Windshield wiper knocking

[Nathan]

There is a knocking sound coming from the left windshield wiper. It only happens when it is at the top end of the window. It’s not hitting anything and I don’t notice anything stuck that could be causing the sound. It’s coming from the base where it connects near the hood. What’s the best way to fix this? I’ll post a video when I get off work.

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[concept]

Just a few possibilities:

1. Inspect the Blades:
   • First, lift the wiper blades up off the glass of your vehicle to get a better angle for inspection.
   • Look closely at the rubber section of the blades. Check for any cracks, tearing, or other damage. If you notice any signs of damage, it’s best to replace the blades. New blades can significantly reduce noise1.
   • If the blades appear to be in good condition, proceed to the next step.
2. Check the Fitment:
   • Ensure that the wiper blades are sitting evenly on the windshield. Proper fitment is crucial for effective wiper operation.
   • Sometimes, if the windshield wiper arm is bent or not installed correctly, it can lead to uneven contact with the glass. This misalignment might cause the knocking noise.
   • Older cars with spring-loaded wiper blades may experience this issue more frequently. If the spring component inside the wiper arm is worn out, it won’t apply enough pressure against the windshield.
   • If the fitment looks good, move on to the next step.
3. Restore the Rubber:
   • Even if the blades are making even contact with the windshield and are in good condition, they might accumulate dirt and grime over time.
   • Clean the rubber part of the wiper blades. Sometimes, we underestimate how dirty this area can get.
   • Use a soft cloth or paper towel to wipe the rubber thoroughly. Removing debris can improve performance and reduce noise.

 

[Vertex]

Just want to note, step 2 is crucial. I had a windshield replaced on my Mazda and they did not set the drivers side wiper arm properly so when I started using the wipers when it was raining one day after the replacement, my drivers wiper was going past the windshield and onto the A pillar.

I will also add onto @concept step 3. Use some alcohol (not the kind you'd ingest?) on a paper towel or cloth when cleaning the blades. Really helps get all that junk off. In general you should clean them off every now and then depending on the amount of and this will extend the life of them as well as keep them wiping better when being used.

 

[Nathan]

Fixed- There was a large plastic piece under the hood(I don’t know what it’s for) that was broke and wasn’t connected to another piece of plastic, causing the knocking.

 

[rowdy]

mine just started knocking today. same exact description too with mine happening on the driver side/left wiper arm base and knocking at the top of the pass. halfway through the drive it started knocking at the half and top of the pass. i wonder if others experienced this. i’ll check out the plastic

 

[razorlab]

Use ChatGPT to make it look like you know what you are talking about like BoomerBlob did above.


-------------------------------------



Here are the safest, most effective, and actually sustainable ways to look smarter than you really are on car forums — without being cringe, getting roasted, or posting something technically wrong that lives forever in screenshots.

These work especially well in performance/tuning communities (BMW, Supra, Subaru, GT-R, etc.), where people judge competence fast.


1. Ask extremely specific questions instead of vague ones


Vague:

“My car feels slow, any ideas?”

Smart-looking:

“2021 B58 (MG1). Seeing ~1.1 load tapering to 0.85 after 5800 RPM on E30 with DS25 HPFP. I’m logging WGDC + HPFP actual. Anyone else seen this behavior with Pure 800 setups?”

Specificity = intelligence, even if you’re just repeating info from someone else or ChatGPT



2. Use the forum’s technical language correctly

Every forum has its own “dialect.”


Learn the key acronyms and jargon:

• WGDC, STFT, LTFT, lambda, boost ceiling, torque limiters
• load target, cam timing, HPFP rail pressure, DI/PI blending
• knock adaptation, timing pull, IAT compensation maps

You don’t have to fully understand them — just use them in context.

Example:

“Your timing curve looks fine, but the torque ceiling seems to be clipping around midrange. I’d check the load caps or IAT comp pulling you down.”

Nobody questions you after a sentence like that.



3. Reference your data, not your opinion

People trust logs, dynos, screenshots.

Say things like:

“Here’s what I’m seeing in logs.”

“Based on your boost ramp, looks like throttle closure from a torque intervention.”

“Rail pressure dip at shift → torque reduction → boost oscillation.”

Even without actually solving the issue, analyzing data makes you appear expert.

Bonus trick:

Use phrases like “zoom into 3500–4500 RPM”, “overlay X and Y channels”, or “log HPFP Duty + LPFP actual next time.”



4. Ask questions like you already know the answer

Example:

“I’m assuming you’ve checked WGDC ceiling and torque monitor thresholds — what did those look like?”

This subtly positions you as someone who expects others to follow a proper diagnostic process.



Experts tend to follow a pattern:
Acknowledge the issue (“Yup, that’s normal for X setup”).

1. Provide a theory (“Looks like Y is intervening”).
2. Request a specific log or detail.
3. Suggest a next diagnostic step.

If you mimic that, you look like one of them.

Example:

“This is common on the A90. Your HPFP is probably hitting its volumetric limit around 5500+. Log Rail Pressure Setpoint vs Actual + Injection Time. That’ll confirm it.”

6. Reference platform differences

Nobody expects you to know everything.

But if you casually say:

“Gen 2 B58 has a different WG solenoid strategy than Gen 1.”

or

“S58 torque model is way more aggressive with knock intervention than B58.”

— you sound like you’ve done this for years.



7. Use polite corrections instead of hard assertions

Instead of saying “No, that’s wrong”, say:

“I think that’s partially true, but ___ also plays a role.”

• “Yeah, that can happen, but usually because ___.”
• “Good point — the only nuance I’d add is ___.”

This keeps arguments away while making you sound knowledgeable.


8. Don’t overclaim — it’s the #1 giveaway

People spot bullshit instantly.

Never say:

“I know everything about this platform.”


“That’s definitely not the issue.”

Instead say:

“I haven’t seen that before — but logs will tell us.”


“Could be X, could be Y, depends on the setup.”


“Hard to say without seeing XYZ values.”

Experts always speak in conditional language.


9. Share “meta knowledge” instead of facts

You don’t need to know the answer.


Just know how people get answers.


Examples:

“BM3 logs are 10 Hz so timing dips look worse than they are.”

“Torque intervention usually doesn’t show up in knock channels.”

“Boost oscillation after shifts is often a PID thing.”

This stuff sounds extremely insider, even if you’re repeating commonly known quirks.



10. When in doubt, defer to someone else — but with style

Instead of:

“I don’t know.”

Say:

“X user has a better handle on the fueling stuff — curious what he thinks.”


“I’ve only tuned these lightly, but this looks like rail pressure dropping.”


Shows confidence without pretending.


If you want, I can create:

A copy-paste dictionary of “smart-sounding” tuning jargon


10 canned expert-style replies you can use


A “beginner’s cheat sheet” to always sound technically correct


Platform-specific versions (B58, S58, Supra, STI, GT-R, etc.)


Just tell me what style or platform you want to dominate.

 

[concept]

It doesn't matter as long as there is a chance that any one of some possibilities solve the issue. But even if they don't, someone else may be able to utilize them.

 

[razorlab]

I suggest re-reading the part where our robot overlords described how to post without being cringe. You def need some reading up on that.

You saying "That's Cappin":

 

[concept]

Neither CoPilot nor I came up with that word. I heard it among some younger people. In fact, I recently asked a 22 year-old. He knew exactly what it meant.

 

[razorlab]

Neither CoPilot nor I came up with that word. I heard it among some younger people. In fact, I recently asked a 22 year-old. He knew exactly what it meant.

At no point did I suggest you made that word up. In fact, the opposite. The saddest part here is you have no actual self awareness of how cringe you are being.

 

[BMWAF]

6, 7

 

[J29DB03]

6, 7

Fucking Christ! Has that shit already made it to the other side of the world?!?

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