WVHillbilly520H 10,369 #26 Posted June 16, 2017 When I was in highschool/auto tech my teacher was an older retired dealership mechanic, He said that "most" products put on the market were "snake oils" to "bandaid" mechanical issues, if your "knock" has gotten worse with a heavier weight oil then you most definitely have a mechanical/clearance issue, whether it's a faulty oil pump, oil passages "clogged" some where or crankshaft/rod end/bearing wear or a combination of all 3, since you've already had the engine off and semi apart, now would be the time to remove it pull the pan and rod caps and like 6bg6ga said visually check for rod wear, if you have calipers/micrometer check rod end size (I.D.) vs crank journal (O.D.) all this info is in the Onan Service Manual and only the P224 24HP has automotive style bearing inserts the 16-18&20 HP are like Kohler/Briggs ,Jeff. Share this post Link to post Share on other sites
Duramax7man7 505 #27 Posted June 16, 2017 I agree with you both. This is what it came down to on my 1970 Onan CCKB Generator with a P19 on it. It has Rod bearings though. A much cheaper fix in comparison to having to purchase new rods. But it is what it is. I will Get an oil pressure gauge and check that first then move forward from there. Share this post Link to post Share on other sites
