Hello, I Have A 2003 Ford 4.0 With The Single Over Head Cam Valve Train That I Swapped Into My 2000 Ranger From A Wrecked Truck 3 Years Ago. It Has Had An Intermittent Issue That I Have Found Very Strange And Cannot Find The Root Of The Noise. It Sounds Like A Steel Ball Bearing Being Dropped On Steel And Is Very Consistent With RPM , It Only Occurs At An Idle And Maybe A Few Hundred RPM After That Before The Noise Stops. But It Doesn't Always Happen At An Idle I May Go Weeks Of Daily Driving The Truck Idling The Truck In Rush Hour With No Noise It Just Starts Making Noise Randomly Some Days. While Rolling Down The Road In Neutral Or Parked I Can Shut The Engine Off And Wait About 30 Seconds And Restart The Truck And Have A 50/50 Shot That The Noise Will Go Away Or It Will Go Away After Shutting The Truck Off Over Night. Raising The RPM And Returning To Idle Will Not Make The Noise Go Away Only Shutting The Truck Off. To Me This Sounds Like A Bent Push Rod, But This Engine Doesn't Have Any. I Was Wondering If Anyone On This Forum Had An Idea Or Dealt With This Issue Before? Thanks For Any Advise!

 

How many miles are on this engine? Check oil pressure with a gauge. I don't know where the oil pressure sender port (for the tool) is on the 4.0l.
Perhaps try either a thicker or thinner oil.
Sometimes another set of ears helps locate/ID a noise.
Ask a more limber friend so they can move their head about the engine bay and under the vehicle.

 

Welcome to the forum

2003 would be a 4.0l SOHC engine
2000 Ranger have a 4.0l OHV engine, last year 4.0l OHV was made, so maybe you have a 2001 Ranger?

When were timing chain tensioners last changed?
2003 4.0l SOHC should have these changed every 100k miles, makes a "rattling noise" when guides start to break, so comes and goes at first, and at start up and lower RPM
Easy to change these

 

The Engine Has 255,000 Miles On It And I Do Not Know When The Timing Chains Were Replaced. Unfortunately The 4.0L SOHC Timing Chains Are Not That Easy With The Over Head Cams. This Engine Was Built With Simple Manufacturing In Mind And The Passenger Or Right Head Is Just Flipped Around And That Heads Timing Chain Runs Down The Back Of The Engine. So The Noise Is Mid Engine And I Am Praying I Don't Have To Dig Into That Back Timing Chain. Additionally This Noise Has Been On And Off For The Past 2 Plus Years And Over 20,000 Miles If This Were Timing Chains I Think Id Be In A Much Worse Situation By Now.

 

This Engine Has Over 255,000 Miles On It. I Would Rather Not Put Thicker Engine Oil In The Truck, I Live In A Colder Climate And After Thicker Oil Blew Up The Original Engine In The Truck I Really Don't Want To Put Thicker Oil In.

 

Also just looked it up the ohv 4.0l timing chain cost around $80 and can be done in vehicle, the sohc 4.0l timing chain kit is over $500 and the transmission needs to be removed and engine out of vehicle.

 

Not the chains....................the tensioners, there are two, easy to change

Like these: https://www.ebay.com/itm/182172149589

You don't have an OHV, you have an SOHC so forget the OHV stuff, that's a different engine

 

Ahh, Ok, Sorry I Was Over Thinking It, I Will Have To Get A Set And See How It Goes.

 

At over 200k its just general maintenance, so needs to be done regardless