Siezed Plugs

[DAMIEN]

Have just bought 1997 E320 estate and left car with mechanic for service he could only remove two of the 12 plugs,said he was afraid they might snap.Any ideas
on how to remove the the other ten?

 

[television]

An alternative to heat is to freeze that works in the same way but the opposite

Henkal's make a range of these freeze and release agents.


When removing tight objects,its no good just pulling on the spanner as it will just bend or snap the plug. Shock is what it needs, maybe a wheel nut impact driver would do the job if there is room, other than that, freeze the plug base and use a snapping / jerking action with the spanner

 

[Uncle Benz]

Or try getting the car fully hot before trying.

This is sadly quite common these days, as manufacturers try to extend servicing intervals. Some say plugs last 40k, some even 60,000 miles. It's not suprising some of them are reluctant to budge.

Having said all this, I have never had a plug I could not remove from a Merc. I have had plenty break off in Ford Ka and Fiesta no matter how they were treated prior to putting a tool on them.

Maybe get a second opinion.

 

[hmang]

An alternative to heat is to freeze that works in the same way but the opposite

Henkal's make a range of these freeze and release agents.


When removing tight objects,its no good just pulling on the spanner as it will just bend or snap the plug. Shock is what it needs, maybe a wheel nut impact driver would do the job if there is room, other than that, freeze the plug base and use a snapping / jerking action with the spanner

got to disagree with shocking /snapping / jerking on seized spark plugs.

the threaded section is essentially a tube, and once you account for the depth of the thread, the wall thickness is not that fantastic.And the part where the washer goes is thin too.

i think air tools or electric rattle guns are dodgy in this application

i'd run or idle the motor until the max temp is reached, maybe also use some of malc's freeze spray on the metal plug base.

a deep socket that will clear the porcelain part of the plug but is too small to fit the hex nut section will bear against the top of the nut section.
you could hit this with a hammer to shock the plug and loosen it in the thread.

probably repeated combinations of all the above

once the plug is moving try tiny back and forth movements to clear the thread as you go and plenty wd40 or similar.

 

[BlackC55]

second that

 

[Ron Palfrey]

Give a good soak in PlusGas first

 

[DAMIEN]

Thanks lads will pass on your good advice.