Common DIY (Do It Yourself) repairs/maintenance

Biodiesel/SVO specific repairs and modifications
The absolutely most common problem with running biodiesel is its compatibility, or lack thereof, with rubber components. This includes nitrile, buna-N and most other rubber and rubber-like compounds. The one compound that shows long-term compatibility with BD is Viton. But…., most vehicles since 1995 will have synthetic hoses that will tolerate BD well. The newest Mercedes hoses withstood BD compatibility tests for 6 months with zero degradation. So, if you cannot find Viton hoses, just replace all of your flexible lines (rubber hoses) with new OEM lines. Also, most Gates? brand hose will tolerate BD and they are working towards all of their hoses B100 compatible.

Filter changes. B100 has the habit of super-cleaning out old fuel systems of all the gunk and crud that has deposited in the fuel system through the years. An injector pump will be destroyed by the smallest dirt or crud particle and changing the filters for the first few tanks of B100 will be required. Most in-line filters are not rated to a very low micron rating (25-50 is good for an inline), but they take out the large particles to keep the primary filter from clogging. The primary filter should filter down to 5 microns. If they don’t, find another brand that does. The smaller the particle, the longer the IP will last.

Occasionally use a biocide or algaecide in your fuel (BD is still susceptible to algae contamination.)

Injector service
Most injector nozzles will last between 100,000 and 150,000 miles. Rebuilt injectors are a common fix to “nailing” problems (similar to detonation in a gasoline engine.) Nailing is caused by a leaking injector allowing fuel into the air mixture before it is fully compressed, causing a “micro-combustion” while the piston is still low on it’s upstroke to compression.

Oil changes
Most anyone can or can changed the engine oil in their vehicle at one time or another, so I’m just going to go over the basics and some tips and safety warnings.

For those who use petroleum engine oil (as opposed to synthetics), remember “hot, often and overnight”. Change the oil while hot, change it at least every 3-4,000 miles (more if used in dusty or overheating conditions) and let it drain overnight.
Always use a new filter (OEM, NOT a “Fram” or other discount store filter) and fill the filter with oil before installing into car.
On Mercedes, change the two O-rings on the housing cover spout (old, hard O-rings allow the oil to drain-back into the engine when sitting and can cause starvation of the main and rod bearings at start-up.) Also, un-bolt and lift-off the oil filter housing cover BEFORE draining the oil (this allows about a quart of dirty oil to drain to the pan for removal.)
Always use a large drain pan and save the old oil for recycling (most auto stores take it for free.)
Wear gloves (rubber, nitrile, etc.) while doing ANY maintenance on diesels.
While the oil is draining from the pan, take the time to lube the suspension with a grease gun, the door hinges, hood hinge, power antenna, etc.
When finished DO NOT over-tighten the drain plug OR the oil filter!
DO NOT forget to replace the oil before starting
Add just a bit less than the specified amount of oil, start the engine, let it idle for a little while, shut it off, let the oil drain back to the pan and then adjust the level.

Filters and other engine maintenance
Changing the air and fuel filters often will be rewarded with year’s worth of reliable service from your vehicle. Since you are doing this yourself, you can afford to do this maintenance more frequently.

Transmission oil and filter changes
This is one of the more important and MOST neglected maintenance jobs on a vehicle. Feel free to email your instructor at the above email for tips and guidance on doing this job. You CAN do it yourself and save a TON of $’s AND save your transmission!

Lubricating the chassis

Most older cars have “zirc” fittings that you can grease with a grease gun. Just pump one or two pumps, don’t pump so much that you “pop” the seals off the suspension component.

Clean any excess grease off the fitting and seals.

For rear-wheel drive vehicles, jack the front end of the car up and use jack stands under it to support the frame so the front wheels are off the ground. Check the wheel bearings for play If play is found, it’s time to re-pack the bearings with grease and then re-adjust them (see your manual, ask about this in class or email me at Boulder Biodiesel for guidance.)

Valve adjustments
On older diesel engines, the valves were not adjusted with hydraulic lifters, but need to be manually adjusted every 12-15,000 miles. This is a DIY job for most with even the basic mechanical skills (my mother did this on our car when I was a kid) and will keep your engine running smooth and powerful (see your manual, ask about this in class or email me at Boulder Biodiesel for guidance.)

Common “old car” (10 years or older) issues

Overheating
This is probably one of the most common issues that us “old car aficionados” have to deal with. Here are some of the more common causes and how to “fix” them:

Overheating can be caused by anything that decreases the cooling system’s ability to absorb, transport and dissipate heat. These can be a low coolant level, loss of coolant (through internal or external leaks), poor heat conductivity inside the engine because of accumulated deposits in the water jackets, a defective thermostat that doesn’t open, poor airflow through the radiator, a slipping fan clutch, an inoperative electric cooling fan, a collapsed lower radiator hose, an eroded or loose impeller or even a defective radiator cap.

Thermostat
Severe overheating can often damage a good thermostat. If the engine has overheated because of another problem, the thermostat should be tested or replaced before the engine is returned to service.

One way to check the thermostat is to start the engine and feel the upper radiator hose (or use an infrared noncontact thermometer to read its temperature). The hose should not feel uncomfortably hot until the engine has warmed-up and the thermostat opens. If the hose does not get hot, it means the thermostat is not opening.

Another way to test the thermostat is to remove it and dip it into a pan of boiling water (it should open). The exact opening temperature can be checked by using a thermometer.

If the thermostat needs to be replaced, install one with the same temperature< rating as the original. Most cars and light trucks since 1971 require thermostats with 192- or 195-degree ratings (or 80deg C in most German vehicles.) Using a cooler thermostat (160 or 180) in an attempt to "cure" a tendency to overheat can increase fuel and oil consumption, ring wear and emissions. On newer vehicles with computerized engine controls, the wrong thermostat can prevent the computer system from going into closed loop resulting in major performance and emission problems if the engine fails to reach its normal operating temperature.

Cooling system leaks
Loss of coolant because of a leak is probably the most common cause of overheating. Possible leak points include hoses, the radiator, heater core, water pump, thermostat housing, head gasket, freeze plugs, automatic transmission oil cooler, cylinder head(s) and block.

Make a careful visual inspection of the entire cooling system, and then pressure test the cooling system and radiator cap. A pressure test will reveal internal leaks such as seepage past the head gasket as well as cracks in the head or block. A leak-free system should hold pressure for at least a minute or more.

It’s important to pressure test the radiator cap, too, because a weak cap (or one with too low a pressure rating for the application) will lower the coolant’s boiling point and can allow coolant to escape from the radiator.

Fan
With mechanical fans, most overheating problems are caused by a faulty fan clutch - though a missing fan shroud can reduce the fan’s cooling effectiveness by as much as 50 percent (depending on the fan’s distance from the radiator), which may be enough to cause the engine to overheat in hot weather or when working hard.

Defective fan clutches are a common and often overlooked cause of overheating. The shear characteristics of the clutch fluid gradually deteriorates over time, with an average loss in drive efficiency of about 200 rpm per year. Eventually slippage reaches the point where effective cooling is no longer possible and overheating results. (On average, the life of a fan clutch is about the same as a water pump.If one needs to be replaced, the other usually does too.)

If the fan clutch shows signs of fluid leakage (oily streaks radiating outward from the hub of the clutch), spins freely with little or no resistance when the engine is off or wobbles when the fan is pushed in or out, it needs to be replaced.

With an electric cooling fan, check to see that the fan cycles on when the engine gets hot and when the air conditioner is on. If the fan fails to come on, check the fan motor wiring connections, relay and temperature sensor. Try jumping the fan directly to the battery. If it runs, the problem is in the wiring, relay or sensor. If it fails to run, the fan motor is bad and needs replaced.

Water pump
Any wobble in the pump shaft or seepage would call for replacement. In some instances, a pump can cause an engine to overheat if the impeller vanes are badly eroded due to corrosion or if the impeller has come loose from the shaft. The wrong pump may also cause an engine to overheat. Some engines with serpentine drive belts require a special water pump that turns in the opposite direction of those used on the same engine with ordinary V-belts.

Belts & hoses
Check belt tension and condition. A loose belt that slips may prevent the water pump from circulating coolant fast enough and/or the fan from turning fast for proper cooling.

The condition of the hoses should also be checked and replaced if they are over 5 years old (though older Mercedes have gone on as long as 25 years.)

Sometimes a lower radiator hose will collapse under vacuum at high speed and restrict the flow of coolant from the radiator into the engine. This can happen if the reinforcing spring inside the hose is missing or damaged.

Radiator
The most common problems radiators fall prey to are clogging (both internal and external) and leaks. Dirt, bugs and debris can block air flow through the core and reduce the radiator’s ability to dissipate heat. Internal corrosion and an accumulation of deposits can likewise inhibit coolant circulation and reduce cooling. A good way to find clogs is to use an infrared thermometer to "scan" the surface of the radiator for cold spots. If clogged, the radiator should be removed for cleaning or be replaced.

Back-flushing the cooling system and/or using chemical cleaners can remove rust and hard water scale, but may do little to open up a clogged radiator.

When refilling the cooling system, be sure you get it completely full. Air pockets in the head(s), heater core and below the thermostat can interfere with proper coolant circulation and cooling. If the cooling system has no bleeder valves to vent air, you may have to temporarily loosen a heater hose to get all the air out of the system.

Some less common problems that can cause overheating

Excessive exhaust back-pressure
A clogged catalytic converter (on newer diesels) or muffler is usually the culprit here, but don’t overlook the possibility of a crushed pipe or a collapsed double wall pipe. Inspect the exhaust system any time you hit a curb or run something over.

Overheated incoming air
Make sure that your cold air intake system is intact and a new air filter is installed at frequent intervals.

Dragging brakes
A caliper that’s sticking or a parking brake that isn’t releasing may be making the engine work too hard.

Overworking the engine
The cooling systems in many passenger cars today are marginal and have little excess capacity to handle extra heat generated by towing or high speed mountain driving in hot weather. Give it a break if the engine starts overheating. The hotter it gets, the less power it will produce and this can cause a domino effect with the driver pushing the engine harder to maintain, causing the engine to overheat more, causing a loss in power, then starting the cycle over again. There are MANY more things that can be covered, and many common items that I’m sure I’ve forgotten to include, so make notes during the class and feel free to email me with any questions regarding your vehicle maintenance or repairs.