Continental C125/C145/O-300 Information Oil Coolers

I am rebuilding the baffling on my C145 powered Swift. Does anybody know if the original oil cooler/baffle installation had a boot or any baffle seal around the square opening in the aft baffle plate? Mine had a makeshift boot around it, but as best as I can tell the only original parts were aluminum angle on the four sides of the cooler which bolted to the baffle plate and had slotted screw holes which allowed you to adjust these angle pieces flush with the oil cooler. Thanks in advance, Mark Culpepper N77752

Mark: They had those 4 aluminum pieces you mention, those were wrapped with a piece of "Adelite" baffling material, maybe a little over an inch wide and secured with a wrap of safety wire. -- Jim

Subject: Oil temp
From: Jerry Swartz <>
Steve: What are you running for oil temps?? N77759 is indicating about 90 degrees C with outside temps in the 70's at altitude. This seems high to me for as cool as it is. It doesn't look to me like there is a direct shot of air going to the oil cooler as the heat ducting goes almost directly in front of it. New cylinders are doing good with about 5 hours on them and little to no oil consumption in the last l 1/2 hours. Cylinder temp is about 185. Jerry Swartz

Jerry... I'm glad to hear your cylinders are doing well! A little higher temps are to be expected with new cylinders for a few hours. I have an EQ5435 oil cooler adapter (which is sometimes called a seaplane adapter). It has -8 hoses and passes a lot of oil even through the original cooler which I soaked in carb cleaner for about a week prior to installation. I tightened all my baffling to get as much air through the right places and to try to eliminate as much going out the wrong places as possible. I do not have a cylinder head gauge. My oil temp gauge reads about 165-185 degrees (F), most of the time in cruise. Maybe a little higher on extremely hot days. I use SAE 40 weight oil year round (TCM recommends SAE 40 above 32 [F] and SAE 30 below). My theory is that lighter weight oil moves faster and cools better, so I do not use SAE 50, although it is popular. Now for the clincher...

When is the last time you heard of anyone having an engine failure in a normally aspirated airplane engine due to over temping the oil? I've been doing this stuff for over 40 years and I can't recall even one time. Hugh Gordon who worked for TCM for over 40 years prior to his retirement about 10 years ago was their chief quality control guy and looked at every engine sent back to the factory for warranty work. He told me that there is "no magic" in the redline. It all has to do with the quality of the oil. His opinion was that oil will not start to "cook" until around 240-250 (F), so there is little chance of doing any damage, if the engine is cooling at all. It is true that oil temp indication reflects the ambient temps and is nearly linear V/V, whereas cylinder head temps are nearly steady once the operating temps have been reached (that's why I don't worry about cyl temps in a Swift with tight baffling). I don't know if I have helped you or not, but maybe I have given you some ideas where to look. Be happy... Don't worry... Steve W

OIL FILTER FOR AN O-300-D...  (060300)
Subj: Swift N2412B
From: Fred Lipscomb <>
How about adding an oil filter to the engine, and which manufacturer? Best: T. Fred Lipscomb

I installed an Air Wolf remote oil filter on the C-145 in my friends C-170. I think it was less than $500. from Chief Aircraft. Be sure to chase the threads of the oil screen housing and install the adapter fitting with neverseize. -- Jim

HIGH OIL TEMPS??? IN CANADA???  (070100)
From: Yves Starreveld <>
Hi, All,  Now that the temperatures north of the border are coming up (OAT 68F), so are my oil temps. After only 10 min flying at 24", they are up to 200F, and I have to reduce power to keep them from rising further. I just finished redoing all the baffles, as they were pretty torn, and things seal up nicely now, with a reduction to about 190F. I have calibrated the gauge, and it is accurate. I am wondering about the oil cooler - it has a series of thick plates rather than radiator-like fins on it. 1) Does a more modern cooler provide greater efficiency? 2) Is there a thermostat in the oil system that I should have a look at? Thanks for any info! Yves

200F is not too hot if it doesn't go much further. The old Harrison cooler with the thick fins is not as efficient as the newer oil coolers, but it will work. The problem is usually with the way the oil is picked up off one oil galley, routed thru the cooler, and returned to the other oil galley at an almost equal pressure, resulting in not much flow. There is an unapproved method of returning the oil to the sump thru an orfice (40 drill) which works very well. -- Jim

From: Yves Starreveld <>
What is a TCM 5435 Adapter? How do you get around using the 90 degree fittings at the front of the engine? -- Yves

We must remember that these airplanes are 50 years old now! A lot of sludge (and worse!) can accumulate in the oil cooler in 50 years! The TCM 5435 Adapter can be seen illustrated in the Parts Catalogue. It is commonly called a C-170 seaplane adapter, but the 125 version was used on many Swifts right from the factory. With the adapter, the hoses go on the back of the engine. 90 degree fittings at the front are no problem, you install a pipe reducer in the oil galley, then a 90 degree AN822 with 1/4 pipe threads to an AN6 flare. Then you put on a straight hose. -- Jim

Subj: Harrison Oil Cooler
From: Ed Lloyd <>
Jim,  I have an annual coming up the end of this month. Thinking about the info back and forth concerning the Harrison Oil Cooler, I feel I want to remove the cooler and flush it just for kicks and grins. How would you say would be the best way to flush the cooler and what kind of solution? I have a shop type chemical cleaning tank we use in the boat business in cleaning engine parts etc. serviced by Safety Clean. The cleaning solution is non-corrosive and I could immerse the Harrison and then blow it out. Am I on the right track or should there be a flow check performed? Thanks.......Ed

The way you describe will work, (kind of) but the best way to clean and flush an oil cooler is to send it to an aircraft shop and have it cleaned using ultrasound. If it works now, it may work a little better if you clean it. It's your call whether you want to spend the hundred and some bucks.  --  Jim

From: Mark Culpepper <>
I just recently overhauled the O-300A in my Swift. While doing so I went ahead and had the remainder of the accessories overhauled. Airmark Components in Ft. Lauderdale FL overhauled my original Harrison oil cooler for $140.00. My oil temps run no higher than 175F on a summer day in Memphis TN where the OAT is 95F. I am certain that this was the first time this oil cooler had been overhauled thoroughly cleaned out) since the aircraft rolled off the assembly line in 1948. Airmark stated in the work order that the cooler was contaminated (clogged). My oil temps prior to the overhaul would run as hot as 200F. The truth is that prior to the cooler overhaul it was probably almost completely clogged. You may be able to reduce your oil temps simply by flushing your oil cooler.

STEVE AGREES...  (070200)
From: Steve Wilson <>
Mark... I agree with you. I soaked my Oil Cooler in carburetor cleaner for a couple weeks. I also installed a TCM 5435 Adapter using -8 hoses, with nothing tighter than 45 degree fittings. My oil temps went from 200-210 (F) to 160-175 (F). I believe that the clean cooler did a lot, but the adapter is a way to move a lot of oil. Over the years I have tried several alternate methods of returning oil from the stock setup and this worked the best for me.

From: Jim Montague <>
Subject: FYI (old AD note)


GLOBE: (Was Mandatory Note 11 of AD-766-5.)

Applies to models GC-1A and GC-1B Aircraft Serial Numbers 1001 to 1119 Inclusive. Compliance required prior to August 1, 1947. If an oil radiator is or has been installed, inspect the forward end of the engine's left oil galley port and remove the steel sleeve, Continental P/N 25206, if found to be installed. This is necessary to insure that positive lubrication is being provided the No. 6 cylinder connecting rod bearing. (Globe Customer Service Maintenance Bulletin No. 13 covers this same subject.)

A 53 year old AD note? Well, I found one of those sleeves still installed just two years ago! This is another where the s/n of the aircraft means nothing. If the sleeve is there, it must be removed. The one I found was on a s/n not mentioned above. The AD pertains to any of the old Continentals that used that type of oil cooler. (A-65, C-85, C-145, etc) It does not include any Lycoming engines.-- Jim

Subj: Re: O-300 Oil Temp
From: Yves Starreveld <>
Hi, Jim,
Just a note to say that installation of the adapter was trouble free. Oil temps now stable at 80C regardless how hot or for how long I climb. (CHT great since I redid the baffle seals also, not to mention an extra 5-7 mph at cruise) Thanks for your help. Yves

Thanks for the note. I'm glad the EQ adapter worked out so well for you. -- Jim

Subj: Oil cooler
From: Don Woodhams <>
I am installing an O 300 engine in place of a stock 125 and it has no oil cooler. It does have a finned cooler on the bottom of the crankcase, should I also install an oil cooler? Just wanted to make sure it cools. Thanks Don.

An oil cooler is not a required item on a Swift with a fixed pitch prop. I have run O-300's here in the North without a cooler and they will run high oil temperature in the summer. The finned item on your crankcase sounds like a heat sink that someone has installed to lower oil temperature. I would go ahead and install the engine without an oil cooler and see how effective it is. If your oil temp. is higher than you like you can always install a cooler later. -- Jim

Subject: Oil Temp Problem GONE
From: "Ed A. Lloyd" <>
First, I want to thank all you 'ole heads' for the suggestions and nudges in chasing this elusive oil temp problem I've had with 56K since I've owned the bird. Special thanks to Steve Wilson. He suggested the problem may be in the adapter itself in one of our conversations and sure enough it was............... Steve said " Not to be the "Grinch," but you also have another consideration. One is that the end of the adapter in the accessory case is the right diameter. If it is undersize (and I have seen a couple cut down for reasons I can't explain) it will not run oil through the EQ5435 and will by-pass any cooling.".............Now in creeping up on the problem, I removed all the -6 oil lines from the EQ5435 and all the -6 fittings and reducing adapters. Replaced all the fittings with straight -8 fittings except one -8 45 degree fitting going into the oil screen housing. Removed the oil cooler and took the bypass valve out to see what the condition was and yuk, what a black gooey mess. Oil had been sitting there for years with little or no flow. Soaked the oil cooler in carb cleaner and blew it out repeatedly until what went in came out clean. Put everything together and did a ground run for fifteen minutes......NO CHANGE! Oil temp only went to 35 degrees C. Oil cooler and screen housing cool to the touch. Crankcase was very warm. With that I hooked the adapter oil out line to the inlet port in the oil screen housing. Did another run and the oil screen housing was barely warm. At least there was some flow. Temp went to 40C on ground run. Still not satisfied, I pulled the alternator and the EQ 5435 adapter. There, in my hand I could see the problem, the 'snout' on the adapter that goes into the accessory case had been cut down 108 thousandths by someone for reasons I'll never know. There was very little oil moving through the cooler or for that matter probably very little oil going through the oil screen either. The outer portion of the adapter, that has all the ports and the relief valve, was improperly machined at manufacture. The oil return port was only open about 1/3 of what it should have been in comparing it to another adapter Joe Sills had loaned me. Took a die grinder to it and opened that hummer up so it could do it's job. Long story short, put it all back together, ground run test for leaks OK, cowling on and around the patch. For the first time since I have owned 56K I saw the oil temp in the green at 80 to 85C (175-180F ) IT'S FIXED. Thank you Steve Wilson and Monty and Don for putting up with my persistence, but it paid off in the end. Monty, any idea why someone would cut down the 'snoot' on the EQ adapter where it goes into the accessory section on the O300? Steve Wilson put me on to that and sure enough that's what was wrong. Can't imagine why though. Cheers.........Ed

Well, I think I might. The O-300 adapter p/n is EQ5435. The C-125 had a slightly different number and the difference is the oil screen in a C-125 is about .100 smaller in diameter and a little longer. If it wasn't so cold out in my shop I would go out and measure for sure! I had an old parts catalogue that illustrated the C-125 type EQ adapter with the note, "for Globe Swift installation". I copied this at one time and sent it to Charlie Nelson at Athens. I tried to find it this morning but it is buried somewhere among tons of unfiled paper here in my office. So why isn't the C-125 adapter mentioned on the Type Certificate Spec sheet? Those early C-125's with factory equipped EQ oil cooler adapters were mostly the N777-- series of Swifts, which were among the first production Swifts that Temco produced. From what I gather Temco was operating in a very lean financial condition in those days. I don't suppose they wanted to spend the money to revise the type certificate. Note I am cc'ing this. Further comment is welcome! -- Jim

Subj: El Reno Adapter
From: Ed Lloyd <>
Mornin Jim,
Dorothy Golding came up with an oil filter adapter made by F&M Co. here in Texas. It's commonly referred to as a El Reno Adapter I think. Any good / bad points or comments on this item? It is PMA and STCed. You might ask why install the device? Would be much more convenient and a cleaner job to change the oil. I would have to re plumb my oil cooler. There are no provisions for the cooler lines on this adapter. If I were to install this filter adapter, can I connect my oil cooler from the oil galleys on the front of the engine and if so, what kind of flow would I expect? Also, could the Harrison cooler be turned around in the baffling mount so the fittings face forward instead of to the rear? The easiest thing would be to rotate the cooler bottom to top, that would place the fittings facing forward, however, the relief valve would then be on top. See any problem with that? Last thing, Steve Wilson said awhile back there may be an AD on the Reno adapter! Know if that is fact? Thanks Jim, and hope you have an early spring up there. The trees and bushes are sprouting and flowering here in central Texas. Bradford pears are white all over now. Cheers..........Ed

I recently installed one of those adapters from El Reno on a Cessna 170 without an oil cooler. If you wanted to have both a filter and oil cooler some study and/or research would be necessary. The AD note is on the TCM adapter. I don't see a problem with rotating the cooler to get the lines oriented the way you want. If you connect the oil cooler to the pipe plugs at the forward end of the oil galleys you will have very little flow and very little oil cooling. The pressure is virtually identical at both points.


Perhaps the most effective way to plumb an oil cooler for an O-300 is to come off one oil galley, thru the cooler, and back to the sump thru an orifice. The orifice is made by welding or brazing up a steel fitting and drilling it with a #40 drill. I don't believe this is approved, but has been used with great success by many for years. The orifice is necessary to prevent excess loss of oil pressure. -- Jim

OIL COOLERS...(050302)
Subj: Questions on oil coolers
From: Mark Kadrich <>
When I got my Swift it came with an oil cooler that looked like it came from an IO540! It was big and had the side mounts and looked like it originally bolted on from the side. Well, when I installed the O300D, I took the factory oil cooler adapter and installed a PMA'd oil cooler. It's standard equipment on many 172s. Michelle's Swift has an oil cooler too. However, hers is plumbed from the front oil galleys and AD 47-25-07 says that you have to remove the restrictor that creates the pressure differential to the cooler. More background - Michelle is installing the Airwolf oil filter system. We wanted to include the new oil cooler but the FBO is concerned about paper. What is the story on oil coolers in Swifts? Is there an STC or 337? Was it optional equipment? I'd like to do the Airwolf filter but would like to get some good information before I do anything else.

There is nothing wrong with running the stock oil cooler in conjunction with the oil filter. Now, if you have the EQ adapter in the oil screen hole, that is a problem. The stock oil cooler is factory equipment and is on the original aircraft spec. Like you say, that AD note caused very little flow thru the oil cooler with the stock setup. Many Swifts have the plumbing revised to go from pressure to the cooler and back to the sump. An orifice is needed to cut down the flow and limit the oil pressure loss. As far as I know that method is not approved, but it works great! A 50 drill orifice usually works well. The EQ adapter was furnished as factory equipment on many Swifts. It is not mentioned on the type certificate, but I have an old parts catalogue that shows the "Globe Swift Installation." The reason the type certificate was not revised in 1947 was probably because Temco was too busy trying to stay solvent and didn't have the time (or money?) to worry about such small stuff. -- Jim

Subj: RE: Questions on oil coolers
From: Mark Kadrich <>
When you say EQ adapter, do you mean in the forward oil galleys or in the oil screen? Michelle doesn't have the adapter so they pick up the oil from the oil galleys in the front of the engine. (I thought that was what the AD addressed) She has two big oil lines in the front of her engine. Mine come from the stock adapter that replaces oil screen. In any event, it is a stock item and since it is, we shouldn't have any problem. Thanx again! m

The EQ adapter goes in the oil screen housing. Do you have an O-300 parts catalogue? Or access to one? Look in the parts catalogue. It is in Figure 11. Oil cooler equipment. The AD note called for removing a sleeve which blocked the oil flow from left to right at the front of the engine and made the flow go thru the oil cooler. If the oil cooler became blocked or blew a hose, the entire right side of the engine then was starved for oil. Not good! That's why the AD to remove it. -- Jim

Subj: Oil in the Intake System
From: Kerby Warden <>
Jim: Pulled a cylinder to check for wear and found oil in the intake wells and manifold. Enough to run out and down the manifold after removing the hose clamps. Have not seen this before. Checked valve guide to valve stem clearance to see if the guides were leaking oil into the manifold. It was within limits and no excess movement with the valve open to seated. The only other place I could see where oil could enter the intake would be in the sump passage. Do you have any suggestions? I can run it as is, and use more oil. OR-- I can replace FWF with my No.2 Engine. Glo & I are still planning on going to Diamond Point. Kerby

I have seen that several times and it was always just valve guides and pretty normal, except once -- if the engine is a C-145 (or has a C-145 oil sump) there is a sheet metal splitter above the carburetor in the oil sump held in with two rivets. If one or both of these rivets is loose oil can leak into the induction system. The O-300 oil sump has a cast integral splitter. The engine I had this happen on was an O-300A but it had the sump replaced with a C-145 sump at some point. The splitter can be seen with the carburetor off. -- Jim

Subj: Oil Pressure for Cont 125
From: Bob Price <>
Jim: The oil pressure gauge begins with yellow and then changes to green at 30 PSI. I am using Phillips XC oil and have kept track of the oil pressure which was in the green (35 PSI)... Yesterday I noticed the oil pressure had dropped almost to the yellow (31 PSI). The temperature gauge indicated 140 degrees F. What should the pressure be for a 125 Cont.? Min and maximum? I have not been able to find any information on this in the archives or the swift books I have from the museum... Should I be concerned? Thanks Jim! Bob Price 3361K

The oil pressure for a C-125 should be 30 - 40 psi at cruise, it can be as low as 10 psi at hot idle. If you have put in XC oil after the engine was operated on straight weight mineral oil for a number of hours or years you may have to change oil frequently until it stays clean for a while. (like every 2 or 3 hours) The oil pressure can be raised by putting in a stiffer spring in the relief valve behind the #1 cylinder. I would not worry about 30 psi oil pressure. If the oil pressure continues to drop note the viscosity of the oil. If it appears to be thin the fuel pump may have a ruptured diaphragm and may be dumping gas into the crankcase.
 -- Jim

Subj: zero oil press
From: Ed Clegg <>
Hi Monty ,
Hope all is well out there in Lake Elmo. A friend has a UGH, Cessna 150 with a O-200 that has no oil press. It was running fine when he shut it down. He said oil temp was at the high end and press was low. It has been extremely hot out here this summer. He let the plane sit for 2 weeks and upon starting there was no press. Pulled the line to the gage, no flow out of the line. pulled the relief valve, looks ok. pulled the screen which I thought was quite dirty for oil of only 25hrs. Come to find out the screen had not been pulled in a year with almost 200 hrs flown. He has changed the oil every 50 hrs. He changed the oil and filter. I have not seen the filter. He pre oiled as best he could from the front plug on the left side. Still zero. Rpm gage is working. He pulled the sump and checked the pickup tube and the screen, both clean. Any ideas short of pulling the acc case? How would you go about pre oiling the system; that is getting oil under press to the pump? Best Always, Ed Clegg

Tom Numelin in CA had that same thing recently and it was just a case of the oil pump losing its prime. The scenario is similar - draining the oil hot - then waiting some time before adding oil and starting the engine. I think if your friend gets some oil in there with a pump or whatever means it will be fine. On Cubs, they just used to raise the tail up high with the engine idling and the oil pressure would come up. To pre oil the system you can try removing an oil galley plug at the front of the case. (a brass hex headed plug about a 3/4" wrench size I believe, maybe 13/16" ) It should be safety wired. Then pump oil in. You can try just using a pistol oiler. If that doesn't work use some other type of pump. Hardware stores have relatively cheap plastic rotary pumps meant for pumping water. I used to have a car power steering pump adapted for preoiling aircraft engines after overhaul. It was mounted on a board and driven by an electric motor via a V belt. (I would think you wouldn't have to be so elaborate.) You just want to get oil in there and prime the pump. This can be avoided in the future by not draining the oil hot and by running the engine right away after changing oil.-- Jim

Subj: Zero Oil Press
From: Tom Numelin <>|
Since Ed's friend has a problem similar to mine, I thought I would share what I found when I pulled the accessory case, which is essentially nothing. Everything looked normal. The lower gear had worn into the accessory case housing by maybe .003" or .004" (photo attached), but that was the only thing we could find. It seems to me that the pump will loose prime every time the oil is changed. The pickup passage from the sump is really big and I don't see how it could retain oil once the pickup tube opening into the sump is uncovered. But gear pumps are supposed to be able to pull a lot of suction (20' of water for some general purpose pumps) so it should be no problem to lift that oil. And judging from my dip stick, it would seem that the normal oil level in the sump is only a couple of inches below the gear pump. So it's all a big mystery. We will put the engine back together and go fly. I would be curious if the Cessna 150 is using a "sea plane adapter" to hook up the oil filter. I am suspicious that it was somehow involved in my problems, and since these type adapters are relatively rare, it could explain why no one else has ever had the problem. A good Mechanical Engineer could probably come up with some scenarios. By the way, I found that the best way to prime the pump was to take the inlet hose off the oil filter and pump a bunch of oil back down into the engine that way. There is no where the oil can go except back through the pump. Whether that would work for Ed's friend is unknown since there are a number of different ways to plumb a filter. -- Tom Numelin Swift 80671

Subj: zero oil press
From: Ed Clegg <>
Hi guys. I had my friend pull his sump in order to check the screen. He did and it was clean. So I placed the pick up tube in a qt of oil, seal it with tape and squeezed as he turned the engine with the starter. Oil came out of the press gage port. He replaced the sump , started it up and had normal press. He is happy as you know what and I , well you should have seen his smile. Thanks for the support, it's nice having friends out there. Ed Clegg

From: Todd Warnock <>
Subject: Re: August #4 GTS Internet Update
The article about the zero oil pressure. I use to lift both my taylorcraft BC12D and Luscome's tail up and it worked to get the oil pressure up just as you mentioned in the old cubs.

O-300 OIL COOLER??? (DEC 03)
Subj: external oil cooler for a Continental O300 C?
From: Barry Sanrford <>
Hi, Monty
My partners and I are doing our first major overhaul and we're sending the crankcase to a machinist to have him inspect it...we'd like to put a direct mount oil cooler on it; get some holes drilled and tapped into the oil passages...the machinist thought there might be some diagrams for where to set to ever hear of such a thing? Thanks. Barry Sanrford >>

Are you talking certified airplane? If so, forget it. You are talking a serious engineering project here. It would not be so hard to duplicate the oil plumbing of a TCM IO-360 but proving it to the FAA would be another matter. There are add on oil filters STCed and available and a larger-than-standard oil cooler can be fitted. -- Jim

Subj: question on Harrison oil cooler
From: David Bentley <>
I have a Harrison AP10 AU10-02 Oil cooler, SCM 1214921130 installed in 1992. What is the life expectancy of this unit?

Darned if I know. I have a Harrison Model 3875 Oil cooler on my Swift, which was installed by the factory in 1950. (54 years ago next February) It still works. -- Jim