Recently my oil pressure gauge has been fluctuating between normal pressure at cruising to low oil pressure. First I changed the oil pressure switch and symptoms returned. When I unplug the switch the needle pegs (correct), Key on on Engine off needle is at 0 (Correct). I then picked up a mechanical oil pressure gauge to check the pressure and the pressure is normal at all RPMs. The next step in a replacement oil pressure gage. Yesterday I went to the junkyard and pulled a oil pressure gauge from a cluster and I removed my cluster with no problem, removed the old oil pressure gauge without any difficulty. Then I went to install the replacement gauge on my cluster and in 2 seconds I broke the plastic studs on the cluster that the oil gauge mounts to. So now it is back to the junkyard for a replacement cluster. I am debating wheather or not to just get the panel or a cluster panel with all the gauges and just transfer the speedometer. The later would be the easiest as I would not have to worry about breaking any more mounting studs.

 

If the wiring is somehow grounding out, it could cause the symptoms you are experiencing.

 

I got a replacement cluster complete with all gauges. I swapped in my Speedometer and fuel gauge then reinstalled the cluster with out any difficulty. The most difficult part was getting the heater control back in. The sliders kept slipping out of position. The temperature cable lock kept popping out of the slot. I finally got it all together. I started the car and so far the oil pressure readings are normal. I will take it to work tomorrow and we will see if it continues to read normal. Total cost was about $40.00 in junkyard parts. If I would't have broke the mounting studs for the oil pressure gauge it would have cost around $8.00 for a replacement oil pressure gauge only.

 

Good deal. Here's to hoping it works out!

 

After two days of commuting to work and back the Oil Pressure gauge is reading correct without any fluctuating. The other junkyard gauges (Temp & Volts) read correct as well. The fuel gauge and the spedometer are the originals that I transfered to the replacement instrument cluster. Parts replaced: Oil Pressure Sending Unit (twice), New Oil Pressure Pig Tail, Instrument Cluster with gauges attached. Heater Control light bulbs.

 

Im having a similar problem when i first start my blazer the oil pressure it aroound 70 but when it gets warm the oil pressure drops to the line above 0 is that normal or is something wrong i just replaced the head gaskets and broke the dip stick i couldnt check the oil level

 

The only way to know what is going on is to get a mechanical oil pressure gage and check the oil pressure. (I picked up an oil pressure gage from Harbor Freight for around $10.00.) To check the pressure you have to remove the sending unit and install the mecanical gage in its place. You can also remove the electrical connector to the oil pressure switch and turn the key on but do not start the Oil pressure gage should go to the maximum oil pressure (the gage should peg to the highest reading). If not then you have a short to ground. Re-connect the connector and again turn key on engine off and the gage should read 0 psi. If not then replace the sending unit. Hope this helps