Got a '97 3.9 4x4 187000 miles. Has been parked a few months (working too much).

Stated and drove a few days ago. Good oil pressure. Drove to store 5 minutes away. Let it set for 5? minutes, started again and took 3-4 seconds for oil pressure to register and check gauge light came on. But once it did, had good pressure while driving.

Did same thing the next day. So changed oil (old oil was on full on dipstick) and added 1 at lucas. Acted OK only 2 seconds from startup to gauge reading that day.

Day 3 on way back home when stopping for cigs it took 15 seconds to reg. Once home shutdown wait 2 minutes started and 2-3 seconds to reg.

Thinking it may be a bad original gauge or sending unit. Putting on mechanical gauge in morning. And maybe adding some seafoam.

Was just wondering if anyonehas ever tried to back flush from oil filter to clean the pickup screen.

Haynes manual says to take off 4x4 assembly from front to drop oil pan and I don't have that kind of free time and it is winter ya know.

Any thoughts?

 

If it was summer I would say use a thin heavy cleaning oil for a year with about 3 oil changes then an engine flush at the end of the year. That should slowly remove any sludge from the engine. Take it easy on the engine that year. You know synthetic oil will not leave any sludge at all just a thin tarnish.

 

You may not have a sludge or blockage problem at all, but you can run a Gunk motor flush or motor medic through it for good measure. Check oil pressure with gauge as stated. If good, change the sender. Start using full syn. Simplest things first.

 

I'm a firm believer in KISS (Keep It Simple Stupid).

Really didn't know synthetic didn't sludge.

Only run the dodge on weekends(wife has a Blazer, I drive company van Dodge Ram CV and gone most of the week), if it gets started then.

Think I will add the gauge. Add a engine flush following directions. Fill with synthetic (maybe add MMO or ?).
Then it will sit for another week letting the screen soak in the oil and MMO.

Running 10W30 now. Should I try 5W30 during winter.

 

Forgot to say... I replaced mine a few months ago. If your engine doesn't change sound or develop ticking when the pressure drops, it's very likely the sender. Mine was dropping to zero and jumping back up. Sometimes staying at zero for half an hour or so. Regarding oil, I would run 5W30. No need for thicker oil at startup as that's slower flow... when it warms, they are both the same.

https://dodgeforum.com/forum/2nd-gen...sure-drop.html

Oil pressure tester

http://www.harborfreight.com/engine-...kit-98949.html

 

Well good news to report.

Put on nipple, brass T, old sending unit, and mechanical gauge.
Started and mechanical gauge immediately went to 70psi. Electric gauge took 3 seconds to start to read.

After engine warmed up, mechanical gauge still reading 40 psi at idle and 80 psi @ 2500 rpm.
Electric gauge reading 40 at idle and about 60 at 2500 rpm.

After setting 20 minutes after warmed. Started and mechanical gauge immediately started reading. 5 seconds for electric gauge to register.

Don't think I will replace the electric sending unit and just leave the mechanical one in place.

Still will switch to synthetic oil at next oil change.

As far at "ticks", no more than usual.

Have small leak at T and nipple connection. Have to replace that and try again.

Question, since the sending unit has a 2 wire connection. Does it still have to have a ground to engine block?

I didn't put any pipe tape on the fittings and had to tighten then a lot and may have cracked the T when I installed it. Hence the small leak.

 

The sending unit is a dual unit on the LA/LA-based Magnum blocks.

That is, one wire goes to the gauge, and one to the LOW OIL light.

So, yes, it still has to have a ground to the engine block.

RwP

 

Well, there goes the pipe tape ideal.

 

Not necessarily.

Just don't cover ALL the threads. Use a narrower stripe at the top, and leave the bottom threads exposed.

Or use something like high temperature anti-seize (with the copper in it).

RwP

 

What kind of mechanical gauges are you going to leave in place? Are you going to leave the check gauge light on?