Things to check at oil change

[bd32322]

For those of you doing your own oil change, what other items do you check when you have the cowls off for the oil change?

Thanks in advance

[driller]

I check for loose sheetmetal screws, electrical connectors, and oil leaks.

[Awful_Charlie]

Generally have a good look around with a torch & mirror, looking for cracks, oil leaks, and chafing of pipes and wires. Also inspect the exhaust for cracks, mouse milk all the slip joints, look at the translucent vacuum filters for contamination, fuel injector lines for cracks, rubbish in the oil cooler (normally have to vacuum something out of there)

A general nosey around really, a) to try and spot something going wrong before it does, and to get more familiar with the aircraft, so abnormal things stand out a bit more!

Ben

[aerobat95]

I pretty much look at all the above as well. I also look at the screws that hold the valve covers. I also like to check my EGT probes and CHT probes and the wires.

[Txbyker]

Check your starter for looseness and the teeth. Check the altenator, pulley and belt.

[bd32322]

Check your starter for looseness and the teeth. Check the altenator, pulley and belt.

What do you mean by checking the teeth - and what do you check? I am a bit ignorant here.

Everyone, thanks for the responses so far btw.

[Txbyker]

Sorry, I meant check the wear on the splines (teeth) of the starter where it engages.

[bd32322]

Also i am reading about a bunch of failures with intake exhaust valves. How would you protect against these? My engine is nearing TBO (1800-ish), but still appears to be fine and is used regularly. I am thinking maybe take out the sparks and do a compression check regularly.

[tomn]

I would be sure to take a close look at your oil cooler lines and other hoses as well. Be sure you know the age of them - as I understand it 8-10 years is the max life. My motor is currently being rebuilt after an oil starvation event due to a cracked oil cooler line thawaterbed out to be 14 years old. I had thought/assumed the hoses were all fine and was not aware of the years on them. Bottom line is to be sure to know every thing you can about your plane and especially the ages and life expectancies of parts that wear out or need to be replaced over time.

[bd32322]

I would be sure to take a close look at your oil cooler lines and other hoses as well. Be sure you know the age of them - as I understand it 8-10 years is the max life. My motor is currently being rebuilt after an oil starvation event due to a cracked oil cooler line thawaterbed out to be 14 years old. I had thought/assumed the hoses were all fine and was not aware of the years on them. Bottom line is to be sure to know every thing you can about your plane and especially the ages and life expectancies of parts that wear out or need to be replaced over time.

Any idea why it cracked? Improper routing of the hose or just age? And what would you check - whether they are brittle or not?

[tomn]

It was apprently just its age - brittle and cracked. The alternator had been replaced the day before and the front cowling had to be removed along with the oil cooler during that work. Moving the line may have started the crank - not sure but it was definitely age that caused the failure. It was routed properly and appeared to be fine. The crack developed under the heat shield below the exhaust pipes - no doubt the hottest area in its routing.

[bd32322]

Generally have a good look around with a torch & mirror, looking for cracks, oil leaks, and chafing of pipes and wires. Also inspect the exhaust for cracks, mouse milk all the slip joints ...

Ben

Will mouse milk last lomg enough. I was thinking maybe a high temp graphite lubricant will be better (made by the same folks as wd40)

<edit> actually looks like i cant find any lube that willstay at exhaust temperatures. The max is graphite dry lube from pb blaster which goes up to 850F </edit>

[Guest]

BD, all the above for sure is great gouge. I also check the entire induction system for air leaks. In most cases you can see fuel dye stains around the gasket areas. The gaskets get brittle with age but are very important in keeping the engine running smoothly and not creating a lean condition in any one cylinder. I also replace tie wraps alot. They get brittle with age also.

[bd32322]

BD, all the above for sure is great gouge. I also check the entire induction system for air leaks. In most cases you can see fuel dye stains around the gasket areas. The gaskets get brittle with age but are very important in keeping the engine running smoothly and not creating a lean condition in any one cylinder. I also replace tie wraps alot. They get brittle with age also.

good point about the tie wraps! But how do you check for leaks in the induction system apart from large and obvious leaks? Is there some trick or some device to be used?

[Guest]

good point about the tie wraps! But how do you check for leaks in the induction system apart from large and obvious leaks? Is there some trick or some device to be used?

Check that the intake pipe for each cylinder is not loose at either end. No tools are involved in this. Pay particular attention to the intake flange mounting on each cylinder. Two bolts hold the flange onto the cylinder. There should never be play under the flange. Under each flange is a gasket. If you see any sign of thin blue, we're talking minute amounts here, then the gasket is not doing its job. Either the flange bolts are loose or the gasket is old and brittle and needs replacing (easy to replace). Generally as the flange gasket wears out, thins, a minute amount of play develops in the pipe. That's why it's important to check for pipe integrity as well as stains.

[bd32322]

Check that the intake pipe for each cylinder is not loose at either end. No tools are involved in this. Pay particular attention to the intake flange mounting on each cylinder. Two bolts hold the flange onto the cylinder. There should never be play under the flange. Under each flange is a gasket. If you see any sign of thin blue, we're talking minute amounts here, then the gasket is not doing its job. Either the flange bolts are loose or the gasket is old and brittle and needs replacing (easy to replace). Generally as the flange gasket wears out, thins, a minute amount of play develops in the pipe. That's why it's important to check for pipe integrity as well as stains.

Thanks for the great advice. I am having some trouble running LOP smoothly because cylinder 2 is running extra lean. I switched the injector with the richest one and it made no difference. So now it looks like i need to do what you mentioned here, i.e., check for intake leaks at the cylinder interface at my next oil change.

[jetdriven]

Thanks for the great advice. I am having some trouble running LOP smoothly because cylinder 2 is running extra lean. I switched the injector with the richest one and it made no difference. So now it looks like i need to do what you mentioned here, i.e., check for intake leaks at the cylinder interface at my next oil change.

If you run WOT when LOP it minimizes the vacuum leak. Try doing the GAMI induction leak test. In short, you do a GAMI test at 10K feet. Then repeat the test at 1500 feet with the same MP setting you had at 10K. An induction leak makes for a dramatically different GAMI profile.

[bd32322]

If you run WOT when LOP it minimizes the vacuum leak. Try doing the GAMI induction leak test. In short, you do a GAMI test at 10K feet. Then repeat the test at 1500 feet with the same MP setting you had at 10K. An induction leak makes for a dramatically different GAMI profile.

Thanks, that is a great idea. If there is a leak, the higher ambient pressure should force more air to the leaking cylinder than the others. So at low alt, the leaky cylinder 2 should really run rough because it will be extra extra lean. Anyway, the times at which the different cylinders will peak will change.

[N201MKTurbo]

FYI all hoses have a metal tag attached to them with the date of manufacture, unless the hoses were assembled by a mechanic instead of a hose shop.

[meddesign]

I would be sure to take a close look at your oil cooler lines and other hoses as well. Be sure you know the age of them - as I understand it 8-10 years is the max life. My motor is currently being rebuilt after an oil starvation event due to a cracked oil cooler line thawaterbed out to be 14 years old. I had thought/assumed the hoses were all fine and was not aware of the years on them. Bottom line is to be sure to know every thing you can about your plane and especially the ages and life expectancies of parts that wear out or need to be replaced over time.

Doing a search of "oil Hose" I found this post.  I just discovered today my hoses are 27 years old or more, a few with 3Q82 dates. This annual is sure been a trip.  Yes I am going to change them with the best type D teflon integral fire sleve ones. 

[romair]

my hoses are also very old...24 yrs. My mechanic is hesitant to change them at annual, because apparently it is not an easy process given how tight the space is in a Mooney engine. He recommended changing them at overhaul, but for me that may still be a couple of years away (original engine, 1800 total time on it, 24 yrs old). For you guys who changed the hoses, how difficult is it?  Can it be done at annual, or should I wait for the overhaul?

Thanks

Stefan

'89 M20J

[jetdriven]

The hoses on an M20J are easy to change. It might take a day's labor, but not difficult. If you get the 124J Teflon hoses the have a smaller OD  as well. Just dont throw the adel clamps away. I really hate to see zip ties holding hoses to other stuff. Some even smear a blob of silicone between the two. Looks awful.

[N601RX]

With the oil filter off, its easy to get to the oil hoses.  The fuel pump ones are tight, but not that bad.  The oil and fuel line behind my panel were still the original ones from '67 when I replaced them last year. I don't understand why the previous owner had left them in that long.

[OR75]

check that the rocker covers are tight ( i keep spare of those cork material seals)

check connections and electric wires coming out of the alternator back

check magneto harness for chaffing etc

check dual magneto box is well attached

[N601RX]

Upgrade to the silicon rocker cover gaskets and you will not have to worry about them again.  They are reusable, don't leak and problem free.