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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53042
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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I have a W210 with M112, and after doing he'd gasket, I need

Customer Question

I have a W210 with M112, and after doing he'd gasket , I need to put the timing chain tensioner back in. Looks like the proper way is to replace it ( which I will), but for this week I need to re use the old one. I know I'm supposed to disassemble the tensioner and then install in three steps ( housing, plunger,spring& cap). But I can't get the thing disassembled anyway. Advice?
JA: Is this your first time dealing with this issue? What size is your engine?
Customer: Yes. 2001 Mercedes e320 wagon. 3.2 liter V6
JA: Are you fixing your E320 yourself? What have you tried so far?
Customer: Yes, initially tried to re install the old tensioner, but as soon as I felt strong resistance while screwing it back in, I backed it out, because I knew something was wrong
JA: Anything else you want the mechanic to know before I connect you?
Customer: My really, I just need to know the proper steps to take apart the tensioner and then install it correctly
Submitted: 1 month ago.
Category: Mercedes
Expert:  Marty replied 1 month ago.

Hi, the tensioner on the M112 motor does not get disassembled like it does on the M104 engine. This tensioner just screws into the housing. You can put the tensioner in a vise to slowly bleed the oil out of the tensioner to make it easier to install. If you install it and tighten it little by little it will also bleed out the oil from the tensioner. Tighten the tensioner to 80Nm.

Let me know if you have any questions. Don't forget to rate my service 5 stars in order for the website to credit me for answering your question.


Customer: replied 1 month ago.
I'm sorry but your wrong on this. I did exactly as you said and pressed out all the oil out of the tensioner so that I could push in the tip with my hands, and then I threaded in the tensioner by hand until it was too hard to go any further by hand, then slowly tightened it with a ratchet.... But then it got extremely tight with 2cm of thread still protruding... It never seated. And now upon backing the tensioner out, I can see that some threads in the female end have been stripped. So your advice was worse than useless, it actually caused irreplaceable damage
Expert:  Marty replied 1 month ago.

My advice is correct. The tensioner on the 112 engine installs exactly as I told you. It sounds like you don't have the chain properly installed. If the chain is doubled up on the crank gear for example you will not have enough slack in the chain to install the tensioner. You need to recheck your chain installation.

Expert:  Marty replied 1 month ago.

Just checking in. Do you need more help with this?