So my 93 yota has 275,000 miles on it. But runs like a dream and always has. Recently, the shifter knuckle, clutch master cylinder, slave cylinder, clutch, and alternator all went bad at the same time. So the truck sat for 3 months while being repaired. When it was started everything was fine. Oil pressure was were it normally runs on gauge. Then after it got warm I noticed a severe decrease in pressure while at a constant 60 mph down highway. Normally the pressure drops off to what is a little over zero at an idle like a stop sign but not while the rpm's are up. So I thought the sending unit was faultly so I installed a manual oil pressure gauge. Tk has 65-70 lbs at start up while cold. Consistently while it warms up as well. But when it reaches operating temp. the pressure starts to drop off. Mind you I'm at a constant speed of 60 mph and the pressure just drops off all the way down to 20. Then at an idle or a stop sign etc., it reads zero. I shut it off and thought the motor was toast. However, there was no loud noises or bangs, no smoke etc. I checked oil and water and all is good. But now it is doing something strange. The term "low end knock" that happens to some vehicles at first start up of the day, occurs in second and third gears while traveling down the road. If I push in the clutch it sounds temporarily like there is no oil in motor. Not loud or metal clattering but the struggling noise of lifters. This coupled with the erratic oil pressure has me scared. Could this be the oil pump is faulty, or the timing chain is worn, IDK, please someone help me.
93 yota oil pressure problems (1 Viewer)
- Thread starter SIS Racing
- Start date
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With those miles and this problem, I wonder if you didn't lose a rod or crank bearing. I doubt your timing chain has anything to do with this, nor the oil pump, but with high miles, anything is possible. If it makes a funny sound at hot idle, pull off plug wires (one at a time) while it's running, and see if one cylinder is different than the others.
If the truck is a long term keeper, you might end up just pulling the engine and rebuilding it (as needed). How is the compression?
If the truck is a long term keeper, you might end up just pulling the engine and rebuilding it (as needed). How is the compression?
joseywales
Renaissance Redneck
Welcome to ‘Mud SIS. Is the motor a 22RE or 3VZE? Not that it makes a huge difference, but could be of interest. If your mechanical gauge drops to zero while the engine is running, I’d say there I’d definitely something of concern going on.
