Proper oil level ??
 

MY 1996 T4R is new to me. I have no history on it.
2 weeks ago the T4r broke down on me (electrical failure). I had the battery recharged and I managed to limp home. But on the way, I noticed the oil light came on. Thinking that I also had an oil problem, I added 2 more cups of oil. The oil light stayed on BUT ONLY in idle. At slow city speed the oil level light turned OFF.

The other day, while working on the vehicle, I checked the oil level (engine off and on a level surface.) It was about 3/4 inch above the highest mark on the dip stick

I have read that an over filled oil level can damage the T4R.
Should I drain some out OR leave it alone ?

I’d get it in the proper range myself. That’s quite a bit over.

FYI- the light is an oil PRESSURE light. It does not indicate levels. If it’s coming on at idle then you have low idle oil pressure. A 20$ harbour freight oil pressure gauge will tell you what is going on.

Could be sender acting funky, or engine, is not good having light on off idle. Worth it to start digging.

Do you mean oil pressure sender unit ?

Yes, V6 has it on oil filter level forward of filter, wire going to it hard to miss.

As far as overfill of the crankcase, easy enough to unscrew drain plug, count to three and reinsert.
Check level, repeat if necessary.
Hopefully you have a faulty oil pressure sending unit which is easily replaceable with a $20 purchase at Auto Zone/Advanced Auto or double/triple that through your favorite Toyota online parts source.
The alternative may be a failing oil pump which isn’t a pleasant experience.

So if you are going to replace the sender(which is an easy place to start) have the gauge on hand. It screws into the sender port and you start the engine and presto you know the answer and no more guess work is required.

It’s good practice to troubleshoot problems and you gain experience in the process. It’ll also give you some idea of the health of your engine.

Finding guage correct threads problem or not ? haven't bought one in ages.

Thank you everyone for your kind, knowledgeable posts.

Right you are. The harbour freight one does not have the correct adapter. It has NPT rather than the needed BSPT but it is close enough to get a couple of turns in and get your reading. No wrench needed, just hand tight for a couple minutes test.

One thing I'm not at all clear on. You guys know a hell of a lot more than me , but it doesn't make sense to me for the oil light to come on ONLY IN IDLE. I was sitting at a stop light, and the oil light was on, however as soon as I stepped on the gas, the oil light went out. Plenty of oil. In fact overfilled a bit.

If the problem is a clogged oil pump filter, wouldn't it be still clogged at higher RPMS ?
If the sending unit is bad, wouldn't it be still bad at higher RPM's ?
if the oil pump itself is bad or failing, wouldn't it still be failing at higher RPM's ?

Seeing as I was having major electrical problems (the alternator or some relay had failed), might that possibly be a factor ?

PPS: I had just changed the oil and filter the day before using 10W-40. (to help get passed the California smog test) and a filter from Auto zone. Maybe the wrong filter ? possible ?

Please school me.

,

The oil change is interesting. I’d get a Toyota filter and some good 5w30 in there, probably not a coincidence.

The oil pressure light tends to come on at idle since that’s when Oil pressure is Lowest. Pressure builds quickly as rpms rise.

The psi that makes the pressure sender trip is around 4 to 5 psi so when you see the light on you have VERY low oil pressure. You should get this solved before you drive your truck further.

I don’t think i have ever heard of anyone on this forum having a bad sender. Could happen I guess but I’ve never heard of it. They do tend to get leaky and need replacing though. I wouldn’t bet on your issue being a bad sender without checking oil pressure first.

Oil pressure has little to do with oil level. Your oil pressure should remain the same until oil level gets low enough for the pump to starve for oil. The light is not an indication of oil level.

You said you were limping it home, how bad was it running?
On vehicles I've owned and worked on in the past, when a engine is struggling to idle and its below 500 or so rpm, sometimes the oil and battery light will come on because there isnt enough rpm for the oil pump to make pressure and the alternator to charge.

Too much oil will cause windage and put air bubbles in the oil.


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@Traveler74 , you didn't answer the question, What is engine rpm at idle.
you say oil light on in traffic, idle rpm's or higher. Two important things to check.
Did you pick filter or did parts guy/girl ? either could have picked incorrectly.
I use Toyota 90915-YZZD1 filter, 6 qt puts it on full mark of Rotella T4.