Rauhbatz

Greetings MB Forum posters...

Im getting ready after 60K miles (total mileage 199K) to change the spark plugs in my 1991 190E 2.3.

Any tips on selecting new plugs and changing them? The plugs are buried pretty deep in the cylinder head so I was curious if I need a thin-walled socket to loosen them.

As they have not been changed for a while, Im also considered putting a little deep penetrating lubricant on the plugs and let it sit overnight before I take them out the following morning.

Any steer from fellow 190 owners is welcome!

Gullwing

I am not sure what plugs I have (just ordered them from a Mercedes website).
Careful the head is aluminum and it gets messed up very easy.
On mine cylinders one, two, and three are fine. I am not sure if I ever want to remove number four anymore. Just changed them a few weeks ago and the threads are pretty much toast.

You don't need a thin wall socket.

Rauhbatz

Indeed one has to be careful with an aluminum head...I'll put some deep penetrating oil on them to help with taking them out.

Not having a mechanics guide is the #4 cylinder at the front or the rear of the motor? I would think the plug nearest to all of the heat (the front) would be the toughest to remove.

Pasha95

For the future if you decide to check the plugs and reinstall them be aware that it's very easy to crack the insulation when you remove the plug wire(s) with their long connectors. MBZ makes a tool that looks like a pair of long nose pliers with an end that grips the connector and makes removal very easy. Just a little bit of trivia FYI.

Rauhbatz

I just completed changing out the plugs. Due to the tight confines I used my plug socket and extension to thread the new plugs back in.

Great tip about the insulator and removal of plug caps. My number 1 spake plug insulator broke off a piece upon removal using channel locks to remove the plug lead. I noticed it missing, looking in the plug tunnel and found it there. I puilled it out with some needlenose...that would have made for a nasty bit if it went in the plug hole.

These old plugs were in there for maybe 60K+ miles; I can't remember when they were last changed. Guess that's what happens with good machinery!

It purrs like a kitten; instant start, nice idle, smooth rpm, Can't wait to see the effect it has on mileage.

300 mi to go till 200K total miles!

Thanks to all respondents...no need to look at new cars the way this vehicle is running!

Gullwing

Number one is up front, number 4 is in the back.
On V engines number one is on the passenger side.