Replace now or wait? 4.0L hydraulic chain tensioners…

[Fwirt]

So I have a 2002 Sport, not a Sport Trac, but there is no forum for the Sport and I think the Sport shares more DNA with the Sport Trac (or even a Ranger) than Base under the hood so here goes…

Didn’t know about the infamous “death rattle” that afflicts the 4.0L SOHC until after I bought the car. Engine seems to be purring right now and according to the Carfax and previous owner it’s been really well maintained. Currently sitting at 143k miles. No chain rattle on startup or running at any RPM so far, and it’s a mid ‘02 so I might have lucked out and gotten the upgraded chain guides. However, all the reports of the tensioners wearing out have me wondering if I’m sitting on a time bomb. So I have a few questions:

- I’ve heard it’s better to change the tensioners before any rattle sets in because by the time you hear it, it indicates damage to the chain guides. But I’ve also heard that changing the tensioners can accelerate guide wear because old brittle guides can’t handle the higher tension from new tensioners. I don’t have any rattle yet, so my guides are probably in good shape and I don’t want to create an issue that doesn’t exist. Should I change them out now or wait until I hear startup rattle indicating that that the tensioners are too loose?
- Oil changes seem to have been pretty regular but I was thinking of running some Seafoam because of some quiet ticking that might be the injectors. Does anyone have experience with Seafoam making the chain guides more brittle? I would imagine that fuel additive has minimal effect but I don’t know about the intake spray since it gets into the oil. I wouldn’t want loose gunk to clog the tensioners.
- I keep seeing horror stories of people cross threading new tensioners and that scares me. But I’ve heard that’s due to incorrect procedure as well, and that after priming the new tensioners in oil you should squeeze as much oil out with a vise as you can so the new tensioners don’t put pressure on the threads as they go in. Is this true? And are there any best practices to avoid cross threading other than “carefully hand thread a few turns and hope for the best?”

I know this is my first post so I’m sorry if this is too much all at once or I picked the wrong subforum.

 

[410Fortune]

Welcome!
Valid questions!!
Yes in 02 the sport and sport trac are
just like a 02-05 ranger, the last year of the gen ii explorer was 01, so by 02-03 the sport and trac are basically identical to a ranger, on paper. The big difference is the sport and trac are spring under rear axle still whereas ranger is still pickup truck with springs outboard the frame rails

Do the tensioners now
Only use ford parts
No threat of cross threading, no need to squish the tensioner to install… I’ve done tons of them. Just clean the area, get good access, carefully thread out the old one, clean and oil the new washer, thread in the new one. It’s that simple
Now it can get more complicated if you screw something up. I nicked a head one time and caused a gushing oil leak. No amount of reseating the washer fixed it, eventually I had to flat file the head… not fun. But it worked

After install hold the fuel pedal to the floor while cranking. This will stop the engine from starting, it is called “flood
Mode” the starter will
Build oil pressure in your new tensioners before startup

Now with all that said
I highly recommend you consider manual tension chain tensioners
No hydraulics needed
They never go slack, always under tension, they stop the cold start rattle before it begins and save your cassettes and guides

Discussed in great detail on this forum
We love the manual chain tensioners
I especially do because it was my idea many years ago thanks to Polaris

The sohc engine is very good after 2000 and very very good after 03-04
We see 300-450k miles from them by owners who are religious about oil changes. Must be full synthetic and must be 3-5000 mile changes the sohc needs clean oil and changing it often is the key to long life from one of these

 

[Fwirt]

Awesome! Thanks for the tips! I’ll check out the manual tensioners, but that already gives me more confidence in just getting the hydraulic ones in ASAP. Just need to convince my wife to let me buy parts for a car that’s “running fine” .

I was already planning to get OEM, any recommendations on suppliers? I was just going to call the local dealership, looked like online prices were about $50/ea but I saw a couple posts saying people got a set for $60, but that may have been many years ago.

I love full synthetic, I usually change around 6-7k but I’ll bump up the interval. I’ve been a fan of Wix filters but it seems like most around here prefer OEM everything, are the Motorcraft filters better?

 

[Fordtruckfan89]

100 for 2 sounds about right for the Ford tensioners from eBay. Ford parts giant is a good place too. Get some of the washers too. I wouldn't prime them before hand, since they have to be compressed to be fully tightened down. Either hold the pedal down like 410 said or unhook the coil pack.

 

[Fwirt]

After reading up on the manual tensioners a bit more they don’t sound that hard to do, and if I can really get a set for under $40 that’ll be a lot easier to explain to the wife… plus in theory I’ll never have to replace them again.

The Alpha Rider ones on Amazon seem to be the ones most people go with? Should I just use the crush washers that come with those or do I need Ford washers?

 

[C420sailor]

Mechanical tensioners are AWESOME

Literally set and forget. No cranking in flood clear mode to prime after the truck sits for a bit. Turn the key and go, never a single clatter.

IMO the single best upgrade for the SOHC vehicles

 

[Fwirt]

I really liked your thread on it, I think it explained the process really clearly. I think I might go with the eBay ones you used as they look less like Chinesium than some of the others. Sounds like the Ford washers are the way to go though.

 

[C420sailor]

You won’t regret it. I’ve installed brand new Ford tensioners in this same engine and had clattering 20k miles later. It’s annoying. This is one and done, and simple.

 

[DintDobbs]

@Fwirt Welcome to this forum! You've basically found the two experts already, but I do have 2 cents.

Pay as much as it costs to get the right parts the first time, do the job right and do it once. Otherwise, you'll spend the time and money again on the right parts and the right job.

You earned your money, you can spend your money. If your wife wants more money, well, women can work jobs too.

You can call a Ford dealer to check if your vehicle has had any TSB's issued, and whether or not they were served. All you need is the VIN. There was a TSB for timing chain guides on 2nd-gen Explorers IIRC (which is the platform your Sport is built on), but I believe post-2001 models were manufactured using the improved guides. If your vehicle has the new guides from the factory, there would have been no TSB on it. A phone call is free, right?

Buy the tensioners now while they're cheap, you don't have to install them now. I've got two SOHC's, one at 197k and one at 230k, neither have been rebuilt, and neither have timing chain rattle. Doesn't mean they never will. Preventive maintenance is never wrong, but if it ain't broke, don't fix it.

Do your diligence to keep the oil changed, as the others have advised. I change annually or at 5k mile intervals, whichever comes first.

 

[Fwirt]

Thanks for the tip about the TSB, I’ll give them a call tomorrow. No recalls showed on the Carfax but that probably doesn’t mean anything.

Yeah, I’m mostly joking about my wife. She gives me a hard time sometimes but she trusts me when I say it needs to be done. I just have a bad track record of overextending myself and money is tight right now anyway. But not so tight I can’t swing this. Especially if I go for the mechanical tensioners. I’ve been slowly fixing everything up over the last couple months (mostly interior and electrical) and I get some flack for spending so much time on it. Of course her priority is that I fix the paint, which is like my last priority.

But I 100% agree, do it right the first time and an ounce of prevention is worth a pound of cure. I learned that the hard way after I bought cheap Chinese replacement keys for $11 and paid a locksmith $40 to have them cut only to find out they were garbage. Then I had to go to the dealership and buy a Stratech key for $50. Which was honestly pretty reasonable IMO since they didn’t charge a cut fee.

I also need to replace the fuel filter and the front turn signal assemblies (cracked and leaking), I haven’t checked the spark plugs yet and I think it might need an alignment. But preventing engine damage now that I’m aware of this is top priority. My goal is to get everything done now so I can just worry about routine maintenance for the next 50k or so.

 

[Fordtruckfan89]

you'll have to pull the thermostat housing, it'd be a good time to replace it with a metal one since you can't unthread the front tensioner all the way with it In there.

 

[Maxmax19773]

I got 2001 SOHC sport 2 door, title says 2002 and door sticker 6/2001 . I agree on checking thermostat housing and replacing it. Mine was toasted. Body bushings were gone , pump went out at 190k , Valve cover gaskets were leaking badly. Immobilizer ring or amplifier ( forgot the name of it ,ring around the ignition lock cylinder thing) went out at 190k , I got ruttle at 190 k , not at start up but wile acceleration. I did timing job.rear cassette was broken Tensioners were worn out, I could squeeze them with my fingers. I replaced everything with ford parts from eBay and RA . I would go with fortune410 advice on tensioners . I got tons of help from him all the time I am facing the issues with my explorer. I discovered this forum when I already purchased the parts and was on the middle of putting everything together) . I would definitely check the spark plugs if I were you, especially if you still have splash guards installed. My maf sensor died at 200k and couple of connectors giving me the hard time). Guys here are always willing to help. I got a lot of help all the time with my issues. I usually need help with identifying the problem, or questioning on order of removal or installation and always get help and more clarity on how to solve it. I got my hands on pretty much every single part of my car and I am willing to help if needed. Also my transmission valve body gasket went out at 200k , I got jerking on low speed. Still on original transmission. Got 220k now. Previous owner changed oils religiously but it was all she did. Car in a way better shape than I got it now ) thanks to my labor ) my perfectionism , willingness to spend money on it , availability of good quality parts on the market and help of this forum ) respectfully. Max in Houston

 

[Fwirt]

Thanks everyone, I wasn’t planning to do the thermostat housing but I might as well prevent some coolant leaks while I’m under the hood.

Are the cheap aluminum housings fine, and are they all more or less the same? From the threads I’ve seen here as long as you reinforce the split gasket with some RTV they don’t leak. Do I need a new thermostat as well or can I just reuse what’s in there as long as everything is still working?

 

[swshawaii]

@Fwirt
4.0 SOHC Metal Thermostat Housing Comparison

 

[oklagp1200r]

Thanks everyone, I wasn’t planning to do the thermostat housing but I might as well prevent some coolant leaks while I’m under the hood.

Are the cheap aluminum housings fine, and are they all more or less the same? From the threads I’ve seen here as long as you reinforce the split gasket with some RTV they don’t leak. Do I need a new thermostat as well or can I just reuse what’s in there as long as everything is still working?

I would replace that thermostat while there!

 

[Maxmax19773]

Thanks everyone, I wasn’t planning to do the thermostat housing but I might as well prevent some coolant leaks while I’m under the hood.

Are the cheap aluminum housings fine, and are they all more or less the same? From the threads I’ve seen here as long as you reinforce the split gasket with some RTV they don’t leak. Do I need a new thermostat as well or can I just reuse what’s in there as long as everything is still working?

Aluminum is the best, I got motorcraft , and it still ok. Probably 5 years ago been replaced. I got 2 port sensors one . I replaced everything sensors, thermostat, and clamps. Maybe overkill but that’s what I do. Be careful with metal clamps that hold sensor in the port of the thermostat housing. I used fish line to prevent to loose mine.

 

[429CJ-3X2]

Be careful with metal clamps that hold sensor in the port of the thermostat housing. I used fish line to prevent to loose mine.

It seems most people pull those wire clips out, but they're actually supposed to be pushed in to release the sensor. I don't remember if I saw that before I did my first one, but pushing the clips in worked on the second one. Less chance to lose them that way! I used cheap aluminum housings, and used my original sensors and thermostats. No leaks or problems. The housings I used have 2 sensors, but my '04 Sport Trac only uses 1 sensor, so I have a "dummy" sensor (no wires attached) in the extra hole.

 

[Fwirt]

@Fwirt
4.0 SOHC Metal Thermostat Housing Comparison

Thanks, I read that thread but it was mostly just a comparison between the Simmons and the Austekk, I saw @donalds and @429CJ-3X2 got away with using the cheap aluminum housings so I’ll give one of those a shot. Just need to make sure the outlet is at the correct angle.

 

[410Fortune]

I have the el cheapo one with red boot in my son’s truck, it’s holding up fine. I used stock coolant sensors with new o rings

The factory housing will eventually explode… like they split in half and leave you stranded kind of explode… that part never should have left the factory plastic imo