View Full Version : oil pressure issues

08-10-2008, 08:24 PM
My '94 Defender has been sitting for over a year. I started it up, and the oil pressure wouldn't build up. I changed the oil and filter, and still no oil pressure. Does anybody know if there's a pressure relief valve or something else that might cause this?

Rob S
08-14-2008, 01:40 PM
Your oil pump has probably lost its prime. You will need to buy a large jar of vaseline and pack the 2 gears found in the oil pump. This will "trick" the pump into thinking it has good prime. It may take a couple tries, and you may get hit in the forehead by one or both of the gears, so bring along some patience.

08-16-2008, 06:03 PM
I'd agree that you've probably gone dry in the pump and lost prime, however I have never been a big fan of the vaseline technique, not for the least that while it's often reccomended, the part most fail to tell you is that you should pull your coil wire and only let it try and pull oil up from the pan at cranking speed. Keep in mind, the crank, rod, and cam bearings are all without the cushion and lube of recent oil running through.
My prefered techniques are, if you're putting the negine together from a rebuild it to spin the oil pump drive to get oil pressure before installing and setting the distributor, or if in the situation you're in, pull the oil pressure switch (or pressure sender, if you have an oil pressure gauge) stick the tapered nipple of your Handi-Vac pump in the hole, and manually pull a vacuum until you see oil entering the clear plastic tube. If you don't own a Handi-Vac pump, go out to the autoparts store and buy one; it's one of the handiest (pun?) tools you'll own. Great for bleeding brakes, clutch, testing vacuum advance units, etc.