My oil pressure gauge is acting funny. When I first start the truck the gauge reads normal but after driving for maybe 5 minutes the gauge drops all the way saying there is no pressure. I don't see any smoke and the truck seems to be running fine. I'm wondering if anyone else has this problem.

The temperature did get a little high on Saturday when in 4x4 for about 20 minutes and the A/T oil light also can on. I turned off the car and let it cool down and haven't had any issues besides the oil pressure gauge the past two days.

1995 T100 with 200k

 

Im not sure if you noticed but the oil pressure gauge is utterly useless, Im not sure wtf it reads but its never been accurate int he 100k ive owned my T100.

As for the a/t oil light, trans heated up a bit too much. Do you have a trans cooler? How old is the radiator?

 

I don't have a trans cooler and I'm guessing the radiator is original. I just got the truck two weeks ago and use it as my beach truck. Which means most of my driving is done around 15 mph and in 4 wheel.

 

Invest in an auxiliary trans cooler for sure.
For you oil pressure, either get an aftermarket gauge or try fixing the stock one. Does the oil pressure gauge move when the engine is revved up? My 3.4 swapped truck shows no pressure(stock gauge) warmed up at idle but it comes up with the engine revved up.

 

I have the same problem, when the engine warms up the oil pressure gauge reads very low, if at all. It does come up a bit with engine revs though. Where on the engine (1998 3.4) is the sensor so I can tap in another pressure gauge? If in fact the pressure is low has anyone had success with moving to 10w40 or even 20w50 high mileage oil? Just bought the truck a few days ago. It has 213k and otherwise seems to run great.

 

I wouldn't say it's a problem. Pressure DOES NOT equal flow. Your engine is designed to run lower weight oil.

 

Ive ran every weight imaginable, the sensor itself is very inaccurate.

 

I agree with Jason, minimum oil idle pressure is something around 5 psi. I think what you see is normal. When you are driving it should be above the first mark.

 

Ok looks like one less thing to worry about. Thanks for the advice!

 

Here's a quick read on motor oil...

http://www.bobistheoilguy.com/motor-oil-101/

The oil pressure sensor is just to the left of the oil filter. You will find a 3/8" NPT plug that you can git an adapter from AutoZone fer about $3 and use that port to install a digital oil pressure/temperature gauge.

 

I can't believe that an accurate temperature reading can be taken from there. With the stock OP gauge you can easily see when the oil is hot, by the pressure it holds at idle.

 

Learned a ton from that link about motor oil, thanks!

 

I have the same low pressure at idle when warmed up, I was told this is normal for the 1997 t100 by the dealer were I bought my truck (140,000 miles)
In my opinion if the oil pressure was to low you would probably be hearing lifters rattling.
When driving at speed pressure comes up to first line on stock gauge.