AFTER it gets dragged up and down the cylinder walls. Usually causes no problem when it's loose but using compressed air can force it into any gaps of the rings, valve seats, etc.

Your car, your money.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Thanks for the clarification....makes sense just to stick with the brushes like MB recommends.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 179k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 77k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Where did you purchase your brushes?

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1991 350 SDL, 2006 E320 CDI

https://www.amazon.com/Cleaning-Brushes-Washing-Cleaner-Bristle/dp/B073DZTW6T/ref=sr_1_2?ie=UTF8&qid=1508204885&sr=8-2&keywords=cylindrical+brush+kit

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 179k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 77k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Put this on your Xmas/wish list.

https://www.shopvac.com/product/shop-vac-5-gallon-4-0-peak-hp-hardware-wet-dry-wall-mount-vac-catnum:3942300

Handy to have and it's one of those things you wonder how you did without. Keep an eye out for specials. I picked mine up for $39.95 at Ace Hardware during one of their spring special savings deals.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

I actually have a shop vac...what I wasn't clear on was to how to rig attachments in such a way as to get down in the hole.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 179k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 77k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

https://www.amazon.com/dp/B00002ND4G/ref=asc_df_B00002ND4G5214320/?tag=hyprod-20&creative=395033&creativeASIN=B00002ND4G&linkCode=df0&hvadid=167152075853&hvpos=1o1&hvnetw=g&hvrand=5379488591468865278&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9030238&hvtargid=pla-273189514049

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Excellent....thanks, Mike!

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 179k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 77k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

That Amazon kit may not be small enough to get in the hole. I use a hose or tubing small enough in diameter and duct tape it to the large vacuum hose. Works every time.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I use a series of rubber hoses with duct tape wrapped around the end as a seal ring. Wrapping a few rounds of tape on a 5/8" hose makes it fit tight into the vac hose. The tape forms a really good seal which isn't necessary but it is quite efficient.

I never blow anything into a cylinder on purpose. I use heavy grease on the reamer when I do glowplugs. Most of the carbon comes out then.

Turning the engine over after reaming glow plug hole blows most of what the greasy reamer misses.

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84 300SD
85 380SE
83 528e
95 318ic

Exactly what I did, worked great.

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Brian
87 300Dturbo 180K #14 head still running R-12 SOLD 12/2017
02 F350 Powerstroke 180K
05 Chevy Express 1 ton w/Royal Utility box 120K
08 Infiniti FX-35 40K
15 Golf Sportwagen TDI 35K
10 Sprinter 3500 chassis with a Class A Winnebago on it. 56K

Turning the engine over after glow plug reaming could possibly suck in some carbon during the intake stroke with some of it landing on/ stuck to valve seat. Safest bet is DO NOT turn engine over and use grease on the reamer then vacuum the rest out.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked