Started up my truck and noticed the oil pressure gage did not move. I then started to hear a clicking. Turned off engine, plenty of oil no electrical issues. Why oil pressure one day none the next.
Should I pull the pan and replace pump or is there another possible problem.
15 years ago I rebuilt the engine but I have only driven the truck 20K mikes in that period of time; 76 F150.

 

Sounds to me like you might have a bad gauge? I'd hook-up a mechanical gauge and check it again....are you still running the stock gauge?

and if your are running a mechanical gauge now..I would replace the Oil line as it may have some crap in it..or some hardend up oil in it? JMO.. Good Luck and keep us posted..

Russ

 

Hex oil pump drive on bottom of the distributor is no longer hexagonal? You should get oil pressure cranking the engine over. You can, if you have no other tools, remove the sending unit and crank it over to test if the pump is even doing anything. Disable the ignition system first.
tom

 

Check the gage first (I don't think that's the problem but it is easy to check). Turn on the key, find oil sender on the oil filter mount and ground the terminal. Gauge should go to max. Remove ground and back to zero. I tend to agree with tomw, the hex driveshaft broke or rounded the corners off. The sure fire way to test the pump is to pull the dist. You will see the top of the shaft at the bottom of the dist. hole (if it's broke maybe not). If the shaft is there, use a long extention and socket and rotate the shaft with a drill motor, maing sure you rotate it counter clockwise. Shortly you should see oil flowing in the dist. bore down near the gear. If not the pan comes off.

 

Thanks for the insight. Gage tests okay. Pulled distributor drive shaft is there. ID of distributor shaft seems worn, has some polished areas on the flats. I was hesitant to turn oil pump drive shaft. What size socket?, what happens if socket falls off extension.
How do I check distributor ID. Can the drive shaft be replaced without pulling the pan. It looks as if there is a retaining spring.

Thanks

 

I think it's a 5/16th, but you can take a set of allen wrenches and see what size fits into the dist. shaft and go from there. Tape the socket onto the shaft of the extension and any other extensions you use together (made a special shaft for the purpose of priming the oil system and I just remove the pump driveshaft I use in it (I tape it also). If the allen wrench fits ok the the dist. it should be ok. If the socket slips on the pump driveshaft then the top of the shaft is bad. If it still doesn't pump oil the pan has to come off to pull the pump to check the pump and lower end of the shaft.

 

Don’t worry about the gauge like rapidruss and bear say. Especially if it runs and you started to hear clicking. That would be the lifters not getting oil. Check the shaft. 390s also have the relation of the shaft falling out and end up in the pan.

 

We have all been waiting 15 years for this information, thank you

 

I always enjoy some smartassery first thing Monday morning.

 

LMAO!!! Thanks for that!

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