I am having an intermittent oil pressure drop when stopping at lights and idle. The gauge goes to nothing and the light comes on. When I take off, it goes back to normal (Middle). Last time it started doing this, I changed the oil (5-20 MC, Lucas and MC Filter) and it went away for a few weeks. Last night it started happening again. But this time it did it while I was driving. I immediately stopped at the nearest AZ and topped off the oil with the 5-20 again. It went away for a few miles and then started again. So I drained some of the oil out of the pan, and put in another quart of Lucas and some 10-30 MC It went away for a few more miles, and then no pressure again. This time I drove it home, and I never got any noticeable ticking or knocking. I must have driven for about 5 to 7 miles with no pressure on the guage, and the Oil Pressure light on. It never seized up, or did anything weird, no overheating? I am stumped on this deal. I am afraid to drive it anymore. I do have to replace my timing chain and tensioners, but that sound (claking) stayed the same. Any ideas? How often do the oil pressure sensors go bad, how long should one be able to drive with no oil pressure?

 

OPS (oil pressure sensors) usually have lengthy maintenance intervals. I'd say an easy 100-120K is just a nice buffer range. It could also be the oil pump screen becoming clogged up. That would explain the constant ON/OFF effect that you're describing. If you're brave enough, I'd go ahead and drop the oil pan, clean it out of any sludge (which will probably be quite prevelant due to the lucas product you use), replace the gasket, oil pump and screen, and then fill up with a thicker oil to run from now on. I'd suggest a 10W40 NON-synthetic.

Oh, and about how long you can drive with 0 oil psi......I would honestly NEVER try to drive ANY distance with 0 oil psi. Oil only has so much of a "sticking" characteristic to the cylinder walls and other areas. It will heat up and burn off of those areas MUCH faster if it can't keep a constant circulation.

 

It sounds like it would probably be the oil pressure sender to me. I had the same thing once and that was my problem. If its the oil pump its not usually an intermitten problem. Its the only thing i could see causing the problem randomly.

 

Yeah, sorry.........I wasn't saying the pump directly. I was saying that the cause could be due to the screen clogging up from debris in the pan. An easy way to check is to drop the pan and just clean it out. Then you'll be able to see in what you clean out if it seems like it's thick and skin-like or just liquidy and clean like it should be. If there's sludge, I'd clean as much out of where ever you can reach after dropping the pan, and then filling with a good detergent oil (10W-40 Castrol or Valvoline).

 

I'd hook up a real oil pressure gage, you know the one with the tube so you'll know for sure.

 

Autozone has them for about 20$ so it's nothing huge out of your wallet. Good idea RacingJake. Manual meters are AWESOME when the electrical ones start to go.

 

With out a doubt do this before you pull the pan! Or just buy a new sending unit. 5 - 7 miles without oil pressure would have caused some knocking and or over heating.
Good luck

 

until it siezes

 

If you have any more of the Lucas, the first thing you can do for your engine is throw that in the garbage. I can assure you your engine is sludged horribly. I would change the oil pressure sensor, change the oil to get the garbage out of the engine, use a good oil filter like Motorcraft, and run either of, and only these two, Amsoils oil flush or Auto-Rx. You will most likely have to run several of these thru the engine to get the trash out of it. Another issue you are probably having is that the Triton engines have small oil return drains from the heads. When these get sludged up, and yours is, the oil can't drain back to the pan like it should and you end up pumping foam instead of oil as all of the oil is in the valve covers. This creates hot spots in the engine as the oil is also a coolant in these engines. With any luck at all, you haven't done too much damage. Now you know why Ford recommends NO OIL ADDITIVES. It's in the book that no one ever bothers to read called the owners manual. And while it appears that you are using the recommended oil, stay with it. The 5w-20 oils are the best for every Triton engine- there isn't a better one.