Thread: Oil Pressure

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I have a 36 Ford pickup I inherited from my dad. It was running fine with about 15 lbs. oil pressure and 30-40 going down the road.

All of a sudden it idles at 0-5 lbs. and 10-15 going down the road. Oil is fresh and full. I am thinking it is the oil pump or a bearing. Any ideas. Is this a common problem??

Roger

Did you perhaps change to a lighter weight oil?
Going from a straight 30 wt to 10-30 or 5-20 will bring the hot pressure down somewhat.

Was the higher oil pressure noted on a fully warmed up engine or one that was cold?
Weather can make a difference as well.

Do you have a mechanical or electrical oil pressure gauge?

I would double check either with a known to be good mechanical gauge.

I did not change to a lighter oil. Been using 15/40 that I use in all my vehicles. I have both mechanical and elec. press guages So I don't think the guages are wrong as they both so same pressure.

Flatties can run forever with very little oil pressure.

oil pressure is a measurement of resistance to the flow of oil going through all points,,,,,if it reads 5lbs then that is how much resistance there is to the oil travel through the block,,and yes if the bottome end bearings are a little worn,,your oil pressure will drop when warmed up.
This is no cause for alarm,,,,as long as you are getting free flow of oil you should not worry to much.

Thanks for your replies. Whatever the problem is, it is not from wear. I am not sure of the mileage on the engine as my dad bought it used and put it in. It does not smoke or use oil.

This did not happen over a period of time. I was driving it about once a week for a few miles to keep it charged etc. One day the pressure was low and it would not come up so this is something that happened over a short period of time. Can the oil pump be replaced with the engine in place? I would try that first to solve the problem before checking the bearings. I have a spare motor but would rather fix this one if possible.

Roger

Could be that the relief valve stuck a bit. 15-40 oil isn't the best choice for a flattie, try straight 30. A different brand of oil sometimes makes a difference, too.