Pentius PLXL4386 cut open

[EvoMan]

This filter if from my Generac 22kW whole house generator that runs on natural gas. This was in use for 1 year with run time less than 50 hrs.

Oil used was Quaker State High Mileage Full Synthetic 5W-30.

It looks good with nothing really obvious in the filter. Nice tight pleat spacing with an internal metal crimped seam.

I installed a Premium Guard PG195EX oil filter along with Mobil 1 15W-50 oil. I plan on leaving the oil in for hurricane season, which runs from June 1st - November 30th. The temps here on the central Florida east coast during hurricane season usually have highs in the 80’-90’s with lows in the 70’s.

 

[martinq]

Good looking filter. I think you could have left it on for another 3-5 years by how clean it looks.
Thanks for the pics!

 

[Elkins45]

I’ve been impressed with every Pentius filter I’ve dissected.

 

[Zee09]

Great pictures thank you

 

[levi]

Great pictures thank you

You only said that because he used Quaker State.

 

[Lawnman23]

Good looking filter. I think you could have left it on for another 3-5 years by how clean it looks.
Thanks for the pics!

IIRC, engines that run on nat gas have much cleaner oil. And yes, I realize it also has very low run hours on it as well.

Someone correct me if I’m wrong about the nat gas oil thing…

 

[slacktide_bitog]

Looks good

 

[JohnnyJohnson]

It would have been interesting to see a UOA on that Quaker State! The price on those Pentius has doubled since I bought my dozen pack.

 

[ZeeOSix]

IIRC, engines that run on nat gas have much cleaner oil. And yes, I realize it also has very low run hours on it as well.

Someone correct me if I’m wrong about the nat gas oil thing…

Much cleaner combustion, so way less sump contamination from piston ring blow-by.

 

[Lawnman23]

Much cleaner combustion, so way less sump contamination from piston ring blow-by.

Makes sense

 

[EvoMan]

There was a discussion last year where there was talk about using a low ash oil to help prevent valve deposits since natural gas doesn’t have the additives that gasoline does.

G

Thread 'Low Ash Required For Natural Gas Engine?'

Oct 26, 2025

I have a 4.5 liter 4 cylinder water cooled engine running natural gas in a Generac generator. I was considering AMSOIL Signature Series but Amsoil tech department said I should use the OE because it is low ash and the SS is not. Even though the manual does not mention a low ash requirement, I contacted Generac and they pointed out that I should indeed use low ash 5w30 SN or later oil and that their own oil is low ash and should be the oil of choice. Is there any research to support the need for low ash oil in natural gas engines? It looks like the best synthetics from most companies are...

• GJ1951
• Replies: 17
• Forum: Lawn Mower and Small Engine

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