I have a 95 Toyota 4Runner with 136,000 miles (original engine). It is due for an oil change but I noticed the oil pressure gauge dropping to L when idling. While driving only going to the first line. When I checked the oil, the stick was dry! Put in 3 quarts to get it to the mid-way point on the stick. No oil puddles, no leaks, no smoke . . . Any ideas?
If the engine is not leaking oil, but the oil is disappearing anyway, there’s only one explanation: the engine is burning oil. You don’t see smoke because the catalytic converter hides it.
As far as the oil pressure goes, try a new pressure sender. They’re cheap. If the pressure still seems low, have it measured with an accurate oil pressure gauge. The dashboard gauge is ballpark at best.
Am I going to be in the market for a new engine in the near future?
Not likely. The pressure dropped when idling becaues the oil level, now not as agitated by the movement of the vehicle, dropped to where the pickup tube was having difficulty picking up a sufficient amount to keep the lubrication system pressurized. Once the vehicle started moving the level rose from the agitation and the pickup was able to keep the system pressured. It doesn’t sound like the bearings were starved. If they were, you’d hear knocking.
A wee bit more history…was the oil recently changed? Do you check your oil regularly?
It is or was slightly overdue for an oil change. I admit I haven’t been checking it regularly, but I will be from now on.
On another topic, I have been reading that the 95’s have an issue with the oxygen sensor/wiring harness. Do you know anything about that?
I think you’re going to need a new engine in the future.
You obviously have an abnormal oil consumption problem if it took 3 quarts just to get it up midway on the stick.
How long has it been since you checked the oil and did you buy the vehicle new? Just wondering if the vehicle may have had an overheating episode in the past, which can cook piston rings.
An engine needs X amount of oil for the oil pump to draw from since a lot of the oil is “in suspension”, which means filling oil galleys and various cubbyholes, along with what is splashed all about.
No oil to draw from means the pump is sucking air and this is damaging the crankshaft bearings to some degree.
Fill it up with oil and run an oil pressure check with an external gauge could help in determining any problems.
A compression test could tell you something about piston ring condition.
Considering how low on oil it was, the oil consumtion, and the large drop in oil pressure, I think its days are numbered.
It would have been good to know how many miles since you last oil change or the last time you checked the oil level. Hint: you need to check it more often.
You may have lucked out and no damage was done, but I would guess there is a lot of normal wear on your engine, but without knowing how long it took to get that low, I don't think anyone can make a reliable guess.