Confused by oil dipstick markings

[DXB]

I got my O-360-A1D back from overhaul at a reputable shop, and I am breaking it in.  The dipstick is clearly different from my old one - the new spacing between 8 and 6 quarts is wider, and the spacing between 6 and 4 quarts is MUCH narrower than previously.  I normally fill to 6 qt and add a quart when it gets to 5, but that will be tricky to do accurately now.  I’m thinking of filling it to 7quarts just to make monitoring easier. Is it normal to mark the dipstick in a custom manner upon overhaul?? If so I’m very surprised it would change so much - it’s the same sump as before.  Any insights are appreciated.  I’ll check the stick by adding a quart at a time when I do the first oil change at 25 hours. 

[takair]

Makes me wonder if the stock marks are not linear, kind of like the stock fuel tank markings. 

[EricJ]

Make sure it is the correct dipstick for that engine.

[bigmo]

I'd definitely follow up with a phone call and ask about it - they may have a perfectly good reason. I think I'd do a measured drain and get an idea of what's in the engine at a known point (ie 6 on the dipstick). That'll at least give you a warm & fuzzy.

[PT20J]

33 minutes ago, EricJ said:

Make sure it is the correct dipstick for that engine.

THIS ^^^^^
The dipstick will have a part number on it and you can download the parts catalog from Lycoming’s website to check that it is correct. Not sure why they would replace the dipstick - Lycoming prices them like they were made of gold.

[MikeOH]

39 minutes ago, EricJ said:

Make sure it is the correct dipstick for that engine.

EXACTLY!

I can't fathom how the markings on the dipstick, for the SAME engine, would be different because of an overhaul.

Only three possibilities: The new dipstick is wrong, the only dipstick was wrong, both are wrong  I'd look for a P/N.  If none, I'd hope Lycoming can supply measurements for the marks.

(My guess: the 'reputable shop' accidentally swapped yours with one from some other guy's engine)

[1980Mooney]

3 hours ago, MikeOH said:

(My guess: the 'reputable shop' accidentally swapped yours with one from some other guy's engine)

I wonder what else this 'reputable shop' accidentally swapped with some other guy's engine.....

7 hours ago, DXB said:

I got my O-360-A1D back from overhaul at a reputable shop, and I am breaking it in.  The dipstick is clearly different from my old one - the new spacing between 8 and 6 quarts is wider, and the spacing between 6 and 4 quarts is MUCH narrower than previously.  I normally fill to 6 qt and add a quart when it gets to 5, but that will be tricky to do accurately now.  I’m thinking of filling it to 7quarts just to make monitoring easier. Is it normal to mark the dipstick in a custom manner upon overhaul?? If so I’m very surprised it would change so much - it’s the same sump as before.  Any insights are appreciated.  I’ll check the stick by adding a quart at a time when I do the first oil change at 25 hours. 

Since you said "overhaul" I assume that this was not an engine "swap" and that you were not invoiced for a new or any kind of replacement dipstick. 

In that case, if I were you, my first call would be to the 'reputable shop' for an immediate explanation. 

• Can they explain what happened?
• Were they aware of a screw up (lost, damaged) and tried to correct it without telling you?
  • Did they lose yours and procure (find) a wrong replacement?
• Are they unable to explain and are completely clueless?
• Are they a shop that uses uncertified mechanics (i.e. automotive mechanics) under "supervision of an A&P") - more common now days to cut cost.
• Did they recently fire a mechanic? (i.e. the one that worked on your plane)

What else did their mechanics screw up that you can't see?

If they can't explain anything and everything to your satisfaction, then I personally would not have a good feeling flying behind this engine.  I would also publicize the name of the shop so others can steer clear.

Edited December 7, 2024 by 1980Mooney

[Ragsf15e]

2 minutes ago, 1980Mooney said:

I wonder what else this 'reputable shop' accidentally swapped with some other guy's engine.....

Since you said "overhaul" I assume that this was not an engine "swap" and that you were not invoiced for a new or any kind of replacement dipstick. 

In that case, if I were you, my first call would be to the 'reputable shop' for an immediate explanation. 

• Can they explain what happened?
• Were they aware of a screw up (lost, damaged) and tried to correct it without telling you?
  • Did they lose yours and procure (find) a wrong replacement?
• Are they unable to explain and are completely clueless?
• Are they a shop that uses uncertified mechanics (i.e. automotive mechanics) under "supervision of an A&P") - more common now days to cut cost.
• Did they recently fire a mechanic? (i.e. the one that worked on your plane)

What else did their mechanics screw up that you can't see?

If they can't explain anything, then I personally would not have a good feeling flying behind this engine.  I would also publicize the name of the shop so others can steer clear.

Well maybe.  Maybe it’s the correct one? My io-360 wasn’t linear either. 4-6 was closer than 6-8.  I think he should verify the part number and check it qt by qt while he fills before getting too worked up about it.

[N201MKTurbo]

Instead of making a big deal with the engine shop, why not just call them with the dipstick part number you have. I can’t imagine they wouldn’t want to make it right.

[1980Mooney]

13 minutes ago, Ragsf15e said:

Well maybe.  Maybe it’s the correct one? My io-360 wasn’t linear either. 4-6 was closer than 6-8.  I think he should verify the part number and check it qt by qt while he fills before getting too worked up about it.

If you are suggesting that the shop found that he had an incorrect dipstick and that they had to replace it with the proper one in order for the engine/plane to be airworthy, then

• They should have invoiced him for a new replacement part
• They should have logged the change in the Engine Log
• And they should have informed him that he had been using the incorrect dipstick and level for years.

 

[1980Mooney]

4 minutes ago, N201MKTurbo said:

Instead of making a big deal with the engine shop, why not just call them with the dipstick part number you have. I can’t imagine they wouldn’t want to make it right.

It is not just about "making it right".  It is about explaining why the engine didn't come back with the same parts - parts that had no reason to be replaced.

If this was a $200 oil change and it came back with a different dipstick you would say WTF is going on.

This is likely a $30,000+ service - clear explanation amd documentation of unexpected (and potentially unwarranted) changes are in order.

[N201MKTurbo]

20 minutes ago, 1980Mooney said:

It is not just about "making it right".  It is about explaining why the engine didn't come back with the same parts - parts that had no reason to be replaced.

If this was a $200 oil change and it came back with a different dipstick you would say WTF is going on.

This is likely a $30,000+ service - clear explanation amd documentation of unexpected (and potentially unwarranted) changes are in order.

So, you have never made a mistake? Wish I could say that.

[DXB]

6 hours ago, EricJ said:

Make sure it is the correct dipstick for that engine.

That does seem to be key... I'll look next time in hangar whether it has a part number on it.   The correct one for my engine seems to be LW-14758.  I found a pic of one on Ebay (below), which seems to have the more evenly spaced marks that I recall from my old one.  I wonder if the one they gave me is off an IO-360 similar to @Ragsf15e's.

I'm not inclined to go on the war path with the engine shop over a dipstick error, but it is a little disconcerting!

 

[dkkim73]

Is it possible that a different sump was fitted (correctly or not)?

[kortopates]

55 minutes ago, dkkim73 said:

Is it possible that a different sump was fitted (correctly or not)?

No but its possible you don't have the correct oil stick part #. If you can read part # on it you can verify.

[DXB]

So... my engine overhauler thinks I'm crazy.  I am not. They definitely sent the engine back with a differently marked dipstick.   Upon further research, I believe the correct part numbers are in this parts catalog: https://www.lycoming.com/sites/default/files/attachments/O-360-A%2520Parts%2520Catalog%2520PC-306-1.pdf   On page 11, it lists three possible oil dipsticks for the O-360-A1D engine (LW14769, LW14780, and LW14768).   I am guessing that the 3 different dipsticks listed for the engine on page 11 match the 3 different possible filler tube lengths listed above it (75735, 75767, and 75736).  I am not sure what filler tube I have; however, if the engine has the same sump, the spacing between marks for all 3 possible dipsticks would be the same, and the stick I have now has markedly different spacing. I interpret this as meaning it is for an engine with a different sump geometry.  

Unfortunately there's not a part number stamped on my current dipstick to prove their error.  So... Could anyone with an O-360-A1D post pix of their dipsticks showing the markings so I can keep after the shop to make this right?

 

[Marc_B]

Out of curiosity have you looked at how the dipstick compares to after an oil change and adding a quart at a time? Seems like the utility in the dipstick is how well it compares to the amount of oil.

[Aerodon]

21 minutes ago, DXB said:

So... my engine overhauler thinks I'm crazy.  I am not. They definitely sent the engine back with a differently marked dipstick.   Upon further research, I believe the correct part numbers are in this parts catalog: https://www.lycoming.com/sites/default/files/attachments/O-360-A%2520Parts%2520Catalog%2520PC-306-1.pdf   On page 11, it lists three possible oil dipsticks for the O-360-A1D engine (LW14769, LW14780, and LW14768).   I am guessing that the 3 different dipsticks listed for the engine on page 11 match the 3 different possible filler tube lengths listed above it (75735, 75767, and 75736).  I am not sure what filler tube I have; however, if the engine has the same sump, the spacing between marks for all 3 possible dipsticks would be the same, and the stick I have now has markedly different spacing. I interpret this as meaning it is for an engine with a different sump geometry.  

Unfortunately there's not a part number stamped on my current dipstick to prove their error.  So... Could anyone with an O-360-A1D post pix of their dipsticks showing the markings so I can keep after the shop to make this right?

 

Yes, both the filler tube and dipstick need to be correct, don't assume that because they are listed in a certain order that they go together.  And they are probably different for different sumps.   Try find a filler tube number and the dipstick number.  Go through the parts manual and see if you can figure out which one goes with which.

[PT20J]

24 minutes ago, DXB said:

So... my engine overhauler thinks I'm crazy.  I am not. They definitely sent the engine back with a differently marked dipstick.   Upon further research, I believe the correct part numbers are in this parts catalog: https://www.lycoming.com/sites/default/files/attachments/O-360-A%2520Parts%2520Catalog%2520PC-306-1.pdf   On page 11, it lists three possible oil dipsticks for the O-360-A1D engine (LW14769, LW14780, and LW14768).   I am guessing that the 3 different dipsticks listed for the engine on page 11 match the 3 different possible filler tube lengths listed above it (75735, 75767, and 75736).  I am not sure what filler tube I have; however, if the engine has the same sump, the spacing between marks for all 3 possible dipsticks would be the same, and the stick I have now has markedly different spacing. I interpret this as meaning it is for an engine with a different sump geometry.  

Unfortunately there's not a part number stamped on my current dipstick to prove their error.  So... Could anyone with an O-360-A1D post pix of their dipsticks showing the markings so I can keep after the shop to make this right?

 

The part number should be stamped or written in black ink on the top of the yellow painted handle. Perhaps the number has been painted over.

I'd call Lycoming tech support. I have found them very helpful.

[DXB]

57 minutes ago, Marc_B said:

Out of curiosity have you looked at how the dipstick compares to after an oil change and adding a quart at a time? Seems like the utility in the dipstick is how well it compares to the amount of oil.

Definitely gonna do that when I change when I change the oil for the first time - don’t have enough mineral oil on hand to empty and refill during the break in period

[MikeOH]

@PT20J is right:  CALL LYCOMING!

I would not trust myself to ferret out the correct sump/tube/dipstick combo.  Give them your engine serial number and have THEM tell you the correct part numbers.

[Greg Ellis]

1 hour ago, DXB said:

So... my engine overhauler thinks I'm crazy.  I am not. They definitely sent the engine back with a differently marked dipstick.   Upon further research, I believe the correct part numbers are in this parts catalog: https://www.lycoming.com/sites/default/files/attachments/O-360-A%2520Parts%2520Catalog%2520PC-306-1.pdf   On page 11, it lists three possible oil dipsticks for the O-360-A1D engine (LW14769, LW14780, and LW14768).   I am guessing that the 3 different dipsticks listed for the engine on page 11 match the 3 different possible filler tube lengths listed above it (75735, 75767, and 75736).  I am not sure what filler tube I have; however, if the engine has the same sump, the spacing between marks for all 3 possible dipsticks would be the same, and the stick I have now has markedly different spacing. I interpret this as meaning it is for an engine with a different sump geometry.  

Unfortunately there's not a part number stamped on my current dipstick to prove their error.  So... Could anyone with an O-360-A1D post pix of their dipsticks showing the markings so I can keep after the shop to make this right?

 

Well, with all this talk I decided to go look at the dipstick in my O-360-A1D engine.  The part number stamped on mine is LW16783-18.  This is nowhere close to the 3 listed in the parts manual.  A quick google search said this one is for the IO-360-M engine.  So I put an email into Lycoming to see what is what.  

[DXB]

4 hours ago, Greg Ellis said:

Well, with all this talk I decided to go look at the dipstick in my O-360-A1D engine.  The part number stamped on mine is LW16783-18.  This is nowhere close to the 3 listed in the parts manual.  A quick google search said this one is for the IO-360-M engine.  So I put an email into Lycoming to see what is what.  

I just emailed them myself based on guidance from multiple folks above - they will be puzzled by the sudden deluge of dipstick-related inquiries 

Just curious, are the marks on yours evenly spaced on your stick or more like the picture in the first post?

 

[Greg Ellis]

9 hours ago, DXB said:

I just emailed them myself based on guidance from multiple folks above - they will be puzzled by the sudden deluge of dipstick-related inquiries 

Just curious, are the marks on yours evenly spaced on your stick or more like the picture in the first post?

 

Mine are not evenly spaced.  They are much like the first photo with a large jump between 6 and 8 quarts.  However, I did get an answer from them.  I have a narrow deck O-360-A1D.  The part numbers you listed were for a wide deck.  My dipstick is correct for the narrow deck O-360-A1D.  I have pasted their response here.

Hi Greg, 

The dipstick part numbers you mentioned below comes from the wide deck O-360 parts catalog (pc-306-1). The serial number you have indicates you have a narrow deck engine where you want to use parts catalog PC-106. PC-106 also has four different options for the gage assembly. LW-16783-18 superseded LW-14758 which is called out in the narrow deck IPC for the O-320-D1A. LW-16783-18 is for an 8QT system that is 19.44” long. 

Additionally, there is also service bulletin 612 regarding LW-16783-18 for the IO-360-M series engines. This Bulletin talks about replacing the LW-16783-18 with LW-14760 for the IO-360-M.