Wecome To RVs and OHVs

This blog is all about RVs (recreational vehicles) and OHVs (Off Highway Vehicles), camping, and survival
and how they work together to provide wholesome family fun and great learning opportunities.
Many posts are intended to familiarize novice campers and RVers with RV systems and basic camping and survival
skills. But even experienced RVers and campers will enjoy the anecdotes and may even benefit from a new
perspective. Comments, questions, and suggestions are encouraged.

Friday, April 28, 2017

Motorhhome Mechanical Maintenance

Motorhomes have at least all of the mechanical components and systems of other motor vehicles, like your car or truck.  That being said, you will have to perform the same regular maintenance (oil changes, chassis, lube, brake service, etc) as are needed on you daily driver.   However, because motorhomes don't get as much use as our daily drivers, the maintenance intervals may be more likely to be determine by the calendar instead of the odometer. 

Be sure to follow the maintenance schedule in  your vehicle owners manual.  Unless you are taking a long trip, you'll  probably need to schedule oil chances and chassis lubes based on time rather than mileage.  At the very least you should change the oil and lube the chassis at the beginning of each season.  It is also a very good idea to change the oil at the end of the season before you put it into storage for the winter.    That means you could sometimes log zero miles between the pre-storage oil change and the start of season oil change.  Why would  you need to do that?  Well, you should be running the engine at least a few minutes each month while it is in storage but even without that,  the oil in the crankcase will absorb some contaminates left behind from before the oil was changed and moisture can accumulate during storage and affect the oil.  Always install a new oil filter when  you change the oil.  If you do the oil change yourself, examine the old oil for possible problems:  metal shavings, moisture, antifreeze, or a burned smell.  Metal shavings sometimes show up in new vehicles as a result of left overs from the manufacturing process but in older engines they are a sign of internal problems and excessive wear.  Moisture may just be from condensation during storage but antifreeze indicates a coolant leak into the engine.  The most common problem is leaking head gasket but it could also come from cracks in the head or the block.  A burned smell indicates the engine has been overheating.  An engine can overheat from internal resistance enough to scorch the oil without ever raising the coolant temperature enough to be reflected on the temperature gauge or to activate the "idiot light".  If you find and evidence of problems you should seek to have them diagnoses and corrected before they can cause further damage.  Chassis lube should be performed together with each oil change.  Be sure you can identify and access all the lubrication points if you are doing this yourself or take it to a qualified specialist.

Air filters should be checked whenever you change the oil or more frequently if the vehicle is being operated in dusty conditions.  Dirty, clogged filters should be replaced.  Clogged filters negatively affect performance and fuel economy.  Replacement paper filters are inexpensive and are easy to change.  An alternative for increase performance is to install a K&N reusable air filter.  These are oil-charged and can be cleaned and reused over and over.  They also are less restrictive than ordinary paper filters, increasing the flow of air into the engine. 

Fuel filters should be inspected and replaced per the vehicle maintenance schedule.  A clogged fuel filter may cause fuel starvation, decreasing both performance and fuel economy.  Many large vehicles have more than one fuel filter, so be sure to locate and replace all the filters.  There may be a small filter in line near the engine and another one back near the fuel tank.  Some filters are internal to the fuel tank and therefore are impossible to inspect and difficult and expensive to change. 

Check the coolant in the radiator.  If it is low there may be a leak that needs correcting.  Typical places for leaks are radiator hoses, heater hoses, heater cores, and the radiator itself.   Correct any leaks and top off with the proper coolant.  If there is any sign of oil in the radiator there is internal engine damage, such as crack in the head or block, that is allowing oil to be forced into the cooling system.   Some cooling system leaks can be temporarily cured by  adding stop leak to the radiator.  However, anything that can plug leaks can also plug the radiator core so it is better to have the leaks properly repaired.

Motorhome transmissions undergo a lot more stress than the one in you family car.   The size and weight of the motorhome are the major factor but it may also be affected by towing a dinghy or a trailer.  You will want to keep a close eye on the transmission fluid.  Automatic transmission fluid should be a deep reddish color.  If it is brown or black or smells burned, the transmission  has been overheating and is in danger of failing.   Check the fluid level when the transmission is warm (vehicle has been driven at least a few miles), with the transmission in PARK and the engine idling.  If it is low, add fluid to bring it up between the marks on the dipstick.  Sometimes if I need to add fluid I will use Lucas transmission additive instead of plain transmission fluid.  The Lucas product contains additives to reduce friction and to treat seals and gaskets to keep them pliable and working well.

Wheels and tires.   Check tire pressure before each trip and, preferably, every morning before hitting the road.  When you stop for gas, lightly touch each tire to see how hot they're getting.  All the tires can get pretty hot on a hot day, but if one tire is hotter than the others, it may be under inflated or there may be some abnormal resistance, such as a sticking break or a bad wheel bearing.   Inflate your tires according to the vehicle manufacturer's recommendations or the the maximum pressure on the sidewall.  For even better pressure settings, have each wheel weighed at a truck scale and use tire weight inflation chart to match the tire pressure to the actual load on each tire.  Over inflation will cause excessive wear in the center of the tread and usually the reduction in surface area in contact with the road will make the vehicle feel squirrelly and ride rougher than normal.  Under inflation will cause excessive wear on both outside edges and cause the tire to overheat and the vehicle to feel sluggish.  Turning the front wheels when stopped may be harder and you might hear tire squeal on turns.   Excessive wear on just one outside edge indicates an alignment problem.  Cupping of tires indicates an out-of-balance condition.  When inspecting your wheels and tires, be sure to check the lug nuts and look for any damage to the wheels.   Damage maybe in the form of dents that come from impact with obstacles or cracking from vibration.  Loose lug nuts might be indicated by a shiny ring behind the nut even if the nut feels tight.  At the very least check the tightness of all lug nuts periodically using your lug wrench.  For an even better check and added peace of mind, check the lug nuts using a torque wrench to be sure they are properly tightened.  Check with your local mechanic or tire shop if you can't find the torque specs in you owner's manual.

Wheel bearings.  The rear wheel bearings on most vehicles are lubricated by oil from the differential.    Front wheel bearings require grease and should be checked and service at least once a year.  You have to remove the hub to get to the wheel bearings.  Once you have the bearing out, inspect it for wear, contamination, and loose or missing balls.  If there are loose or missing balls, replace the bearing.  Inspect the race (the part the bearing rides on in the hub).  If it is rough or shows other signs of wear, it may also need to be replaced.  Usually you can press or drive the old race out and press in a new one.  If that doesn't work,  you will have to replace the hub.  If the old bearing is serviceable, clean it with solvent and dry it thoroughly.  Then pack it with wheel bearing grease.  You can buy a tool to pack bearings.  It consists of pair of shallow cones that clamp on the sides of the bearing and has a grease fitting through which you force grease with a grease gun.  The old mechanics standby method of packing wheel bearings doesn't required any tools, just your bare hands.  Put a dollop of grease on your non-dominant hand.  Hold one edge of the bearing with the wide side down in your dominant hand.  Press the bearing down into the grease  until is squeeze out the top side of the bearing.  Then rotate the bearing to put grease into the next segment.  Continue until the entire bearing has been filled with grease.  When reinstalling the hub, tighten the axle nut to the torque specified for your vehicle.  It it is too tight it will put extra  pressure on the bearing and cause excessive wear and over heating.  If it is too loose the bearing will rattle and wear unevenly and the wheel may wobble.  The axle nut has a slotted cover through which a cotter pin is inserted through a hole in the end of the axle to prevent the nut from spinning as the wheel turns.  Always use a new cotter pin.  The old one will have been weakened by bending and unbending during installation and removal and might fail.

Air conditioners.   Many motorhomes are equipped with automotive dash air conditioners.  There is little owner maintenance associated with these systems other than to make sure the condenser (looks like a small radiator in front of the radiator) is clean, that the fan belt is in good condition and properly adjusted, and that the clutch on the compressor goes on and off as you turn the A/C on and off.  Testing and refilling the coolant in the system requires special equipment and training.

Belts and hoses.  Belts and hoses are made of rubber and are subject to deterioration over time as well as wear and tear from use.  Inspect the fan belts to be sure they aren't frayed or show signs of slipping (a slick, high gloss on the side of the belt that contacts the pulleys).  Check to see if they are properly adjusted.  You can usually adjust a belt by loosening one of the accessories it drives, like the alternator, power steering pump, or air conditioning compressor, pushing the accessory to tighten the belt (you might need some leverage such a a large screw driver or small crow bar to do this), and then re-tightening the mounting bolts for the accessory.  Any frayed, cracked or badly stretched fan built should be replaced.  There may be multiple fan belts.  Sometimes they are simply redundant or added safety but usually there are different belts for different accessories.  Be sure to inspect and adjust all the belts.  Many newer engines have a serpentine belt instead of fan belts.  Serpentine belts are wider and flatter than regular fan belts and the inside of the belt has rubber teeth that fit into corresponding teeth on the pulleys or sprockets.  Serpentine belts weave around wrapping around several pulleys on the front of the engine.   If your vehicle has a serpentine belt instead of fan belts and it is damaged, it will have to be replaced.  There will be a tensioner that holds the belt tight.  It usually has notch  or square slot to fit a 1/2" ratchet to move the tensioner so the belt can be removed.  It also has to be moved to install the new belt.  Unless the tensioner is damaged, it should automatically maintain the proper tension on the serpentine belt.  Check all the clamps on radiator and heater hoses.  These are common points where leakage occurs and can usually be corrected by tightening the clamp (if it is a screw type clamp that can be tightened).  Crimp clamps may have to be replaced.  Make sure the leak is from the end of the hose and not around the clamp where over tightening may have weakened or cut into the hose.  Heater hoses often leak at the connections and often there is enough slack to cut off the damaged end and reinstall it without having to replace the entire hose.   If the hose is hard and brittle it will have to be replaced.  After checking the clamps on the radiator hoses, squeeze them where you can reach them to see if you can feel any weak spots.  Those with  internal wire reinforcing will be difficult to test this way, but plain rubber hoses often have soft spots you can feel.   When you find one with soft spots, replace it before it ruptures and allows the coolant to escape and cause the engine to overheat.

The engines for on board generators required the same kind of regular service as the vehicle engine:  change oil and filter, check and, if necessary, replace air and fuel filters.  The schedule for the generator motor is normally done according to hours on the meter but it is always a good idea to service it at least once a year regardless of low use.  Check spark plugs.  If burned or crusted, clean or replace, being sure to set the gap to the proper measurement.  Most RV generators are air cooled.  But, if yours is liquid cooled, inspect the coolant, hoses, and radiator as you would the vehicle cooling system.

Some motorhomes are equipped with hydraulic or electric leveling jacks.  The jacks themselves need to be inspected, cleaned, and lubricated.  The hydraulic fluid level needs to be checked and proper hydraulic fluid added if it is found to be low.  DO NOT use regular motor oil!  Check all the electrical connections and clean an tighten as necessary.

Motor  on!

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