I have a 56 F100 with a 272. This weekend the oil light came on, and stays on intermittently. According to the dip stick the oil level is full. I am using 10W40 standard Havoline oil. It goes off when there is light throttle and about 1,500-2,500 rpm. Otherwise it is on. I have an oil pressure guage, but it stopped working about a year ago/or that is when my problems started. However, until this weekend I have never had the oil light come on except in steep downhill situations, i.e. a driveway. Obviously I have parked the truck and will be working to fix this problem.

Should I:
1. Change the oil pump?
2. Get a new oil pressue guage/re-connect this one?
3. Start looking for a good rebuilder
4. Consider a SBF?

Any suggestions are appreciated. Thanks.

 

I'd definitely get a new gauge. I'm not much for lights though. I haven't had this particular problem with my Y (yet!), but I'm thinking oil pump or possibly the distributor shaft. Might wanna take the valve covers off and make sure your getting oil to the top end also. That's where I'd start at least.

 

Thanks! I will do that and post my discoveries. I have read elswhere in these forums that about 50psi is normal for a 272. Any thoughts or experiences on what psi I should be running and at what RPM?

 

Decade,

Get a good oil pressure gauge before you stress out. I prefer SW mechanical gauges over electric.

There are many things that can make your light come on: bad ground, bad sending unit, bad wiring, lose connections, etc. Same with electronic gauges. That's why I prefer mechanical gauges.

An engine just doesn't lose oil pressure all of a sudden unless something BAD happened inside and then that 272 would let you know by making some noises I would think.

I really doubt that the oil pump or distributor shaft would go out that fast either.

Y-Blockhead

 

You might try another oil sending unit for the light but an oil pressure gauge will give you a better feel for what the actual oil pressure is. 10-15 lbs oil pressure at hot idle would be more than sufficient. You didn't mention if this is just showing up all the time or just when hot.

 

Thanks for the advice. I do have a mechanical pressure gauge. I will get this set up this weekend as well as check the sending unit for the light.

The problem showed up more and more as the engine warmed up. The light came on intermittently at first and then it was constant after a few miles. I drove two miles, picked-up a load of compost, then drove two miles home. (Yes, I still use it as a truck) By the last mile the light was on continuously.

Also I have been mining this forum for a little more infomation and some have suggested that you run 5.5-6 quarts of oil. Apparently this will help with not getting false warnings. When I had the oil changed they only put in enough to get up to "full" on the dip stick. It is still in the "full" range. Any thoughts of trying this.

Thanks for all the help, Jeff

 

I would do the following things:
1. Install a mechanical oil pressure gauge. run the engine and see what you get.
2. pull the rocker covers and see if you are getting oil to the rocker arms. above idle it should oil enough to throw oil on the exhaust manifolds.
3. If you don't get oil at the rockers or Don't have oil pressure, Pull the oil pan and see if the oil pickup screen is plugged. I don't know if you have been inside the engine before, but I've seen y-blocks with an inch of sludge in the oil pan.
Good luck!
Craig

 

I installed a mechanical oil pressure gauge and only get 7 psi max. The pressure varies between 5 to 9. 5 at idle, about 7 at about 2,500 rpm. It varies. I didn't go any higher. Next I will pull the valve covers and see what happens. I am moving slower than I thought I would but my very active 3 year old wants to play baseball so obviously priorities intervene. Thanks for all the advice.

 

With the very low oil pressure I sure wouldnt be running the engine until it is fixed. Go ahead and try a new oil pump, and clean the pan and pickup of sludge. Probably will not correct the oil pressure, but you would need one anyway. An extra quart of oil isnt going to help. I expect the tired motor is due to be rebuilt.

 

Check the oil pump to pick up connection also to ensure you are not sucking air into the pump.

Y-Blockhead

 

Thanks, I will check the connection between the pick-up and the pump. I think I will add the oil and check under the covers briefly. I do not intend on running it anymore than to investigate this stuff. I will plan on dropping the pan to clean off the pick-up. As far as I can tell from the ID numbers this is at least a correct if not original 272 with the 4 spd. I do want to keep this stuff in the truck. If this doesn't do it I will get the pump. If that doesn't do it at least I will have some new parts already for the rebuild. Thanks.

Hopefully my next post isn't rebuild related but I thank you all for the realistic advice.

 

The oil pressure switch that controls the light on the dash (it's been a troublesome terd since day one) gets plugged up, or leaks past the threads, so it's time for a new one.

Ford used the same switch on cars/trucks: 1956/68.

B6AZ-9278-B (Motorcraft SW-667)

 

NumberDummy: Thanks for the tip on the light. Although I think that I do have a pressure problem. My new gauge is recording low pressure. If I keep getting warnings even after I have re-established pressure then maybe it is time for a a new switch, etc. But I would have to agree with some of the other folks here that my problems probably are coming from either a blocked pick-up, bad pump, loose connection with the pick-up, or sludge. I will find out shortly and report back. Thanks.

 

Just exactly when is the oil light coming on?

If it is when you are stopping, slowing down, slamming on the brakes, or descending hills, consider the truck oil pan. It looks like something that is more suited to cooking a turkey in than for controlling the oil so that it stays around the pickup.

If this is your problem (and others have had it, too) you will either need to be thinking about a baffle or a different pan to solve the problem.

 

Wild.Bunch: The light has always come on when I am parked or driving on a steep grade. But the recent problem has been that it comes on constantly now regardless of angle. Also my oil pressure gauge is only reading 5-9 psi. Thanks.