1966 New Yorker low oil pressure question

[ascari]

My -66 New Yorker has been sitting for about three weeks. When I started it today the oil pressure lamp won't come off, so I immediately cut the engine. The oil looks clean, level is correct, and the oil and filter have less than 200 miles on them.

The last thing I want to do is drop the oil pan to get to the pickup tube/filter screen since that would to be a miserable job in 90 degree weather without any A/C in the garage. So my question is what are the other common things that could be wrong?

Any help would be greatly appreciated!

By the way, it's the stock 440 engine. Before today it always purred like a kitten, no funny noises etc.

 

[CBODY67]

Priority oil feed is to the hydraulic lifters FIRST, then the mains. If no lifter sounds, you're probably ok.

One time, years ago in the middle 1970s, STP came out with a whiz-bang "better" oil filter with two stages of filtering media. So I got one and we put it on when I got the oil changed. The oil light did not go out immediately, as it always had done. No engine sounds, either. After running it a while, we put a normal FL-1A Motorcraft back on it and all was well again. NO MORE STP filters!

Might be a bad sending unit? Might get a pressure gauge and screw it in place of the sending unit and check the oil pressure. What viscosity of oil in the engine?

Just my experiences,
CBODY67

 

[ascari]

Thanks @CBODY67 ! I will check the pressure, I left my pressure gauge at another place but will grab it when I go back there next week. I read somewhere (this forum?) that 15-20 psi at idle is OK. Does that sound correct?

I'm going to do oil and filter this weekend anyway to see if there's any metal in the pan before cranking it again. I put in 15/40 at the last oil change, that should be OK even in summer, right? Or should I go with a higher viscosity? And no STP filter!

 

[myskin]

Thanks @CBODY67 ! I will check the pressure, I left my pressure gauge at another place but will grab it when I go back there next week. I read somewhere (this forum?) that 15-20 psi at idle is OK. Does that sound correct?

I'm going to do oil and filter this weekend anyway to see if there's any metal in the pan before cranking it again. I put in 15/40 at the last oil change, that should be OK even in summer, right? Or should I go with a higher viscosity? And no STP filter!

15w40? Seems too heavy. Thick oil sounds like a good thing to do. But, if the pump can’t pump it…I’d go 10w30

 

[Big_John]

My -66 New Yorker has been sitting for about three weeks. When I started it today the oil pressure lamp won't come off, so I immediately cut the engine. The oil looks clean, level is correct, and the oil and filter have less than 200 miles on them.

The last thing I want to do is drop the oil pan to get to the pickup tube/filter screen since that would to be a miserable job in 90 degree weather without any A/C in the garage. So my question is what are the other common things that could be wrong?

Any help would be greatly appreciated!

By the way, it's the stock 440 engine. Before today it always purred like a kitten, no funny noises etc.

While there's a bunch of things that can go wrong, you need to first verify that your pressure is actually low, as @CBODY67 suggested with a known, working oil pressure gauge.

The problems with the oil light could be the sender or it could be that the wire from the sender to the bulb has shorted to ground somewhere.

From there, the next simplest thing to check is the shaft that drives the oil pump. I have seen those break and that just involves pulling the distributor and then the shaft itself.

What also happens is the pickup screen gets clogged, often from broken valve guide seals and/or plastic gear teeth from the timing gear. Sorry, but that involves pulling the pan.

And 15W-40 oil is fine. I run that in all my cars. I wouldn't go any heavier though and heavier oil will not cure your problem.

 

[CBODY67]

I ran 10W-40 when it came out and was easy to get in the later 1960s. As an upgrade from 10W-30. In those days, it was known that a multi-weight would lose its higher viscosity over time, due to the chemistry used to make them. 10@-30 could become 10W-20, over about 3000miles or so. So 10W-40 is fine, as is 15W-40 or 20W-50, from my experiences.

CBODY67

 

[bigmoparjeff]

A few years back I lost oil pressure on my "69 Imperial all of a sudden, and it turned out to be the oil pump. Most likely, the pressure regulating valve failed. I didn't bother pulling the pan to check the screen. It's pretty easy to slap a new pump on and see what happens, rather than go through the hassle of pulling the pan off just to find that everything is clean.

These days you can also buy an endoscope camera for under a hundred bucks and inspect the pickup going through the drain hole.

VEVOR Endoscope Camera 1080P HD Triple Lens Borescope Inspection Camera 4.5" IPS | eBay

It is applicable in auto engine inspections, sewer checks, HVAC ducts inspections, industrial pipelines checking, etc. Say goodbye to difficult-to-reach space. See Beyond the Standard: Screen resolution: 854 x 450, lens resolution: 1920 x 1080.

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Jeff

 

[ascari]

Thank you everybody! Step one will be to reclaim my wayward pressure gauge and take a good reading. I'm assuming the thread is NPT, right?

Regarding oil, I'm in the South and I've been using 15/40 in the summer and 10/30 in the winter, so based on the comments above I'm not too far off in that regard.

By the way, everybody on this board seem so much nicer and more tolerant of "newbies" than in some other places. That means a lot to a novice trying to make sense of the first C-body!

 

[Big_John]

Step one will be to reclaim my wayward pressure gauge and take a good reading. I'm assuming the thread is NPT, right?

Yes, NPT.

The sender should be 1/8" NPT and if you look on the opposite side of the engine block, there's a pipe plug that you can remove and leave the existing sender in place. That pipe plug is 1/4" NPT.

 

[ascari]

Thanks for the info! Perfect! I don't remember from the top of my head exactly what NPT thread is on my gauge, but I'm guessing it will fit one or the other.

 

[ascari]

Sure enough, the oil pressure is reading 20psi at idle with an external gauge. I've ordered a new sending unit hoping that will fix the problem.

 

[live4theking]

I've replaced so many oil pressure sending units over the years that it doesn't even surprise me any more when they go bad.
My first 68 NYer
89 Ramcharger twice
2007 T&C
2014 DGC

They just seem to go bad.

 

[ascari]

@live4theking Maybe I should have ordered two just in case!

 

[twostick]

15w40? Seems too heavy. Thick oil sounds like a good thing to do. But, if the pump can’t pump it…I’d go 10w30

The reason for 15w40 is it's a HD diesel oil and still has an acceptable level of zinc and phosphorus that flat tappet cams need. Regular 10w30 passenger car oils don't have enough anymore.

It will pump just fine.

Kevin

 

[ascari]

Installing a new sending unit did the trick. Thanks everybody for your help!