4.0 SOHC

[adsm08]

-keep timing chain tensioners changed every so often?? I mean, honestly, my 07 is still quiet and has the originals at 118,000 miles. Maybe changing them out is not as big a deal as some make them out to be. Most people probably never change them and still get 200,000 miles or more out of the engine.

Well the weak point that caused them to be an issue was reliably fixed in production by 05.

I would still change them every 100K miles or so. It's $75 for Ford ones, takes an hour or less to do, no special tools required, just a 27mm wrench, or socket, and its good cheap insurance.

 

[RonD]

+1 ^^^

Since there are no "warning signs" new Motorcraft tensioners are cheap insurance
Because the downside of a broken timing chain guide is pretty far down, lol

 

[Mike Tonon]

Some are also claiming now that the pressure from the new spring can be a little much and cause guide wear, too. But once I get a longer extension, I will change it.

 

[RonD]

The tensioners are hydraulic, the springs are just used for startup
The problem was the original springs would break or lose tension

The spring's only job is to hold the chain tight on start up until oil pressure can take over
If the spring can't do that then the loose chain will bang on the guide on every start up, until there is oil pressure, and over time that will cause a guide to break.............and now you have the "rattle" of the broken guide

This wasn't a 100% failure rate at all, maybe 15% which is high, but many 4.0l SOHC engines probably went 400k miles as is
The new design springs don't have more tension than original design, they are just better springs that resist breaking and losing tension
But nothing is 100% reliable, lol.........................so like changing trans fluid or engine oil, differential oil, belts and hoses, I would just add the tensioners to the 100k mile list of things that need attention, along with O2 sensor, they also only last 100k miles or 12 years which ever comes first, just FYI

 

[Mike Tonon]

I understand that they don’t have more tension than the old ones, when new. But I’m assuming engineers didn’t figure people would usually change these out and just keep running them. So maybe new, they have a little extra pressure.

 

[RonD]

Maybe, but the point of any tensioner is to hold the chain or belt as tight as possible as the chain or belt heats up and cools down over its life, as the length changes when the metal expands with heat then shrinks when it cools down, also to absorb sudden changes in RPMs between crank and cams in the case of timing chains or belts

 

[Mike Tonon]

All of the O2 sensors?

 

[RonD]

Rear can last a bit longer as they use up less chemicals detecting oxygen since most of the oxygen is gone after the Cats use it to burn off emissions
But yes, best to do all

Upstream O2s start to show a FALSE Lean as chemicals get used up, so engine runs Richer than it should and MPG suffers, ain't much but ain't 0 either, and its a slow process so you may not notice it much at first
By the time you get a code, or do notice it you could have paid for new O2s at least two times over in the extra gasoline burned for no reason, lol
You can pull a couple of spark plugs(one from each bank at least) and have a look, if that very light brown color is looking a little darker....................well its time

 

[Mike Tonon]

My check engine light came on years ago. When the truck was about 8 years old and maybe 50,000 miles. I had it scanned, they said it was a certain O2 sensor. I tried to change it, but the thing was in a very difficult area to get at with the tools I had and very rusted. So I left it, put a bottle of this stuff called Cataclean in the fuel tank and the check engine light went of the next day and never came back on.

 

[Mike Tonon]

I went to emissions about a month ago. It passed, so my O2 sensors are probably fine, right?

 

[gw33gp]

Cataclean is an excellent product. A friend was having problems passing CA emissions with his GMC van. I had heard about an additive that works well for improving emissions. We went to an auto parts store to see what we could find. Cataclean looked good and he tried it. After pouring it in the gas tank and running it a few days, he went back for the test and passed.

As to the spring in the tensioners. It doesn't apply as much force on the chains as the oil pressure does. As RonD said, the spring's function is to apply some pressure during start up. After the engine starts, the hydraulic pressure pumps up and overrides the spring. Even if the spring had more pressure when new, it would still apply less pressure than hydraulic tension from the oil pressure. That is if your oil pump is working properly.

I guess you could say the spring is still adding a little more pressure to the hydraulic force but it would be not enough to create a problem.

 

[Mike Tonon]

Another thing I’d thought... could adjustable tensioners be made? Something that would have a little set screw in the middle that we’d back off half a turn and bring back in at a specific torque every oil change or so, to keep the springs pressure the same? The spring looses tension slowly, correct? Or does it just get weak, suddenly?

Also, if I’m passing emissions, should I still change the O2 sensors?

 

[RonD]

You can run any O2 sensor until it sets a code
Point was, that after 100k miles or 12 years they could start costing you money in wasted fuel, and no code for that

So just changing them in that time frame is basically free because of the fuel saving over then next 100k miles or 12 years
Because they will go FALSE Lean as they get older, 100% for sure, that's the failure mode

You can get sets of 3 or 4 O2 sensors for $60-$80
Motorcraft O2s run about $50 each, so $150-$200

Whats a tank of gas cost these days
And how many tanks over 100k miles or 12 years

Just a heads up
All Rangers used narrow band O2s(1983-2011)
There is no difference between upstream or downstream O2s, they are the same
Different part numbers are in reference to the LENGTH of the 4 wire lead(pigtail) connected to the O2 sensor
So it could have a 6" lead, 10", 1ft, 1.5ft, 2ft, ect...............

You can look at your leads ahead of time, find the longest one, and get the set of 3 or 4 with that length, you can zap strap the extra length

 

[Mike Tonon]

You can run any O2 sensor until it sets a code
Point was, that after 100k miles or 12 years they could start costing you money in wasted fuel, and no code for that

So just changing them in that time frame is basically free because of the fuel saving over then next 100k miles or 12 years

You can get sets of 3 or 4 O2 sensors for $60-$80
Motorcraft O2s run about $50 each, so $150-$200

Whats a tank of gas cost these days
And how many tanks over 100k miles or 12 years

Just a heads up
All Rangers used narrow band O2s(1983-2011)
There is no difference between upstream or downstream O2s, they are the same
Different part numbers are in reference to the LENGTH of the 4 wire lead(pigtail) connected to the O2 sensor
So it could have a 6" lead, 10", 1ft, 1.5ft, 2ft, ect...............

You can look at your leads ahead of time, find the longest one, and get the set of 3 or 4 with that length, you can zap strap the extra length

I’m big into using OEM and doing things top notch with this truck. But isn’t Bosch the OEM brand for Ford O2 sensors? If I go with Bosch, they’ll probably be cheaper and be about the same quality, correct?

Also, how do you get these things out??? I tried changing one years ago and gave up. The thing was completely rusted in and in a very tight spot.

 

[RonD]

Yes, O2s are like any part of the exhaust system, RUSTED, lol

It's because there is no cheap coating that will last very long, and stainless steel exhaust pipes are $$$
So they are just bare metal and rust

I would check with an independent muffler shop and see if they will quote a price to loosen each O2 sensor so you can then do the swap at home......, or to replace each with one that you provide, shouldn't be that much more
They have the tools and experience to remove rusted out exhaust parts, they do it daily, lol

They can also drop the exhaust system to get hard to reach O2s, they have any replacement nuts and bolts on hand

And exhaust shops don't usually charge the $100-$150/hour rates of Repair shops

But if you like to buy tools, the crows foot flare nut wrenches can be good for O2s
O2s are 22mm but 7/8's also fits
Don't try using an open ended wrench you will just round off the nut
You CAN cut the wires off the old O2 and slide on a closed end wrench or deep socket
Or use a flare nut wrench

These look interesting but never tried one myself: https://go.harborfreight.com/wp-content/images/prtn/img97177.jpg
A heavy duty crows foot flare nut

You can also buy O2 sensor sockets, they have a slit in the side so wire can stay attached when sliding the socket on
But.............the old ones are whats hard to get out, so IMO just cut the wire and use the regular 22mm socket if you can
Putting in the new one doesn't require that much torque to tighten, spec is 30ft/lb, so not much pressure is needed