Topic: oil pressure sending unit


rdt52flthd    -- 08-18-2019 @ 12:57 PM
  Until the last few days everything was OK on my 1952 original v8 with 70K miles. The oil pressure was about 42 lbs. while driving and about 10 at hot idle. The next outing it started out at 42 and after 3 miles it began to drop to about 10 when the engine got up to operating temp. This did not change regardless of RPM. After a few hours and it was cool I checked that the oil was at the full mark, I started up and it was at 42 lbs. again. I went down the road a mile or 2 and it began to drop again. I am using 20 W 50 and 180 thermostats.
First question: does this sound like a sending unit or something wrong with the oil pump?
Second question: How long until a hot engine returns its oil to the pan? I remember those attendants showing drivers a dipstick out of a hot engine to sell unneeded quarts. Thanks, it's always a pleasure to read what the true experts have to say.

Best to all, rdtflthd


carcrazy    -- 08-18-2019 @ 4:24 PM
  My guess is that the oil pressure sending unit is getting tired. My '53 Ford has very low oil pressure indications when the engine is hot and idling. I installed a S-W mechanical oil pressure gauge in an auxiliary panel below the dash. When the original gauge reads about zero, the mechanical gauge reads about 20 PSI. I use a straight SAE 30 weight detergent conventional oil.


37RAGTOPMAN    -- 08-21-2019 @ 3:23 PM
  oil pressure problem
is this ALL OF SUDDEN PROBLEM ?
how old is the oil , what color, and what brand,
are you reading the gauge that is in the car or a mechanical oil pressure gauge,?
I would use a GOOD mechanical gauge. to see what the oil pressure really is,
so this would rule out the oil pressure sending unit,
if OIL PRESSURE is ok replace the sending unit
if oil pressure is still low,
I would check the pick up screen on the oil pump,
did you ever use silicone sealant on or in the engine, ?
this cr-p has a habit to work it self into the oil pump screen and many other passages causing many problems
a USA made 80lb oil pump would be my next step ,the pump gears could be worn,
hope this helps, 37Ragtopman

This message was edited by 37RAGTOPMAN on 8-21-19 @ 3:37 PM


rdt52flthd    -- 08-23-2019 @ 7:46 AM
  Thanks ragtopman. I am using Kendall oil and it is clean. I'm going by the IP gauge, but will get a proper gauge as you suggested. I have never had the engine apart in 10 years of ownership, but there is evidence it was apart some time before that because it is .40 over bored. The pan was removed and cleaned about 6 years ago and everything checked out. rdt.

Best to all, rdtflthd


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