Least favourite preventative maintenance task?

[montana maule]

Someone showed me a trick for changing oil. With an awl or other sharp instrument make a small hole on the top and back end of the filter. Apply shop air with a rubber tipped blow gun. Oil is blown out of the filter into the sump and drains out. If done correctly very little oil is in the filter when removed.

[gbarrier]

Gary Raiser, Certainly repairable. Would think it would be easier to work your arm around and get at it from the bottom. Before you do all that a couple things to try. Check the tubing from the cylinder to the gauge. Check for a break or loose fitting. If good, remove both ends and blow it out and try. If to no avail, then remove the line from back of gauge again. Inside the hole in the fitting on the back of the gauge is a small shunt. It has a screwdriver slot in it. Use a small screwdriver and unscrew it a couple turns and try again. The shunts limit the volume of air that go in and out. Sometimes they will work out a little and the needle shakes with each engine stroke. If this happens, turn it in a turn. If the needle is sluggish screw it out a turn to allow more volume. If that doesn't fix it send it to an instrument repair shop. Lots of folks probably have them laying on their shelf that they removed when they installed stuff like the JPI units but I suspect that if they have age on them they are quite inaccurate.

Montana Maule, That's pretty cool. Ill try it.

[chris_01]

Someone showed me a trick for changing oil. With an awl or other sharp instrument make a small hole on the top and back end of the filter. Apply shop air with a rubber tipped blow gun. Oil is blown out of the filter into the sump and drains out. If done correctly very little oil is in the filter when removed.

I've done the first part 'make a small hole in the top/back end of the filter'. then taking out the dip stick - Having put some flexible oil-slide below, I just turned the filter 180 degrees to make the little hole facing downwards and let it drop empty for a few minutes. Then I was able to take it off without messing around big way.

[G-MAWL]

Someone showed me a trick for changing oil. With an awl or other sharp instrument make a small hole on the top and back end of the filter. Apply shop air with a rubber tipped blow gun. Oil is blown out of the filter into the sump and drains out. If done correctly very little oil is in the filter when removed.

Why would you risk blowing something (that may be unknown to you) from the filter into the engine ?
Seams a strange thing to risk versus a 15 minute clean up.

Derek

[Andy Young]

Someone showed me a trick for changing oil. With an awl or other sharp instrument make a small hole on the top and back end of the filter. Apply shop air with a rubber tipped blow gun. Oil is blown out of the filter into the sump and drains out. If done correctly very little oil is in the filter when removed.

Why would you risk blowing something (that may be unknown to you) from the filter into the engine ?
Seams a strange thing to risk versus a 15 minute clean up.

Derek

I was thinking the same thing. In theory, it shouldn’t be a problem, as you will be pressuring the “dirtyâ€￾ side of the filter and forcing the oil through the filter element, which should act to trap any particles same as it does during normal operation. However, if you exceed 80psi in the filter, you will open the filter bypass valve, allowing oil from the dirty side of the element to pass directly into the sump, perhaps carrying contaminants with it. Again, probably not an issue, since you’re draining it anyway, but for me, the benefits don’t outweigh the risks.

Different issue, but reminds me of something I saw at a boat trade show years ago. A new company was trying to sell a device to make it easier to drain the oil on inboard or inboard/outboard boat engines (can’t just drain it out the bottom on a boat). You removed the oil filter, then screwed their gizmo on in its place. It was just an adapter with a long hose attached. The hose went into a bucket, and you then started the engine and ran it until the oil light came on, using the engine’s own oil pump to pump all the oil into the bucket.
Should be fine in theory, but...

[montana maule]

I realize it is in the "we've never done it that way" realm. Limiting the air PSI would be logical. 20 psi is enough to push warm oil out of the filter. I have not noticed any change in oil analysis to suggest blowing contaminants out of the filter. On cutting and inspecting the filter there is no damage noted. After 40 years of changing oil and cleaning up messes I had to try it. It was just and idea to throw out there.

[Andy Young]

I realize it is in the "we've never done it that way" realm. Limiting the air PSI would be logical. 20 psi is enough to push warm oil out of the filter. I have not noticed any change in oil analysis to suggest blowing contaminants out of the filter. On cutting and inspecting the filter there is no damage noted. After 40 years of changing oil and cleaning up messes I had to try it. It was just and idea to throw out there.

Fair enough. I’ll admit to being tempted as well.

I used to work on Mazda’s for the living. The old RX-7 had the filter mounted on the very top of the engine, upside down, screwed into the top of the oil cooler. Worst case scenario there. We used to poke a hole in the top with a screwdriver, and wait for 15 minutes. All the oil would drain out under gravity. If you skipped this, or didn’t wait long enough, all the oil would run down into the oil cooler fins, and over the rest of the engine and exhaust.

Why can’t they just mount all oil filters vertically, right side up, and easily accessible?

[Kirk]

I believe I saw a tool advertised for the filter punch. It was a metal hoop with a sharp pointed threaded rod that was tightened down with a thumb screw. The pointed end pierced the filter case.

The idea being to let gravity drain the filter, but low pressure air would do it.

Kirk

[chris_01]

as said - a hammer and a screwdriver does the job in the same way.. Don't need yet another special tool for one thing