i am going down the road and my oil gauge drops to zero and as soon as it hits zero it goes back up to normal, it happened once last week and then once yesterday, i change my oil religously at 3,000 miles with rotella and i checked the oil and it was good. could the gauge be going, is there a way i can check this, any other ideas on what to check?

 

It is probably your oil pressure sending unit. Mine went out last year. It is a simple fix. I have a 2000, 24V, so I'm not sure where the sending unit is on your block...mine was down below the fuel filter. Hopefully that is it. Sure gives you a heart attck though when you are rollin' down the highway and the pressure drops to nothing

Good Luck

 

yeah when it happened the second time i immidiatly shut the truck off and pushed it home. thankfully i was like right beside my house and had a good neighbor...

 

I would also say that it's the sending unit.

 

i sure as heck hope so...

 

The only thing is... hopefully someone can offer a better place to buy a replacement. At the dealer it was $200. Which is alot, but the peace of mind was worth it. If you want to find out what the pressure is, get a mechanical gauge for testing purposes. If it has pressure...it's the sending unit (Or I guess maybe the gauge). My neighbor had a mechanical gauge so I borrowed that to make sure there was pressure, then drove my truck to buy the new one.

 

I got my replacement sending unit at Autozone, for 20-something.
On the 12v it is behind the PS pump on the side of the block.

Chris

 

Save yourself from having to replace it twice and buy the sender from Cummins.
Aftermarket autoparts senders don't last.
Believe me I've tried several times on different CTDs when the owner insisted on being cheap. They were all back in less than a year with a bad sender. Even worse a couple of them shot their innards out and started leaking.

 

Take Infidel's word on the cheap sending units. I bought one at Autozone and it lasted about 500 miles. My local dealer had one for $38, said the part number had been superceeded by the part number for the gas engine, we'll see how long it holds up. If this one fails, I will just go with a mechanical gauge and be done with it.

 

I thought about a mechanical gauge, but what to do about the dash gauge? I imagine you'd have to figure out some kind of resistor to put in the old oil pressure switch wiring so that the gauge not working wouldn't cause other things in the dash to panic. I don't know if my 96 has a BCM, but it might freak out the PCM, right?

Chris

 

Unplug the oil pressure switch and see what happens. I don't think it will make a difference.

 

I think I read somewhere here (in the past) that you could have someone "flash" the computer and the gauge will read in the middle even though it doesn't really work anymore--This would keep the check engine light from always being on. I guess it tells the computer to ignore it. I'm not sure if it works, I went with the replacement sending unit. It is good to know you can get them anywhere though. $50 is not too much even if it not a super reliable unit to find out if the sending unit is the problem. It would stink to drop 200 at the dealer to find out that the sending unit aint whats broke.

 

mine did the same it was the sender. dodge wanted a couple of hundred, local cummins dealer, p/n 4088390 $73.00

 

'98 is the only 12 valve year where the oil pressure gauge can be reflashed into basically an idiot light.

 

Take it from those of us who know, GET IT FROM CUMMINS,went the other route and it lasted about 3 months!!!