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SkyTech LS starter solenoid

Mike S

Senior Curmudgeon
This was in a prior post from Heinrich Gerhardt, and I thought it was worth having documented and easy to find.

"The solenoid mounted to the LS starter is a Ford PMGR unit as used on most Fords from around 2000-up. Just go to an autoparts store and get a solenoid for a 2005 Crown Vic. The Crown Vic only has one engine available, so it's an easy one to remember."
 
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Brand and part numbers...

For me the stock solenoid showed signs at 300 hours/3 year?s and failed at 400hr/4yr round numbers.
I replaced it from Napa with Echlin Ignition ECH ST421 which lasted less than a year and failed with almost no warnings.
Now it is replaced from O?Rielly with BWD S5613, only a few hours on it but working fine.
I have now on the shelf a spare from Amazon a Standard Motor Parts SS754
And another VAFer used Auto Zone?s Duralast SS1115

Any reports of which has been better or worse for you?
 
So, why are so many of these Ford PMGR solenoids failing at such low hours? Skylor had an interesting theory: on airplanes, the ring gear and starter nosecone are exposed and pull in dust and grit kicked up by the prop and deposit that dust on the plunger of the solenoid, which eventually binds it up. To be clear, I'm talking about the smaller metallic cylinder, not the white plastic part. The clearance is pretty tight on that plunger. Of the three I've had fail in 750 hours, all have had sticky plungers. Cars have their ring gear and starter nose enclosed with a dust shield.

Or, the problem is cheap offshore-sourced parts. Including the ones that Sky-Tec supplies.

As shown below, the solenoids we're using look like this:

41FL9nhDneL._SY463_.jpg


There are ones available which have rubber dust caps on the plunger; need to check if they will fit in the Sky-Tec housing. If so, could be an improvement.

413Ab4aekrL._SY355_.jpg
 
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I literally just put in a new Skytech 149-12LS starter complete on a Lycoming O-360 A1A and it is doing the same thing after 10 hours.

Click no start. Not the battery or master relay. Seems to be the starter solenoid. Arrrggghhh. Any help appreciated.

Was assisted by an A & P. He says send it back for another?!?

What say ye all.
 
I received a rebuilt LS from Sky-Tec and the solenoid lasted just a few hours... failed in Furnace Creek, Death Valley of all places. That experience is what drove me to figure out these LS starters.

You have 2 choices: send the starter back and wait until they replace the solenoid under warranty or you can just get the above-referenced solenoid and replace it while the rest of the starter motor remains attached to your engine.

On one hand you could make the point that Sky-Tec is responsible for the failure and have them warranty it, but on the other hand, I'd rather have my airplane back in the air in a day with less work on my part.
 
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Bad Solenoid...bad bad bad bad.

My Skytec 149-12LS began showing signs of a problem this summer -- right around the end of phase I with about 100 start cycles.

The first flight of the day wouldn't be a problem, but the second and third hops, after the engine was nice and hot and the ambient temps were > 95?F, turning the key would yield a "clunk."

I found a BWD S5613 at Advance Autoparts and installed it. The BWD unit looked a little different than the original -- the piston rode in a bronze liner, the electrical connections were more robust.

The piston in the original solenoid was sticking about 2/3rd of the stroke. The metal, once I removed the carbon/dirt/whatever, was pitted. Each time I depressed the piston I could see little puffs of dirt come out of the mounting holes...

B
 
That?s what I will do. Replace the solenoid. If it works I will carry a spare solenoid. Thanks for the replies.
 
It's not the dust...

Can't be the dust - I had the same issue on the second attempt to start, there was definitely no dust on it because the plane did not fly since then. There was not any dust on it. And the solenoid is a closed system which showed a short circuit inside when checking.

I did order a new starter (maybe I did the error to order the same Skytec 149-12XLT) from Aircraftspruce Germany after communication with Lycoming.

And the Ford Crown Victory Solenoid from a local US car shop.

The Ford solenoid works fine since I got it few days later. So I did order another one to be prepared for the future.

Altough on stock, the starter arrived after 4 weeks.

Regarding the warranty:

Lyconing says contact the local distributor
The official local Lycoming distributor - they did not even answer
Hartzell says they won't do anything because I did repair it myself
Aircraftspruce Germany refused to cancel the starter order (long before it arrived) although in Germany they'd have to by law

So forget the big name companies, if you have a problem they leave you alone.

And from today's sight would have been better to have a Superior engine because for the Lycoming there is no exhaust system with mufflers available. But it was easy to get the Lycoming engine via Vans.
 
same same

I have had the same issue since new. Starter not engaging when warm/hot.
Tech support at Van's said they have switched to the Skytec XLT because of the poor solenoid performance issues. I changed out the solenoid to the BWD S5613 from Advance auto parts. A very easy change for $32 vs buying an XLT starter for $540.

The new solenoid functions smoother, but the spring is noticeably lighter than the old one. Seems that there could be a small risk of the starter not disengaging cleanly - we'll see.
 
Skytec 149-12LS starter will not engage when engine is hot

From this thread, sounds like a solution has been identified. But I'm just leaving a comment that I have same problem with the Skytec starter in my RV.

Starter will engage when engine is cold, but on 2nd / 3rd starts when engine is hot, the starter will not engage, and will just go 'click' ... And it definitely has something to do with the temperature of the engine.

Last summer, July-2019, during annual the shop said I needed new starter, so brand new Skytec 149-12LS was installed, and right afterwards, 50 hours or so, no problems.

Then over the winter, after stopping to fill-up for fuel, etc, with engine still hot, the starter would not engage sometimes on first or second attempt to start.

Then this spring, I installed new battery, which seemed to help, for about a month or so. And now, summer is here, and weather is hot, the problem is back, and seems worse.

Two days ago, I got stranded after stopping to fuel-up at an airport. The ambient air temperature was 90F, and the engine was hot, and when attempting to start, the starter would just go 'click', and not engage.

So I decided I would take the top cowl section off the engine to help cool the engine down. I did this, and as soon as I finished taking engine cowl off, and set aside tools and such (just maybe 3 minutes had passed) ... I attempted to start the engine, and YES, the starter would engage, and turn over the engine.

So that's my story and experience with the Skytec 149-12LS. Its definitely a temperature related issue with the starter/solenoid.

At any rate, I'll be going out to Advanced Auto to get a BWD S5613 replacement solenoid. Thanks.

Tom Uldrich
N986JW
 
Same issues, third master solenoid, second starter solenoid, 153 hours, No it is not the installation - all new wires and grounds - checked multiple times. These starters are marginal at best. I would not recommend them installation.
 
It happens

My engine was equipped with a Sky-Tec 149-12LS starter. Earlier this month, I pulled the plane out for short flight. Hit the start button--click. After several "clicks", I put it back in the hangar and pulled the cowl. I hooked a volt meter to the solenoid on the starter and hit the start button--voltage went from 0 to 12.5 volts. OK, so it's not wiring. I called Sky-Tech (now Hartzell), got an RMA and returned the starter/solenoid. 11 days later I received a completely new unit. Although a few months out of warranty, they replaced at no charge. Failure happened at 146 hours--glad it was at my home field. Prior to this, there was absolutely no warning of the impending failure. I now will carry a spare solenoid for cross country trips.
 
122-12XLT starter "clicks" when engine hot

I recently had an issue with my skytec 122-12XLT click when warm. Replaced my battery (PC690) which was almost 5 years old with new. Still acts up when hot.

Has anyone successfully resolved the soleneoid issue for more that a few hundred hours. The mechanic i spoke to recommended the skytec 122-NL starter as being "bullet proof". I am thinking that might be a good change if it works with my PC680 and fixes the problem.

Anyone have experience?

Jerry Ludwig
N925JL
 
As a revival to this thread, I also experienced a 'click' no start situation after a flight and a hot engine/starter. I have the standard IO-390 (not the newer, more powerful version) with 75 hours (first ran October 2020) and the 149-12XLT starter wired per Van's instructions on the -14A. I will try it again when the engine is cold, but my supposition is that it was heat related as I checked the connections. In the meantime, I picked up a new solenoid from the auto parts store. Has anyone had luck when they changed the solenoid? Or is there some other updated thinking on this? TIA
 
Had similar problem with LS starter. Replaced battery and new solenoid on the starter. Nothing bought new starter ant still nothing. It would start with h a jump. Ended up being a weak starter solenoid on the firewall.
 
Failure Report:Starter Solenoid

IO-360-M1B
Hours: 196 (but originated at ~40 hrs)
Issue Description: click-no-start
Root cause: Failed solder joint
Discussion: In course of diagnosis, I touched the terminal and the condition was temporally solved. Closer inspection found that the contact post plate had a slight looseness. The solenoid was checked with an ohm meter and the wiggle produced a wide variance in resistance.
Action: Replaced solenoid with "Standard" brand, a Borg Warner (BWD) part was not available on short notice but using the part number found this part for the Crown Vic. SkyTec site had torque specs, and used red loctite on the allen screws.
Pilot/builder: Super happy.
Note: 10mm box end, and a 5mm allen socket driver required for this job.


EDIT: Allow this extra comment - - The SkyTEC manual (downloadable) has a good diagnostic procedure up to a point. In my case, using an ohm meter from ground to this start trigger terminal allowed a wiggle and caused the resistance to vary wildly. This confirmed it as the bad part before finding the fractured solder. This test should be added to your diagnostics. It can also be powered directly with 12v if the wire back to the contactor is removed. The starter should not engage the motor but only push out the pinion. This can be done on the plane and post wiggled to see if it is intermittent. As a field repair, I would have attempted to re-solder that joint to get home (if it was one hop) if tools and/or the part was not available. It would have to be a large soldering iron with the mass involved though . . . .

EDIT-2: Solenoid = Standard Motor part # SS-754 ~$25 @ RockAuto. "Standard Motors" is the manufacturer.

Click.no.start.jpg
 
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IO-360-M1B
Hours: 196 (but originated at ~40 hrs)
Issue Description: click-no-start
Root cause: Failed solder joint
Discussion: In course of diagnosis, I touched the terminal and the condition was temporally solved. Closer inspection found that the contact post plate had a slight looseness. The solenoid was checked with an ohm meter and the wiggle produced a wide variance in resistance.
Action: Replaced solenoid with "Standard" brand, a Borg Warner (BWD) part was not available on short notice but using the part number found this part for the Crown Vic. SkyTec site had torque specs, and used red loctite on the allen screws.
Pilot/builder: Super happy.
Note: 10mm box end, and a 5mm allen socket driver required for this job.

EDIT: Allow this extra comment - - The SkyTEC manual (downloadable) has a good diagnostic procedure up to a point. In my case, using an ohm meter from ground to this start trigger terminal allowed a wiggle and caused the resistance to vary wildly. This confirmed it as the bad part before finding the fractured solder. This test should be added to your diagnostics. It can also be powered directly with 12v if the wire back to the contactor is removed. The starter should not engage the motor but only push out the pinion. This can be done on the plane and post wiggled to see if it is intermittent. As a field repair, I would have attempted to re-solder that joint to get home (if it was one hop) if tools and/or the part was not available. It would have to be a large soldering iron with the mass involved though . . . .

View attachment 15029

This cracked solder joint seems to be a somewhat common failure-mode of these solenoids. I have seen another Skytec fail like this and I had an original one fail on a 2005 Ford Ranger with a crack in the same area I lived with it operating intermittently for a year before I finally replaced it. If the car wouldn't start, I could reach underneath and wiggle the wires and it would typically start after that.

Skylor
 
Same issue.

Thanks for this thread.
I had the same issue with my Skytec 149-12LS.
Advance Auto parts no longer carries the BWD S5613 solenoid.
O Riley’s has it. The part number is the SS754. Exact replacement.
Auto Zone does not sell the solenoid only but will sell you a complete rebuilt starter for a 2005 Crown Vic for about $80. One could just swap out the solenoid and return the core.
 
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Had the same 149-12LS starter problem on my IO-360-M1B.

Lycoming sent me a replacement starter at 93 hours, now with 147 hours on the replacement starter it is doing the same thing.

For me the options are:
- Get a replacement starter from Lycoming (under warranty), either another 149-12LS or as currently recommended by Lycoming the 149-NL stater. The 149NL is reported to be trouble free, but weighs a pound more.
- Go get a replacement solenoid as discussed in this thread and hope another China solenoid is better made than the original Hartzell part.

I’d be interested in pros/cons on these options.

Carl
 
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- Get a replacement starter from Lycoming (under warranty), either another 122-NL or as currently recommended by Lycoming the 149-NL stater. The 149NL is reported to be trouble free, but weighs a pound more.

Changing to the 149-NL would necessitate changing the ring gear on the fly wheel from 122 teeth to 149 teeth.... No?
 
Changing to the 149-NL would necessitate changing the ring gear on the fly wheel from 122 teeth to 149 teeth.... No?
Sorry, had my numbers mixed up. My post now corrected. Both have the same 12/14 pinion pitch.

Lycoming is sending me the 149-NL as a replacement for the 149-LS.

Carl
 
Skytec Starter issues

I had an issue with my starter engaging for a blade or two of prop turns on my RV3B, and then prematurely disengaging from the prop ring gear before the engine started.
Just a tip before going out and dropping big money on a new starter or even a new solenoid: I removed my solenoid and cleaned it up and lubed it, and also cleaned off any contact points. Also I oiled the shaft of the starter gear. This solved the problem.
That being said, I did buy a SS-754 solenoid from O’Rileys Auto Parts for $49.
It’s identical and I think it’s good to have a spare based on the numerous issues reported.
 
Starter problems… solved !

I bought that “Standard Motor Products” SS-754 starter from O’Rileys auto parts…perfect match.
I had a problem with my starter prematurely disengaging during start, so I thought it was the solenoid (it wasn’t but at least I have a spare solenoid now!). Also thought it was my battery going bad…not the case.
I came to the conclusion my SkyTec 149LS starter was bad, and decided to disassemble it for inspection. It is 13+ years old and was full of gunk and magnetic fibers from normal wear on the brushes over the years so I did a thorough degrease-cleaning. I also discovered the hardened steel stop snap-ring on the starter shaft groove had some how expanded and slid forward out of the shaft groove and was bent/expanded.
I replaced that with 2 stainless steel snap rings (to match thickness of original stop-ring) from the hardware store for $1.89. I reassembled, cleaned electrical connection points, and now it works perfectly ! $1.89 vs $800.00 for a new starter !
 
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This seems to be the current "SkyTec Starter failure reporting" thread, so here's mine:

15 hours TT. SkyTec 149-12LS. Just finished up a 30 minute flight. OAT about 20C. Parked for about an hour to do some business. Got back to the plane and the starter would not turn. I could hear the firewall solenoid(s) click, but the prop did not crank an inch. Pulled the cowl and proceeded to do a tug test on all the wiring, all OK. Wiggled the ground connection between the starter solenoid and starter, it's secure. A bystander offered to stick a multimeter probe onto the starter solenoid lead to verify 12V, and instead the starter turned like normal. Re-cowled, and the starter has been fine ever since.

Based on this and other threads, I suspect infant mortality for the starter solenoid and it looks like I ought to carry a replacement with me in my flight bag.
 
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This seems to be the current "SkyTec Starter failure reporting" thread, so here's mine:

15 hours TT. Just finished up a 30 minute flight. OAT about 20C. Parked for about an hour to do some business. Got back to the plane and the starter would not turn. I could hear the firewall solenoid(s) click, but the prop did not crank an inch. Pulled the cowl and proceeded to do a tug test on all the wiring, all OK. Wiggled the ground connection between the starter solenoid and starter, it's secure. A bystander offered to stick a multimeter probe onto the starter solenoid lead to verify 12V, and instead the starter turned like normal. Re-cowled, and the starter has been fine ever since.

Based on this and other threads, I suspect infant mortality for the starter solenoid and it looks like I ought to carry a replacement with me in my flight bag.

Autozone $48!
 
Based on this and other threads, I suspect infant mortality for the starter solenoid and it looks like I ought to carry a replacement with me in my flight bag.
I am carrying one in my plane but hope I would not need it anytime soon. Harzel has promised a fix for this when I asked them during Oshkosh but it is not known when they will have the replacement and how they would honor it. I would hate to have to deal with this on the tarmac.
 
LS solenoid available

Anybody really wants a spare solenoid for the Skytec LS starter, send me a PM. I've got a used one (maybe a couple hundred hours???? don't really remember) available for the cost of shipping.

The short story on it: working when removed. Never had any solenoid related issues. The starter was pulled for other reasons (and eventually replaced with a B&C).

Well, that didn't take long. The solenoid has been spoken for.
 
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Anybody really wants a spare solenoid for the Skytec LS starter, send me a PM. I've got a used one (maybe a couple hundred hours???? don't really remember) available for the cost of shipping.

The short story on it: working when removed. Never had any solenoid related issues. The starter was pulled for other reasons (and eventually replaced with a B&C).
Hi Steve,
If you have not shipped the shunt yet, perhaps you can put this with it as it would fit my starter.
 
I'm curious about the starter operation from the group. Is it true that the starter solenoid only controls the engagement of the starter? What I mean is will the starter motor run even if it does not engage with the flywheel or does the solenoid also enable to the motor?
 
I'm curious about the starter operation from the group. Is it true that the starter solenoid only controls the engagement of the starter? What I mean is will the starter motor run even if it does not engage with the flywheel or does the solenoid also enable to the motor?

If you are asking about the LS starter, the double "contactor" circuit it is based on a long standing issue and Vans solution. The firewall starter contactor is the primary "switch" that actuates the solenoid/contactor (the “Standard Motor Products” SS-754 mentioned by Drake above) on the starter, in series.

The “Standard Motor Products” SS-754 has a dual function. The motion of the plunger acts on a yoke lever that extends the pinion/sprag to engage flywheel teeth. The end of that plunger stroke actuates an internal high amperage contactor/switch that connects the large 12v input cable to the starter motor power input. These are the two larger lugs on the end of the SS-754.
 
I'm learning a lot about these SkyTec starters in this thread, thank you!

The “Standard Motor Products” SS-754 has a dual function. The motion of the plunger acts on a yoke lever that extends the pinion/sprag to engage flywheel teeth.

I have not taken mine apart yet, but the pictures I found online of these starter solenoids show a plastic shaft that I guess plunges forward of the solenoid. You mean to tell me that that little plastic ding-dong is all that physically causes the teeth to move forward and engage with the ring gear?? Is there some illustration of how this mechanism works? Wouldn't that be prone to failure?

The end of that plunger stroke actuates an internal high amperage contactor/switch that connects the large 12v input cable to the starter motor power input. These are the two larger lugs on the end of the SS-754.

So this connector wire is not a ground (as I believed) but carries the starter current from the solenoid to the starter when the solenoid is engaged?

 
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I have not taken mine apart yet, but the pictures I found online of these starter solenoids show a plastic shaft that I guess plunges forward of the solenoid. You mean to tell me that that little plastic ding-dong is all that physically causes the teeth to move forward and engage with the ring gear?? Is there some illustration of how this mechanism works? Wouldn't that be prone to failure?

It's nylon -- sometimes it's steel. It moves aft when the solenoid is energized. The nylon catch pulls one end of a pivot arm in (think see-saw), which moves the other end carrying the pinion/sprag gear forward engaging the starter ring gear. Once the plunger has reached its full travel limit, contacts at the back are closed, energizing the starter motor.
 
LS starter internals

I have not taken mine apart yet, but the pictures I found online of these starter solenoids show a plastic shaft that I guess plunges forward of the solenoid. You mean to tell me that that little plastic ding-dong is all that physically causes the teeth to move forward and engage with the ring gear?? Is there some illustration of how this mechanism works? Wouldn't that be prone to failure?

Well, yes they are prone to failure....just not in the way you'd expect. I've had the chance to pull 3 of the LS starters apart (mostly to find enough good parts to make 1 good starter).

Brief history of the three starters involved:
1. 100 hour starter with broken casting nose piece (my fault...I caused it....longer story). This was the earliest manufactured starter of the bunch.
2. 800 hour starter with a loose solenoid core (loose within the metal housing).
3. ~200 hour starter (donated from a friend), fully functional and working when replaced by a different Skytec model.

Long story short...I ended up pulling all 3 apart after finding the internal plastic throw-out fork worn. Here's some photos of the internal guts.

IMG_0203.jpg
IMG_0208.jpg

Top photo shows the throw-out fork from starter #2 in the above list (white fork and ring on the right, along with the planetary ring gear which doubles as the top of the electric motor). Also in the photo is the throw-out fork from starter #1 (black throw-out fork and white throw-out ring) on the left side.

The bottom photo shows the throw-out fork assembly from starter #3.

Notice the worn (oversized) holes in the arms from #2 and #3. The debris around the holes (I thought at first it was some type of white grease) turns out to be plastic dust, worn from the ID of the arm hole where the throw-out ring snaps in. Compare these to the new looking parts from starter #1 (black arm, white ring).

Wish I had photos of the complete "exploded" starter assembly, but couldn't find any. So, a brief description of the starter assembly construction. The motor shaft drives 3 metal planetary gears inside a stationary plastic ring gear/motor top cover. This in turn drives the steel output shaft of the starter. The throw-out arm assembly, actuated by the on board starter assembly solenoid slide up and the output shaft so the starter output gear can engage the engine starter ring gear.

The plastic parts from all 3 do appear to be some type of glass filled material. Probably nylon or polycarbonate (my guess....not enough of a plastics engineer to say for sure). You can find similar looking material used on many auto parts, including engine related ones. So, the material isn't surprising. What is surprising is the wear in the throw-out fork holes.

To end my tale of the 3 starters, I did manage to put one working starter together. Ended up using it for about 4 months.....while I waited for delivery of a B&C starter (all metal internals ;) ). Decided I'd take the 1ish pound hit on weight increase.
 
Thanks for the explanation. I was wondering if Ryan should have heard the starter motor spinning, but I guess the answer is no.
 
So, why are so many of these Ford PMGR solenoids failing at such low hours? Skylor had an interesting theory: on airplanes, the ring gear and starter nosecone are exposed and pull in dust and grit kicked up by the prop and deposit that dust on the plunger of the solenoid, which eventually binds it up. To be clear, I'm talking about the smaller metallic cylinder, not the white plastic part. The clearance is pretty tight on that plunger. Of the three I've had fail in 750 hours, all have had sticky plungers. Cars have their ring gear and starter nose enclosed with a dust shield.

Or, the problem is cheap offshore-sourced parts. Including the ones that Sky-Tec supplies.

As shown below, the solenoids we're using look like this:

41FL9nhDneL._SY463_.jpg


There are ones available which have rubber dust caps on the plunger; need to check if they will fit in the Sky-Tec housing. If so, could be an improvement.

413Ab4aekrL._SY355_.jpg

I've had the solenoid above with the rubber boot (made in Brazil) on the LS on my -6 for a couple years now and so far still working fine. You have to trim the lip off the rubber boot to make it fit the LS, but that's a minute with a razor blade. You can find these solenoids with rubber boots on fleabay. Search "Ford PMGR solenoid".

Looking at Stevea's post above seems to corroborate what I said 5 years ago about dust and grit causing the problem with solenoid plungers sticking and also the abrasive wear on the plastic parts.
 
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SkyTec parts alternative

Slightly off topic

SkyTec starter on another aircraft sheared the pinion / drive gear when the engine backfired
SkyTec don’t supply parts and don’t rebuild
Any suggestions for alternative sources ?
 
Parts source

Slightly off topic

SkyTec starter on another aircraft sheared the pinion / drive gear when the engine backfired
SkyTec don’t supply parts and don’t rebuild
Any suggestions for alternative sources ?

See if you can find a scrap one of the same model, that has a good set of parts you need. That will get you back in the air.

After that, put in an order for a B&C starter.
 
...I replaced it from Napa with Echlin Ignition ECH ST421 which lasted less than a year and failed with almost no warnings.

Now it is replaced from O'Rielly with BWD S5613, only a few hours on it but working fine.

I have now on the shelf a spare from Amazon a Standard Motor Parts SS754

And another VAF'er used Auto Zone Duralast SS1115

Any reports of which has been better or worse for you?

BWD S5613 doesn't seem to be available anymore, at least not from a reputable source.

I just picked up a Standard Motor Parts SS754 from O'Reilly for $43. The same part number is available for about $30 from Amazon and Rockauto. I'm skeptical about automotive knock-offs from Amazon, though I'm guessing all of these are made in China.
 
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