Mblifer

Hi all. I am new to mb. Just bought my first one. 1985 500 sel with 98k on it. This car is beautiful and mechanic owned. The first gremlin I have encountered is that I have no dash,console or shifter lights. All fuses are good . Anyone have some advise on how to fix this?

Also at what milage should I replace the timing chain(s)?

Thanks

alabbasi

Try moving the dimmer dial back and fourth really quickly. The contact may be dirty which will cause this issue.

BENZITCH

Replace the chain now. If it has never been changed, change the rails also. These usually go by miles, and type of use, but age is also a real detriment to the chian and tensioner. You also have the motor that is real expensive to do a valve job on, if the chain were to let go. Just my opinion.

83126

Mblifer

Thanks benzitch. Got the lights working. It was the dimmer riostat, pulled it out small squirt of wd-40 works great.

How can I check the chain. The euro mechanics I bought the car from said no worries yet on the chain because it's a double roller. However after researching everyone agrees 100k is the time to do it. Looks like abt 400.00 in parts. Is it worth pulling the front of engine apart and doing all parts including crank sprocket,or will snaking a new chain in throught the heads sufficient?Car runs like nothing I have ever driven before. It smokes most new cars and turns heads.

Thanks

vdubpower

i think but im not 100percent sure, but u can remove the valve cover to assess the chain and the plastic guide which they say is usually the culprit

heard to the w126 forum on benzworld, massive info on this car there

Mblifer

car runs great now. I'm on the second oil change and the slight tapping from passenger side head has not stopped or gotten worse.

Question , how difficult is it to change a bad lifter?

Mblifer

Checked the chain today............ Looks like its off almost 20 degrees..

Will not be running it until I change the chain. Got lucky this time.

vdubpower

so it was the chain making the noise?? scary

Mblifer

I'm sure that contributed to it. I checked for excess clearance on the rockers/lifters at tdc and they were tight. Guides and rails were good. Changing them anyway.

Talk about a lucky m117 !! There is over an inch of slack in the chain and 20 degrees off. Technically that engine should have blown.

Oddly enuff the cyl heads and valve train are spotless,,,,like so clean the castings look new. I'll post pictures later.


Yeah scary, very scary

Mblifer

Chain is done. Smoothed out the idle, but now no power she is flat. Marks all lined up have a buzzing in fuel lines driverside next to the fd. What is that? Is the sound normal?

Maybe gummed up fuel system? Hope I didn't open pandoras box

vdubpower

not sure what the issue is

the benzworld.org forum on w126 has alot of experts and is very active

BENZITCH

I'm not a mechanic, but did you put the distributor back correctly after doing the chain and guides?

Mblifer

Yes , double and tripple checked ign timing, and cam timing .. Spot on.

Update:
Car will start but only idle. Will not move at all.
Compression test is 150psi in all cylinders (dry)
Put non resistor plugs in...

Here is the odd part. I attempted an adjustment on the mixture
As soon as I did that I developed a massive vac leak.
What would cause this?

Stuck
-airvalve
-throttle switch
-fuel meter

I am sure there is a simple fix on this. Car drove till I adjusted the mixture.

Last thing, the check valve for the smog pump is disconnected and plugged. What would that do?

Thanks, I'm frustrated she is not drivable

RyanRichter

Before you fixed chain slack and degrees, nothing wrong. No power loss or fluttering?

Mblifer

Ran like a champ. The other issues listed after the chain were caused by a 100% blockage in the cats.

She is back on the road and has never run better.

RyanRichter

Good to hear! Nothing like a potato in the tail pipe to keep you in the carport!