Mileage is 93,000km. A very noisy power steering pump was just recently replaced. I am now able to hear other sounds. There is what I would call a rattling/knock. It is somewhere between a ticking and a heavier sound. It is not a steady rhythm and varies in volume. It can be heard under the hood, but also alongside of the vehicle. Given the service years, it crossed my mind that it may be something in the exhaust system, as I think, for example, there are two catalytic converters. The engine oil, 5W-30 synthetic, was very recently changed. Does anyone have any comments about how to do further diagnosis? Thank you.

 

First thing to do, when engine is stone cold
Remove fan belt from crank pulley
Start engine
With no fan or accessories spinning the engine bay will be VERY QUIET, you will be surprised

You can run the engine without the water pump for 60-90 seconds, but can repeat this test as many times as you want once engine is cold again
But 60-90 seconds is a long time when searching for a noise in the engine bay, its not that big, lol
You can REV the engine a few times won't hurt anything

If there is no more noise then the noise could be an accessory/pulley

 

Thanks for the instructions on the method to separate internal engine noise from auxiliary equipment noise. I have yet to try it.

Since my first post for this thread, I have done some further searching. I am still confused about the acronyms OHV, OHC, and SOHC, as they may apply to my engine. I think the OHV means a push rod engine, but not sure of the difference between OHC and SOHC? Is my 1999 likely to be OHV design? Is there something specific in the view under the hood that would confirm my engine design?

I have seen some concerning comments about engine noise/knock/rattle being related to timing chain problems. It seems it may be fairly common?? Do you know whether timing chain problems are any more likely depending on either the OHV or OHC design?

Apologies for so many questions!

 

1990 thru 2000 Rangers and 1994 thru 2000 Mazda B4000 used the 4.0l OHV engines, yes, OHV means pushrods, but has Over Head Valves, OHV

Earlier engines called "flat heads" had valves next to the pistons in the block, Flat head V8 block seen here: https://www.carscoops.com/wp-content.../06/FordV8.jpg
OHV had better flow so better power and MPG

OHC means Over Head Cam
SOHC mean Single Over Head Cam, on each head if it's a V6 or V8 engine, so one cam does both intake and exhaust valves on 1 head
DOHC means Double Over Head Cams, so there is one cam for intake valves and one cam for exhaust valves on each head, on a V6 or V8 there would be 4 cams

General speaking SOHC still had 2 over head valves per cylinder, like an OHV engine
DOHC would have 4 valves per cylinder, 2 intake and 2 exhaust valves for better flow

In 2001 thru 2011 Rangers and Mazda B4000s got the 4.0l SOHC engines, they had better power than the 4.0l OHV engine, so be aware if you google search Mazda B4000 you can get mixed info, because both 4.0l versions can/will come up

 

Thanks for clarification of OHV and OHC nomenclature. I read it to mean that specifically there are three basic configurations; i.e., OHV, SOHC and DOHC. I also read it to mean that my 1999 Mazda is an OHV engine.

As I continue to read back in time on the forum, I see discussions about SOHV engines that have timing chains both front and back. There are comments about extra work, such as engine or transmission removal, that must be done to service the rear chain. Would this apply to my OHV engine as well?

 

Its SOHC, no such thing as SOHV, 1 letter matters a lot , lol

Any time you see SOHC or DOHC the engine will have long timing chains(or belts)

OHV engines have 1 timing chain in the front and its short and usually never an issue, so no your 1999 4.0l OHV doesn't have the long timing chains that 4.0l SOHC engine did/do

The 4.0l SOHC was first used in 1997/8 Explorers, but not in Rangers or Mazdas until 2001 and up