Learn from me! What kind of oil sensor do you have?

Just curious, what was the cause of the engine damage ? Did the oil drain plug fall out, filter loose ? From what you mentioned in your post you did not seem to lose oil pressure, if that is the case the light probably would not have been any help.

Oil pump failed, then bearings. All metal shavings material in the oil filter stuck to a magnet so it seems to me that it was bearings. I had a neighbor mechanic for catapiller check it out. That was his deduction.

Was the engine run with a low oil level? The metal shavings in the oil filter may have come from the oil pump failing. I don't believe the metal used in engine bearings is magnetic. Engine bearings are usually a soft outer facing with a copper backing. Also, if the oil pump failed first, it seems it would not be able to pump any oil and therefore pump metal shavings into the oil filter.

Mike, You bring up a good point. I guess that I might never really know why if failed for sure. The engine was not low on oil at all. It was exactly on the full line when it died. In fact, now that I think about it (this should have occured to me sooner), the oil filter was partially collapsed because the metal shavings were clogging the oil filter and oil was not able to flow through the filter very well. So the oil pump probably still worked. But the metal shavings did stick to the magnet.

I'm a computer nerd by trade, so I just assumed (I know better) that my mechanic neigher was correct when he told me what the engine did.

I'm capable enough to swap out my engine. Resourceful enough to find answers when I'm stumped. But sometimes I turn my brain off and trust what someone else tells me because that's what he does for a living. That can get a guy in trouble.

Now that I'm thinking on my own.....I did notice that my plastic timing chains were broken (in pieces in the oil pan) and the chain was rubbing on metal....enough to wear some deep grooves. It was probably metal worn by the timing chain that plugged the oil channels in the rocker arm assembly. Just my own educated guess.

Darin

Yep, it's sometime hard to tell what failed first is a situation like that. I was just curious as I have never really heard of any oil pump failures before on those engines. If the timing chain was rubbing that bad it could have contibuted to the failure also. I know that if they rub for too long they will wear a hole in the timing chain cover and let coolant into the oil. That will kill any engine very quickly.

That's not just Toyota: that's how every car I've ever owned, or worked on, is wired. (I'd guess that every idiot-light equipped car is wired in that fashion, except perhaps some of the newer vehicles with sophisticated computer-monitoring systems.) There's a reason for doing it this way: it's simple, inexpensive, and effective. Of course, it does rely on one assumption, as you discovered: the operator (i.e., you) must check for the "on" condition of the warning light BEFORE starting the engine. Truth is, even if it were wired as you suggested such that an open circuit would illuminate the light, you'd still have to monitor the light before start-up. Otherwise, a failed lamp would deceive you just as surely as a disconnected sensor wire.

Being an aircraft pilot, I am very attentive to my engine instruments, particularly during start-up. I check the operating condition of all my "idiot lights" before turning the key to "start" and I specifically watch my oil instrumentation during start-up (I've modified my truck's instrument panel so that I have both a oil pressure gauge and an oil pressure warning light -- see below). I not only watch to see that the light goes out, but I monitor the pressure gage to make a mental note of how quickly it rises and to what level. By doing this every time, I can immediately spot if something is out of the ordinary (e.g., oil pressure comes up too slowly, or pressure rises too high). It's unfortunate that most automobile drivers are never taught the importance of such things.

Btw, this degree of engine "health awareness" saved me an engine once. I was driving a FIAT 2000 Spider on a desert highway at night when I felt a bit of a jolt from under the car, as if I had just hit a large rodent. The first thing I did was look down at my instruments and I noticed the oil pressure gauge rapidly dropping off. I immediately took my foot of the accelerator and put the gear in neutral, let the engine wind down, and then shut it off, all while still coasting at over 50mph. Sure enough, something had impacted my oil sump and dented it sufficiently to break off the (non-ductile cast aluminum) oil pump pick-up. All I had to do to service the engine was drop the pan, pound out the dent, and replace the oil pump. Imagine the damage if I had continued for several miles at 70+mph with zero oil pressure?

When I replaced the "Deluxe" package instrument panel in my '89 Toyota Truck with a panel from an SR5, I was dismayed to discover that the newly acquired oil pressure gauge came IN LIEU OF an oil pressure warning light (instead of having both). So I added my own in one of the extra warning light slots along the bottom of the panel. Since the panel did not include the little red "oil can" icon mask to go over the lamp, I re-used the one from my old Deluxe panel. Works great and gives me a redundant oil pressure monitoring system.

- Michael