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1982 onan 4.0 genset -Synthetic Or hdeo ? #4472585
07/27/17 11:15 PM
07/27/17 11:15 PM
Joined: Jan 2014
Posts: 520
AZ
leroyd92 Offline OP
leroyd92  Offline OP
Joined: Jan 2014
Posts: 520
AZ
I drained the black 30 wt ( assuming) and refiled with supertech 15w40.

Since this is air cooled, should i stay with. 15w40 or go to a full synthetic 10w30 ?

I'm in az,i do personally see us running the generator in 80-100 weather and also cold ( 30 is coldest for us )


Supertech Junky
Re: 1982 onan 4.0 genset -Synthetic Or hdeo ? [Re: leroyd92] #4472614
07/28/17 01:44 AM
07/28/17 01:44 AM
Joined: Oct 2010
Posts: 950
South Eastern, CT
AMC Offline
AMC  Offline
Joined: Oct 2010
Posts: 950
South Eastern, CT
I would stick with HDEO, whether synthetic or not. If you look at the additive package, volatility and TBN of HDEO compared to any PCMO; HDEO pretty much blows everything else away, especially with the additives.

For your machine and climate, I would recommend an HDEO 10w-30. Wal-Mart carries Rotella and Delo HDEO 10w-30 for a good price. That should cover your temp range and give good protection. Synthetic 5w-40 HDEO would work very well also. 15w-40 might start off a bit thick for a machine that doesn't get a lot of use and the temp can get to 30F degrees.


18 Honda CR-V - Mobil-1 AFE 0w-20
17 Ram 1500 SLT - Napa Synthetic 5w-20
14 Yamaha Super Tenere - Mobil Delvac 15w-40
Re: 1982 onan 4.0 genset -Synthetic Or hdeo ? [Re: leroyd92] #4472827
07/28/17 08:12 AM
07/28/17 08:12 AM
Joined: Dec 2016
Posts: 7,191
Waco, TX
Linctex Offline
Linctex  Offline
Joined: Dec 2016
Posts: 7,191
Waco, TX
I'd stick with 15W-40

Is this Onan 1800 RPM or 3600 RPM?

If it's 3600 RPM, it will last forever.
If it's 1800 RPM, it will last forever & ever & ever & ever & ever.....


"The evidence demands a verdict".
(Re:VOA)"it's nearly impossible to actually know the particular additives that are in there at what concentrations."
Re: 1982 onan 4.0 genset -Synthetic Or hdeo ? [Re: leroyd92] #4472885
07/28/17 08:51 AM
07/28/17 08:51 AM
Joined: Jul 2016
Posts: 1,702
Jacksonville, FL
FlyNavyP3 Offline
FlyNavyP3  Offline
Joined: Jul 2016
Posts: 1,702
Jacksonville, FL
I think you're right on the money with the ST 15w40 you already have installed in the engine. Robust add pack at a value price. I wouldn't change a thing.


Luke
P-3C and P-8A Maritime Weapons and Tactics Instructor, Instructor Tactical Coordinator and Mission Commander
Re: 1982 onan 4.0 genset -Synthetic Or hdeo ? [Re: leroyd92] #4472948
07/28/17 10:05 AM
07/28/17 10:05 AM
Joined: Mar 2008
Posts: 5,969
South Florida
bubbatime Offline
bubbatime  Offline
Joined: Mar 2008
Posts: 5,969
South Florida
15W40 minimum
20W50 for any long stretches of use (several days of use)
Absolutely no xW30 weight oils

Originally Posted By: AMC
For your machine and climate, I would recommend an HDEO 10w-30.


No. The guy lives in Arizona. 15W40 minimum for his engine/climate. The SuperTech 15W40 he chose is a great choice.


17 Chrysler Pacifica Mobil 1 5W30
13 Yamaha XT250 Valv MC 10W40
10 Acura TSX 2.4 Maxlife Syn 5W30
06 GMC Sierra Nextgen 10W30


Re: 1982 onan 4.0 genset -Synthetic Or hdeo ? [Re: leroyd92] #4472975
07/28/17 10:33 AM
07/28/17 10:33 AM
Joined: Mar 2011
Posts: 292
NM, USA
pkunk Offline
pkunk  Offline
Joined: Mar 2011
Posts: 292
NM, USA
15-40 is the lube recommended by Onan. I use 15-40 in mine anywhere from S. AZ to the mtns of NM where I live and never had a problem.


2008 Mini Cooper Clubman (toad)
2000 Mercedes ML320
1994 Dodge 2500 Cummins
1999 Ford F53 V10 Coachman Motorhome 34ft
Re: 1982 onan 4.0 genset -Synthetic Or hdeo ? [Re: pkunk] #4475010
07/30/17 08:17 PM
07/30/17 08:17 PM
Joined: Oct 2010
Posts: 950
South Eastern, CT
AMC Offline
AMC  Offline
Joined: Oct 2010
Posts: 950
South Eastern, CT
Originally Posted By: pkunk
15-40 is the lube recommended by Onan. I use 15-40 in mine anywhere from S. AZ to the mtns of NM where I live and never had a problem.


I was assuming 10w-30 was the factory recommended weight and 15w-40 was just everyone's suggestion to go a little thicker because it is an old engine.

I will stick with the first part of my post though, HDEO is the way to go. 10w-40 PCMO is going to have a lot less additives.


18 Honda CR-V - Mobil-1 AFE 0w-20
17 Ram 1500 SLT - Napa Synthetic 5w-20
14 Yamaha Super Tenere - Mobil Delvac 15w-40

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