oil pressure sensor

[CaptainDave]

I need to replace my oil pressure switch because it's leaking (I was told). I have the new one. Is there anything to this job other than unscrewing the oil one and screwing in the new one? Should I use high-temperature thread sealant or is Teflon tape the better choice? I need to change the oil so I'll do this at the same time. Sorry if this is a very basic question but I'm just learning to do things on my car that are more advanced than putting in new wiper blade refills! Thanks.

[action]

Use thread sealant. Any thread sealant should work.

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[tomo]

I am not a fan of using a thread sealant on an electrical component as some of them will insulate the fitting from a good ground. I would use nothing as the pipe thread should seal just by tightening.

[TonyC]

I say verify that the thread sealant is not an insulator, and use it if it doesn't interfere with electronics (package should say so). You don't want to deal with leaks in that spot again for a very long time.

This is why: Aside from the fact that it's extremely hard to find the necessary gasket for the adapter, there is also the extreme risk involved in removing and installing the sender. If you don't vise-clamp the adapter properly, you will break the aluminum casting in half-a-snap, leaving you stranded unless/until you find a replacement. And then, that replacement will very likely have the same issue you had with the old one, causing you to do the same job and run the same risk over again. Ask me how I know all this.

You have to remove the adapter to replace the sending unit and clamp it down at the sender's end to do that job. That will mean getting a new gasket for the adapter. If you cannot find one in the parts stores, you can cut one from bulk gasket material by tracing the old one. This is an example of one of those jobs that is more complicated than it looks.

---Tony

[action]

I say verify that the thread sealant is not an insulator, and use it if it doesn't interfere with electronics (package should say so).

This is why: Aside from the fact that it's extremely hard to find the necessary gasket for the adapter, there is also the extreme risk involved in removing and installing the sender. If you don't vice-clamp the adapter properly, you will break the aluminum casting in half-a-snap, leaving you stranded unless/until you find a replacement.

---Tony

There are few to zero electronics in any 1966 Lincoln engine system. Much less the oil pressure sender circuit.

In my opinion, there is nothing proper in using vise grips to remove or reinstall a sender of any type. Adverse things happen when the incorrect tool is used for any job. For under $10 one can get a socket for the job. Crushing the sender with a clamp or pliers is a problem. The idea is to use a socket to turn the sender.

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[TonyC]

I think you might be right about the sealant; there should be no issues. In fact, I used Teflon pipe tape on my last sending unit, and it caused no problems.

In my opinion, there is nothing proper in using vise grips to remove or reinstall a sender of any type. Adverse things happen when the incorrect tool is used for any job. For under $10 one can get a socket for the job. Crushing the sender with a clamp or pliers is a problem. The idea is to use a socket to turn the sender.
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This I have to respectfully refute...but first I have to clarify something that other readers may be confused about: I am not suggesting applying vise-clamps on the sender; the vise clamps are to go on the adapter, at the spot the sender screws into, to reinforce the walls when torque is applied to the sender. Not bracing the adapter at the threaded end with vise-clamps will cause adverse things. No matter what socket you use on the sender, and that was exactly what I did last time, the twisting force alone will break the aluminum casting at its weakest spot, causing even worse problems that not even a J B Weld patching will fully cure. The adapter must be braced in a clamp or vise to give external reinforcement to the aluminum shell before attempting to twist off the old sender and twist on the new one. Don't doubt me on this; I reiterate, ask me how I know all this. And I know I'm not the only one who ended up on a scavenger hunt for a replacement adapter because I didn't reinforce the casing.

In any case, there is not enough space down there to apply a brace or use a socket on the sender, so Dave will still have to remove the adapter from the block to attack that sender. Sure, he could try a box wrench on it, but without bracing it's all but guaranteed he'll end up removing the adapter anyway after the casing breaks.

---Tony

[CaptainDave]

I had no idea I'd get any more of a response than "yeah, simple job, don't sweat it"! Thanks for the warning Tony. Now, what adapter? What gasket? I thought this was plug-and-play. Maybe I should have the shop do it after all.

[frasern]

When I bought my '67, It had been parked for a number of years due to an oil leak. It was the adaptor in question, which had split where the sender threads in. This is very hard to see, even with the adaptor out, a very close inspection is needed, but that could be what is leaking, not the sender itself.
The adaptor, which could also be called an oil filter housing, is the aluminum casting behind the steering reservoir, which the filter, and sender, are on.

[action]

Here is the oil filter adapter for 61 to 68 MEL engines.
This is for sale on Ebay by Bakers for $135
The sender screws into the end of the adapter just above the filter.
As pictured the orientation isn't correct for how it is mounted and I am sure you get the idea

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[LithiumCobalt]

On neither of my 462s have I used vise grips or any other tool to brace or clamp down on the housing when replacing one of these switches. Unless you're torqueing the sensor off/on gorilla-tight with pipe wrenches (which is also unnecessary), there is no need for bracing or clamping or any other nonsense. All the hype about bracing/clamping is a solution in search of a problem, in my opinion. It's a simple procedure. If you're not careless, you won't have a problem. Turn the old out and crank the new one in until you get resistance and then check for leaks. If you get a drip or two when running, simply snug it up a little more.

[frasern]

I agree mostly with Nick, but remember this is an aluminum part. If it feels super tight coming off, heat it, or use Tony's approach.
When going back together, use the factory torque spec. If it leaks tighten it a little at a time, and if the leak gets worse, you may have the cracked housing I described, that's how I found it, the more I tightened, the wider the crack spread. The crack was along the mould flash, making it hard to spot until it spread.
I believe a previous "gorilla" had over tightened mine, and over time, with heating and cooling cycles, it cracked due to that pressure. When I replaced the housing, I chased the threads (slightly) with a pipe tap, mostly just to ensure roundness, used loc-tite, and didn't over tighten, and it has been fine.

Edit; I just checked the '66 manual, and there is no factory torque, I may have used one from a generic engine book, but can't remember it. I guess just don't overdo it.

[TonyC]

Nick had one thing to his advantage in his experience. In four letters, it was L U C K. Somebody upstairs decided to give him some of that. But he is otherwise wrong; his luck is NOT the norm. My experience, on the other hand, is; that's why those oil-filter adapters for MEL engines are becoming increasingly harder to find, and running very pricy when you do find one. OCC's $135 example used to run for half that, until demand increased.

"Gorilla" is relative; what may be "baby orangutan" to one may be "King Kong" to someone else. They had to torque those senders in more than finger-tight to seal against leaks, but steel against aluminum usually results in a one-use-only scenario (maybe a prelude to torque-to-yield, which non-dealership mechanics hold at the same level of esteem as COVID-19). Extreme care must be taken...but I find I'm about to repeat myself.

Fraser, I can't check my copy of the '66 shop manual, and I don't remember seeing it there; but the '67 does have that torque spec. The limit for the oil filter adapter is 10 to 13 foot-pounds, same as the timing-cover bolts and the mounting bolts for the steering pump.

Dave, it isn't that simple, but it does not require a $10,000 degree from the ASE, either. The hardest part of the job is getting to the three bolts that hold the part in place, due to the routing of the steering lines. The rest is easier, just taking off and putting back on is the hard part.

---Tony

[LithiumCobalt]

I have about the worst luck in the world. If it could have broken, it definitely would have for me. I don't think successfully replacing this on two cars without issue was related to luck. And the reason that they are expensive used is because they aren't made and haven't been made in some time. There is no aftermarket option, so you're stuck with parts cars. Supply is drying up, not that there is an inherent problem with the adapters. Of course, if you apply too much torque and start jerking stuff around, you run the risk of breaking something. Somehow I accomplished preserving them and not through any means of special care.

[action]

Tony, that OCC adapter for $135 is an OCC thing. Cleaned, painted and includes a FL1A to get someone to part with a hundred dollars.

Here is a $35 one that includes shipping
https://www.ebay.com/itm/254879510692?h ... SwjwJgNv7M
Yeah the link will go away in some months but I don't think the supply of used adapters is going to be an issue. Unfortunately the slabside has gotten popular with resto-mod guys. Many of those owners yank the MEL engine and puts something else in there. Creating a source of donor parts.

As far as the design having issues that requires extreme care .... well the same design was used on FE engines. Both MEL and FE were introduced in model year 1958. MEL was used in the beginning for Mercury but became a Lincoln only engine a couple years later. FE was used heavily in the 1960s in the Ford and Mercury product line. The engine was produced into the 1970s almost 2 decades and had two distinct generations. Likely the number of FE engines exceed MEL engines by ten fold.* The oil filter adapter on the FE was the same design as MEL. An aluminum adapter with a steel oil pressure sender threaded into the adapter. It has been said the FE engine was never a static design. Improvements were always being made to that engine by the company. And they never changed the material design of the oil filter adapter.
*The proof of this may be that there are 10 FR oil filter adapters listed on ebay at first glance. It was a very popular engine.

I have zero experience with the MEL oil pressure sender, however I have replaced a number of FE senders both the gauge type and the warning light type. And it was pointed out to me that the pliers I was using on the warning lamp sender might be an issue. And a special socket was made for the job. With a socket one can use a torque wrench. That does not work for the much larger sender for vehicles equipped with a oil pressure gauge. That sender has a squared base a thin open end wrench is needed. I have never cracked, split or broken an aluminum FE engine oil filter adapter. Nick's luck must have rubbed off on me before I ever heard of Nick. Not sure what else to say other than do not use vice grip pliers.

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[TonyC]

Which I still disagree with for the same reason I already cited, and not for the sake of arguing. You both were lucky, whether you admit it or not. When I needed to replace my adapter, I had the worst time finding one, taking nearly half a year to finally come across one. That prompted me to go on the hunt for a second one, which took me about three or four years to finally find (that was mostly due to my Germany assignment, admittedly, but it was still a needle-in-a-haystack search after I got back). At least now I'm prepared should that sort of thing happen to me again.

I'm aware of those owners who yank the old engines in favor of a five-figure conversion to something newer "just because." I'm also aware that most of them don't bother considering the value of the old engine, just chucking it into the rubbish tip, so that puts an "Ix-Nay" on the idea of part supplies increasing.

The adapter gasket is hard to find on its own, but oddly it is included in some engine-gasket sets. So you don't end up spending $100 or more on a complete set of engine gaskets just for the one, that's why I suggested tracing the old one on bulk gasket material and cutting it out.

To clarify, my recommendation is just that: A recommendation. It is up to the reader to either follow it or disregard it...and since I prefer to be diplomatic I won't use "See, I told you so," except maybe to those who saw my warning, disregarded it, and ended up with exactly the problem I had. As the iconic Jigsaw would say, "The choice is yours."

---Tony