Q: When I am driving my truck on the road the oil pressure gauge jumps around. I have checked the oil and it is at the full mark. What could be the problem?

A: Don’t ignore this. If your engine is running low oil pressure, then internal engine damage could result. However, you may be just getting a faulty reading since the gauge is acting erratically. Your oil pressure gauge works with the oil pressure sensor, which is screwed into the block, to transmit a reading. A faulty oil pressure sensor can cause the reading on the gauge to be erratic. You may have a bad oil pressure sensor. You should also inspect the wires going to the sender to make sure they are not loose, corroded, or shorted. If a new sending unit doesn’t work, you can check the oil pressure with a manual pressure gauge. Then you will need to determine if you have a gauge problem or an actual oil pressure problem.

Q: How do I find my vehicle's oil filter wrench size?

A: Go to an auto parts store and look up the replacement oil filter for your vehicle. Then just use that filter as a guide when selecting the correct wrench size.

Q: How tight should I tighten the oil filter when I do an oil change on my car?

A: Check the directions on the oil filter or the oil filter packaging. Generally most oil filter manufacturer's recommend putting a thin film of oil on the gasket, spinning the oil filter on until the gasket contacts the engine, and then turning the filter another 3/4ths to 1 full turn. Always follow the directions that come with the filter.

Q: What could cause blue smoke to come from my car’s tailpipe?

A: Blue smoke indicates oil burning. This usually signifies that the piston rings are worn. When the piston rings are worn, oil can bypass the piston and enter the combustion chamber. The oil is then burned with the air-fuel mixture. Your engine may need rebuilding.

Q: What is the difference between 5W-30, 10W-30, and 10W-40 oils?

A: The difference in the oils is viscosity. Viscosity is defined as the resistance to flow. Oils that have two numbers in their rating are called multi-grade oils. Oils that have lower numbers are lighter (thinner) than oils that have higher numbers. Multi-grade oils are tested at various temperatures, allowing them to be used in a variety of climates and conditions. When the engine is cold the oil must be thin enough to get to all of the engine’s components, but when the engine warms up the oil must not be too thin as to enhance engine wear. For example, 5W-30 oil acts like SAE 5 when cold and SAE 30 when warm. Always refer to your owner’s manual for the correct viscosity rating for your vehicle.

Q: The oil drain plug on my car does not get tight. What can I do?

A: The oil drain plug’s threads are stripped out. This can happen if the plug has been over-tightened. You have two options. Replace the oil pan or use an "oversized" self-tapping oil plug to create new threads.

Q: I recently had my oil changed and now it seems that my engine is leaking oil. What could cause it to leak related to the oil change?

A: On some vehicles when the oil plug is removed oil may collect in a frame member. This is a poor manufacturer design, but does happen on some vehicles. If the technician doesn’t clean inside this frame member it will appear that the engine is leaking oil. However, the old oil is just dripping from where it collected on the frame. If this is not the case, check to see if the oil is leaking from the oil plug or oil filter. Some oil plugs have rubber or plastic gaskets. Over time this gasket can become cracked. Another thing that could have happened is that the old oil filter gasket got stuck on the engine block without the technician noticing it. If the new oil filter is installed without removing this old gasket, an oil leak will develop.

Q: I took off my oil cap and noticed a white mucus type material. What is this and is it harmful to my engine?

A: It sounds like you have sludge buildup in your engine. This is generally caused by not changing the oil at regular intervals. Some owner’s manuals indicate oil change intervals of 5000-7000 miles. I would change the engine oil every 3 months or 3000 miles - whichever comes first. Sludge in the engine will increase friction, reducing the engine's life. There are oil flush additives that you can use to try and get rid of this gunk. Go to your local parts store and ask for an engine flush additive. You can also check with local repair facilities that have more aggressive methods to flushing the engine by using a special machine.

Q: What will happen if I mistakenly put in 10W-30 in my engine instead of what the manual calls for – 5W-30? Will it cause damage?

A: The difference between 5W-30 and 10W-30 is the viscosity (thickness). Many new cars now recommend 5W-30 to be used all year long. While others, indicate that it is OK to use 10W-30 in warm climates. The lower viscosity (5W-30) is used to circulate the oil quickly throughout the engine when the engine is cold. Check your owner’s manual and see if the manufacturer allows the use of 10W-30 during warmer climatic conditions. The correct viscosity of oil should be used so that the warranty will not be void.