Oil and Electrical Gauge Questions

Oil:

Hello fellow newsgroupers! I have a 91 5.0 LX with approximately 102,000 miles on the motor. Two weeks ago I changed the oil (Valvoline Max Live

10w40) and filter. I went approximately 1500 miles past my normal 3000 mile change.

I have a few questions...

  1. Does the gauge display oil pressure?

The gauge from mustangs of that year, is a vertical indication which reads "N-O-R-M-A-L" with the N at the top of the normal range and the L at the bottom. My gauge at idle hover right at or below the "L", but rises to about the "A" during normal driving.

  1. Is this normal, should I be concerned? I checked the oil level, and that is good. If not, what corrective actions should I take?

Electrical:

At idle, or a stop light, (during the day with the air conditioner running), the charging indicator will dip down close to the - (negative) symbol on the gauge. At night with the air conditioner and lights on (once again at idle or a stop light) I get the same indication. However the needle will move upwards to the + (positive) symbol during normal driving.

Same question as above. Is this normal, should I be concerned? If not, what corrective actions should I take? Any advice is appreciated.

Thomas

1991 5.0 LX, AOD Completely stock with the exception of a Densecharger Cold Air Induction Kit
Reply to
sariwa1
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I would check my oil pressure with an oil pressure gauge to be on the safe side. These stock meters are very inacurate. You could also check your oil sender connection for corosion, corosion will add resistance in the circuit and cause a low reading.

As for your choice of oil...good greaf get that oil out of your engine. You caught on to the marketting hype...these oils have seal softeners in them that will eventually ruin them. All those softening additives should only be used in cars that are on their last breath to stop them from dumping/burning all of their oil...Get a good synthetic...

Your alternator's low voltage reading is typical of cars with aftermarket pullies...again, coroded connections will produce those low readings...A quick whip out of the voltmeter will tell you if everything is fine. Your batery voltage should be around 14V when the car is running...

Hope this helps,

Serge

Reply to
Serge

I'd be willing to bet that this is electrical too. As Serge pointed out, this is typically an issue with the sender or the gauge, not oil pressure. I've had these cars reading almost 0 oil pressure. You'd think 5,000 miles of 0 oil pressure would cause the thing to at least make some noise, if not lock up.

I'd do as Serge suggested and test it with a separate gauge that doesn't rely on the sending unit. If it's good, you might want to try to replace the sending unit as they're known to go bad, clean up connections that are known for corroding.

Your battery voltage could be quite a few things. Corrosion of any point of the charging system (including the block ground) will cause an issue. At this moment in time I'd be happy with the situation you're in because mine needs a block ground and I can't get the bolt out.

With accessories off and the car running, you should get, as Serge said, 14V at the battery. The car, with stock pullies, should also be able to handle the A/C on at a stoplight without getting that close to the red zone on the gauge. If you're talking it goes below the middle line and to the next one down, that's ok... if you're approaching red, you have problems somewhere. You could get the alternator checked (had mine done free at a local shop), get the charging system checked (free at places like Advance Auto, Auto Zone, etc), and research any grounding issues.

Good luck...

JS

Reply to
JS

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