1988 420SEL Preventative Maintenance
 

As of Thursday, I will be picking up an '87 420SEL. I am thrilled to own what I believe to be one of the best MBs ever made. The car has 135k miles on it and has not had a new timing chain and chain rails performed, yet. I want to do this, ASAP, and I was curious does anyone know what is the approximate going rate for new chains and rails for the 4.2L ?? I cant get in touch with my indy mechanic for the next 2 days, but want to get the cash ready.

Also, knowing very little about the 126 chassis; can anyone give model-specific recommendations for what preventative maintenance I should do now to make this car into a nice reliable daily driver.

Thanks,

John
'83 300D 398k miles
'85 190E 2.3 152k miles (sitting in the junkyard after dying for me last week in a head-on collision).
'87 420SEL 135k miles (coming this week)

Put a chain in it, service it and check the belts, oil leaks and such.



Joe

Out here in Connecticut the chain, tensioner and upper rails run around $450 at an indy and $650 at the dealer. Look here for an excellent discription of the proceedure:

http://www.pindelski.com/cars/W126/W107_timing_chain/W107_timing_chain.html

Be sure to have the mechanic check the condition of your cam sprockets as well. My chain has been replaced but my sprockets are getting worn, so I'm planning a four day weekend over the summer to do all new upper and lower sprockets, guides, rails, tensioner and chain. Allot of work but only $450 in parts and worth it to me for the piece of mind.

I've been doing lots of smaller tuneups items with terrific results over the last few weeks. Some easy ones that seem to be 420sel issues: all new fuses (easy and a must!), alternator voltage regulator ($15), Idler Arm Kit ($30), AC Monovalve ($30). New transmission fluid and filter might also be a good idea.

Basically anything rubber or plastic and all your fluids should be suspect in a 15 year old car. That said, I've never had so much fun fixing a car before. They're a real pleasure to work on, you'll love it.

Blu420- just curious- why the comment about the fuses? Also, since I have the same year car w/ the same mileage, I'd like to do these small repairs also. Where did you find the info on what to replace?

Hi John,

The fuses were just very easy and cheap. I checked mine and they looked original or at least very old. Also with the 'torpedo' fuses they can often be blown even if they look fine. Several disintegrated as soon as I removed them. It cost $15 and took 15 minutes to do them all. It brought my car back to life, lots of little things that 'sort of' worked suddenly worked perfectly again.

Voltage regulator just screws into the back of your alternator with two screws, just remember to disconnect your battery first.

Monovalve is described well here:
http://mbdieseldiy.tripod.com/monovalve.htm

Idler arm is also easy but requires lifting the car and working on your back for 30 minutes. Made a terrific improvement in handling on the freeway. Its well illustrated in the CD's.

Everyone will tell you to do searches, most of these topics have been discussed at great length. Hope that helps, I'm still figuring allot out myself.

Good luck!

Congratulations on you purchase.

One thing that I would recommend, is that you check oil consumption before you bring it in. Check to see how much oil you need to put back in to bring it to its previous level. My thinking is that since the valve covers are going to be off anyway, might as well take care of the valve seals. (the seals themselves are cheap - its the labor of getting everything out of the way, that isnt)

Eyeball the P/S gearbox for leaks. A leaking box will deteriorate one of the subframe mounts.

Check out your lower ball joints..see if they have been replaced. Tie rod ends will be next to go, after the ball joints. After that, it will be the upper balljoint/control arm parts.


You will have a good time with this car. The backseat has enough room for a threesome. :D

-Larry

Larry,

You've got me looking at my back seat in a whole new way :D