Packard Forum Index » General

I was having a low oil pressure issue with my '52 in hot weather using 10W30 and a old mechanic friend suggested using Valvoline racing oil . . .50 weight! It's a high quality oil that does not break down and I've not had any more trouble. She runs quieter, smoother and cooler. Of course she's in the garage in cold weather.

You can also put a shim under the oil pump spring to help with the pressure.(IE:an old nut.This works as well.An old fix too.I am not sure 50 wt is the answer.Yes that is an old remedy but how do you know its cooler unless you have guages to tell you so.Also thicker oil flows more slowly.I think you would be better off checking the oil pump,and maybe shimming up the spring than going with such heavy oil.Also, does it have enough zink and phosporous?I doubt it. Brian

Great tip Brian. Next time I have her on a hoist, I'll look at shimming. Do you like the 15W40 diesel oil?

I am sure it is ok but according to Motor Head their HI-Z has more of the additives in question.And its cheep.Not to mention the industry is always changing standards.With the additive it really doesnot matter what you use. I favor Valvolive 30wt myself.Remember the book says the light will "flicker" at idle.or even stay on.All this means is the pressure is 5 lbs or less. (Dont quote me here.)My jist is this is normal.When R.P.M. goes up even a little it goes out.My car did this as well at first.It did seem to stay on longer than I would have liked.Hense the Spacer under the spring.By the way make sure your pump is in good shape.(Mine had no detecticable wear.)Most likely a weak spring.Gee after 58 years I would guess thats ok.I hope this helps. Brian

By the way all.Do any of you know if those springs are avalible? Brian

There has been so much written on this subject of proper motor oils, especially since the requirement for catalytic converters on trucks thus decreasing the zinc/phosphorous additive in the 15W-40 oils, that I hesitate to even try to summarize it.

But just sticking with the topic of low oil pressure (which wasn't the question in the original query, but we seem to have worked our way there anyway), here's my take. If the oil pressure rises to and stabilizes at the correct pressure with a cold engine at idle, you can assume the pump and pressure relief spring are fine. If it rises with a cold engine to the normal oil pressure with a bit of throttle, your oil pressure relief valve spring is Ok, but the pump itself may or may not have some wear. In either of these cases shimming the oil pressure relief valve will not increase the pressure with a hot engine at road speed. The oil pressure is created by the pump and at a constant pump output is dependent on two characteristics, (1) bearing and other clearances, and (2) viscosity of the fluid. So if you use a higher viscosity oil you will increase the pressure because it is more resistant to flow, you are compensating for increased clearances. Though the heavier oil has this greater resistance to flow and cushioning effect, it is by that virtue slower to circulate in the engine and thus less efficient at transferring heat away from bearings, etc.

So, if you need a much heavier oil than was originally specified to get more normal oil pressure at road speeds then you really should drop the pan and check the rod and main bearing clearances; heavier oil will buy you some time, sometimes quite a bit, but it's not the long-term answer.

Regarding motor oil questions: For the conventional flat tappet Packard 6- and 8-cylinder engines suggest looking at Classic Car Motor Oil. It is rated for API Service Categories: SH, SJ, and SL and comes in 15W-40 viscosity. It has 1,600 ppm ZDDP. It is made by D-A Lubricant Company, and the Indiana Region of the Classic Car Club is selling it. For information go to www.classiccarmotoroil.com or call at 317-225-0040. Roller tappet 8s and 12s are not affected by the new formulations. Makes sense to me for my '37 Six and '47 356.

Yes, I have heard of that stuff as well.I have been using Zboost from motorhead oil. ZDDP additive.I would think both would be fine.take your pick I guess. Brian

Owen, Thanks for your input on the pressure relief spring.It was suggested to me by an old mechanic.From what you said my trouble seems to have gone away not from the shimming but from the clean oil pan and clean oil.In my case straight 30 wt.And 1 1/2 bottles of Zboost.Of course it has not been run in warm weather yet.Still waiting for spring. We have it today at least. Brian

Sounds like all may be well, and I'm glad to hear it. I'm not saying that the pressure relief springs don't sometimes fatigue, just that there are other possibilities.

Thinking to your comment on cleaning the oil pan, I can't think how many times myself and others have suggested to folks with a Packard and without prior history that they should drop the oil pan and clean it out. But I myself was negligent with that same advice on my own 56 Caribbean for some time, though the engine was quiet and had great oil pressure. When I finally did drop the pan, it was relatively clean, BUT the intake screen on the pump suction was about 1/3 blocked off with sludge.

It can be a bit of a pain on some models to drop the pan, but the cost (gasket) is cheap and it's really almost an imperative if you haven't already done it. Nice feature of the 39 and back Classics is that there is an access plate in the oil pan for this purpose (cleaning the screen that is).