At some point in production the oil pressure gauge / sending unit on 4.7's was changed from a real gauge that showed actual oil pressure to an "idiot light" setup that still hooked to the gauge but just puts the needle to a point just over half way regardless of the oil pressure. (assuming that it's not zero anyways!) I don't know the exact year it changed, but I can tell you that the 98's have a real gauge and the 03 has an "idiot gauge".

I troubleshot this on my 4.7 when it did the same thing awhile back and proved (to myself) that the sending unit was bad by removing it and putting a temporary mechanical gauge on the port and verifying pressure.
Mine had similar symptoms on startup with "low" reading / lights when first starting. Changing out the sending unit cleared up the problem.

The other possibility is sludge in the pan with a partially clogged pickup tube / screen. Major PITA to get the pan off, start with the sensor first.

Bob

 

First off, the other gauge type is found on the 5.2 and 5.9 engines because it's more of an old school type of engine and not so modern as the 4.7. Second, the exact year it changed was in 2000 when the 4.7 was introduced and the reason the 98s have a real gauge is because they only offered the 5.2 and 5.9 engines!

That being said...



LOL

 

Hmmmm..... OK, my bad on the 4.7 coming out in model year 2000, but I think that there still may have been a "design change" somewhere in there on the 4.7 gauge. The '00 sending unit (for the 4.7) is two wire and the '03 is a single wire. Also, the '03 descriptor for the part is "with lights" where the '00 is "with gauges". There's definately a gauge in my dash, it just ACTS like an idiot light!

And I betcha my pair of 150lb Newfies would LOVE to snack on those two judges!

Bob

 

They simply changed the style of the sending unit and no your gauge doesn't just act like an idiot light if it's functioning properly. Basically they did the upgrade to the new style oil pressure sending unit because the Ram got the new cosmetic upgrade in 2003 where as the Durango got it in 2004, and the Dakota in 2005. The new style oil pressure sending unit is only found in the 2003 year and the older styles are on the 1998-2002.

They did this minor modification of the sending unit because the 2003+ Ram, 2004+ Durango, and 2005+ Dakota does not have an oil pressure gauge in the cluster on all of the packages (IIRC, the SXT package did not include it). Basically the Ram was available with the 4.7 in it so Mopar didn't want to waste the money and keep around the old style oil pressure sending unit. In other words the oil pressure sending unit is a multi-function to use either the dummy light or the actual gauge read out.

Also, here's a picture of a 2003 oil pressure gauge, and it reads higher than normal at the cold start. Check yours at cold start because it should read higher than normal until proper flow is achieved. You might need a new sending unit if yours doesn't change at all unless it's off.



Here's a picture of the gauges of a 2003 Ram on the inside and you can see where there could be gauges (where they'd put them on higher end packages) but instead the left side says DODGE and the right side says RAM.

 

Widow,

Thanks for the information, I've been educated!

My oil pressure gauge has *never* started high, it always comes up to just over 1/2 way after 2-3 seconds of running. I worried about this awhile back when it became even slower (5-6 seconds after starting) but after checking the pressure with a mechanical gauge I verified that the pump was working properly. After buying the wrong sensor (2 wire) the first time, I got the correct (one wire) and everything went back to normal again.

Also, my gauge does not change with engine speed changes, it just sits at 1/2 gauge from idle to 70mph. Never really concerned me as it's done that from day one.

For what it's worth, I run Mobil 1 Sythetic which seems to flow a lot better in the sub-zero cold that we get here. My winter startups are much quieter (no lifter click) than they were before changing over.

Thanks!
Bob

 

Mobil One Fully Synthetic 10W-30 flows like water at tempertures to like -54 F degrees! It's all I use in all my rigs for winter, towing, and summer driving. It's formulated for everything you through at it.

 

I changed over to it last year at your reccomendation and have been happy ever since! That's one of the very first things that I noticed, very quiet startups in extremely cold (-18 deg) temps.

Bob