Howdy fellas, hope you guys are having a good day.

Just had some questions for you more knowledgable folks out there that know more about these 4.0 SOHCs.

So my issue is that I'm having a loud rattle that's coming from somewhere in the engine bay. If I go under the truck it sounds like it's coming from the cats or above the passenger side cat, but since sound gets redirected through those openings anyway it could be misleading (my guess). When you're up top standing over the engine bay it sounds like it could be coming from the driver side through not really sure since it's loud on both sides of the motor.

What is confusing me is that when i rev the engine slightly it goes away for a minute or two then it comes back slowly. By that I mean the sound progressively gets louder and louder over time when it's just idling. It's a very metallic-like rattle or tick. I'm crossing my fingers it's not the timing chain guides considering this motor is supposedly newly rebuilt and has 18k miles on it or so, but I'm not too sure

Any input is appreciated. Thanks.

 

"supposedly newly rebuilt"..............so what does that mean, do you have paper work on the rebuild?

Yes, it is the timing chains, that's the only thing that makes a sound described as "a rattle" on the 4.0l SOHC engines.

Rear timing chain, passenger side rear, was usually the first to make the noise.

Yes, it will get quieter as engine RPMs increase, because oil pressure goes up, then rattle comes back as tensioner "relaxes" again.

Once you hear the noise there is no fix other than pulling out the engine and redoing the cassettes(guides and chains), and new tensioners.
The noise means the guides are broken, damage done

1997 to 2003 were the years that the 4.0l SOHC engines had the high failure rate for the timing chains.
Newer design for the tensioners pretty much fixed this problem, 2004 and up, but any engine with 2 LONG timing chains can have timing chain problems, just the nature of that setup

 

I have the paperwork of the parts used for the rebuild. Pretty much everything is new minus of course the block. And I say "supposedly" since I take any word from previous owners with a grain of salt.

Is there no possibility of internal rattle on the cats for example?
Just now I went to go pick up some dinner and on startup there was no rattle. Once the idle went down there was still no sound. It wasn't until I got back home after a 5ish mile drive and let it sit for a minute that it came back. Additionally, this time with revving the engine up it didn't go away, it just rattled faster.

Thanks.

 

Get a piece of wood or rubber mallet and "tap" on exhaust parts, if parts have broken loose inside you will hear the rattle.
COLD exhaust, do not do it when hot or you will make it rattle, lol.


How long have you had this Ranger?

How many miles have you driven before the rattle was noticed by you?

 

I bought it a little over a week ago.

The PO had mentioned the rattle before I bought it. Along with any other potential issue that he had known of but he seemed like an honest guy and had paperwork for most of the work he had done to it. Regardless, he had said the rattle was intermittent and it would sometimes go away for a week and then come back another week.

When I was inspecting it initially there was no rattle at all. It wasn't until a few days of driving it that the rattle showed up. By then I had driven it over 250 miles.

I'll grab a rubber mallet and test that out.

 

The timing chain issue was a design flaw in the long chain tensioners, there are two

The springs used in the tensioners would not provide enough tension on start up, before oil pressure takes over.
And then the oil pressure would also not provide enough tension at certain RPMs

When tensioners lost tension chain would start to "bang" on the guides, you wouldn't hear anything at this time
When the guide broke away from holder THEN you would hear the rattle, but only at start up and then at 2,500-3,000rpm
And it would steadily get worse over time.

There should be a warranty on engine rebuild

The newer design for the tensioners seemed to have eliminated the problem
And many people replaced tensioners on pre-2004 4.0l SOHCs just on spec, it wasn't a 100% failure rate just a high failure rate, so better safe than sorry, lol.
As said, by the time you can hear the noise guides are broken, so new tensioners won't help, they may quiet it a bit but long term guides need to be replaced

 

I was having the exact same issues on my Dodge Ram. Intermittent metal on metal rattling sound that only presented itself at certain RPMs and would
go away after the engine warmed up (metal expanded and the gap causing the rattle closed up). It turned out to be where the manifold mounted up to the
rest of the exhaust system. To go off what Ron said, try smacking all the joints/connections on your exhaust with a rubber mallet and see if you can get
it to make the noise. That's how I diagnosed my problem.

 

I hope you are not having the timing chain rattle i did. Mine was on the passenger side towards the rear. At first it was every so often then over a few weeks the rattle got worse. I ended up putting a newer engine in my truck with low miles on it. So far so good.. but its very sad. Take a video of the rattle if you can.

 

After some more digging it seems all the symptoms are pointing to a timing chain issue.

Is there a particular set that I'd need to get?
2001 Ranger 4.0 4x4 auto

And possibly any way to get to it without removing the motor. It's only from the passenger side it seems.

Thanks

 

Engine must come out to replace the passenger side rear chain, the only access is from the rear of the engine.

Any newer kit will have the newer tensioners

 

Well i thought i'd just revive this thread since im having the same issue's. I have an 02 ranger and the rattle is getting worse, used to only happen every once in awhile on a cold start, but now almost every cold start, and very faint rattle when running. it has 203k with NO engine work. Besides that, put a trans in the truck 2k ago, burns no oil or anything, and besides the rattle engine sounds great. So, what should i do, should i bite the bullet and pull the motor and fix it, and if so, once i pull the motor, how in depth is fixing it going to be.

 

You do need to pull the engine to change rear timing chain(the one that rattles first and the most) but not much else
Intake, valve covers, water pump, front engine cover and flexplate or flywheel

Engines generally last 400k, before rebuild would be recommended.

You can pick up used 4.0l SOHC engines, BUT..........it MUST BE 2005 or newer
1997 to 2004 would need new timing chains as well.

Timing chain parts are important as well, thread here discusses that: http://www.explorerforum.com/forums/...ources.317039/

You should also use a timing tool kit to set up the timing, these can be found "used once" at sites like ours or on ebay, lol.
Google: OTC 6488

 

See, the motor is great besides the rattle so if i were to do anything, i'd fix the motor, not get another. Would you recommend doing this is the near future to avoid more damage or do i have at least "some" time before it craps out completely. Also seeing the motor is good besides that, i replaced the trans, and the body is pretty decent, would defiantly worth it.

 

Its "probably" OK to run for a while, but "probably" is the key word there, I have no crystal ball, wish I did, but not for this, I would get Lotto numbers, no offense, lol.

The 4.0l SOHC engine IS an interference engine, 100%
It has been stated in other articles that it is a NON-interference engine, but that was the 4.0l OHV engine also used in Rangers and Explorers, so some confusion there.

Interference means the pistons and valves SHARE some space in the cylinders, so a piston all the way up, and a Valve all the way open WILL hit each other.
Timing chains prevent that from happening, the Cam(valves) and Crank(pistons) are timed so they can never hit each other.

So if a timing chain should break on an interference engine, it never goes well for the valves, they get bent so head(s) must be pulled, usually pistons are OK, but still not a good thing.

Chances of that happening when all you have is a rattle is almost 0, but again "almost 0" is not 0.
It could happen with NO rattle, stuff happens, lol.

But out side of that happening no other damage would occur, rattle only effects the parts you will be changing, i.e. the guides and chains(cassettes) and tensioners

While engine is out replace rear main seal if that wasn't done with new transmission, should have been done.
Also best to do oil pan gaskets, and clean out the pan, can get debris from "rattle" breaking up the guides

 

So if i go in there and stuff and fix it, front and back parts i guess, will i have to like re-time the engine or something, I've never done anything this in depth before

 

You need to lock the cam(s) in place with a special tool before removing the chain. If you do this you wont need to go through the hassle of re-timing. It also prevents the valves from hitting the pistons during disassembly.

 

 

Probably timing chain issue if it is a 2002 4.0l SOHC engine

But can also be an accessory pulley, loosen/remove fan belt and spin each pulley manually, you will notice if it has a problem

 

hah, wish mine would be an accessory pully

 

Not all rattling noises are the tensioners or have to do with the timing chains.. and just because the 4.0 sohc sucks so bad about having that issue, if you have any, ANY other rattle, tapping, squeak, gurgle, anything, the google search results are almost 100% all revolving around the friggn timing chain. Well my issue isnt and it's impossible to find any info on anything else about the motor because thats every diagnosis on the engine.. then somebody says the ohv is better, or swap it to a 5.0 or you gotta pull the motor to get the rear guides. Yea, thanks i read all about that a hundred times. But when i have an odd sound that's intermittent and really hard to describe, its impossible to get any leeway.. if somebody asks the dumb question in a blog and theyre oblivious enough to look over the thousands of explanations of the exact same problens.. stop answering with the same thing.. is like everybody has a different sound.. "well mines more of a tapp". Or "mines more of a rattle". Or " mines a rattle tap". Its not different... people who have to ask their question on a blog when the issue is waaaaay past being an oddball issue and literally every search with any version of the words 4.0 sohc noise or rattle..

my issue is only occurring very intermittently and seems to do it more when cold bbmut will only make the squirting or gurgle or dash jingle when raising rpms above 4 grand. Will make the noise for a second snd sometimes will "brrr br br brrr brrrr". Happens in a straight line as well as turning, uphil or downhill. Can hear it with windows up and can hear it from the outside as well., like it could be a crank positoon sensor sound if it had one of those geared sensors when they skip teeth. But all my cam/ crank sensors are all electronic.. sometimes it sounds like its in the dash on drivers side corner around the cluster but sometimes soubs under tge hood and sometimes under the cab. But no codes besides the p420 or exhaust ho2 crap because i have a straight pipe with a cat back/ no cats tho.. anywho im stumped...

 

Cold engine
Remove fan belt from crank pulley
Start engine, Battery Light will stay on
See if noise happens, REV engine a few times
Engine bay will be very quiet with no Fan noise, so easier to pin point noises
If no noises then its likely an accessory bearing or tensioner/pulley is the source of the noise, spin each by hand after engine is off

You can only run the engine 90sec to 2 minutes without the water pump, so be quick about it
But you can repeat the test when engine is cold again

Also when driving and noticing a noise, turn Climate Control to OFF, this turns off the AC compressor full time, otherwise it ALWAYS ON, it cycles on and off randomly to dry the air in the cab
If you no longer hear the noise after that then could be AC compressor bearing is the source of the noise

As for "4.0l SOHC rattle"
Its like "I have a flat tire whats wrong?"
98% of the time the "correct" answer is the tire was punctured by road debris and has a hole
But................
Could be leaky valve stem, bent/leaking wheel, split band, ect..............other 2% for why a tire is flat

98% of the time when the word "rattle" is used to describe a noise with a 4.0l SOHC.............. "timing chain tensioners" will be the response
If you used the word "squealing" instead you might get "Cam synchronizer" as the response, 98% of the time on a 3.0l for sure, lol

 

I don't know if you are getting the same gurgle kind of noise I hear occasionally, but mine is more likely to happen at idle or approaching idle. Sometimes, it will continue continue a short time when accelerating after idling. I am pretty much convinced it is the check valve in the vacuum reservoir down by the front right wheel well. Several years ago it happened very frequently for a year or two, then the check valve completely stopped working. I replaced the entire vacuum reservoir, because the check valve is inside it (at least on my Ranger it is). After that, I did not hear the gurgling for a very long time (3 or 4 yrs?). In the last 6 months or so is has happened a couple times but nearly not as bad as it used to be.

 

Does the vacuum reservoir down by the front right wheel well accumulate water? GURGLING?

 

No, it is just a kind of gurgling sound. I think it is the check valve rattling back and forth in a type of resonance.