Generator oil change questions

[jvalich]

Originally Posted by Soppy

I change mine once a year . I don't bother exercising the generator , and haven't had any problems. I just run regular 10-30 motor oil . Although synthetic oil may last longer, the moisture and other contaminants still remain in the engine.

Soppy:

Ypu may want to check this out. Exercising your generator with a load - RV Travel

Also, I purchased Mike's book right after I purchased our Motor coach as I was very familiar with electrical safety on boats (20 yrs of boating) but wanted to learn about issues/conditions that can arise with the new to me coach. Main lesson, Most understand the danger of water and electricity but just because it's not in the water doesn't mean it can't kill ya.

A bit of exercising not only helps keep the genset in top shape but helps make sure it's working when you do need it.

[udid]

Originally Posted by jvalich

Soppy:

Ypu may want to check this out. Exercising your generator with a load - RV Travel

Also, I purchased Mike's book right after I purchased our Motor coach as I was very familiar with electrical safety on boats (20 yrs of boating) but wanted to learn about issues/conditions that can arise with the new to me coach. Main lesson, Most understand the danger of water and electricity but just because it's not in the water doesn't mean it can't kill ya.

A bit of exercising not only helps keep the genset in top shape but helps make sure it's working when you do need it.

Exercising the generator has more to do with getting those ring/s in cylinder to push up against the walls of the cylinder (load) then it has to do with anything electrical wise.



Electrical items either work...or they don't work. Exercising the generator does nothing beneficial with the electrical item/s.


The single biggest reason it's recommended to exercise the generator is because they know most folks do not use fuel stabilizer and/or the correct concentration and several months later after storage they pay the price for it.


I always use the 80 gallon treatment (Sta-bil) in my fuel tank (60 gal.) just prior to last fill up before going into storage. Never had a generator start/run issue (fuel related) after months (5-7) of storage.

[Mr_D]

Originally Posted by udidwht

Generators do not fall under the 'X miles or Once per year' that has been the greatest trick played on folks to boost revenue. Much like the old...Change your oil 'Every 3000 miles'. LOL!

Generators run at a fixed RPM's where as vehicle engines are all over the map. Hence the need for either a 'Normal OCI or Severe duty OCI'. Generators are far easier on oil then vehicle engines.

It's best to do (1) oil analysis and you will know how much life is left within the oil. These days any good name brand oil will easily live beyond 1 year.

Not all generators run at a constant speed, some of the Onan's are variable speed, up to 3,600 rpm.

[Mr_D]

Originally Posted by udidwht

Electrical items either work...or they don't work. Exercising the generator does nothing beneficial with the electrical item/s.

Actually there is a benefit to the electrical components due to "exercising" the generator. The gen windings accumulate moisture, this breaks down the insulation and shorts them out. This is per the manufacturers published data plus it helps keep the slip rings from corroding.

[udid]

Originally Posted by Mr_D

Not all generators run at a constant speed, some of the Onan's are variable speed, up to 3,600 rpm.

Yes but they are not idling at RPM's like vehicles. Big difference.

[udid]

Originally Posted by Mr_D

Actually there is a benefit to the electrical components due to "exercising" the generator. The gen windings accumulate moisture, this breaks down the insulation and shorts them out. This is per the manufacturers published data plus it helps keep the slip rings from corroding.

Moisture evaporates as well. Nothing can be done about it. Electrical items are designed to take that into account even when not ran. Manufactures spell that out only for mere profit. They know the encouragement of one using their generators more often equates to ultimately needing service = More profit.



I spent 10 years in the Navy as jet engine mechanic and earned my degree from Embry-Riddle. I know what I'm talking about.

[udid]

Originally Posted by Old Scout

....news flash--not all generators run at a constant RPM--example: QD7500.....by the time you pay for an oil analysis, you have covered the price of a DIY oil change....IMHO, whether you work your genset hard or it sits a lot--an annual oil change is money in the bank--opinions may and do vary!!!!!!!

Not even.

The cost of (1) oil analysis will very much likely tell you that your oil has a lot of life left in it. The only way to know that is to do an oil analysis. No way around it.

Moisture build up in a generator is from actual generator use (combustion process).

[F76Marion]

Believe who you choose, but I am engine professional and a licensed ship's engineer of many years before I came ashore to work in the Detroit engine test labs.

Those that said that the life of engine lube oils is essentially one calendar year are correct. If the data was not owned by customers, I could show it to you, but this is even true of Mobil1 according to a friend that is one of the engineers there. The oil is good basically forever, but the anti-wear and anti-corrosion additives calendar out almost regardless of engine hours.

Exercising a generator to dry out the windings is left over from the electrical varnish used before WWII. It no longer applies. (Unless your APU is that old.) It is my contention that it was left in the manual by those that sell the parts.

Thermal cycles do nothing good for any engine. (Chitt, that is what we did in some tests to brake them - fast.)

If you want it to be trouble free, figure out how to drain the gas out of the carburetor so it does not foul the fuel control jets. This is never very hard to do. Some Gensets have carburetor drains built in. Then if you are going to be leaving it alone for months (like 4 or more), learn how to "fog" the engine so all that bear metal inside does not corrode.

Unless you live adjacent to tidal water, this should be all you need to do.

My newest generator is a 45yo Onan with several thousand hours on it and it would start right now if I had batteries in that coach, but the Dodge 360 blew a piston, so it is in the workbay and the house bank is out on the charging shelf. The oldest is a 48yo Honda. It gets stored dry and fogged, so it can take a little cranking, but if the house lights go down, I can count on it to run.

Frank

[udid]

Originally Posted by F76Marion

Believe who you choose, but I am engine professional and a licensed ship's engineer of many years before I came ashore to work in the Detroit engine test labs.

Those that said that the life of engine lube oils is essentially one calendar year are correct. If the data was not owned by customers, I could show it to you, but this is even true of Mobil1 according to a friend that is one of the engineers there. The oil is good basically forever, but the anti-wear and anti-corrosion additives calendar out almost regardless of engine hours.

Exercising a generator to dry out the windings is left over from the electrical varnish used before WWII. It no longer applies. (Unless your APU is that old.) It is my contention that it was left in the manual by those that sell the parts.

Thermal cycles do nothing good for any engine. (Chitt, that is what we did in some tests to brake them - fast.)

If you want it to be trouble free, figure out how to drain the gas out of the carburetor so it does not foul the fuel control jets. This is never very hard to do. Some Gensets have carburetor drains built in. Then if you are going to be leaving it alone for months (like 4 or more), learn how to "fog" the engine so all that bear metal inside does not corrode.

Unless you live adjacent to tidal water, this should be all you need to do.

My newest generator is a 45yo Onan with several thousand hours on it and it would start right now if I had batteries in that coach, but the Dodge 360 blew a piston, so it is in the workbay and the house bank is out on the charging shelf. The oldest is a 48yo Honda. It gets stored dry and fogged, so it can take a little cranking, but if the house lights go down, I can count on it to run.

Frank

I have dozens (over many years) of oil analysis's that prove otherwise. Some of them are on oil that have been run tens of thousands of miles and more than (1) year. The only way to know with absolute 100% certainty is via an oil analysis. No other way. Oil today is nothing like oil even 10 years ago.

[tizzyfit]

With almost 5000 hours on my Generac Quietpact 75D, I change the oil, oil filter, fuel filter and air cleaner annually. Today, when I pulled the front panel off the gen set, the alternator drive belt was toast. So, both belts, both tensioners, radiator hoses, and thermostat have been ordered. There is no way to get to the tensioners to replace them so the gen set is coming out so the top and sides of the shield can be removed to make the job easier. Whoever the FOOL was who designed the bracing for this gen set install managed to place the center support directly under the center inspection cover making it impossible to access ANYTHING through that cover without removing the gen set from the chassis frame. It will be nice to properly flush the coolant system while it's out of the motorhome and checking for any worn items that could fail in the near future. I want this gen set removal to be a once in a lifetime experience.

[F76Marion]

Originally Posted by udidwht

I have dozens (over many years) of oil analysis's that prove otherwise. Some of them are on oil that have been run tens of thousands of miles and more than (1) year. The only way to know with absolute 100% certainty is via an oil analysis. No other way. Oil today is nothing like oil even 10 years ago.

Udidwht,

I will not argue about lube oil analysis. I buy it frequently to track expensive or critical engines. But, the analysis is usually in the 20~25$ range. As that cost is more than the cost of a premium lube oil for they typical RV APU, it is simply not cost effective. It is the reason my LA360 was scheduled for service. I have been tracking an internal coolant leak. A piston cracked first.

Yes, modern lube oils have improved, and engines have improved, but physics and chemistry have not changed the combustion by-products that damage the lube oil. As said, calendar is a big issue and I could not help but notice that you put some value in the 1 year rule. Yes, you can go longer, but spending 25$ to save a 3 quart lube oil change is just not make any economic sense at all.

Frank - the refugee from dyno land

[udid]

Originally Posted by F76Marion

Udidwht,

I will not argue about lube oil analysis. I buy it frequently to track expensive or critical engines. But, the analysis is usually in the 20~25$ range. As that cost is more than the cost of a premium lube oil for they typical RV APU, it is simply not cost effective. It is the reason my LA360 was scheduled for service. I have been tracking an internal coolant leak. A piston cracked first.

Yes, modern lube oils have improved, and engines have improved, but physics and chemistry have not changed the combustion by-products that damage the lube oil. As said, calendar is a big issue and I could not help but notice that you put some value in the 1 year rule. Yes, you can go longer, but spending 25$ to save a 3 quart lube oil change is just not make any economic sense at all.

Frank - the refugee from dyno land

One doesn't need to do an analysis every oil change. One analysis will tell you all you need to know after a given number of miles/time driven. The cost is moot. When you factor in what owners spend for everything else they do to their rigs/setups it's a drop in the bucket. We don't own RV's to penny pinch.

[tizzyfit]

Originally Posted by udidwht

One doesn't need to do an analysis every oil change. One will tell you all you need to know after a given number of miles/time driven. The cost is moot. When you factor in what owners spend for everything else they do to their rigs/setups it's a drop in the bucket. We don't own RV's to penny pinch.

"We don't own RV's to penny pinch"...........You really need to read more of the comments on this forum, it could change your mind this statement. So there's no misunderstanding, humor is intended by my comment.

[udid]

Originally Posted by tizzyfit

"We don't own RV's to penny pinch"...........You really need to read more of the comments on this forum, it could change your mind this statement. So there's no misunderstanding, humor is intended by my comment.

I'm well aware of such comments. LOL! My opinion regarding that has always been.


Then RV's aren't for you.