About 55 years ago I was riding with my Grandpa in his 56 ford pickup when the copper line to the oil pressure gauge broke. He fixed it beside the road up in the mountains. Every time I see a copper line on an airplane engine I think about that.

I had this happen once 30-40 years ago -flying club 150 had quick drain oil tube down near front strut . Cold weather made garden hose drain rigid and all it needed was a push up and oil came out. Right after takeoff oil pressure went to zero while temps went up . Luckily field off of airport was farmers field was short grass .
Changed engine afterwards .

I had the same exact thing happen on SPORT CUB #3 while ferrying it from YKM to NYC in 2006, only back then they were using Tygon to run the oil pressure line! Had just taken off from Sikeston, MO, had my dad and brother in trail in a Stearman Cloudboy and a Champ (had picked up with them at Blakesburg), anyway had taken off and about two minutes into flight smelled hot oil in cockpit, looked down and saw it running down the INSIDE of the firewall. It was pumping out of a crack in the Tygon at the engine fitting and running back up the fire sleeve into the cabin. RTB'd to Sikeston REAL quick. Went to Lowe's Aviation Dept. and bought some copper. Problem solved, until the SB and then SA came out . I think actually that copper line work hardens from that little engine shaking around.

I've got a Grumman Yankee that I swear is trying to kill me.......

Last summer coming home at night hugging the Yosemite mountains to avoid the layer of smoke in the valley, About 30 miles from home I glance down to see the oil pressure gauge slowly dropping. I crap my pants and turn for the closest airport. The smoke is so bad in the valley that anything lower than my 9000 feet just takes me into imc. I call atc where I get a pilot report that it clears up in about 20 miles. Longest 20 miles of my life watching the oil pressure drop. Something is gonna blow up eventually! Turns out my home airport is really about the closest I'm gonna get that's got clean air and options in case I need to ditch.

9 miles out and 9000 feet with a pretty good tail wind.......I turned the motor off. Dead stick landing on the runway at night. It saved the motor. No damage except for the 6 quarts of oil I left on the back of the airplane.

I have an oil/air separator that once it starts a vacuum, it wants to drain the motor. Threw it in the trash and built a better one that'll never do that again. Never Ever had a problem with it until I replaced all the hoses in the engine bay. Clearly it wasn't happy with the routing of my vent hose.

Lesson learned

Zzz wrote:

Cub271 wrote:

I think this might be why he won't let me take the Sport Cub off-airport.

Yeah, probably so. Sorry about that.

Shock Monster, That story raised the hair on the back of my neck. Glad it had a happy ending.
Mike

I am a relatively new pilot and haven't been on the site for a few days. On friday my dad asked me to order parts for the oil line for our sport cub and I forgot. Tonight this is the first post I read. Monday I will be ordering parts! Thanks for sharing.

There should be a .062" restricter hole in the fitting in the engine side of the line, also, a loop in the line to reduce vibration.

Copper lines can be annealed, (softened back up) after they have been work hardened by heating them red hot (after removing them,,DUH) and quenching them in cold water, this also works on brass tubing, making either easier to bend with out kinking.

Zzz wrote:A question I have is: Will all the oil in the tank/pan exit via the oil pressure line, given the opportunity? In studying this about the O-200 oil system design, I think the answer must be yes. It's part of the pressurized system of oil passages in the case. My guess is it would have ejected all the oil the pickup could get out of the tank until it started sucking air. Correct me if I'm wrong.

Even with an orfice in the oil pressure fitting, it would still empty out all of the oil fairly quickly. When the oil quits coming out of that fitting, you no longer have oil pressure to your bearings. The orfice does slow things down and perhaps give you time to notice smoke/low gauge pressure. With the line being completely broken, your gauge would have been on zero - but for how long? Do you scan your gauges every few minutes - or take them for granted most of the time? It doesn't take long for a problem to develop. The guy in this thread that mentioned a warning light has the right idea - an oil pressure gauge is a tool, the light is a much better warning. I have long been a proponent of a light and a buzzer on critical functions.

I got rid of all my round engine gauges last fall, since then all I have is the GRT EIS. I quickly became lazy, as in no more scanning multiple individual gauges while interpreting what they are telling you. Now all I do is make sure the red light STAYS red, as in steady ON. If it starts blinking, then you start paying attention. It is front and center in the panel. Super easy to set up, hell you can change the upper and lower limits, in flight. Inexpensive too, and light weight and less complexity under the panel. NO oil line of any type coming inside the cockpit either, that is SO 20 th. century

I used the blinking light alarm for real once so far, I left the radiator cap off the Rotax 912S, about as stupid a thing to do a leaving the dipstick out, and it did indeed alert me to the problem way before any damage was done. Best of all after landing and taking the cowl off and determining the problem, I found the cap sitting right on top the engine! My normal place for it when checking fluid levels is on the cowl, in my field of view out the windshield, but I had the cowl off this time. My new procedure if taking the cap off when the cowl is off is to put it on my seat, the same technique I use with my vehicles that have removable gas caps, that seems to be pretty idiot proof.

courierguy wrote:....that seems to be pretty idiot proof.

"There's no such thing as fool-proof to a sufficiently determined fool".

hotrod180 wrote:

courierguy wrote:....that seems to be pretty idiot proof.

"There's no such thing as fool-proof to a sufficiently determined fool".

That fits a lot of things in aviation. Gear warning buzzers and lights, which don't prevent gear-up landings in land planes and gear down landings in amphibians. Low fuel lights, which don't keep pilots from running out of fuel. Stall warners which come on 7 or 8 knots above stall, which don't prevent pilots from stalling. "Stall-proof" airplanes--like the Ercoupe, once touted as "The world's safest airplane", which is belied by the facts over the years--it's one of the least safe with one of the highest fatality rates of all GA aircraft.

Cary

182 STOL driver wrote:I had this happen once 30-40 years ago -flying club 150 had quick drain oil tube down near front strut . Cold weather made garden hose drain rigid and all it needed was a push up and oil came out. Right after takeoff oil pressure went to zero while temps went up . Luckily field off of airport was farmers field was short grass .
Changed engine afterwards .

On my Maule I have a quick drain valve with a reinforced rubber hose of the valve to close to the front strut under the cowling.

I found a simple machined aluminum plug I jam in the end of the hose and secure with safety wire so if the valve somehow failed I would not lose oil. A belt and suspenders thing, I think a good idea.

Ive got a 59 C172 with a Lycoming 0360 upgrade (about 15 years ago). I think I will replace the copper oil lines with flex. Is there a basic kit available for this, and I assume an A&P is required to do the switch?

There should NEVER be a hard oil line from the engine to the firewall. They WILL fail, and when they do, you're going to lose oil.

Replace with a braided metal line.....flexible. Two of the airplane's I've bought had copper lines. One failed and I landed and pinched the line off, flew to town. The other I noted on the pre buy and replaced first.

MTV

Now time for a dumb question from someone who is quite green when it comes to A&P. Is there a reason an oil pressure line is routed through the firewall instead of a pressure sensor that is engine mounted with wires going to an electric gauge?

deckofficer wrote:Now time for a dumb question from someone who is quite green when it comes to A&P. Is there a reason an oil pressure line is routed through the firewall instead of a pressure sensor that is engine mounted with wires going to an electric gauge?

I think some of the modern sensor kits for various EFIS brands do use transducers instead of bringing oil through the firewall via hose.

Zzz wrote:

deckofficer wrote:Now time for a dumb question from someone who is quite green when it comes to A&P. Is there a reason an oil pressure line is routed through the firewall instead of a pressure sensor that is engine mounted with wires going to an electric gauge?

I think some of the modern sensor kits for various EFIS brands do use transducers instead of bringing oil through the firewall via hose.

This is how my vintage 2007 Rotax delivers oil pressure to the electric oil pressure gauge.

There is a service bulletin out for some of the older engines that may experience fluctuating or "bouncing" oil pressure needles. This could be two things, either the sending unit is bad or failing, or the more likely is that the ball bearing and spring that moves back and forth to regulate the pressure is worn and sticking.

The fix is either replace the sending unit, or the spring and ball bearing and shim kit for said spring. Depending on which of the two is awry, that is.

Once again the experimental aircraft are ahead of the curve, running an oil line through the firewall seems archaic to me, dangerous too The stubby little transducer on my Rotax uses no oil line, one less thing to worry about. It's interesting to me how the cert and exp camps can "compare notes" on what has worked for ever and is worth emulating, and what can be a new, better way to do things.