wb6wsn

I'm new to Mercedes ownership, having recently bought a 1987 420SEL (a really big change from my previous 1983 Olds Gutless Cierra 4-banger). The body looks near perfect, it's very clean inside, motor & trans very smooth. It also shows about 177k miles, but I have found that the odometer was rolled back by 100k about 8 years ago, so the real total is 277k miles. So far, I have replaced the flex discs, thermostat, fan belts, engine air distribution hoses and motor mounts. Brakes are almost new, work fine, but sqeak like crazy. Gas mileage running about 15MPG, but I barely passed California smog (high HC). Heater blows air, but air is only slightly heated, temp gauge holds at 80C.

So, considering the age & true mileage, what else should I check? What else might I expect in the near future? Gimme a brain dump to help get me up to speed!

Thanks in advance!
Ed

C43AMG

I would "flush" the tranny - it may have been "serviced" but flushing ensures all old fluid is evacuated from the system.As far as the heater blowingair that is "only slightly heated" , there is a valve in the firewall ( I don't know its correct name) that allows coolant to flow through the the heater core - this is probably stuck halfway preventing you from receiving full heat.I would get this looked at and replaced if necessary ( not expensive).In regards to the brakes - how many miles do the rotors have on them?Since you replaced everything else with regards to the breaks I would look into replacing these also.Sounds like you acquired a nice vehicle,the W126 is one of the best built MB's made,good luck with the vehicle and post some pics when you get the opportunity.

harkgar

go to mbcoupe.com and you will find lots of advice.

harkgar

I gave you the wrong link. Here is the correct one:

http://www.mbcoupes.com/w126index.htm. They deal with coupes but the engine and transmission are the same as in the sedan

Happy resesearching.

BENZITCH

The heat most likely is the monovalve. It is an easy fix, and not very expensive. Usually the diaphrams go and they just don't work any longer.
It is located to the right of the battery, as you face the car. It is not a difficult DYI at all.
Bruce
BENZITCH

Untertürkheim

I don't understand why a "flush" would be necessary. With the pan off and the torque converter drain plug out (proper service procedure) you get close to 90% of the fluid out. Put a new filter on, fill it with Mobil 1 Trans fluid and repeat every 25-30k miles. Keep it up and the trans should last forever.

I would also change the differential fluid, from my experience nobody ever does it, and by this time the fluid in your car is probably burnt and putrid. Again, I'd reccomend the M1 synthetic stuff (what I use). Do this every 50k miles and you'll have a quiet differential forever.

Have you changed the spark plugs, air filter, fuel filter, etc? If your car is having trouble with smog it very well may need a tune up. I've used Bosch Iridium +4 plugs with very good results, better fuel economy and more power. You may hear different opinions though.

The only thing that may present a major issue at this milage would be timing chain stretch (probably time to change it anyway) and head gaskets failing. With proper care though, that car will run forever.

C43AMG

I don't skimp on my maintenance. I would rather spend the extra money to have it ALL evacuated from the system, this allows me to have a baseline for all my future maintenance schedules.BTW - I agree with all of your other suggestions.

Untertürkheim

Glad to hear you don't skimp on the maintainance, in that case, you'll have this car until you decide you don't want it anymore. Perhaps I was a bit shortsighted in my reccomendation though. For this first time, a flush would be very good, (provided the pan, filter, and torque converter drain plug come off anyway). The reason I do not flush the system is that I am running fully synthetic Mobil 1 transmission fluid in it, and I would rather have 50 cl of used (but clean) M1 in my transmission fluid cooler than an equivalent amount of new regular (inferior) transmission fluid that a flush would leave there.

C43AMG

ad4nr

I fill the coolant through the upper right side radiator hose. Air in system seems less likely.

I can't remember where I learned this. I have driven a M-B diesel since 1975.

Jimbo Jim

the mono jet valve reg the temp, when no current on the valve remains open so hot water passing thru, when connected the hot water stops.
being Cal u wanna her not to feed hot water, in vancouver I can live with valve not shutting at all.
yours fail could be the computer control the temp, or cheaper to install copper valve inline, and let hot water in when u want it.