Oil gauge showing L when warm

[postaL]

I picked up my '94 Runner about a month ago. THe guy who sold it to me told me about the oil gauge showing L when it warms up (H when it starts).

I also looked over the paperwork he gave me w/ the truck to see if it mentioned anything and it does. "Oil shows L when warm". Could that be a bad sensor somewhere? and if so, which one? and where is it?

If it is something else, what could it be?

(3.slow v6, automatic tranny, 4x4)

 

[fourwd1]

could be a lot of things

sending unit
oil pump
engine wear
low on oil
wrong grade of oil

 

[postaL]

could be a lot of things

sending unit
oil pump
engine wear
low on oil
wrong grade of oil

We can rule out:

Wrong grade of oil
Low on oil

My valve gaskets are leaking (going to replace this week or next), could that be the cause?

What sending unit are you talking about? The oil lift in the oil pan? or, is that the oil pump?

What other kind of Engine wear could cause this?

 

[Ulfr]

it could be worn out crankshaft bearings... But most likely the sending unit, it's on the left side of the engine IIRC, on the lower front end.
On 3VZ-E that is

Of course it could also be the oil pump, but I find it very unlikely that the oil pump fails...

The gauge might be faulty, or the engine could simply just be this way...

 

[rustyrazor]

Maybe Sludge

It could be that there's sludge building up.

Mine did the same thing and I've heard of others where the oil gauge reads low.

I used Mobil Clean for my first oil change and it brought the gauge pressure up a bit.

I also ran Mobil 1 15w50 full synthetic during the summer. It reduced the valve train ticking and it brought the gauge pressure right up. It's pricy though so I went back to Mobil clean for the winter.

 

[Steve8v92]

I had the same problem RECENTLY was all freaked out, found the sender was faulty, cheap and easy replacement.
Also, since your in there you can hook up a mechanical guage to the exact spot and verify that you have good oil pressure or not.
Trust me worth it for peace of mind. Hope this helps bro

 

[postaL]

I had the same problem RECENTLY was all freaked out, found the sender was faulty, cheap and easy replacement.
Also, since your in there you can hook up a mechanical guage to the exact spot and verify that you have good oil pressure or not.
Trust me worth it for peace of mind. Hope this helps bro

I purchased the new sender unit today, $70!:awais:

but whatever... it'll be in tomorrow. I'm going to swap out the fuel filter while i'm messin' around in there.

Thanks for the replies guys, i'll let you know if that solves the problem.

 

[Steve8v92]

I would seriously consider sinking the 20$ for a guage and some tube and fittings to really measure the psi coming into that send, it will tell you for sure if you are OK and you'll sleep easier
I do not have the specs, but if you want I can find them for you

 

[postaL]

I would seriously consider sinking the 20$ for a guage and some tube and fittings to really measure the psi coming into that send, it will tell you for sure if you are OK and you'll sleep easier
I do not have the specs, but if you want I can find them for you

I'm a newb when it comes to this engine stuff (beyond maintenance) so if you can explain what i'd need to make or what to buy to measure that... i'd really appreciate it

 

[Steve8v92]

You are going to need a pressure guage good up to 50psi,
than a length of hose that goes to the engine from the guage, you will need to buy the same fitting that is on your new guage you bought, (same size)
Put some thread sealant on the end that is going into the engine,
make sure your fittings on your line are tight than run the engine,
run it at idle, record the psi, than 1500
than record it at high idle
the pressure should be higher at higher rpms obviously.

Go into a NAPA or something explain to them that you need an mechanical oil pressure guage (not one you are putting in your truck) just a mechanical and you need the hose, than show them the fitting on your new sender they should be able to match the fitting for sure.