Prior owner

I switched to the tempest massive extended electrode plugs and although I only have about 35 hours on them, it ended my plug fouling problems.

Mine was like that. I sent it to LASAR on exchange for an overhauled one (get the hardware package as well), and the difference was night and day..... taxis and rolls out straight with no play. I also installed the Mooney SB kit that is a washer/shim That changes the geometry of the front gear a tiny bit (drops the nose a little bit) when I had the front gear apart. The only drawback is that the kit reduces prop clearance..

I have to wonder though- does sealing it really do anything to increase the flow through the fins....or are you just cutting off the flow at the top and the bottom of the cooler that normally would provide some airflow around the wells on each end of the cooler? I didn’t see any deduction in oil temps after sealing the cooler...

I think that’s the way they were built. I sealed mine with silicone baffle material..

I can’t believe that someone from the anal retentive club didn’t pipe up when they saw that picture. I guess This post gets me into the club. Your vacuum is reading kinda high...

Just don’t replace your compass bulb with an LED....At least the one I used made it so dark I couldn’t read it! The LED emits light forward only, and the incandescent emits light in all directions... the compass is illuminated by a hole in the side of the tube where the bulb slides in- so it needs a Bulb that can emit 90 degree Beam. Did anyone else have this problem?

Most likely the rod end is worn out...

Not the C’s cooler... it’s very basic.

Not me- There was another poster who was having issues with their JPI- I only have the Garwin, but it has checked against a handheld thermocouple device and is accurate. I do understand the relationship between airspeed and engine cooling, so yes, whenever I don’t need to climb in a hurry due to terrain, procedure, or a clearance, I Sometimes climb at higher air speeds. My issue is that even after leveling off, the oil temp remains high and never comes down. Unfortunately, there is no cooler relocation STC for M20 C’s....so we’re stuck with it in the front cowling. Wish I had a Ray Jay to flick on and climb at 130...

Have not had a pitot static check done, but I will get it checked at some point. I do have the equipment at work as well... Aircraft does stall indicated within 2 mph of book stall speeds. I climb at 115 to 120 IAS mph. (And Yes, this did become a long, convoluted thread....)

Everything is routed correctly, including having the oil cooler inlet hose connected to the lower end of the cooler. I am going to order new hoses and remove the fittings on the case to look for obstructions, then do a flow test from the case to the cooler with pressure pot. It’ll be a couple of weeks before hoses get here.

@47U has Graciously provided me with a document that answers all of my questions. I now know how the Older oil screen equipped Lycomings without a vernatherm are converted over, and what the options are for oil cooler hose routings... It is frustrating working with a modified aircraft when you cannot find information regarding its original configuration in order to follow its evolution to its current state. Thank you @47U !! Lycoming Service Instruction No. 1008C : https://www.lycoming.com/node/15780 I will not be connecting my oil cooler in series with the oil filter, as the tech rep suggested. Thanks also to @M20Doc ! Hopefully, the ramblings of this madman (Me) will now cease...!

These are questions I wish I could answer, but without a torn apart A2D case in front of me with the original oil screen configuration, I’ll never figure it out... [Edit] [Edit] I need help identifying whether the picture below taken through the Airwolf oil screen adapter housing is, or is not, a hole in that has been machined for Vernatherm use. My engine originally came with an oil screen housing. The above adapter and spin on filter were installed 17 years ago, per the airframe logbook. A vernatherm was installed into the adapter at that time. I must verify that the accessory case is machined for a vernatherm before I may re-install it. If the case isn’t set up to accept a vernatherm, then a plug must be installed on the adapter where the vernatherm would normally be installed. Since I am not familiar with what an accessory case machined for a vernatherm looks like, and I cannot find any Relevant information online, I need someone who has actually seen a vernatherm port in a Lycoming case to compare their recollection with my picture above... Is this case machined for a vernatherm? Help!

Exactly. The airwolf tech rep was adamant that the system have a vernatherm. He said that if the oil circulates continuously, it will just get hotter and hotter.

I spoke with the Airwolf oil filter tech rep. The Oil cooler AND the filter hoses are all installed wrong for their STC remote oil filter installation.... Top fitting on accessory housing where oil cooler hose Is attached is supposed to be capped off. The oil is supposed to route from the oil filter housing (on the firewall) outlet to the oil cooler, then from the cooler to the airwolf adapter housing on the accesssory case (The one with the vernatherm in it). So, both of my oil cooler fittings on the accessory housing have to be plugged. This means 4 new hoses have to be ordered... I’ll update in a couple of weeks after I’ve got it configured correctly.

Oil filter installation may be an issue- I don’t think my engine came with a vernatherm valve, and I don’t know if the accessory case was drilled for it. The Airwolf remote oil filter STC says that the upper outlet should be capped, and a vernatherm should not be installed if this is the case.. Ive got some tech rep calls to make... I believe that my accessory case is the one below.... airwolf kit comes with a cap for the plunger outlet that “must be used if the engine didn’t come with a vernatherm installed”

Clarence, all hoses have been removed and cooler has been removed, flushed, cleaned in the ultrasonic and tested for flow. Both hoses are way too long (which is causing the tight bends), so I am going to replace them with ones that I will measure for proper fit. I will remove the output fitting to check for any restrictions, then connect my pressure pot To the system with a hose Connected to the cooler And check flow. Il report back this weekend. Thanks again, Dave

Well dang....and there I was thinking we found the problem... thanks for that important bit of info.

I believe so....but I don’t think the plug at the top is an NPT, So I’ll need a different plug. This is crazy..!

No, the remote oil filter connections come from the airwolf vernatherm housing that is supplied with the Remote oil filter STC kit. They are correctly attached to the oil filter hoses. There must be a plug screwed into the accessory housing below the airwolf housing where the Outlet to the oil cooler is. So, I guess that the vernatherm stays pushed open Due to the blockage and oil is diverted to the cooler with the crazy arrangement that I have....

No wonder the vernatherm pressure valve is open all the time- the oil cooler circuit is obstructed by a plug! Amazing that the cooler has been circulating oil and getting hot! Nothing is attached where I circled in blue..I hope M20doc can confirm this...

Oh man, it looks as though things are really messed up..

Well Doc, thank you. Now I have a completely new set of questions.... Below is a pic of my oil cooler hoses, as they were installed when I bought the plane ( I have not changed the routing). I highlighted the connections for clarity (sorry, I wish I had a better picture of the accessory housing handy). The red hose with the 90 degree fitting goes to the bottom of the cooler. The green hose goes to the top of the cooler. In the Lycoming Operators Manual I found what is supposed to be an accessory housing for my engine, an O-360 A2D... but my housing doesn’t look like that. I found a pic of a housing that looks like mine in an old Lycoming Overhaul Manual. I highlighted that picture to match the highlighting of the picture I took of my accessory housing & hose arrangement. Is something wrong here? Both of my cooler hoses are attached to the TOP of the accessory housing.... isn’t the oil flowing from the engine to the cooler supposed to be connected to the fitting below the oil screen housing, the return to the top of the accessory housing (below my remote oil filter housing)??

Well, the fact that you have the Harrison cooler pretty much blows my "inefficient oil cooler theory" right out of the water...! I am going to have to look at everything, including the remote oil filter installation.

Had a very interesting discussion with Aero Classics Oil Coolers tech rep.... Mooney M20C’s either came with the Harrison or the Stewart Warner oil cooler (that much I knew). The Harrison has poor heat rejection compared to the Stewart Warner, so if your aircraft has the SW cooler, it will run cooler. The Aero Classics oil cooler that is typically specified as a replacement at most aircraft parts suppliers is PN 8000075. This is a 7 row cooler. This is the one that I have. It is better than the Harrison, but my understanding is that it is not as good as the SW cooler. Aero Classics also has another cooler that is certified for the M20C that is a 6 row cooler with a taller fin design. It has the exact same physical dimensions. It has 30% greater heat rejection than the oil cooler model that I have. It is also about twice the price. He said that these coolers do a great job of cooling the oil in the M20C’s. I removed my oil cooler, soaked it in Marvel Mystery oil overnight, flushed it, cleaned it in an ultrasonic cleaner with stoddard solvent, ran shop air through it, checked the air flow rate and solvent rate through it, and it seems completely unobstructed...however, these oil coolers are designed very simply- the oil does not zig-zag through the cooler, it simply flows from one side to the other taking the path of least resistance. It might be very difficult to tell if one of the oil rows was blocked... but in my limited experience, it seems to be flowing just fine. I don’t know what I’m going to do at this point. Going to check the hoses again. New hoses and upgraded cooler will run me $1200 +. So, what cooler do you have installed in your C/D? Does it run hot or not? From what I gleamed talking to the rep, the SW oil cooler does a pretty good job cooling the oil in the M20C. Perhaps those of us with the SW cooler aren’t having oil temp issues?