HELP Spark Plug #5 is stuck
07-11-2024, 01:59 AM
#1
Senior Member
Thread Starter
HELP Spark Plug #5 is stuck
I have a 09 ML 350 wiith 270k miles.
I need help removing plug #5, the car is not shaking vigorously ( back fire)
Any suggestions would be appreciated. I don't want to force it and brake the plugs.
I need help removing plug #5, the car is not shaking vigorously ( back fire)
Any suggestions would be appreciated. I don't want to force it and brake the plugs.
07-11-2024, 08:49 AM
#2
MBWorld Fanatic!
You're saying that you've removed the boot and the spark plug is seized? You might try running the engine for a couple minutes to see if warming the block helps. A bit of penetrating oil at the plug base might help (wick up any excess with a paper shop towel before pulling the plug out).
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Joshinator99 (07-11-2024)
07-11-2024, 01:50 PM
#3
Senior Member
Thread Starter
You're saying that you've removed the boot and the spark plug is seized? You might try running the engine for a couple minutes to see if warming the block helps. A bit of penetrating oil at the plug base might help (wick up any excess with a paper shop towel before pulling the plug out).
**Update... a little online research said DON'T use WD-40... They suggested KROIL.
I'll gt order one now.
thanks
07-11-2024, 07:36 PM
#4
Senior Member
Kroil
Definitely use Kroil and soak the area. Slowly start out then back in … back and forth applying more Kroil it will get in the threads and work. Hopefully the plugs have been changed in the past.
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Joshinator99 (07-11-2024)
Yesterday, 03:25 PM
#5
MBWorld Fanatic!
Try a heat gun to heat the plug.
Do not remove plugs from an aluminum head on a hot engine, EVER!
Aluminum heads you gotta go slow. After soaking for a few days with the
Kroil, move the wrench back and forth to try to work the penetrating oil into the
threads, start small tiny movements. Too much, and you'll take the thread with the plug.
Gradually work the plug out, and with every counterclockwise turn, turn it back
again partially, working the penetrating oil into the plugs.
I actually had to do this recently on my wifes 06 ML350. I didn't use Kroil and
I only waited a day. I found out about Kroil in the W211 diesel threads.
They have an issue they call the black death where the injectors get baked in with oil
that turns to asphalt more or less. And Kroil is apparently the penetrating oil of choice.
I bought some (expensive and not available locally) but so far have not used it.
Eventually you'll get it out. I also said a prayer while doing it.
I had a plug work itself loose once and fly (kabonk off the inside of the hood)
out at 55mph in a 70's Toyota PU. Searching in the dark on a rural road, I got so lucky.
Plug was resting comfortably on a bumper bracket. Threads were f'd. I forced it back in,
drove home, and later added a helicoil. Only problem when I went to change the plugs next time,
the helicoil stuck to the plug. So I bought another one.
Do not remove plugs from an aluminum head on a hot engine, EVER!
Aluminum heads you gotta go slow. After soaking for a few days with the
Kroil, move the wrench back and forth to try to work the penetrating oil into the
threads, start small tiny movements. Too much, and you'll take the thread with the plug.
Gradually work the plug out, and with every counterclockwise turn, turn it back
again partially, working the penetrating oil into the plugs.
I actually had to do this recently on my wifes 06 ML350. I didn't use Kroil and
I only waited a day. I found out about Kroil in the W211 diesel threads.
They have an issue they call the black death where the injectors get baked in with oil
that turns to asphalt more or less. And Kroil is apparently the penetrating oil of choice.
I bought some (expensive and not available locally) but so far have not used it.
Eventually you'll get it out. I also said a prayer while doing it.
I had a plug work itself loose once and fly (kabonk off the inside of the hood)
out at 55mph in a 70's Toyota PU. Searching in the dark on a rural road, I got so lucky.
Plug was resting comfortably on a bumper bracket. Threads were f'd. I forced it back in,
drove home, and later added a helicoil. Only problem when I went to change the plugs next time,
the helicoil stuck to the plug. So I bought another one.
