So I just bought this dodge dakota 318 4x4 slt with auto tranny for 2500 bucks. I've noticed 2 problems since I bought it.

1. The horn doesn't work... pain in the *** but can't be that hard to fix. Idk with my old 87 dodge ram I can just take the steering wheel off and fix the button but is it different because these have airbags?

2. After the trucks reaches operating temperature (about 10 mins of driving) the oil pressure will fall and the oil light will flicker when coming to a stop and idling. The truck idles at 300-400 rpms which concerns me a lot but it has never stalled. If I increase the idle to about 700+ the oil pressure goes right back up. I heard it could be the rod bearings but I'm praying it isn't. Once the truck gets really warm 20 mins or more of driving the oil light wont flicker anymore it will just come on at idle. Also I have to bring the idle to about 1000 rpms to keep pressure. The truck has 200k on the dash but the original owner showed me a receipt of a rebuilt (Yes rebuilt) engine AND transmission at 149000 miles. Cost him 4400 bucks to get that job done. If it really was the rod bearings I would expect a loss of pressure all the time though even if the oil is cold and thick.

I don't have a mechanical gauge so I can't really check it I'm just relying on my gauge... not really the best thing to do but whatever. I mean at 149000 miles any repair shop would most definitely replace the rod bearings no? I mean they would have to be one half ***'d place not too. The truck burns a slight little blue smoke on startup but nothing else after that, also a lifter rattles for like one second before getting oil pressure up there. The lifter knocks 3 times then stops once it gets the pressure.

Sure hope I didn't get myself in over my head with this truck. If it is the rod bearings assuming no damage to the crank ( :/ ) what price could I look at for replacing them?

 

1. Could be something as stupid as the horn itself dieing or the clockspring in the steering column.

2. I'd get a mechanical gauge on it to confirm, my guess would be the sender is crapping out though.

 

Thought I'd add these videos for a little more info.
Also how do I go about changing the oil pressure sender unit.

http://www.youtube.com/watch?v=iJYAH8obSXc

http://www.youtube.com/watch?v=pZ1-933kzJs

For some odd reason now in park it has pressure and drive it doesn't but the rpms don't change? lol... Before it used to do it in park too.

 

The Tach and Horn share the same fuse. Change it.
The Oil Pressure Sending unit is a common problem. It is on the passenger side of the distributor. It is simple to do but it does need a deep socket or the special socket.

 

Your problem does seem a little worse, but my truck would do something like this due to low brake fluid, bad brakes, or just when it simply needed an oil change lol. Seems kinda odd, I know, but it did always stop afterwards.

 

Kinda funny you said that because I don't know when the owner previously changed the oil and the oil is pretty dirty. Maybe I should put in the 25 or so bucks for an oil change see if anything happens.

Maybe throw some STP oil treatment in there for good luck?

 

When I got my 94 I had exactly the same problem. I changed the oil and went to a Mopar filter. Although the oil was fresh from the used car lot I bought from I strained it and had a lot of large carbon particles and some other junk. I cut the filter open, although it was one of the bad brand to see what it had done as far as filter and found more crud. Pressure was better but not great. I ran the Mopar filter and oil about 300 miles and changed again, once again cutting the filter open amd straining the oil, results were even less crud. Ran that oil change 600 miles and changed again. All has been fine now for 15K and over a year. Keep in mind the least expensive filter is junk, wont mention brand but its orange. Walley world filters are junk also. I always use a Mopar filter on the 94 V-8 now. Just changed oil on 89, 3.9 and had to get STP filter, because it seems the smaller filter used for the 3.9 is getting hard to find around here.

 

Definitely get the oil changed lol

 

your pressure gauge is probably correct. a low idle will give a low oil pressure reading.
does it run fine on the highway and oil pressure is ok?
the oil pressure is determined by a mechanical pump, the slower the engine runs the lower the pressure, the faster it runs the higher the pressure.
i don't know if yours has a EGR valve (my haynes manual is with the truck when i sold it) but if it does i would check to see if the EGR valve is defective or the passages are plugged with carbon. that will effect the idle. mine almost stalled at stops and i would have to rev it to keep it running.
the only issue i have is after an engine rebuild there should be no carbon in the heads, this may mean you have a bad EGR valve.

 

Yeah but there is a difference between a low pressure reading and no pressure reading and an oil light. If it was low at idle with no light I wouldn't be concerned, but it literally drops off the gauge. My friend who is a mechanic whom I trust said that it could be as simple as an oil change too so I went out and bought some 10w-30 Pennzoil with a purolator oil filter or whatever they are.

Other then the gauge being weird the truck runs pretty damn smooth. No knockin or banging engine is real smooth. On the highway it's great oil pressure is above the halfway about where it is on a cold start.

It's weird when I first start it up on cold its above half by a good amount and will stay at there until the engine reaches full operating temperature then just drop off. There is no in between. It's either up or down.