61 ford falcon

I have a 61 ford falcon. Her oil light has been going on (the oil is full and she runs well).
It happened once this summer in the heat, but it is a cool day today, after driving about 70 miles. I let her cool down and the light goes off.
Is it that she just needs and oil change and new filter or is it more serious and does she need an new oil pump? what should I check? I usually change the oil once a year. I drive her around 500 to 1000 a year. she has 74000 original miles.
Thank you for your help

There are several possibilities here, including a bad oil pump. After all, that pump is likely the original one and after 50 years… But, more likely than a failing oil pump is the likelihood that excessive oil sludge is clogging the screen on the oil pickup in the crankcase, and may also be plugging oil passages in the engine. Just as the oil pump is 50 years old, your engine’s internals may be suffering from five decades of sludge build-up.

To put this in human terms, what disturbs me the most is that you are apparently treating a probable low oil pressure situation as if it was a headache, rather like a possible stroke. This is a situation that needs to be attended to pronto. If you want to keep this car running, I urge you to STOP driving it, and have it towed to a competent mechanic for diagnosis.

With any luck, the mechanic can break down the engine, clean out the sludge, do a compression test, and get you back on the road. Hopefully there has not been too much damage caused by probable low oil pressure.

The infrequency of the oil changes can cause a filter to gum up. I would start with the oil and filter change. If the light comes on again, even for a blink, except right after start, then get it to a mechanic for a diagnosis.

It could be something as simple as a defective oil pressure switch. You mechanic will need to hook up an oil pressure gauge to see what is actually going on. Based on his findings, you might need new bearings, a new oil pump, maybe just a switch.

You didn’t say what weight of oil you are using but any 5wXX oil will be too thin, ie. 5w30. Even a 10w30 could be too thin, this engine may specify straight weight oils, like 30HD for outdoor temperatures above 40°F, 20HD above 10°F etc.

Have your mechanic test the oil pressure.

Your problem might be as simple as a faulty oil pressure switch, which is very inexpensive to replace, but you need to find out for sure about the actual oil pressure, and as VDCdriver suggests, you need to do it ASAP.

If the oil pressure tests low with a calibrated gauge, the mechanic will have to explore inside the engine to find out why, but I don’t think that’s going to be necessary.

Others may disagree, but I see nothing wrong with a once-a-year oil change for a car driven only 1000 miles per year.

Those models had a road vent tube and once the engine was worn to the point that blow-by was evident at a hot idle the engine was on a steep down hill to the grave yard. Is smoke very evident from your vent tube? If so the engine is likely very gummed up with rings and lifter beginning to stick and the bearings are on their last legs.

First things I’d check are the oil pressure sending unit for cracks, change the oil filter to be sure it’s not clogged or damaged, and it both these are OK pull the oil pan and clean the oil pump pick up screen.

I had a similar problem with a 1971 Ford Maverick which had an engine similar to that in your Ford Falcon. We were on a vacation when the oil light would flicker on when I came to a stop. The engine seemed to be running well with no strange noises. I took off the oil cap while the engine was running and could observe that oil was being pumped throught the rocker arm shaft. I reasoned that if the oil pressure was really low, the valve lifters would be clattering. I replaced the cap and continued the trip. We had no problems. I had the car checked out when we returned home and the problem was a defective oil pressure switch.
Have your Falcon checked out, but I would bet on the oil pressure switch.

I agree with the others, however we had a 60 Falcon that required an engine at about 68K. What we were told then by the Ford dealership that those engines had a habit of making it to about 60-70K and then self-destructing. They never expected to get much more mileage out of them back then and 70K was like 200K now. Have the car checked for actual oil pressure with a gauge, check the oil intake screen, but highly suspect it may be bearings in the engine.

I think you probably just have worn bearings. At 1000 miles a year this engine will probably outlive you. When this car was on the road a lot of people used straight 30 weight oil in the summer. Atlantic oil company at that time made 5w20 for the winter and 20w40 for the summer. If the light coming on at an idle bothers you use 20w 50 and you probably never see the light again.

oldtimer 11–I didn’t know that 5w-20 oil was available back then. The only multiviscosity oil I remember seeing in those days was 10W-30. I bought a Ford Tempo in 1985 and the manual specified 5W-30. It was hard to find and the dealer told me I could substitute 10W-30. Back in the late 1950s and early 1960s, many people, including myself, used straight weight oils. I used 20 weight in the winter and 30 weight in the summer. This was in a midwest climate.

In 1961 non detergent oil was still very common and was preferred by many car owners. Quaker State is still fighting the reputation that its non detergent oil made for them 50 years ago. I owned a 1961 Ford Falcon in 1964 and the engine was a bucket of sludge that smoked and clattered after 50,000 miles of in town driving, using Q-S ND oil. It required a “ring and insert” job at 80,000 miles. The valve cover weighed more than 10 pounds and the rockers were barely visible due to the sludge. The quality of modern oils is possibly the most significant reason for the extended life of engines today.

If this is the original engine, I’m willing to bet it’s just worn out, as others have suggested.

Oil pressure is developed by the oil pump’s pushing oil against/through small passages like the spaces between your crankshaft surfaces and their respective bearings. If those spaces wear too much, the spaces become bigger, the oil passes through more easily, and the pump has a more difficult time maintaining pressure, especially at idle and when the oil is warmed up. It’s like maintaining pressure in a balloon with a leak.

The oil pumps themselves rarrely wear out, as they’re a simple design and constantly bathed in flowing oil. But after 50 years, a worn pump IS a possibility.

Have the engine checked out. If it’s sludged up, get it cleaned out. If it’s worn out, you have a decision to make.

@LauraSue - you’ve gotten lots of good advice here. Which engine do you have? The 144 or 170 cubic inch 6? These were very simple engines. If it’s diagnosed as either sludge or worn bearings, if you can find a mechanic familliar with rebuilding older engines you might be able to have it fixed for a reasonable amount of money.

My first car (Mustang) had the 170 six, which I had the pleasure of rebuilding after my sister blew a piston.

What I have seen in oil pump wearing out,is not so much it the gears in the pump. Its the spring in the relief valve. I had one stick open and lost all of the oil presser at 70 mph. That motor put a rod right thru the oil pan. In the op’s case I would replace the oil sending unit first. If that don’t fix it. Then I would take the valve cover off and drop the oil pan and replace the oil pump and screen. With the valve cover and oil pan I would clean all the sludge out. I would bet the oil presser will be back to livable reading. I did this with Ford 300 6 cyl. I did roll new bearing in that one only because I had pulled them for inspection. They were all in spec. This one was weird. It would have good oil presser hot or cold. Then it would go to zero but did not knock. The presser was tested with a test gage.

Rod Knox made a good point about ND (non detergent) oil. It was not specified by Ford, detergent oil was. But a lot of older mechanics and car owners at that time did not trust detergent oil, so it is possible that the original owner or one of the early owners used an ND oil in it.

If I remember correctly, the general rule at the time was; no oil filter, use ND; oil filter, use HD (or just plain detergent) oil.

Falcon’s were one of those cars that got abused a lot by their owners. They were so cheap at the time, they were almost considered disposable. It wasn’t uncommon for them to get very little maintenance, unlike a “real” car.

The engines used in 61 only had 4 main bearings. They upped them to seven in the later models of this engine, 200 and 250 cu in engines.

You indicated that while the engine is cool it is fine but when it becomes heated the oil pressure light comes on. This is consistent with low oil pressure due to worn bearings. While the engine as well as the oil is cold the metal contracts to make a tighter fit of the bearings and the oil is thicker both of which would increase oil pressure until the engine heats up again. I’m sorry to give you the bad news but you need to take care of it before more damage is done.

A oil pressure gauge will confirm that.

fatdaddy, you are right, the point I was trying to make is that if LaurenSue is using a modern 5w30 oil, it will be like the bearings are worn out because that engine was designed for heavier oils. The bearings have more clearance to begin with.

But if she is using the correct oil, then it probably is the bearings.

Ford engines of this era were notorious for their very small oil return holes in the head. Unless the oil was changed religiously (and sometimes that didn’t help either) the holes in the head would plug up with oil sludge. The oil couldn’t return to the pan quickly because of the plugged return holes so it would sit at the top of the head and bake, which would only plug the holes up even worse. It didn’t take long after this happened before the whole top of the head was a big gritty mess. Since there was so much oil trapped at the top of the engine lots of it would leak down the valve stems and into the combustion chambers. That’s one of the reasons Fords of the time were often followed by a big cloud of blue smoke.

Of course, with all the oil trapped at the top of the engine there was an oil starvation problem for the rest of the engine. Worn rings, cylinder bores and, of course, bearings were the result.

The problem was so bad and so common that “cheater kits” were available at parts stores. As I recall, these kits ran a copper line from the valve cover(s) to the oil pan to provide a way for the oil to return to the pan.

Pull a valve cover on the engine (It’s really easy on these engines) and look underneath. If there’s a load of sludge covering everything the entire engine will need to be boiled and completely overhauled. Anything less is just a temporary band-aid on a potentially very serious problem.

I was only 9 years old at the time so my memory is a little fuzzy, but my Dad bought a new 57 Ford for his 50 mile commute. I remember him carrying an oil can and when the lifters would get noisy, he’d squirt some oil on them until the dealer took care of the problem. I remember them saying something about the oil holes not being drilled big enough. The next car was a 58 Chev. Geeze, new car and you had to hand oil the lifters. We also had a 61 Merc. I really liked the Ford products for ride and style but they did have some issues back then.