Lifter clatter at start up and then again while driving

[97fordrunner]

So my '97 has developed a nasty lifter clatter at initial cold start but goes away a few seconds into it then after it is warmed up and the motor is at a cruising speed with minimal load it comes back loud enough to hear it over the exhaust and the radio. I have also noticed that the oil pressure gauge sometimes bounces it never stays at 0. Does this sound like an oil pump issue or just a oil pressure sending unit? the truck has just turned over 160xxx

 

[Big Jim M]

So my '97 has developed a nasty lifter clatter at initial cold start but goes away a few seconds into it then after it is warmed up and the motor is at a cruising speed with minimal load it comes back loud enough to hear it over the exhaust and the radio. I have also noticed that the oil pressure gauge sometimes bounces it never stays at 0. Does this sound like an oil pump issue or just a oil pressure sending unit? the truck has just turned over 160xxx

First thing to do is make sure of how much pressure you have.. If the gauge ever hits 0 when the engine is running that is a bad sign.
A lifter clatter for a few seconds at startup isn't a bad sign. However at hiway speeds it is a terrible sign.
Make sure the noise you hear on the hiway is truly a lifter noise. And not a vlave closing clatter from cheap gas or some other minor problem.
I rarely advise getting a REAL oil pressure gauge to anyone...but in your case I think I would at least install one and lay it on the consol if I didn't want it screwed to the dash.. JUST to know what pressure I had when the hiway noise occurs.
BTW I always look around for a gauge with a wide sweep for the needle and get one that is highly readable in the LOW PRESSURE area! A gauge that is 10-20-30-40- Doesn't tell me what I'd like to know.
Big JIm

 

[97fordrunner]

Great suggestion, thanks for the help BigJim, I'm heading to the parts store now.

 

[97fordrunner]

Well guys I got an oil pressure gauge in and when warmed up at idle it reads 20psi then if you take off hard it drops to around 12psi then goes to about 40psi until at a cruising RPM then it settles in around 30psi. Does that look normal or should it not dive at acceleration?


Also now that I have a different gauge the Check Gauge light stays on how can I over ride the wiring for the oil pressure sensor? Can I put 12 V to it or is that to much?

 

[Big Jim M]

That is minimum but sufficient if the lifters stay quiet at hiway speeds. If there isn't enough pressure to keep the lifters quiet there isn't enough to lubricate the bearings.
So I'd drive her like she is.
Big JIm

 

[Bird]

At 160k, you're experiencing the symptoms of worn pushrod ends / rocker arms due to poor upper oiling characteristics of the 4.0 - get a Delta Camshafts rocker arm kit, replace the rockers / pushrods and you'll be good to go.

Bird

 

[97fordrunner]

Delta huh, I'll look into that, Thanks