How To: Perform maintenance cleaning of common parts.

Routine maintenance falls into many categories such as replacing spark plugs, cables, air filter, breather element (if equipped), cabin filter (if equipped), fuel filter, cleaning battery terminals, fluids, etc. There are other things which are just as important, but don't usually get cleaned such as the mass air flow sensor, idle air control solenoid, PCV, and the air charge temperature sensor. Those parts either get cleaned or replaced once there is a problem, but not as preventative maintenance.

This is the mass air flow sensor on a 1995 Aerostar with a 3.0L:

This is the recommended chemical spray for cleaning it:

Some chemicals leave a residue behind that sticks to the element, and causes it to attract dust & dirt. This spray leaves no residue, and evaporates quickly. This is the inside with a block off plate held in place with two T-20 security Torx screws:

It's not necessary to remove anything other than this plate to get to the two internal elements. Here is a view with the plate removed:

The two elements are shown in the small cut out of this picture as well as the opposite side of the MAF:

This is a diagram of how the MAF works:

The next thing on the list is the throttle body. The plate should be cleaned on both sides with fuel injection safe intake cleaner:

This will clean, and lubricate the moving parts of the throttle body. Don't use carburetor cleaner on a fuel injected engine! Oxygen sensors, and other parts might get ruined if you use harsh cleaning chemicals that are not approved for fuel injected vehicles. The next part on the list is the idle air control solenoid valve. Spray intake cleaner into these two channels on the bottom of this part:

The next part is for the 3.0L engines. It's the air charge temperature sensor which is on the top of the intake manifold:

This is what the sensing element looks like:

The small stem in the open part of the housing detects the temperature of the air flowing into the engine. This is a graph of the temperature curve in proportion to voltage:

This is the pin out for the sensor:

The last thing on this list is the positive crankcase ventillation (PCV) valve:

This part usually gets replaced, but a few blasts of cleaning spray does a good job getting all of the oil deposits out.

Another neglected part of maintenance cleaning is the oxygen sensor. Some are easy to reach while others are a major project to remove. As technology progresses, the vehicle's computer requires more precise metering of the proper fuel mixture. Older vehicles had a single wire O2 sensor while others (such as my 95 Aerostar) have a 4 wire sensor. Some vehicles have 4 oxygen sensors making things even more complicated. To start, you will need the proper tools to remove them. Here is a master tool kit:

This is a crow foot set:

This is a heavy duty socket to remove stubborn sensors:

This is a socket made by K-D tools on top of the oxygen sensor:

This tool uses a 1/2" drive ratchet. If you see that the sensor is stuck, one trick is to loosen it, then tighten it, then loosen it again. The twisting action will help break it free before the socket breaks first. The sensor should be sprayed with a cleaner such as MAF cleaner, intake cleaner, or electrical contact cleaner. Only use O2 approved chemicals. Anything else could damage it. Anti-seize compound should be used on the threads to prevent it from getting seized onto the exhaust pipe:

This is a pin out of a universal 4 wire O2 sensor:

Here are some internal views:

So you can clean your 02 sensor? I just removed mine today. It's the original one from 1991. I removed my upline one. Does it help you pass emission inspections?

An old part like that might need to be replaced. Their response time gets slower with age. You could clean it, and see if it helps. A clogged sensor wouldn't be able to give an accurate reading, so it won't hurt to clean it.

I forgot to say that I've already replaced it. Maybe I might need to clean my downline one.

I was working on a 2001 Mazda MPV van, and decided to remove the sensing element inside of the MAF sensor to clean it. It has a unique design with 3 separate elements which are inside of a plastic body. Here is the side view:

You could see 2 out of 3 elements. Here is the top view with the 3rd element:

Isn't the "3rd element" actually an integrated IAT (air temp) sensor?

What about the 5th element? Can you clean that, or will Mila Jovivich and/or Bruce Willis jump out and try to stop to you? (ya know, to save the universe.)

Very funny! : I think that the 3rd element is for sensing temperature like you said since there was no external air sensor. There was some sort of sensor with a vacuum line on the air cleaner box though.

BrooklynBay said:

Very funny! : I think that the 3rd element is for sensing temperature like you said since there was no external air sensor. There was some sort of sensor with a vacuum line on the air cleaner box though.

Click to expand...

Could be a map sensor. Some cars, especially wacky foreign stuff, do have both a MAF and a MAP sensor.

That sensor said boost sensor on the top of it. It's not a turbo equipped vehicle, but it might be a MAP sensor like you previously said.

Fuel filter replacement.

The fuel filter in the Aerostar doesn't require any special tools to disconnect. The fuel lines have small clips which disconnect with a small needle nose pliers or a flat screwdriver. Here is a picture of the fuel filter on my 1995 van:

The filter was stuck on one of the fuel lines. I had to use a wrench as a pry bar between the fuel line, and the filter.

I used a bench grinder to cut the old filter open. Here's is an internal view of the paper cartridge:

As you could see, the cartridge is very dirty. I had a rough idle, hesitation, stalling, and hard starting. It seemed to happen after I filled up with gasoline a few weeks ago. I suspect that the gasoline was either contaminated or watered down. I used a bottle of fuel system cleaner, and it was a little better, but not perfect. A week later, I added another container of fuel system cleaner. It was a little better, but still not perfect. I could tell that there was still some restriction, and the fuel wasn't flowing in a steady flow. It felt like a series of surges instead of a continuous flow. I bought a new filter from Autozone. The part number is FF679. Here's the new filter:

Battery terminal maintenance.

Corrosion around battery terminals is very common, and is known to cause problems over a period of time. There is a handy gadget called a memory saver which is designed to retain the computer & clock's memory (and keep an alarm from false triggering) by providing a constant voltage source into the vehicle's electrical system. This is what it looks like:

It uses a standard 9 volt battery to provide the necessary voltage:

The light bulb under the hood should be unplugged before using the memory saver to prevent unnecessary current drain:

The memory saver is now inserted into a non ignition controlled (constant voltage) cigarette lighter:

It's now time to clean the battery terminals:

These are the tools:

This is the battery brush:

The battery brush is cleaning the inside of the terminals:

The top of the battery brush cleans the top posts of the battery. It's important to apply anti-oxidant to the terminals to prevent future corrosion:

How to replace oil.

The subject may seem simple, but some people have asked how to replace oil. This is for all of the people who want to know but are afraid to ask. You place the vehicle on ramps so that it tilts back, then remove the drain plug:

Always check the condition of the seal around the drain plug, and replace if necessary. This is the oil filter:

The proximity of this filter is very close to the exhaust system, and the starter. There is limited room to work, but just enough room to keep the job simple. The filter is removed with a special tool:

The new filter has a gasket. You should prime this gasket with oil to lubricate the rubber surface:

It's a good idea to fill the new oil filter with oil prior to installation so that the engine doesn't run dry until the oil circulates:

Only fill it part of the way. Filling it up to the very top will cause some oil to spill all over you when you turn it at an angle. Add 5 quarts of oil, start it up, and take it off of the ramps. Check the dipstick with the engine off while it's on level ground.

Battery post shim.

Last week, while trying to give somebody a boost, I noticed that my negative battery terminal was loose. The bolt & nut were as tight as possible, but the lead on the battery post & terminal were slightly worn (possibly due to maintainance with a wire brush tool & old age). In the past, a replacement terminal or a screw wedged into the corner of the old terminal always worked, but there is a better solution. I came across a part called a post shim which is basically a lead crush sleeve that slips over the top post. Here's a link: http://www.autozone.com/autozone/ac...ter=3&itemIdentifier=257147_0_0_&viewAll=true. Installation is very simple. You clean the post & terminal, apply an anti-oxidant, spread the top terminal, press it over the repair sleeve, and tighten the nut & bolt.

You can use coke as an anti-oxidant too.