So I let my engine idle for about an hour to get some air pockets out after changing the thermostat gasket.

when it was super warm, it started making this sound

https://photos.app.goo.gl/WyzkFdZaRh2FFNSa8

after I turned it off, and let it sit for a couple minutes. I restarted the car. The noise was gone. But slowly started to come back again.

https://photos.app.goo.gl/A1n3zof2TuG5vNpJ7

my diagnosis was low oil. But I just changed the oil, and the oil stick doesn’t say to add. It’s 10w-30, so maybe it’s too thin? My other though was the oil pick up.

father listened to it, thinks it might be the clutch/something in between the engine and bell housing.

I appreciate your help as this is causing me some anxiety.

 

You have to post the URL as a "link". Here's your second URL link...I'll grab the first for you in a minute. I haven't listened for any diagnostics.

https://photos.google.com/share/AF1Q...c1ZjZILUQycG13

 

Here is your 1st URL link...

https://photos.google.com/share/AF1Q...hqLUhNRm1yNVpR

 

I'd suggest removing the bell housing (transmission) cover then listen. Could be loose flex plate bolt, could be flex plate hitting starter? Remove the bell housing cover and have another listen and you can visualize a little better.

 

Is this thread related to the same thread you posted earlier in November?

Weird engine noise under quick load. (Video links)

 

I think this is what my dad was saying to do too. Remove that cover underneath and look.

however, isn’t it weird it only happens when the engine is super hot?

thank you for reposting those links

 

With this noise, retarding the engine timing fixed it. Although you’re right, it was in the same area.

 

You really need to remove the cover. With a bright flashlight, determine if you see any suspect bolts which are loose, turn the flexplate and evaluate for any cracks in the flexplate all the way around 360°, and evaluate if you can see any hitting of the flexplate against the starter pinion/bendix, etc.

 

Will do, I'll get on it this weekend and check the flywheel. Thanks for the input.

 

You have a manual (flywheel) or automatic (flexplate)?

 

i have a flywheel.

 

What year, model, engine and transmission are you working on?

Does depressing the clutch stop or change the noise?

 

Sugar Bear - Good questions. I was going to get back to this thread, but the eyes began closing. 😴💤

 

good points. I’m currently driving it to the gym and back now and no noises (not hot enough)

1969 442, g block 4 speed M21

 

I listened to both videos - again. Pay careful attention to two sounds, actually. (1) Listen for the constant raspy/sandpaper sound/noise; which is in marked contrast to the (2) clunking sound. I would suggest the throw-out bearing is bad or the retainer is bad. The constant raspy/sandpaper sound is metal-on-metal, IMO - reminiscent of a bad throw-out bearing free-wheeling. A throw-out bearing should not free-wheel...there is supposed to be friction in that bearing.

 

My experience is the throw out bearing, Norm got it.

 

Thanks guys. I’ll do some research on that. Any advise on making that an easy job and replacing other things while in there?

 

Can’t really make any suggestions w/o more information such as clutch travel, spongy vs. hard & firm, slippage, mileage and basic visualization of the retaining ring & release arm. R&R of a throw-out bearing is straight forward and requires only moderate skill level.

 

I mean I’d be the last to suggest you ‘need’ a new pressure plate &/or clutch assembly just because you’re replacing a throw-out bearing.

 

If you’re having any issues shifting into/out of gears now’s the time to mention any issues.

 

Has the transmission oil level and oil condition been checked?

 

I have been trying to crack the square 9/16 nut on that M21 for 2 days now. I’m waiting for a socket to come in as it’s bent 2 wrenches already with a breaker bar. But that’s what led me to finding this noise, as I was under there working on that bolt.

 

I drive it often. No issues shifting. Sometimes finding reverse. But nothing patience doesn’t fix.

I feel like it should have more power to the wheels, the way it idles and Revs in neutral. But that’s about it.

 

Put penetrating oil on the plug while waiting.

 

That's unfortunate. Clem Kadiddlehopper must have installed that bolt. No reason that plug needs to be tightened w/ such force.

 

^^x2^^ Soak that plug.

 

Got the plug out.

I put a pump in the hole and down into the transmission and couldn’t get much fluid pumped out. I thought it was empty. Then I started pumping new fluid in and it immediately started leaking.

I wonder if the old fluid is super thick!

I might drill out the bottom and put a drain in while it’s in the car.

 

I'm completely at a loss. What do you mean "..it immediately started leaking". From what location is it "leaking"?

 

Not that I was thinking of your "leaking" issue the past three hours, but I stopped on occasion thinking where a leak would be coming from. Are you talking about transmission oil running out of the fill hole when you fill the transmission w/ oil? Is that what you mean by "leaking"? I would not consider that a leak (if that's what you're talking about).

I don't believe a 4-speed M21 has any serviceable oil requirements. It is a sealed system & does not require servicing unless for obvious reasons the transmission innards need to be worked on and transmission removed & drained. Albeit, there's no drain plug on an OEM M21. Aftermarket units yeah, some have designed an oil drain plug.

Your system, and only because you choose to do do, should only require siphoning out as much fluid as possible and refilling to the top of the fill hole. That's it - done. If you're siphoning cold transmission fluid, yeah, it's going to be much more viscous cold than hot. So, take it for a drive before you elect to siphoning out any oil.

Regarding drilling into the casing to insert a drain plug. IMO, you're placing yourself at risk. Yeah, "maybe" the casing metal you're drilling out "might" fall out with the oil as it drains; but, then again - maybe it won't. If you seriously elect to do this, I'd use a really good strong magnet which can bend 90° to capture any residual metal filings you know you're going to leave inside the transmission housing. I just don't see the benefit.

 

I would not drill out the bottom to put a plug in. If the transmission has to come out to replace the throwout bearing then stand the transmission on the tailshaft to drain it. If there isn't a drain plug or it is stuck/seized try removing the fill plug and the lowest bolt on the shifter cover to drain some fluid.

To Norm's point about no service intervals, if the oil you were able to extract looks ok then leave it alone.

 

it started leaking from the fill hole (as in, it’s full, time to stop putting fluid in)

 

that sounds like a good idea. If I have to take it out, I will at that point.

 

OP hasn't stated number of miles on vehicle. Getting back to the real issue which wasn't removal of the trans. oil filler plug, it's most likely going to need at a minimum a new release (throw out = TO) bearing. Under normal, daily driver usage you'd expect a clutch assembly (including TO bearing) to last ~60k - 70k miles. The only time a TO bearing really gets any wear is during engagement/acceleration from a complete stop. How often that has occurred & to what degree is a complete crap shoot as no one can predict how the vehicle was driven by any PO. If any PO was pulling some tasty hole shots with that clutch, you can rest assured you'll need a new clutch assembly. If the TO bearing is worn on a 1969 4-speed M21 you should insist on replacing the complete clutch assembly & resurfacing the flywheel (if not replacement of the flywheel). Take the car to a reputable transmission shop with classic car transmission experience & get some estimates.

 

BTW, to impart any significance to the issue at hand, if the TO bearing disintegrates you know you're dead-in-the-water, right? Plan on walking & having the car towed. Not trying to impart terrible news, but preparing you for the worse case scenario - you will not be able to engage or disengage the clutch w/o a TO bearing.

 

Then you drive it home without the clutch and fix it in the morning. Has nobody else ever had to drive a stick without a clutch before?

 

Yes, I have. Whatever.

 

Have you noticed that you have as many posts in this thread as everyone else combined?

 

Yes, I have. And I have driven home with only reverse and 4th gear.

 

You've contributed ZERO to this thread.

 

I rolled a '68 VW bug twice over sideways and once over end-to-end. Trans stuck in 3rd - no clutch. Drove it 30 miles home and parked in front of my folks yard. Mom was alarmed. Popped all the windows out, roof crushed had to exit via the windows.