Mechanical tips for the new bus owner

By Mark R. Obtinario

Most of us when we have purchased a bus have little or no clue as to where to start now that we have the bus in our possession.

Most of us would not have purchased a bus if we didn't have some confidence in our ability to repair and maintain our bus.

Most of us have some experience and knowledge in shade tree mechanics.

But when we open the hood of the bus we get overwhelmed by the size and the scope of what is under the hood.

I have a few pointers as to where to start.

The bad news is the power package is the most expensive part of the bus. If it goes bad it is going to cost many thousands of $$$ to fix or replace.

The good news is that regardless of the power package, the power packages installed in buses were designed for much longer service lives than the family car or pick-up. Given even rudimentary care the power package in a bus should last longer than the bus body.

Having said that, oil is comparatively cheap. Buy the best, keep it fresh, keep it topped off, and make sure you get the proper oil for the engine.

If you have a Detroit Diesel 2-cycle engine the only oil you should be using is Chevron Delo 100 40wt down to 30 and Chevron Delo 100 30wt below 30. Delo 100 is the only oil that is approved by DD. Use of multi weight oils in a 2-cycle DD is a waste of good oil and can ruin your engine. Because of the characteristics of the 2-cycle engine the oil will work as if it is the low weight number and not the high weight. 10wt or 15wt is not nearly heavy enough for a diesel engine.

If you have a 4-cycle diesel engine you need a good heavy duty diesel engine oil like Rotella, Delo 400, Ursa, etc. Multi weight oils are okay to use in 4-cycle engines. Synthetics are okay as long as they have the correct service requirements. It can become a real cost item since most bus engines are going to take more in gallons than most cars take in quarts.

If you have doubts about how good your engine is, invest in oil sample analysis. It is not expensive and can give you peace of mind.

The cooling system on a bus is huge. Most are in excess of 20-gallons. It takes a lot of coolant to fill the system from a rear engine to a heater/defroster core by the front windshield. If you have a problem with a leak it can get very expensive very fast if the leak isn't fixed properly.

If you have a leak and have to break into the system, each heater core has a bleed screw built into it somewhere. If you don't bleed the system you will never get the system purged of air and you can end up with voids in the system that can cause hot spots in the engine.

Most diesel engines have some sort of cylinder liners. Some are dry. Some are wet. In either case you have dissimilar metals that can result in electrolysis. The electrolysis can be especially severe if the engine isn't run on a regular basis. The explosive nature of the diesel combustion process can also cause cavitation in the water jacket. Keeping your coolant up to snuff can't be emphasized enough. Cavitation and electrolysis is exacerbated if you don't have good coolant. The use of a water filter with an additive package or an additive package added to the coolant is not a bad idea. NAPA has an additive product called Nacool which works well.

Make sure your radiator(s) and cooler(s) are kept clean and free of debris. If you have anything except for a front engine bus you are working against fluid dynamics to get air to go through your radiator. The more you make it easier for the air to not go through your radiator the more problems you will have with overheating.

Don't go cheap on filters. Fram may be okay for the family car but you want premium filters like Napa Gold, Wix, Baldwin, Fleetrite, etc. for your diesel engine. If you have an automatic transmission you will have oil, transmission, water, fuel, and air filters. Many times you will have more than one for each.

Diesel injectors and pumps can have their useful life greatly shortened if any water gets into them. Keeping your fuel clean and free of water is very important. If you get moisture in your tank you will also get algae growing in there as well. Moisture and algae can really plug up fuel filters quickly. Use of an algaecide is not a bad idea if you have had problems or if you don't anticipate running your engine any time soon. Raccor water/fuel seperators are a good add on, particularly if you don't run your engine very often. Purchasing fuel at a location that dispenses a thousands of gallons of fuel every day will reduce your chances of getting bad fuel.

To keep everything working correctly you need to take your bus out for a run once in a while. Sitting and not moving is bad for the tires, it can allow all of the oil to drain off of gears in the transmission and rear end allowing rust to form, and piston rings can rust to the cylinders and break when trying to start. When I say run, get your bus out on the road and give it a good run--long enough that the engine is up to full operating temperature.

If you are busy converting your bus and it isn't in a condition that will allow you to run down the road prepare your engine for storage and leave it alone. Running a diesel engine, even at fast idle, for extended periods of time is harder on it than not running it. Turning it over once in a while (not starting, just turned over) to keep things loosened and lubed is not a bad idea.

Batteries and tires have a service life that is shortened if they are not used. The more they sit the sooner they will fail. If your bus is going to be laid up for quite a while during your conversion process you will need to plan on spending the $$$ for replacements before you start out on the road. Regardless of the amount of tread, your tire's sidewalls will fail if they have sat for several years. Exercising your bus will also exercise your tires. The oils in the rubber in your tires will move around keeping the rubber pliable. By not moving the rubber will dry out and lose pliability. It can also allow the steel belts to rust. Either will cause premature tire failure, most often in the dark, a long way away from help, and most probably in the rain nor snow.

Don't run your bus on fast idle to keep your batteries charged. It wastes fuel, it is hard on the engine, and it can be accomplished by a trickle charger much more efficiently.

Most buses will get to you with space for two 8D or mulitple Group 31 batteries. You will not need that much battery capacity to start your bus unless it is really cold and it has been a long time since you started your bus. One large CCA Group 31 is sufficient to start most 12-volt diesel engines. If your bus is 24-volt you are going to need at least two 12-volt batteries.

If it has been a long time since you have started your bus there are some things that can help you start you bus.

First, make sure your battery(s) are fully charged.

Second, make sure your battery cables are clean and tight on both the battery(s), the starter, and the ground. A diesel engine uses the heat of combustion to keep the fire going. A slow cranking engine will not create enough heat to get the engine to fire properly.

Third, if you can, plug your engine heater in before you try to start. Your engine has a lot of metal that needs to heat up before you have proper combustion. The warmer the ambient temperature and the warmer the block is the easier it will be for your engine to start.

DO NOT use starting fluid. If you have to use starting fluid you have other issues you need to address.

Investing in shop and service manuals for your bus is a good use of your $$$. You may not be able to find specific manuals for your bus but the engine and transmission companies still have their manuals available. You may not have the tools or the capabilities to actually do the work but you will have a better idea of what is involved when a technician tells you about a problem with your bus.

If your bus has air brakes you should take the time to take a class in air brakes. They are usually available at your local tech school, community college, or sometimes by companies that sell air brake products.

Good luck and remember this is all supposed to be about fun.