RV Maintenance

graphic of mechanic

Let me take a few minutes and talk about the maintenance items on a motorhome that need to be addressed on a periodic basis.


One of the most important items, from a safety standpoint, is proper tire maintenance.

“RVers don’t wear out tires—they kill ‘em!”

Most RVs are overloaded, their tire pressures are too low, and they are driven too fast—and all these conditions cause tires to run hotter than they should.

Use Proper Tire Inflation. Have your RV weighed—each axle and side separately. Know what your RV weighs (with all your usual “stuff” in it) on all four corners—and inflate your tires to the proper psi based on the heaviest load carried on each axle. (The tire manufacturers have a booklet or chart showing proper tire inflation for a given weight on a particular tire.)

Be sure to put the same pressure in the tires on the same axle. For example, inflate both front tires to the required psi based on the weight of the heaviest front wheel. And please be aware that it is often the case where the front and rear tires should be inflated to different pressures—not the maximum pressure stamped on the sidewall of the tires. You probably already know by now that too much pressure in the front tires causes a very stiff and often uncomfortable ride.

Shield Tires from UV Rays. When you are camped for long periods of time, or the rig is stored, put tire covers over the tires so that they are shielded from the ultraviolet (UV) rays of the sun. Continuous exposure to UV rays causes the sidewalls to prematurely check and crack—eventually making the tires unsafe.

Take Off Some of the Load When Parked. If you have hydraulic levelers on your coach, put them down and raise the coach a couple of inches when you are parked (or storing your RV)—to take some of the pressure off the tires and the axle bearings.

Don’t Store RV with Tires on Concrete. If you habitually store your RV on a concrete pad, put a piece of cardboard or wood under the tires so that they are not in direct contact with the concrete. The chemicals in concrete adversely affect the rubber compounds in the tires, and can cause them to deteriorate more rapidly.

Don’t Use Tire Dressing on Tires. Be kind to your expensive RV tires—don’t put tire dressing on them to make them look pretty. Tire dressing inhibits the ability of the sidewalls to breath. About twice a year, give your RV tires a good scrubbing with soap and water and a scrub pad, and then rinse them off with plain water. That’s all—nothing else.

Don’t Keep Tires More Than Seven Years Old. Many RVers think that their tires are still safe if they still have nice deep tread on them. But what many RVers don’t know is that their tires are on their last legs and about to become a safety hazard (due to unexpected blowouts) if the tires are more than 7 years old. Yes, folks, I said only 7 years old—even when they have lots of tread left.

Usually, when RV tires are 7 years old, they have been left sitting in the same position for long periods of time and exposed to the constant battering of the sun. If you look closely, the sidewalls of the tires have become checked or even cracked. The checks lead to cracks and the cracks usually lead to eventual tire failure.

If you have been driving your RV, and you suddenly seem to have several blowouts in a fairly short period of time, then your tires are trying to tell you that they have outlived their useful life and are now hazardous. If you encounter a blowout on a front tire of a motorhome traveling at 65 miles an hour, you have a real problem on your hands.

Replace Tires With Proper Load Rating. Always be sure that any new tires are the correct load rating for your RV. Never, never put automobile tires on your coach just because they both have 16-inch rims! Most RV tires need to be load rated at E or F—nothing less. The load rating specifies how much weight each tire can carry, either singly or as one of a dual pair—and the ratings are different.

Many of you might be surprised to learn that a tire in a dual arrangement cannot carry as much of a load than if it is on an axle by itself.

For example, a popular RV tire, when inflated to 80 psi, has the following maximum load ratings:

This means that the two tires on the front axle can carry a maximum load of 7,780 lbs, and the four tires on the rear axle can carry a maximum load of 14,620 lbs.

Obviously, this tire combination gives you room to spare on an 18,000 GVWR coach, a little spare room on a 20,000 GVWR coach, but is dangerously close to maximum load rating on a 22,000 GVWR coach. (I, personally, would not want this tire combination on a 22,000 GVWR coach.)

Know what you need, and don’t let a tire salesman sell you a tire that is unsafe for your RV.

Know the Age of Your Tires. Most RVers don’t know the age of their tires and don’t know the secret of determining tire age—stamped on each and every tire that is manufactured.

When you are buying new RV tires, be sure to insist that the age of the tires (from date of manufacture) is within the last six months. You would be surprised at the number of tire people who don’t know how to check the date on new tires.

The date of manufacture (to the nearest week) is always molded into the sidewall of every tire. Look for a series of four digits (sometimes inside a circle or ellipse, and sometimes just by themselves). You will find a series of four digits showing the week of the year and the last two digits of the year. For example, a date code of 1601 means that the tire was manufactured during the 16th week of 2001. Similarly, a date code of 4803 shows that the tire was manufactured during the 48th week of 2003.

Several years ago, when my lady needed new tires on her RV (because the sidewalls were checked and cracked and the tires were older than 7 years), she called around to several tire shops to get the best price on four new RV tires—with the correct load rating for her coach. When she finally called up the dealer with the best price, she was told that the tires were in stock and that she could bring in her motorhome. However, when my lady said that the tires had to have dates codes more recent than six months old, the dealer, after a long pause, said that he would have to have them shipped from a local distributor. And, yes, my lady insisted on seeing the date codes on the four new tires before they were installed.


Properly maintaining your chassis and house batteries is second on the list of important maintenance tasks. If you are a serious boondocker, then you know the importance of keeping your batteries in good shape, the connections tight and corrosion-free, and the fluid levels at the proper level.

Most RVers do not faithfully check the fluid (electrolyte) level of their batteries on a regular basis. Leaving your RV connected to shore power for long periods of storage causes the batteries to be overcharged and the electrolyte boiled out of the cells, because the RV converter does not have the sophisticated level-of-charge sensing circuitry for proper charging of batteries.

It is suggested that you check the water level of your batteries at least twice a month if the RV is in hot weather or your batteries are undergoing heavy use (like when you are boondocking). Make sure that the electrolyte level never gets below the top of the internal plates, exposing them to air. And remember to always use distilled water (not tap water) for topping off your battery cells. Other water will work, but the chemicals in the water can shorten the useful life of your expensive batteries—not a good idea.

Using a hydrometer is the best way to check the state-of-charge of your house batteries, but the process can be messy and very corrosive if you are not careful with the fluid that always drips out of the tube. (There are many, many RVers who have a vast collection of shirts and jeans that are full of holes due to the sulfuric acid from their house batteries.)

However, for most RVers, it is far easier to use a digital voltmeter (even a cheap one will work just fine) to check the state-of-charge in their house batteries. An analog voltmeter (one with a needle that moves back and forth) is not accurate enough for checking the state-of-charge of batteries.

When using a digital voltmeter to check your house batteries, it is important that the batteries are at rest—neither being charged nor under a load (for example, powering a light). Turn off all house battery loads (most RVs have a master disconnect switch), and unplug the RV from shore power (so the converter won’t be charging the batteries). Now your batteries are neither being charged nor discharged, so the voltmeter reading will be fairly accurate.

The state-of-charge of your batteries can be determined by measuring the voltage between the positive and negative battery terminals. There are specific voltage readings that correspond to the amount of charge in your batteries. Many solar dealers have a chart that shows the voltage vs. the level of charge.

Because of the narrow voltage range between fully charged and fully discharged, the use of a digital voltmeter (not an analog meter) is a requirement for accurately measuring the state-of-charge of your batteries.

Here is a brief look at a chart showing the voltage level vs. state-of-charge for a 12-volt battery (or a multiple-battery bank wired to produce 12 volts).

For those of you who have Heart or Trace inverters (now Xantrex) and the proper digital monitor panel, you can check your battery status a lot easier. Let’s say, for example, that you have two 12-volt house batteries, each with an Amp hour capacity of 100 AH. Since they are wired in parallel, your house battery capacity is approximately 200 AH. You can simply read your digital monitor to determine how many AH have been drained from your battery bank. When you have drained 100 AH, your battery capacity is at about 50%, so it is time to recharge your batteries. Ah, the advantages of modern electronics.

Let me take a moment and talk about house batteries—just in general terms. The usual longevity of house batteries is about four years—but repeatedly discharging the batteries below 50% charge or letting the water level drop below the top of the battery plates will significantly shorten the life of your batteries.

Most newer RVs come from the factory with two 12-volt deep cycle batteries installed as standard equipment. However, the internal construction of 12-volt batteries is different than 6-volt batteries. The internal construction of 6-volt batteries makes them much more rugged and able to more easily accommodate the many, many cycles of discharge and charge.

When you are finally ready for new house batteries, it is a far wiser investment to get two six-volt golf cart batteries (the Trojan T-105 is the RVers’ favorite) rather than two 12-volt deep cycle batteries. You will end up with more AH capacity and longer battery life, in the long run. However, you need to be aware that the 6-volt golf cart batteries are taller than the 12-volt batteries, and not all battery compartments (such as mine) will accommodate the taller batteries. (I have been tempted, more than once, to attack my battery box with a welding torch to make it deeper.)


You should change the engine oil in your RV at or before recommended intervals. The engine and tranny in a large RV work very hard and should be treated with care and respect. If you use regular motor oil, you should change your oil every 3,000 miles or so. If you use synthetic oil, you should change oil every 5,000 miles.

Because the engine is working so hard to propel your 18,000 (or more) lbs. monster down the road, you are urged to always change the oil filter whenever you change oil—and this advice applies to both gas and diesel engines.

I also strongly encourage you to switch to synthetic motor oil in your engine. Synthetic motor oil runs cooler, provides better engine lubrication, and thus longer engine life, as well as allowing you to lengthen the time period between oil changes


The transmission in your motorhome is probably the hardest working and most abused part of your rig. Most RVers just get in their coach and drive, up hill and down, letting the transmission decide when it is time to shift.

The engine and transmission can pull a fairly good incline without shifting down— but the temperature in the transmission can climb to levels where the innards are almost frying. Many RVers find that installing a transmission temperature gauge is one of the smartest investments that they have made. Many RVers also add an additional auxiliary transmission cooler to keep their transmission fluid at cooler temperatures.

Because the transmission works so hard to push or pull your motorhome and toad down the road and through the mountains, it is strongly recommended that you change your transmission fluid, and the filter, every two years or so—and when you do, switch to synthetic oil. With synthetic oil, your transmission gets better lubrication, will run about 20-30 degrees cooler, and should give you better service in the long run.

Some RVers also change to synthetic lubricant in the differential as well, with some RVers reportedly picking up 2 or 3 miles per gallon in fuel mileage—usually when the engine, transmission, and differential are all using synthetic lubrication.


It is a good idea to periodically check the water level in your radiator or overflow reservoir, especially if you are traveling in hot weather and climbing steep grades. Check periodically to be sure that you haven’t boiled out some of the fluid (even if your temperature gauge did not show your rig getting hot).

The more recent motorhome chassis have damped temperature gauges, and the gauges will show a sharp rise in temperature only when something has gone wrong. With older motorhomes, you could watch the temperature gauge and know when you were climbing a grade and when it was time to shift down into a lower gear.

It is suggested that you change your anti-freeze every two years or so.


Most of us don’t give much attention to our brakes (or brake fluid) unless we hear funny noises when we depress the brake pedal or if we notice that our brake pedal is spongy. It is a good idea to check the thickness of your brake pads (if your newer motorhome has disc brakes) or your drum brakes (on many older motorhomes), at least once each season. Be especially concerned with the front brakes, since they do most of the work when you are trying to stop your 10-ton monster. Most disc brakes can be checked by looking at the back side of the wheel rim, but drum brakes cannot usually be seen without removing the rear wheels—and this is a real pain with dual wheels.

Of equal importance, however, and almost always overlooked by RVers, is knowing when your entire brake system was flushed out and the brake fluid replaced. Brake fluid absorbs moisture over time and results in lowering the boiling point of the brake fluid, as well as causing unwanted corrosion in brake system components. Most RVers are not aware that they should change their brake fluid every two years, just like anti-freeze.

Remove the cap from the brake fluid reservoir, and check to be certain that the fluid level is where it should be (never below the fill line). Also take a look at your brake fluid. Is it nice and clear, with maybe a little yellowish look to it, or is it an ugly brownish black? If your fluid is brownish black and not clear, it is time to have your entire brake system flushed out, new brake fluid added, and all wheel cylinders bled of air.

For those of you of a pecunious bent, (i.e., have short arms and deep pockets— who don’t like to spend money), it is true that your RV will most likely run just fine and stop just fine if your don’t change your fluids at regular intervals— but, in the long run you will save potentially expensive repair costs.)

Check Fluid Levels

Most RVers are fairly religious about checking their engine oil and transmission fluid levels to be sure they are at the correct levels, but for many folks that is all they do.

It is also suggested that you occasionally check the fluid level in your windshield washer tank and also the oil level in your hydraulic oil tank (if you have hydraulic levelers). It is only a mild irritation if your windshield is dirty and there is not enough fluid left to squirt your windows, but it can be a major inconvenience when the oil level in your hydraulic tank is insufficient for you to be able to extend your slide-outs when you arrive at your next camp site.

While you are near the front of the motorhome, take another minute and carefully look at the small hoses that run along your wiper arms and are attached to your windshield squirters. The sun and weather eventually cause these very small hoses to crack and finally break.

If you find a badly cracked or broken washer hose, the fix is easy. Almost any auto parts store carries the 1/8" rubber tubing used for the squirters. Buy about three feet of hose for each wiper. Sometimes the hose is fitted to a small fitting right on the front of the motorhome, and other times the hose goes through a small grommet on the front of the rig (disappearing somewhere inside). Just be sure you buy a long enough piece of tubing to make the repair.

Hydraulic Levelers

Yes, it is a good idea to keep your levelers in top shape. Extend your levelers as far as you can—but do NOT raise the back wheels off the ground. Crawl under your motorhome, take a clean ragn and wipe down each of the now-exposed rams (that shiny, round metal rod pushing down on the leveler foot) and wipe off any dirt and "crud" that might be present. Take a Q-Tip and carefully remove any dirt or grime around the seal where the ram retracts into the leveler. Spray a littie lithium grease on the exposed rams. Don't leave a lot of grease on the rams—just a very light coating of grease will be fine.

Entry Steps

Extend your entry steps and then squirt a dab of lithium grease (the kind in a pressurized can similar to spray paint) on every single pivot point on your steps. Then retract and extend the steps several times to spread the grease where it needs to be.

Water Heater

It is a good idea to periodically drain your hot water tank and flush out the gunk that has accumulated in the bottom of the tank. Obviously, do this when the water heater has NOT been on for several hours and both the city water and the water pump have been turned off!

Drain the water heater by removing the plug and/or anode rod located near the bottom of the tank. You can buy a special flush rod from your favorite camping supply store or make your own out of some 1/4" copper tubing.

The idea is to get some water pressure into the back of the tank and let all the gunk flow out the drain. Keep moving the flush rod around until all the gunk seems to be gone from the water draining out of the tank.

Replace the plug (and anode rod, found on some water heaters—if it appears badly pitted or mostly eaten away).

Remember to go turn on the city water supply and refill the water heater before you turn it back on. Once the water heater is filled with water, double check to be sure that the drain plug is not leaking.


Most of the time, the majority of RVers have the privilege of having full hookups— and the generator in the RV is often neglected.

Generator components, especially the slip rings, can become corroded unless they are frequently exercised.

It is a good idea to run your generator at least once a month for about an hour or so, but be sure that you have a fairly heavy load on it—like one or both air conditioners.

Of course, it goes without saying that you should change the generator engine oil and oil filter at the recommended runs times specified by the manufacturer. In general, it is a good idea to change your generator oil and oil filter about every 150 to 200 hours. If you have a new RV, the generator oil and filter should be changed after the first 50 hours of use. Manufacturers recommend changing the spark plugs after every 500 hours of operation.

If you are a Quartzsite regular, or tend to frequent other locations where there is a high concentration of dust in the air, it is a good idea to also change your generator air filter at fairly frequent intervals.

Holding Tanks

Always try to dump your tanks before your RV is stored for any length of time. If left for long periods, it is possible that fluids, especially in the Black tank, can evaporate and leave a pile of sludge on the bottom of the tank that hardens as the water content diminishes—definitely not a good thing to happen. If your Black tank is less than ½ full, flush the pot several times or add water until you have your Black tank almost 3/4 full. It is the swirling action of the water as it exits that helps to pick up and remove most of the “stuff” at the bottom of the tank.

Get in the habit of not putting any food waste down the sink. Wipe off your dishes with paper towels, scrape scraps into the garbage can—try not to get any food waste into the Gray water tank, where it can decompose and make a terrible stink, sometimes rivaling that of the Black tank.

RV Exterior

The best advice that I can give you in this area is to not waste lots of money on all the fancy potions for keeping your exterior looking shiny and fresh. Wash your RV three or four times a year with a good quality automotive soap and clean water. Then, after drying your RV, apply a good coat of automotive wax. A wax that is primarily carnuba wax is the best. Forget all the fancy stuff.

If your motorhome or trailer has been neglected and is oxidized, there are many automotive potions that you can get at your local auto parts supply house. If you are less inclined to do-it-yourself, many of your favorite RV store locations have the facilities, equipment, and personnel to do the job for you—but at a fairly hefty price.

Air Conditioners

The majority of RVs today have roof-mounted air conditioners. As long as they are working, we tend to forget all about them (other than being careful while driving under low-hanging trees).

I strongly suggest (from first-hand experience) that at least once a year you climb up on top of your RV and check the plastic enclosures that surround your air conditioners. After a few years in the sun, the plastic coves break down from the UV exposure, and crack around the front bolts that secure the cover to the air conditioner unit. As time progresses, these cracks get wider and longer. Then one day while you are cruising down the freeway in a stiff crosswind, you might unexpectedly hear a funny “thump” sound and maybe even glance at your side mirror and be more than a little surprised to see your air conditioner cover flying across the roadway!

While returning from my annual pilgrimage to Quartzsite a few years ago, I happened to lose both of my air conditioner covers, with only three days between happenings. Fortunately, in both cases, I was near my favorite camping supply store and was able to get replacement covers by using plastic money. (Getting the covers is the easy part. Trying to free up frozen bolts on top of your motorhome can be a most “interesting” and very frustrating experience.)

Be safe, rather than sorry, and check your air conditioner covers for the tell-tale cracks around the bolt holes. Once you notice the cracks, replace the covers before they fly off and hit another vehicle. If you just happen to be in heavy traffic, you could unfortunately and without intent, cause a massive traffic accident, as other drivers try to avoid your flying missile.

For most of us, it is far too easy to forget about the simple maintenance tasks— such as taking the time to clean or replace the air filters in our air conditioners. The rather poor-quality mesh filters fouond in most roof-top air conditioners is easy to remove from inside the RV. Simply take it to the sink, rinse it out until the water flowing through it is no longer dirty (and the filter looks clean to the eye).

Ideally, this task should be done every three months or so, but many of us seem to forget about this task.

If you have a basement air unit, there are usually two or more regular furnace-type filters located under the bed. These filters, too, should be replaced on a regular basis. It is a simple matter to raise the bed, and look at the condition of the filters. You will often be surprised at just how dirty they have become—sometimes making the "missus" question her house-keeping ability.

The only problem that you might encounter with basement air filters is that some of them seem to be a non-standard size (not readily available at your local home improvement store).

Auxiliary Braking System

Yes, folks, even your toad brake should be checked every now and again. The most important thing to check is that your break-away system functions properly. After lots of road use, it is possible for your break-away connector to get very corroded and cease to function properly.

About every six months or so, check your break-away system. When you are hooked up and about to head off on another adventure, take an extra minute and check your break-away operation. Go to the front of your toad and physically pull the break-away plug out of the socket on the front of the toad. Be sure that the toad brakes have been applied by your toad brake system—go take a look. Then, while you have the connector in your hand, look it over carefully and see if it looks OK. The electrical contact parts should not look oxidized or corroded. If you see this, take a few minutes and clean up the connections on both the plug and the socket.

While you are checking over your toad brake system, now and then take a few minutes and carefully examine all the parts of your towing setup—the hitch, drawbar, hitch ball, baseplate, tow bar parts, and the tow bar itself. Look closely for any welds that look like cracks have developed or parts have become loose. It has happened in the past, that some where in the towing setup, a part or parts (usually welded) have failed—and, yes, toads have become detached from the unit towing them.

Be safe—rather than sorry. A few minutes checking your towing setup might well be the best few minutes you have spent.

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