My oil gauge/reading

[JayBee]

I've been meaning to run this by the board for awhile but didn't have a decent enough digital camer until recently.

My oil gauge reads kind of low but the car runs pretty good for a motor that hasn't been rebuilt for almost 100,000 miles. New everything back then; bearings, rings, oil pump, etc. The gauge has never gone higher than the first line since the cluster was changed to this rallye dash, it still gets there at higher rpms though. Oil was changed 800 miles ago (20W50 + 1 qt Lucas oil additive) and a Mopar filter. I do have that 90 degree offset oil filter adapter too. There's no strange noises coming from the motor either. Electrically there's a new wiring harness and new 5v regulator and I think I have the right sending unit, it looks like a bell. Is there any way to test the gauge? What PSI do the gauge markings equate to?  Should I be looking at something else? Any thoughts would be appreciated...Thanks     

Picture 1 is with car idling in park
Picture 2 is with car idling in drive

[MEK-Dangerfield]

That's scary low to look at given your thick oil choice. That lug that fits on top of the sending unit can be grounded, and hopefully your gauge will peg with the key in the "on" position. My only guesses are the sending unit, or maybe the gauge isn't quite working right.   


    Mike

EDIT: If the gauge pegs, then I would look at the sending unit. If it is leaking oil, that's a clue...

[JayBee]

Thanks Mike. I just tried what you suggested, can you tell me if what I saw was normal. The gauge didn't "peg" per say but rather climbed slowly, almost in steps, all the way to the top. I had to hold the ground wire for a few seconds and it didn't start to move as soon as I touched ground either. I ohmed the jumper wire and the windshield's stainless to battery ground as a check to make sure there wasn't any resistance too.

John

BTW, "scary", you're just looking at pics, try being behind the wheel 

[422STROKER]

How does it look cold?

Tom

[JayBee]

How does it look cold?

Cold - the needle covers the top part of the "L". You can see the space between the "L" and the first hash line but no white from the L's top is showing. Hope that describes it well enough without a pic. I'm trying to type this out while your still on-line Tom.

[422STROKER]

It should be much higher when cold, something is off, can you pick up a cheap(10 dollar) mechanical gauge to hook up temporarily?

If it's not making noise then there is some pressure.

For reference my car has 60-70PSI cold vs 30PSI Hot.

Tom

[moparmaniac59]

If you are really concerned and want to ensure it's not the resistance reading electrical gage, I'd suggest getting a direct pressure reading gage and plug it in to really get a true reading of your oil pressure. I did this on my car and then once I knew what was going on, I removed the pressure gage and stuck with the electrical reading gage. Good luck and I hope it's just a messed up gage!


                                               Matt B.

[422STROKER]

I agree Matt, I'm thinking the gauge is a bit off, but you never know until you verify vs a mech gauge.  I have one kicking around here somewhere if needed. 

Jaybee, you coming to Carlisle?

Tom

[JayBee]

Fist off, thanks for the replies and suggestions. I may just try a cheapo gauge.

1. Sorry, when Tom asked "cold" I thought he meant with the motor off. Actually, hot or cold the needle stays about the same. It does get to the first hash line around 2000 rpm and more.

2. Carlisle, nope. Couldn't get time off work in both July and August. Besides, I wouldn't have the money for two major Mopar weekends and always do go to the Nats.

[422STROKER]

I'd like to go to the Nats too some day!

well, as far as the gauge goes, judging by the looks you had the gauge cluster done over, maybe the companies that calibrate these things could give you an idea of pressure vs lines.

I just went through something similar with my temp gauge, have a mech gauge and now know what the lines mean on the factory ones.LOL

Tom

[Chryco Psycho]

I would use a mechanical guage to check the engine  at least

[ShelbyDogg]

My pressure is always around the 2nd line away from the max line. Cold or warm. I would put a T fitting in then run the sending unit and a mechanical gauge to see if  the pressure is really low. If not then put an idiot light sender in along with the other sender, so it will pop on and get your attention on long drives.

If you really have low pressure pull the pan and check a couple of bearings to see if it is time for a rebuild.  Throw one of those $200 318s in it for driving around while you freshen that one. You can find those everywhere.

[miketyler]

The gauge didn't "peg" per say but rather climbed slowly, almost in steps, all the way to the top. I had to hold the ground wire for a few seconds and it didn't start to move as soon as I touched ground either.

The oil gauge like the fuel gauge isn't "instant" reading. Oil pressure fluctuates and to generalize the fluctuations it is intentioanlly dampened. What you describe is correct behavior for the gauge. I would start with a new $5 sender. If it still reads low than you may indeed have low oil pressure. The mechanical gauge is the best and actually has oil flowing into the back of it. They are the most accurate.   

[JayBee]

As soon as I get a break from all my kid's baseball games I'll get a mechanical gauge and see what readings that gives. I appreciate all teh replies and ideas too.

[JayBee]

Here's an update. I'd like your opinions please.

Background: Connected $25.00 mechanical gauge. Ran car in small draftless garage for about an hour, temp's needle reached same spot as in earlier pictures. So, all the numbers are with motor hot. All rpms are from the car's rallye tach. All PSI's were higher with motor cold.

1. Hot, car in drive, about 600rpm = 14 to 16 PSI (even saw 10PSI just before the car felt like it was going to stall, too much cam IMO).

2. Hot, car in park, about 950rpm = 30 PSI.

3. Hot, idling at 2,000rpm = 46 PSI.

Would you drive this 100,000 mile motor? I plan on taking it to the Nat's, about an 800 mile round trip. Where can I get a new sending unit from? Please, let me hear from any and all. Thanks for everything up to now and hope you Carlisle guys and girls are having a great weekend.