2019 Mustang GT idle thudding/knocking, authorized engine replacement

[accel]

I hear the the tick loud and clear. Subtle typewriter tick, just like most of the posts here where people want ford to buy back.. You know why ford resells em? Cuz aint nothing wrong with the car.

Sell your car to the dealer or private party. If either of them will hear the tick you will not get a dime on your car.

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[Dfeeds]

I don't know if the rattle is problematic or not, but I do believe it's normal after calming myself down and doing some homework. That rattle is also present with the 5.2l voodoo engine found in the gt350. I also believe that it is NOT piston slap. Piston slap sounds more metallic, and wouldn't be that constant rhythmic sound because the piston wouldn't be slapping the entire timepm. I actually heard piston slap day at a stop light, briefly, concurrent with the rattle. Also, how many confirmed engines have been replaced? I've only seen the one from bigriver, and the rest were buy backs. This gen 3 coyote feels alien with all the new stuff they threw at it to make it so beefy. Dyno numbers and trap times heavily suggest it's underrated, and much closer to, or above, 500 HP with 93 octane. New cams, rods, bearings, larger valves, new heads, new intake, 12:1 compression which used to be something you'd only see in race cars, 12 injectors programmed to function at different times to optimize power and fuel efficiency, and then there's the plasma transfer wire arc thermal lining. I've done some reading on the new lining and the tech is fascinating. It's also supposesly a lot more durable, and allows for tighter clearances (which could, theoretically, cause piston slap but not cause structural damage to the block). However, apart from some hear-say, I couldn't find any actual evidence of just how durable the new linings are. Nissan wants to use it, though, for the GTR, and that's telling. Then there's the twin disc clutch that has some unpleasant sounds that most people seem to have, myself included. Then I stumbled upon some info from ford saying the grind/klunk is normal. Then someone else chimed in saying they had engineering friends who explained why it's noisy. Basically, one disc engages and the second disc has to "catch up." The poster said that his friends were surprised it wasn't making even more noise.

Now does any of this mean these cars are without flaws and everyone needs to stop their witch hunt? No, unfortunately, not necessarily. What it does mean, however, is that there's a lot going on under the hood that even experienced mechanics aren't used to or given a basis to compare with. Let alone a bunch of new mustang owners who only ever turned a wrench to build a cabinet from target. I really do feel a little sad knowing a couple of members gave up a car they loved over something that is still just conjecture.

@stangman638 It definitely sounds similar, but I feel like the rattling sounds less metallic. It almost sounds similar to the sound my old mountain bike would make when I'd pedal really fast then just let the pedals loose.

 

[GT Pony]

I've done some reading on the new lining and the tech is fascinating. It's also supposesly a lot more durable, and allows for tighter clearances (which could, theoretically, cause piston slap but not cause structural damage to the block).

I've never heard that tighter piston to cylinder clearance can cause piston slap. I had a C5 Z06 that had slight cold start piston slap for a couple minutes until the pistons heated up alittle and expanded enough to decrease the piston clearance, and the noise would disappear.

 

[bootlegger]

I've never heard that tighter piston to cylinder clearance can cause piston slap. I had a C5 Z06 that had slight cold start piston slap for a couple minutes until the pistons heated up alittle and expanded enough to decrease the piston clearance, and the noise would disappear.

That's the opposite of what causes piston slap. Piston slap happens with forged pistons, as they don't expand until warm. For that reason, they are sized slightly smaller. When cold, they have a lot of loose space, thus the slap. Once they warm, they expand and seal things up, then there is no more slap. The 2018-2019 GT rattle has nothing to do with piston slap, as many people have the same rattle all the time. Also, we don't have pistons made of the same material as the GT350.

 

[Dfeeds]

I've never heard that tighter piston to cylinder clearance can cause piston slap. I had a C5 Z06 that had slight cold start piston slap for a couple minutes until the pistons heated up alittle and expanded enough to decrease the piston clearance, and the noise would disappear.

You're correct. I had piston slap on my mind because I was thinking of the other thread. What I was getting at is that, if the pistons are sized a bit larger for the new liners, thermal expansion could cause them to grow too large and cause similar scoring to what was shown in pictures. Although this also poses the question on if the pistons are undersized to begin with to accommodate for the higher rpms and the assumption that people will spend more time at WOT, causing more thermal expansion. This would mean that the piston slap heard (and to clarify this is NOT the rattle) could be normal like the TSB claims for the GT350. But, and I'll keep saying this, I have no idea for sure. The hypereutectic pistons have less thermal expansion than forged aluminum so they may not be undersized. It's hard to make a one size fits all application. If you want boost or are racing then you want smaller pistons to accommodate for more thermal expansion. If you don't have those veriables, but have the smaller pistons, then you'll get more piston slap than normal. On the flip side, if you increase the piston size for tighter clearance, then you run the risk of thermal expansion causing an issue. With the new compression ratio and higher red line, I have no idea what Ford's engineers went with. The lower viscosity oil being used could very well be in order to keep the internal components cooler with the increased flow (and also the drop to 5w30 for track use), implying the pistons are larger for tighter clearances, but with measures in place to try and prevent too much thermal expansion; not just for CAFE standards like so many preach. In this case, deviating from 5w20, specifically with the gen 3 coyote, could potentially cause harm in spirited daily driving.

 

[GT Pony]

On the flip side, if you increase the piston size for tighter clearance, then you run the risk of thermal expansion causing an issue. With the new compression ratio and higher red line, I have no idea what Ford's engineers went with.

Would be interesting to compare the piston-to-cylinder clearance between the Gen2 and Gen3 Coyote to see if it's tighter or looser on the Gen3. Anyone have access to the Factory Service Manual for the 2018+ ?

The lower viscosity oil being used could very well be in order to keep the internal components cooler with the increased flow (and also the drop to 5w30 for track use), implying the pistons are larger for tighter clearances, but with measures in place to try and prevent too much thermal expansion; not just for CAFE standards like so many preach. In this case, deviating from 5w20, specifically with the gen 3 coyote, could potentially cause harm in spirited daily driving.

Oil temps definately get higher in track use, so Ford must think 5W-30 is able to give adequate protection on the track instead of oil thicker than 5W-30. Maybe 5W-20 is too thin for really spirited street driving - guys that really push the engine hard on the street. What oil viscosity is specified for Australian 2018+ Coyotes for street use? It was 5W-30 for the 2015-2017s.

 

[Why]

If you spent more time just driving around enjoying the car, and less time worrying about nothing, you will be happier.

 

[Dfeeds]

Would be interesting to compare the piston-to-cylinder clearance between the Gen2 and Gen3 Coyote to see if it's tighter or looser on the Gen3. Anyone have access to the Factory Service Manual for the 2018+ ?



Oil temps definately get higher in track use, so Ford must think 5W-30 is able to give adequate protection on the track instead of oil thicker than 5W-30. Maybe 5W-20 is too thin for really spirited street driving - guys that really push the engine hard on the street. What oil viscosity is specified for Australian 2018+ Coyotes for street use? It was 5W-30 for the 2015-2017s.

5w-30, from what I've seen, is considered to also be on the thin side for tracking a car. Normally one would want Xw40 or Xw50, and Xw30 is then the "normal" oil. I know people are laying on about the whole CAFE thing, but there really is a chance this engine needs the thinner 5w20, or 5w30 when at the track. I would love to see a factory service manual of the gen 3 coyote. If you manage to get your hands on one then please share!

 

[Dfeeds]

If you spent more time just driving around enjoying the car, and less time worrying about nothing, you will be happier.

Which is exactly what I've been doing. This car is a little more revy than I'm used to, but it's a lot of fun!

 

[Nomadic]

I test drove an '18 auto 3.55 last week and when I popped the hood after the test drive I noticed the engine made a little ticky/flappy sound. It wasn't major but I noticed it. But I didn't think much of it.....just characteristic of the engine. Didn't sound like something was wrong.

 

[GT Pony]

5w-30, from what I've seen, is considered to also be on the thin side for tracking a car. Normally one would want Xw40 or Xw50, and Xw30 is then the "normal" oil. I know people are laying on about the whole CAFE thing, but there really is a chance this engine needs the thinner 5w20, or 5w30 when at the track. I would love to see a factory service manual of the gen 3 coyote. If you manage to get your hands on one then please share!

Lots of talk about thin oils and CAFE on bobistheoilguy.com. There were links to letters between the EPA (I think) and Ford discussing it, and what Ford had to do to get CAFE credits (ie, spec 5W-20 and factory fill with 5W-20, and make oil caps and manuals all show 5W-20). And also threads showing quotes from engine testers within Ford, and people from Ford Performance group saying the modular V8s (like the Coyote) showed less wear with 5W-30.

The Gen2 and Gen3 Coyotes are different, but Gen2 Coyotes in Australia are speced for 5W-30 for everday use (per owner's manual), while in the USA Ford speced them for 5W-20. No difference between the internals of the engines. Just no CAFE requirements in Australia.

Next time I'm on my other computer I'll post up the piston clearance for the Gen2 Coyote. I dont have Gen3 info, but maybe someone reading this thread does and can post it up to see if the piston clearence is tighter or looser, or the same in the Gen3.

 

[Dfeeds]

Lots of talk about thin oils and CAFE on bobistheoilguy.com. There were links to letters between the EPA (I think) and Ford discussing it, and what Ford had to do to get CAFE credits (ie, spec 5W-20 and factory fill with 5W-20, and make oil caps and manuals all show 5W-20). And also threads showing quotes from engine testers within Ford, and people from Ford Performance group saying the modular V8s (like the Coyote) showed less wear with 5W-30.

The Gen2 and Gen3 Coyotes are different, but Gen2 Coyotes in Australia are speced for 5W-30 for everday use (per owner's manual), while in the USA Ford speced them for 5W-20. No difference between the internals of the engines. Just no CAFE requirements in Australia.

Next time I'm on my other computer I'll post up the piston clearance for the Gen2 Coyote. I dont have Gen3 info, but maybe someone reading this thread does and can post it up to see if the piston clearence is tighter or looser, or the same in the Gen3.

I've also seen those older quotes from the Ford engineers stating to not use 5w20. I'd be lying if I said 5w20 didn't strike me as thin, initially, as well. This thread isn't about this but I've spent way more time reading up and trying to decide between 5w20 and 5w30. Some guys have said it doesn't make a differencr in noise, on here, and it's getting colder so I decided to just stick to factory spec. I also saw a quote from Ford saying the coyote clearances are tighter and benefits from 5w20 (which may hold more merit for the gen 3 than gen 1 and gen 2). From what I do understand about oil pressure, with how high this car revs, a thinner oil definitely isn't a bad thing. Even with 5w20 my oil pressure skyrockets when I open her up. If it was abnormally low I'd switch to 5w30 in a heart beat. It really bothers me that so much, even regarding the engine rattle, is conjecture.

 

[stangman638]

Lots of talk about thin oils and CAFE on bobistheoilguy.com. There were links to letters between the EPA (I think) and Ford discussing it, and what Ford had to do to get CAFE credits (ie, spec 5W-20 and factory fill with 5W-20, and make oil caps and manuals all show 5W-20). And also threads showing quotes from engine testers within Ford, and people from Ford Performance group saying the modular V8s (like the Coyote) showed less wear with 5W-30.

The Gen2 and Gen3 Coyotes are different, but Gen2 Coyotes in Australia are speced for 5W-30 for everday use (per owner's manual), while in the USA Ford speced them for 5W-20. No difference between the internals of the engines. Just no CAFE requirements in Australia.

Next time I'm on my other computer I'll post up the piston clearance for the Gen2 Coyote. I dont have Gen3 info, but maybe someone reading this thread does and can post it up to see if the piston clearence is tighter or looser, or the same in the Gen3.

I think it would be wise to use what ford suggests in manual. 5W30 track use is not the same as the engine being punched here and there on the highway. I think Australias climate is different than much of the USA, if I lived in miami or southern Texas I may use 5w30..

 

[Dfeeds]

I think it would be wise to use what ford suggests in manual. 5W30 track use is not the same as the engine being punched here and there on the highway. I think Australias climate is different than much of the USA, if I lived in miami or southern Texas I may use 5w30..

There's the kicker, Ford recommends 5w20 across the board for the US. And, here in IL, it's not uncommon to have stretches of time where the ambient temp is damn near close to 100°F. The one big benefit I can see with 5w20 is keeping things running cool due to the lower viscosity creating higher flow. However, and this is iffy, I've stumbled upon forum posts where people have said their car has felt like a furnace on 5w20 when standing by the engine, much more so than 5w30. I also noticed that right away. My engine felt like how my old 302 HO felt after driving on a really hot, summer day (it's been around 60°F here). But that could also be because more heat is being effectively dissipated. Don't quote me on that last part. It's a guess

I am sticking to 5w20 for now. A lot of the evidence floating around anout CAFE is telling, including the ex Ford engineer claims, but that's all a good 10+ years ago. A lot has changed since then. Clearances could very well be tighter, and the protective properties of 5w20 could have increased due to better tech with additive combinations. The thought still looms in my mind that, if the people who had cylinder wall damage were using 5w30, would they have had a problem? Then again, maybe they all were using 5w30, and that was the problem. The oil viscosity difference at 217°F is only about 2-3 depending on brand and type, so it could also have no bearing at all.

 

[GT Pony]

The thought still looms in my mind that, if the people who had cylinder wall damage were using 5w30, would they have had a problem? Then again, maybe they all were using 5w30, and that was the problem.

Is there info that shows what weight of oil was being used in the engines that had cylinder wall damage?

I highly doubt cylinder wall damage was caused by using 5W-30 instead of 5W-20. If an engine was that sensitive to oil viscosity it would be destroying itself even on 5W-20 during warm-up until the oil thinned down at operating temperature (200+ F).

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