epstep Report post Posted April 4, 2016 I recently bought a used 2014 Tiffin Allegro 36LA. I am getting ready to change the oil in the engine and the generator. Unfortunately I can not find out what the previous owner used. I am told if you use the Mobil 1 synthetic and you had used the high mileage its not recommended to go back to the regular Mobil 1. And what brand of grease for the front end is recommended? Just your thoughts as well for the generator. Share this post Link to post Share on other sites
jleamont Report post Posted April 4, 2016 epstep, two different answers, first what make/model generator do you have? Coach engine; (V10) I would use Mobil one full synthetic or Motrocraft OEM oil with a Motorcraft oil filter (Probably an FL820S filter) you can pick up a Motorcraft filter at any Ford dealer or Wal-Mart also carries them. I wouldn't recommend any other filter especially since you are most likely still under Ford warranty. Here is your oil and coolant spec and capacity: Item Specification Fill Capacity — — Motorcraft® Gold Antifreeze/Coolant ConcentratedVC-7-B (US); CVC-7-B2 (Canada) WSS-M97B51-A1 25.9L(27.3 qt) Motorcraft® SAE 5W-20 Premium Synthetic Blend Motor Oil (US); Motorcraft® SAE 5W-20 Super Premium Motor Oil (Canada)XO-5W20-QSP (US); CXO-5W20-LSP12 (Canada) WSS-M2C945-A 6.6L (7.0 qt) with filter When Synthetics first came onto the market if you switched back and forth on occasion you would get an oil leak (late 80's early 90's, people blamed it on the oil switch over, but was it caused by that, who knows). I have made this switch before and never experienced any issues with newer engines, I wouldn't be concerned with what oil they previous owner used. Share this post Link to post Share on other sites
epstep Report post Posted April 4, 2016 Thanks for the reply my generator is a Cummins/Onan I believe a 10k I will need to check that when I get back down to where I store it Share this post Link to post Share on other sites
wildebill308 Report post Posted April 4, 2016 jleamont is right on the money but I want to add my two cents. I would use Mobil 1 5-20 in the main engin and 10-30 in the generator. There is no problem switching between regular and synthetic. You can also add regular oil to the synthetic if you needed to or vise versa. For grease, guess what, Mobil 1 HP chassis grease is Certified to the NLGI GC-LB specifications for both chassis and wheel bearing lubrication. I just bought a couple of tubes as I am doing my annual maintenance. Bill Share this post Link to post Share on other sites
epstep Report post Posted April 4, 2016 The question was switching between different grades of synthetic, thanks for the heads up on the grease. Share this post Link to post Share on other sites
wolfe10 Report post Posted April 4, 2016 Why would anyone have used "high mileage" oil on a 2014 vehicle??? Share this post Link to post Share on other sites
epstep Report post Posted April 4, 2016 Its not hi mileage on the rig, my mh has 5500 miles its whether the person used full synthetic, I have no way of knowing. I read some where if you used the full synthetic blend vs regular synthetic you were not supposed to revert back I hope I have this right Share this post Link to post Share on other sites
jleamont Report post Posted April 4, 2016 The only reason I would not revert back is....if you do you just threw out the reason for the synthetic oil in the first place and wasted the money. The confusing part to most is there was a myth a while ago that they are not compatible. In short the synthetic products are just better refined, with more comprehensive additive packages over conventional oils. In the RV industry I consider the engines in a Gas unit working hard or in a more "Severe Duty cycle", considering this I would run only full synthetic oils in the powertrain (exception; transmission, Follow Fords Specific oil recommendation and product, this oil is like no other, you will know once you smell it ) your rear axle is equipped from the factory with full synthetic oil. Some manufactures recommend running full synthetic oil after your first oil change, they want fast break in. So at 5500 miles this is where I would begin my change over, understand it might take a few change intervals to get all of the oil residue out, but again no issues with it, you are at a good starting point. Has it ever had the oil changed before? You can tell by the filter, if it has a bar code sticker on a Motorcraft filter its the factory filter. Either way I would make the transition now, doesn't matter but just curious. I second Bills Grease recommendation, that is the product I use. The old saying comes to mind "pay me now or pay me later" high quality products now should make the "later" less painful or push it out farther. Double check the generator model and report back, you can call Onan at 1-800-888-6626 for their tech support to help you with an oil choice. I have in the past for coolant recommendations for ours and they were very helpful. Your factory fill was a synthetic blend, just in case you were wondering; https://www.fordparts.com/Products/Chemicals-MotorOils.aspx Joe Share this post Link to post Share on other sites
epstep Report post Posted April 4, 2016 Thanks guys, I appreciate the input. Share this post Link to post Share on other sites
jleamont Report post Posted April 4, 2016 Your Welcome! enjoy your motorhome! Share this post Link to post Share on other sites
kaypsmith Report post Posted April 4, 2016 Joe has good advice on this issue, I second change over now on that gas engine, and I wonder if he had a good steak this weekend. Share this post Link to post Share on other sites
jleamont Report post Posted April 4, 2016 Joe has good advice on this issue, I second change over now on that gas engine, and I wonder if he had a good steak this weekend. Not yet, I seasoned it Saturday Share this post Link to post Share on other sites
wildebill308 Report post Posted April 5, 2016 Let me try to answer the generator oil question. This is from the Onan RV Generator Handbook. “Gasoline Engine Oil Quality – Use oil meeting any of the following API Performance categories: SJ, SL or SM where SM is currently the highest quality available. Look for the “Energy Conserving” designation to optimize fuel economy.” NOTE: Multi-grade oils (such as SAE 15W-40) are recommended for year-round use in Cummins Onan. I highly recommend Mobil 1 full synthetic oil. You can use what ever viscosity you feel would be best for your application. I would use the 10-40 high mileage. It was developed for cars that have longer oil change intervals but can be changed to meet Onans recommendations and provide better protection. Mobil 1 High Mileage 10W-40 synthetic motor oil meets or exceeds the requirements of: ACEA A3/B3 API SN, SM, SL Mobil 1 High Mileage 10W-40 is of the following quality level: API CF As you can see it meets or exceeds the requirements of the Onan Handbook. Also to make the OP even more confused about oil. Basically all oil is compatible. Using/adding different weight and grade or viscosity will affect the end quality for a given application. On the other hand if they weren't compatible how could they make a synthetic blend like you are running now. Bill Share this post Link to post Share on other sites
