Mazda Protege FSDE "is this rod knock?" thread (2024 edition)

[Diamond_Dave]

I just spent the last three months chasing some noises in my daughter's MazdaSpeed Protege and wanted to collect all the information I found in one location. Since there are more Protege5 on the road today than other Proteges, I'm putting it in this forum and hopefully people can find when they search. If you find errors in what I've recorded or you want to add something below, let me know.


Here's the noise that developed:
https://youtu.be/BpR9q_vdqxo

Here's the noise after I went through this discovery process:

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These Protege all use the same 2.0L FS-DE - Protege (DX, LX, ES), Protege5, MazdaSpeed Protege (adds a turbo obviously). They are solid lifter design using a Variable Tumble Control Solenoid (VTCS) intake. By this time (May2024), the majority of these cars are going to have 100K+ miles and often 200K+ miles. Add to that, the pricepoint means that many have deferred maintenance across multiple systems.

HOWEVER, the most common issue is a loud engine noise that could either be the dreaded connecting rod knock or valvetrain / lifter noise. Both sound similar, but obviously a rod knock means you need a new engine and a lifter noise requires some maintenance. Here is a troubleshooting process that I researched and found results with.

Let's start with what is and is not rod knock: rod knock is what happens when the connecting rod of a piston bends. A bent connecting rod is shorter and therefore the piston cannot make a complete compression stroke.


Rod Knock Symptoms
Metal shavings in oil
Louder on bottom end (and when listening from below the engine)
Constant noise AND occasional and uneven noises
Major changes in how vehicle drives; low on power, engine gets hotter, more noticeable smoke out the tailpipe
Faster since crankshaft spins twice as fast
Higher oil consumption (in the form of blue / grey smoke - smokes all the time)
Loud uneven clatter sound at startup
Overheating
Loss of compression + reduction in power/performance
A rod knock will only sound worse (louder) as the engine heats up. It will not go away as the engine gets warmer
Difficulty starting engine consistently


NOT rod knock symptoms / sounds
noisy lifters (especially hydraulic)
failing belt tensioner
Failed/failing knock sensor
Gets quieter after engine warms up
Consistent sound - like a metronome
crank or waterpump pulley contacting timing cover


Other frequently stated issues
Loud Injectors
Exhaust gasket leak
Spark plug noise
Knock sensor noise

 

[Diamond_Dave]

Here are some videos that I felt were very helpful for understanding the noises in my engine. you'll soon learn how terrible an actual rod knock is and how the engines don't like to run. I don't endorse any of these videos or projects.

Sounds of noisy HLA (Miata video) 91 Miata HLA noise before and after oil change. Washer switch workaround

Wrong type of Mazda engine, (Mazda2) but great example of what rod knock sounds like on a 4cyl mazda
https://www.youtube.com/watch?v=wKm3g4pdS8U

Wrong type of engine but great depiction of how violent rod knock is - subaru - rod knock - Subaru Engine / Rod Knock Vs Piston Slap

 

[Diamond_Dave]

As I was researching these engines and sifting through all the misinformation online, I was explaining to my kids as there can be like 10 different things you can test for and "passing a test" might add 1pt to the score, where failing a test might add 10pts. You know the drill. Lowest score wins. But the goal is to isolate with knowledge. The moral is that you need several data points before you can be confident of the direction you need to go.

Do NOT post online until you perform steps 1 and 2. Take a video before you begin this project.
Vid1 - hood lifted, turn video on, video angle from passenger corner about 5ft from engine. Start the engine and let idle for 10sec. Now gently increase RPM a few times to 4K RPM and then let your foot off the accelerator so the engine can drop to idle.

Now perform this same test after each Step below to help track your progress. If you just take a 2sec video at night and let your cat hold the phone as it runs around the apartment parking lot you are going to get freaked out when every single person tells you it's a rod knock.

Also, it is important to note that while there are many sounds an engine can make that are irritating or sub-optimal, the majority of them pose no risk to catastrophic damage and you could probably drive your car for the next 5yrs without issue. With 95% of the people owning these cars seemingly mechanically illiterate, I wanted to put an updated resource in one spot that caters to a non-mechanical person with limited tools. Likewise many of the videos posted online might sound similar, but you can't compare a V8 in a truck making sounds to the FSDE.

Lastly, use your brain here when asking other people for help. Did you recently overheat the engine? Did you run the engine out of oil or too low on oil? Did you recently do the timing belt without any experience? Was the car even running well before you heard this noise?

 

[Diamond_Dave]

Here is my personal list in my personal order of easiest and least expensive.

STEP 1 (Free, a little effort to drain partial oil)
- check current oil level. If it is already 1Q low, don't lie to yourself or others about it or add oil to act like it wasn't a problem. This is you diagnosing something for yourself. Drain ~2Q into a pan. Look for shavings (looks like glitter or even chunks of metal). If you see shavings or metal, stop. You are cooked.

 

[Diamond_Dave]

STEP 2 (Cost ~$30 2Q of cheapest ATF fluid to flush, then 1 filter and 4q of high mileage synthetic)
Add 2Q of ATF. Important that it is about half the oil capacity because this will help thin any sludge and allow the ATF (with heavy detergents) to cycle everywhere in the engine. Remember, there's a reason you don't run your car with ATF fluid because it is so much thinner. That means less overall protection. Idle the car for about 5mins and slowly work it through the RPM range a few times (up to about 5K RPM).

Turn off engine and let oil drain to pan for about 5mins. Drain oil, refill with fresh oil + filter. Start the cfar, let the fresh synthetic cycle and then go on a short drive. The engine temp should come up quickly and you should notice an immediate reduction in noise if your issue was noisy lifters. This is an extremely popular and proven service in the Miata community for 1990-2005 Miata. This mainly works with Miatas because they use hydraulic lifters and the ATF thins out the oil enough to assist in draining the hydraulic lifters so that new, fresh oil can pump in and out. In fact, I've done this numerous times on my own Miatas with great success, so that is why I had no issue trying with these engines in spite of them using solid lifters.

(NOTE: if you have access to a compression tester or want to pay a shop to do a compression and leakdown test, might as well do that now as it is very effective. However, those will cost in the ~$200 range and this post is for people that don't have the money for that type of service. You can also buy a compression test kit on Amazon for between $20 and $100, but I didn't have a great experience with the test kit I bought so you are on your own there.)

 

[Diamond_Dave]

STEP 3 - (maybe $40 if you can't re-use your VCG)
Inspect each piston for slop
Great video - wrong engine - 55sec knock at startup

How to EASILY Diagnose Engine Connecting Rod Knock! Spun Rod Bearing

Freddy shows you how to diagnose engine connecting rod knock or spun rod bearing and goes through the steps to find out if it's a connecting rod knock, and w...

youtu.be

1:15sec - rhythmic to out of balance sound (knocking)
3:20 he shows how to rotate the crank while using a socket extension on top of the piston
Remove the valve cover and all spark plugs. Car in neutral. Gently put a socket extension inside spark plug hole and rest on top of piston. Crank engine with a breaker bar until the sockwet rises up and then starts to drop. Gently press down on the socket extension. If there is slight downward movement, that is a bent rod. If no movement, move to next piston.

When I did this test, i was super nervous because it is so definitive. Since the car passed this test, it was easier to move on to the next test.

 

[Diamond_Dave]

STEP 4 - Remove timing cover and inspect idler pulleys
cost $0 to ~$150 depending on what you need to replace
There are plenty of videos but here is the timing belt service that I used - 02-03 Mazda protege5 timing belt and water pump replace
On the timing belt side of the engine, there are several components that can be the source of this rhythmic ticking noise - timing belt tensioner (two of them), water pump power steering pulley, AC pulley. THere could also be an issue with some of the rotating components contacting the timing belt cover (and they crack with age). This honestly is so much work to do, that if you commit to doing it, then you might as well buy the timing belt / waterpump kit for ~$100 and just do that service. However, nobody wants to do a fresh timing belt service on an engine that is toast, so..
The major issue with this step is you'll need to remove the crank pulley and be careful to A) not move the belt B) re-torque the crank bolt properly.

Once you have the timing cover removed, bolt the crank pulley back on, install the valve cover and spark plugs and then run the engine to see if it is easier to identify the noise. if there are no obvious horrible sounds coming from the pulleys or water pump, reinstall the timing covers and valvecover and spark plugs and passenger motor mount. This is s ton of work to do just to "test" if something is making noise, but it also will give you better peace of mind with the health of your timing belt/waterpump, so it isn't like it's useless.

In my opinion, if you get to this stage and there were no metal shavings in your oil, your engine doesn't overheat, your car runs fine just makes an annoying ticking sound, the piston test showed no play in all 4 pistons, and when you removed the timing cover all the components appeared to be functioning, then it's time to just drive your car and stop worrying about a noise.

 

[Diamond_Dave]

Nevermind. All questions were answered on a short drive yesterday. At one point the engine just seemed unhappy - struggling to accelerate, and then boom + loose marbles on the ground sound.

Le sigh. Off to source engines now.

 

[BenjiHoggi]

Nevermind. All questions were answered on a short drive yesterday. At one point the engine just seemed unhappy - struggling to accelerate, and then boom + loose marbles on the ground sound.

Le sigh. Off to source engines now.

View attachment 328902View attachment 328903

Aww dang, that's a real bummer. Keep us up to date on the process of sourcing an engine.
I don't need one (yet) but I've looked preemptively and wasn't too happy with the options I found. Would be curious to hear how it goes.

 

[Diamond_Dave]

Aww dang, that's a real bummer. Keep us up to date on the process of sourcing an engine.
I don't need one (yet) but I've looked preemptively and wasn't too happy with the options I found. Would be curious to hear how it goes.

Yeah, I was just coming across some of your old posts and the sounds were so similar as well as the diagnosis process. Sourcing engines will just be looking for a lower miles unit and then doing some cleanup and maintenance prior to install. Just work.

 

[BenjiHoggi]

Yeah, I was just coming across some of your old posts and the sounds were so similar as well as the diagnosis process. Sourcing engines will just be looking for a lower miles unit and then doing some cleanup and maintenance prior to install. Just work.

I hope they're not TOO too similar
They definitely sound like valvetrain noises or maybe a tensioner. They haven't gone away but that was also like 30k miles ago and the car is still running strong at 200k, fingers crossed. Probably will do a valve adjustment and timing belt and maybe see if I can quiet it down a little.