M20 Ogler Posted February 11, 2019 Report Share Posted February 11, 2019 An M20F I’ve been considering has oil stains on the engine block around cylinder bases and rod guide tube ends. The AI who did a prebuy and was nice enough to let me read the report noted it but did not consider it to be a huge issue. He put it in the non airworthiness items squawk list with items such as a missing hubcap etc... It got my attention because I’ve not seen this on other engines. This engine was overhauled in 2003 and has about 700 hours on it. Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted February 11, 2019 Report Share Posted February 11, 2019 5 minutes ago, M20 Ogler said: An M20F I’ve been considering has oil stains on the engine block around cylinder bases and rod guide tube ends. The AI who did a prebuy and was nice enough to let me read the report noted it but did not consider it to be a huge issue. He put it in the non airworthiness items squawk list with items such as a missing hubcap etc... It got my attention because I’ve not seen this on other engines. This engine was overhauled in 2003 and has about 700 hours on it. ya, they do that. Quote Link to comment Share on other sites More sharing options...
Rwsavory Posted February 11, 2019 Report Share Posted February 11, 2019 At our last annual the mechanic repaired a very small oil leak, more of a seepage really. It happens and is no big deal. Quote Link to comment Share on other sites More sharing options...
TTaylor Posted February 11, 2019 Report Share Posted February 11, 2019 The only time a Lycoming Engine doesn't leak is when it has no oil . Continue to chase small leaks but you will likely never stop them all. 1 Quote Link to comment Share on other sites More sharing options...
Vance Harral Posted February 11, 2019 Report Share Posted February 11, 2019 The Lycoming IO-360-A1A in our 1976 M20F had staining of the type you describe when we bought it in 2004. Still has it, still going strong 15 years and 1000 hours later. Periodically the oil blowing and dripping around the engine compartment gets bad enough that we get nervous and chase down the leaks. To date these have amounted to either seals, gaskets, fittings, hose clamps etc; or minor seeps from case bolts we're told aren't worth worrying about. But we've never done anything major like pulling a cylinder, R&R'ing the oil pan, etc. We just live with a certain amount of leaking. I feel like the key is look as hard as you can for actual cracks in the case and cylinders. If you can't find any, a bit of leaking and staining seems to be just par for the course. Quote Link to comment Share on other sites More sharing options...
warren.huisman Posted February 11, 2019 Report Share Posted February 11, 2019 My mechanic told me it is either "leaking" Lycoming's or "cracking" Continentals. Not sure if it is true...... Quote Link to comment Share on other sites More sharing options...
Yetti Posted February 12, 2019 Report Share Posted February 12, 2019 We R&Red a couple of cylinders on my engine 3 years / 300 years ago. New seals and O rings on them. They have the signs of the oil you are describing. Lycomings like to mark their spot. Quote Link to comment Share on other sites More sharing options...
RLCarter Posted February 12, 2019 Report Share Posted February 12, 2019 51 minutes ago, Yetti said: We R&Red a couple of cylinders on my engine 3 years / 300 years ago. New seals and O rings on them. They have the signs of the oil you are describing. Lycomings like to mark their spot. 300 years? You've had it awhile .... Quote Link to comment Share on other sites More sharing options...
Yetti Posted February 12, 2019 Report Share Posted February 12, 2019 Just now, RLCarter said: 300 years? You've had it awhile .... 300 hours or 300 years whatever it takes 1 Quote Link to comment Share on other sites More sharing options...
RLCarter Posted February 12, 2019 Report Share Posted February 12, 2019 4 minutes ago, Yetti said: 300 hours or 300 years whatever it takes Yep, write the check and move......... Quote Link to comment Share on other sites More sharing options...
rbridges Posted February 12, 2019 Report Share Posted February 12, 2019 The only oil leak I chased was the crankshaft seal. The rest I consider a rust inhibitor for the motor's exterior. Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted February 12, 2019 Report Share Posted February 12, 2019 Not to be a debbie downer, but my leak was caused by a cracked case.Tom Quote Link to comment Share on other sites More sharing options...
carusoam Posted February 12, 2019 Report Share Posted February 12, 2019 Know where the leaks are coming from... Some are easy to fix... Some are not... Rubber parts have a tendency to age and are generally easy to replace... Silk thread in between the case halves is a tough one... cracked engine blocks are better to have on somebody else’s engine... If that was your mechanic, working for you, on your PPI... now is The time to ask him how to handle each leak you see. Be confident with what you are buying... some parts are only a few bucks...a cracked block is an OH waiting to happen... My Lycoming came with the need for having all its rubber bits replaced... small hoses and hose clamps that were decades old and not working properly.... it’s cork valve cover seals were equally ancient... None of it was expensive or difficult... getting to know your mechanic can really help a lot... PP thoughts only, not a mechanic... Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
Yetti Posted February 12, 2019 Report Share Posted February 12, 2019 10 hours ago, rbridges said: The only oil leak I chased was the crankshaft seal. The rest I consider a rust inhibitor for the motor's exterior. Yep replaced that too. Found by the grumpy IA on annual. Put a finger on it and move the prop. The last one we found were the case half bolts around the nose. Put some permatex in the case bolts and that sealed it back up. Number 4 cylinder is an oily cylinder. Case of oil is cheaper than a tear down. Quote Link to comment Share on other sites More sharing options...
mike_elliott Posted February 12, 2019 Report Share Posted February 12, 2019 11 hours ago, ArtVandelay said: Not to be a debbie downer, but my leak was caused by a cracked case. Tom Ill bet it was around #2 Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted February 12, 2019 Report Share Posted February 12, 2019 Ill bet it was around #2 #2 cylinder? Close, the shop said it was by the alternator.Tom Quote Link to comment Share on other sites More sharing options...
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