I own a 2005 Ford Ranger 4L V6. I had timing chain problems and after a lot of money and challenges..it was sorted out. When the mechanic assembled the engine the engine light was flickering, which never happened when the rear chains were replaced. After disassembly again he saw that the oil pump and bearings were damaged from pieces of debris that went through. we now replaced the oil pump, Balancing shaft complete, crank bearings and the heads were totally refurbished. All original Ford parts (that's another story...availability). Now the oil pressure on cold start is approx. 3 bar but goes down to 0.8-1 bar when the engine is on temperature. as soon as it revs up it goes back to 2.7-3 bar. After driving about 5 km, on idling we can hear a faint ticking noise again!!

Please help...we do not know what to do anymore. the motor was almost refurbished with all original parts and even Ford oil. WHAT ELSE CAN BE WRONG? PLEASE HELP!!

 

Welcome to the forum


A "bar" is 14.7psi
So oil pressure is fine, I would expect 8 to 12psi at idle with warmed up oil, so just under 1 "bar"

Fuel injectors make a ticking noise, and Ford injectors can be loud.
I would use a long small diameter hose and listen to each fuel injector while engine is idling.
Also check other areas with the hose to see if you can localize the noise.

With engine stone cold you can remove the fan belt from crank pulley and start the engine, Battery light will stay on, this makes engine compartment very quiet, since fan is not spinning, so you can hear noises better.
BUT!!!!!!, you can only run the engine for 2 or 3 minutes this way as there is no water pump for cooling!!!

Other "tick" noise can also be a spark plug wire arcing, when it is very dark open hood while engine is running and look for the arcing, little flashes of light near a spark plug wire or at spark plug boot or on coil pack

 

Thanx a million for your reply. what made me worry is that the engine oil light flickers slightly at idling speed just as the idle comes down after revving and stabilizes. i spent all that money having all redone as described in my post and do not want to risk anything..? will it be wise to up the oil grade to 10w30 rather than the 5w20 as prescribed by ford? will it make a safe difference?

 

With all that bottom end work and still having a flickering light at idle is concerning. I would put an external oil pressure test gage on it to ensure it's right, and replace the oil pressure sending unit.

 

I am starting to think that the engineering shop has made a mess up with the crack cutting and new bearing liners. The vehicle idling oil pressure when at temp is between .8 and 1 bar. everything else is A1 after the repairs. Goes like a bat out of hell. Just the oil pressure all of a sudden.

 

Somebody suggest I order a Melling M328 hi flo oil pump and replace the new stock one. Any ideas on this guys?

 

Oil pumps do not create pressure, but volume. So before I would do anything if it were my issue, I would verify that the oil pressure is correct through cold to warmed up. That would take an external gage connected to the oil pressure sending units port on the block.

 

We had an external oil gauge on. Cold start it sits at 3 bar pressure. As it warms up it drops down to 1 bar pressure. When reved it goes up to 2.8 bar. At this stage it runs 5w30 full synthetic oil. We are trying 10w40 mineral oil tonight. Hopefully makes a difference.

 

Synthetic oil may be your problem and you shouldn't be using it until the engine is broken in anyway, it's quite a bit thinner then regular oil even though the ratings are the same.

IMO these older engines were not designed to run on synthetic oils because they are too thin.
If you want to make your engine last longer, just change the oil on a regular basis.

Did the machine shop check the rod bearing clearances as well ?