the regular additive manufactured by Primrose.


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Hello , I am new to this forum. Just wondering what results you have come up with so far ?
Guess I need to update this. Been super busy and haven't done this as planned.

We are now entering the middle of February. Winter is not yet over, regardless what that retarded groundhog said, but deep enough into the season to get a good feel for how this additive works in regards to winter protection.

The biggest telling factor for me, this winter, has been the decrease in fuel filter replacements, and the move back from a 10 micron filter to a 7 micron filter. This is a Davco filter, and on my truck, there is no other filter in the system. My filter is also the cheap non-heated version, and deals with the elements directly as it is pretty openly exposed to the weather, especially if the wind is blowing hard in it's direction. Fuel lines are also not insulated. I had planned on taking care of that this year, but other issues distracted me from that. So, still running with non insulated fuel lines.

Last year, I spent much time trying to find locations that winterized their fuel the best, and avoid bio-diesel as much as possible. Filters would stop up so quickly, that I gave up on both the 7 and 10 micron filter and ended up using a 25 during the coldest part of the year. I also spent quite a bit of money treating my fuel with Power Service mostly, as directed by the bottle. If the Power Service helped, I couldn't tell.

Last year's results? Lots of fuel filter replacements, and one near breakdown due to icing in the filter.

This winter, I haven't been in the severe negative temps that some have seen in recent weeks, but plenty time right at the zero mark. Plenty snow and hard winds to battle as well.

This year, I decided to start treating my fuel at the beginning of winter, and plan on treating it year around with the Primrose fuel additive. Winter Klenz during the cold months, the Summer blend the rest of the year.

My results this year have been very impressive. I have had zero fuel filter issues, filters look much cleaner, and the fuel looks much clearer and cleaner than ever. Any nastiness that had formed inside the tank is gone. I have used nothing but 7 micron filters, in addition to a couple 10 micron filters that I still had laying around.

Unlike last year, I have shut my truck off every night, even down at zero degrees, without concerns of fuel problems.


Now that the winter icing/gelling concerns have been addressed, onto the things that have most impressed me about this product.

As some of the members here know, I dealt with significant downtime this spring, ultimately having to replace a head and then the injectors 250 miles after the head replacement was finally taken care of. All in all, my truck sit around for almost 3 months. Let me tell you, nothing good comes from a fuel system sitting and stagnating all that time, and that sitting is most likely what cause the injector failure. Just speculation, but I feel pretty confident about that.

After the injector replacement, the truck wasn't right. It never ran as well as it should have, and I was constantly dealing with very long crank times. A few checks of the oil revealed that those extended crank times were likely due to fuel leaking from or through the new injectors and into the crankcase because my oil level was rising due to fuel dilution.

The fuel dilution and starting problem was not going away, so I ended up scheduling the truck to go back into the shop. This time a different shop, but the earliest I could get my truck in was going to be the week of Thanksgiving. The plan until then was to just shorten up the oil change intervals, and use some Lucas to help out with the fuel dilution until I could get the truck into the shop.

At this time, (October, 2018), I began reading some reviews from a couple people on Facebook regarding their use of Primrose additives. One single truck owner, and one small fleet (30 or so trucks, I believe). The guy from the fleet had documented a huge reduction in maintenance costs for the fleet after transitioning to using the additive, then a rise in maintenance costs upon stopping the use of additive, and again a reduction in maintenance after going back to using the additives. These were salesmen for the product, just people discussing some real world experiences.

At this point, I discussed the product deeper with Will (@FuelrelatedWill), and he gave me all sorts of information about the product, and several real world experiences similar to the one I posted about in the above paragraph.

Winter was getting close, so i decided to order a case of the Winter Klenz. I believe it was around the middle or end of October when I began using the product regularly. By my next oil change, fuel dilution had dropped off significantly, starting problems were happening far less, and truck was just running better. By Thanksgiving, the starting problems were 100% gone, as was the fuel dilution. Truck was running better than I can ever remember it running, and I called the shop to cancel my appointment.

Fast forward to February, 2019. Truck has had zero mechanical issues and runs amazingly well. It starts better than it started when it was new. Even in very cold temps, a couple engine revolutions and this thing is fired up and running smoothly, thanks to the actual increase in Cetane.

I could honestly not be happier with the results of this product. Ordering my 2nd case now, this time the summer blend.

My next test with the Primrose products will be their oil additive. I'll explain more about that later, but what I am targeting with this product is blow by. Looking for the reduction or possibly elimination of blow by on the engine. It's had blow by since it's birth, LOL.


curmudgeon extraordinare
Got to meet @FuelrelatedWill at MATS this past month.

And yes, I did put the half bottle into the tank as you suggested.

It would seem my truck was more susceptible to the quality of fuel .ore than anything. I fear I've got a leak in the charge air cooler the way it's acting.

Got an average of 8.8 mpg over 1855 miles. My high was 9.3 and my low was 7.2. the 7.2 was fuel from a Phillips 66 station around Danville IL that likely had really low fuel turn over.

I did replace my fuel filter after 2 tanks after pouring in the half bottle. Didn't seem to really matter

This rig weighs 16,500#.



Active Member
mndriver, Thank you for investing your time to meet up at MATS. It was nice to meet you!
Were those the same fuel stops you used on the way to MATS?


curmudgeon extraordinare
No, I took a different route home than coming down.

For the most part, I was 8.7 to 8.9 most tanks.


curmudgeon extraordinare
I have only taken one other trip with it. That was last October when I bought it.

I suspect I have a hard mechanical issue with a boost leak I need to find first.


Active Member
Time for the soap and water😁
Boost leaks can be a big loss in performance and mileage. For that truck you should be getting at least 10-12 depending on the wind.
I have a buddy with a clean 04 Duramax like yours.
I call him tomorrow and see what he is getting for fuel economy pulling his dump trailer around town. I’ll text ya what I find out.