Glad to hear you like it, they're amazing cars to be sure .

RE : new monovalve, install the new one and leave it unplugged, you should have more heat than you can stand .

If not, maybe the 'stack' in it isn't correctly assembled, I mis assembled mine once and had weird heat until I fixed it .

Failing that, can't you use the new diaphragm in the old valve body ? .

Dies it smoke at all with that much enrichment ? . 1/16 of a turn is a lot, the ALDA is very sensitive if everything else is good .

By pass the aux. water pump for now to prevent and bottle neck in the coolant circulation .

The armature end of it has a delicate, crumbly white plastic cap you're supposed to remove occasionally and dribble one or two drops of light machine oil into, I've resurrected quite a few of them from junkyards .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

thanks for the info Nate...



the only smoke i could observe was a single puff of black right at a warm start. otherwise, nothing i could see in the rear view with lots of rodding around. it definitely made a performance improvement so the ALDA seems responsive to the change. if my mpg seems low, i'll dial it back but for now with great performance and no smoke, i'm happy.



it's great to hear you've revived a few aux pumps. i'll give that a try if i can get to the dang thing! i see there's a removable firewall panel but it stills seems like a bugger to access.


-dan

I've received far more help here than I can ever repay....

For me an S Klasse is simply TOO DARN BIG but my brother who owns two of them, drives them like Sports Cars in the twisty bits so do go have some fun, they're NOT plodders .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

yes, they're the size of a Crown Vic. my heart wants the look of the 300D, i love the round headlamps with amber inners. but this'll do for my 'starter Benz'. as i was test driving today with a friend, we commented on how long the hood extends out but that with the near vertical windshield, it had great visibility. and i could NEVER own a Benz that didn't have the hood ornament sticking up. nope.


-dan

couple of data points... it started at 16F yesterday after sitting out all night. happy with that. put a boost gauge on it and am running 10psi max. spec is what, 11? not sure of the gauge accuracy (a VDO boost) so i'll just leave well enough alone. drives great on that amount anyway.

the cruise control works but gets twitchy after about 20 miles. i suppose the servo box needs a good cleaning and lube.

the exhaust system is in great shape but i'm surprised at how much growl there is from it. i LIKE it, being an old gearhead, but doesn't seem very Mercedes like. for being a 1,000lbs heavier than my Civic and 5 less HP, this thing moves out pretty well!

If you're happy with it, leave the boost as is .

The exhaust should be dead silent, a growl means either a leak / hole or m ore likely one of the rubber donut hangers broke, allowing the exhaust to touch the body .

IIRC there are 4 of them on this car and you shoud go buy for new 1975 350SL (R107) hangers and replace them all .

The R107 hanger, unlike any other M-B exhaust donut, has a bit of bicycle chain molded inside it so it will never rot and fail....

Someone here will post up the proper part # shortly ~ it begins with 107 and looks different than the normal round donut .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

ok. great info. i've never been in one of these beasts so good to know normal is quiet. i'll check the hangers out when i do trans fluid and filter. it's a really large diameter exhaust on these things!


drove it 125 miles round trip today for work. flawless. it'll be interesting to check mpg tho i haven't been easy on the throttle. it's a fun vehicle to dip your toe into it at 50mph!


-dan

Be aware someone may have modified the exhaust ~ I removed the resonator on my 300CD as I like to hear the engine .

My brother has two W126's, an '81 with the 5 cylinder and an '87 with the 6 cylinder, both were dead silent until the pipe ahead of the resonator began leaking in the '87, he's to cheap to fix it , it's still not very noisy .

Look for fluffy black deposits anywhere in the exhaust system ~ those will be the leaks .

These cars are meant o be driven hard and enjoyed ~ if you're not sure, go watch the movie "Ronin" .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

couple updates....

took the new rubber top off of an MTC monovalve and put it on the old OEM solenoid. works fine but still having low heat issues. bled the system today with vacuum on the small rad hose on the top of the rad but haven't driven it. got about an extra 3/4 gallon into it. earlier had put in a new circ pump but that didn't make too big of a difference. car is up on ramps and the top rad hose pushes fluid now instead of air. i'm sorta wondering if i have a fresh air blend issue going on with my tempid heat.

put new alt-wp belts on. replaced the broken L bolt and missing adjuster. can't believe how quiet the motor is now without the squealing from the old loose alt belts. which of course meant taking off the ac and ps belts. PITA but whatever. at least each system has a threaded tensioner.

-dan

To see if it's the monovalve acting up, turn the heater on, unplug the Monovalve and go for a drive .

You should get roasted out of the car .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

I’ve done that. Still tepid heat.

O.K., maybe there's still some air in the water jacket.....

? Can you lay your hand on the upper radiator hose ? . if so, the engine is running far too cool ~ maybe the thermostat failed and is stuck open .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

test drive after air bleed... warmer but not the way it should be. monovalve was unplugged. my dash temp gauge sits just a tad below 80C, like 78 or 79, rad hoses seem about that temp. is that the normal range these run in cool/cold ambient temps?

-dan

Yes, that's right where you want it .

I'd say time to disconnect the three heater hoses and begin flushing, see what comes out, should / must be an unrestricted flow, I often have to reverse the flow repeatedly to get all the crud out .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

well, i recapped my Temperature Regulator control unit tonite... the silver box on the right of heater fan. it solved all my heater logic woes! it would never act the same way twice... sometimes put defrost on upon startup, sometimes not, temp wheel would work on full hot or full cold but anything in between caused all sorts of wierdness like warm air coming out of the center vents or blow cold when the wheel was in the red zone.

now it works as i *believe* the system was designed... high fan and defrost on start, temp wheel ramps fan speed up and down according to cabin needs, center vents blow cold air when wheel is in the blue and close when the wheel is moved warmer.

i'm still not getting great heater output but i shot all the heater hoses, thermostat housing, and engine with an IR thermometer and it is running 140F despite my gauge saying about 78C. i'll swap t-stats as a first step. it'll be interesting to see where the gauge rests after that.

i have parts to recap several more Regulators and have 2 more coming from eBay that i'll rehab, one i'll keep as a spare but at some point will make the other available.

-dan