*Update*


Did the deed today. Drained the radiator. Pulled the old T-stat and installed new. Here's where I got a little ... unconventional ... After a LOT of reckoning, I decided the engine block plug was a little too odd to get to ... So, I used my MityVac, which has very long, thin hoses. I shoved the MityVac's hose down the hose running down from the thermostat and pumped out about a quart. Then I pulled the hose near the front of the engine on the driver's side (above the oil filter), inserted the MityVac hose and pumped out about half a quart more. Total removed from pulling the radiator plug and the bootleg MityVac method: 11.1 quarts. I used an airlift and my compressor and put in 11.1 quarts. Ran it for a good ten minutes with the heat on, then went for a drive. Heat got nice and hot. Gauge stayed right around 82C. Sat at stop lights. Ran it a good half an hour. Stayed right at 82C.


Phew.


Thanks for all the advice. And yeah, I was a wuss to not pull the block plug but it would seem the MityVac extractor got a lot of it.


Good thing, too ... it was nasty green coolant. No rust, though. Very encouraging.

Good deal ~! .

Me , I'da flushed the beejeebers out of it but as long as all is well , you're golden .

__________________
-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 hear ya, but doggone if the coolant removed wasn't pure green. Previous owner was stickler for maintenance. Radiator looks too new to be original. But it's got the correct fluid and fluid mixture in it now, with a new radiator cap and thermostat.


2470 mile trip, here I come!



(Again, worry more about my wife ... she's driving an ML)

That was actually a pretty smart idea with the MityVac! Kudo's to you.

Me, I just undid the drain plug from the bottom (it really isn't that hard) and was treated to an unexpected coolant-shower. I had expected it to come out quick (like how it is when you drain your oil), I just hadn't expected it to come out that violently and splash literally everywhere.
I was wearing safety glasses so I didn't get any in my eyes, but I got a big gulp of it in my mouth. I didn't swallow, but dear Lord, anti-freeze tastes disgusting. Yuck. I've heard that animals like to drink anti-freeze because it's sweet tasting. Well, whatever was in the Benz was bitter as hell!
Also used a whole roll of paper towels getting the garage floor cleaned up again. It was pretty bad.

Doing it your way with the MityVac certainly is a lot cleaner! Have fun on the road trip!

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

I thought I'd already posted my solution but I didn't find it - pics in my build thread.

I remoted mine to the RF wheel well with parts from our Parker store and a length of their good flexible hose. There's a 1/4 turn ball valve right as it exits the engine bay (remember this is in an S-10). Put your drain pan in the appropriate location in the wheel well and turn the valve - coolant drained. Remember to remove the radiator cap or it'll stop in a minute.

I guess you know that the block drain is located on the passenger's side right under the turbo - impossible to get to if the turbo is hot and darn hard to get to even on a hoist with a cool engine. Well worth the effort to make up the remote if it's something you'll do more than once. I have to do mine several times a year as the racing association wants us to run straight water (though a little water wetter is OK).

Dan

I removed the block drain plug from both my 300D's in the last year or so, when switching to Evans Waterless Coolant. Did both from the top, w/ long 1/2" socket extension, w/ one arm between heater tube and shock mount and other arm from alternator, if I recall. Came out fairly easy. I just polished off the copper washer on sandpaper. No leaks, though the new coolant doesn't build much pressure. Neither engine has the top-mount air cleaner, so easier access.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Most modern coolants have the bitters added , called ' toxgaurd ' because pets and Children both like to drink it one once ingested , you're going to DIE .

The remote drain valve sounds clever .

The Mity-Vac is nice but , it WILL NOT remove the accumulated sediment so important to remove .

I hope all here know to always have the heater on full hot whenever you're flushing / changing coolant and the Mercedes split core/matrix design traps a lot of old coolant in it .

I am not familiar with waterless coolant , what's that ? .

__________________
-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

Nate,
I don't know exactly what Evans contains today. People say the earliest versions were pure propylene glycol, which is safe since used as a food additive. I used their latest (NPG+, I recall). Regardless, I wouldn't drink it. Some say you can go cheaper and use straight anti-freeze w/ no water, some saying a newer "environmental" coolant is pure p.g., but I haven't seen it in my local auto parts. I suspect there is a reason Evans exists, so wouldn't be too creative. I buy Evans on ebay ($42/gal). Slowly converting all my vehicles to Evans. I recently did my wife's T&C minivan which has rear heat, so more involved. I also changed all rubber hoses to silicone. I always flush well w/ citric acid and pull the block plugs. Several episodes of Wheeler Dealers showed Ed China installing waterless coolant (didn't name the brand). Jay Leno swears by it in his fleet, especially hs older vehicles w/ rare cooling parts to protect. In my 300D's, my goal is to never have to pull the heater cores (very hard & expensive).

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Thanx Bill ;

I'm always interested in learning new things .

One of my first Diesel Coupes was a N/A that had been allowed to sit for several years with tap water in it after the Evil Servo cracked , it rusted out the water pump , welch plugs in the block and all those damn steel tubes used to pipe the coolant around under the hood , the alloy thermostat housings (both) , the radiator and on and on.....

When the heater matrix developed a pin hole leak that would grease up the windshield in less than 24 hours , I gave up .

it never ran hot nor overheated , not even in Death Valley with the AC (yes , I learned how to make Evil Klima I work well) cranked up all the way so I used the non pressure radiator cap from a '49 Chevy and sold the damned thing at a dead loss ,the next owner thought it wonderful .

If it's o.K. , I'd like to hear everyone's comments and thoughts on various coolants and why .

__________________
-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

So strange (but so like the experience of others). The temp gauge needle jumped up suddenly to around 100C after driving awhile. Heater operates fine. I verified the fan clutch is okay (stops dead quick when I kill the engine at operating temp). So, I've been measuring the thermostat housing, hoses and block with an IR thermometer. All the IR readings are fine ... 80ish on the block near the temp sender, mid-70s on both sides of the thermostat housing, 70s on the top radiator hose, 50C on the bottom. Scanned the radiator and all readings seemed fine. There is one spot on the starboard side of the block that reads in the 90s, but it's on the opposite side of where the sensor is.

Finally, I smacked the damn dash above the instrument cluster. Viola, the temp gauge dropped back to the halfway point it seems to consider "normal" (even though the IR actually reads cooler temps).

So is this possibly a buggy instrument or sender? I'm not getting any troubling readings with the IR and the fan clutch seems fine.

Is it possible that, even though I used an airlock to refill and have burped uphill once or twice, there is still a little air in the system?

Is it normal for the starboard side of the block to be warmer than the portside (where the sensor is located)? I believe this is a general truth about engines ... but it could also be a bad info.

Thanks for any advice.

Usually, when a temp reading moves fast (<2 sec) it is an electrical problem since the actual temperature can't change that fast. If you have a vapor or air pocket, the temperature at the sensor can change quickly (say 5 sec).

You can get air at the sensor. A few years ago, after filling one 300D w/ new Evans waterless, after 10 miles on the freeway, I noticed the temp gage quickly going off-scale. I pulled over, while my wife fussed about the new coolant not working. I found the reservoir empty and added more coolant (expected it would drop as air purged out), then the temperature quickly dropped to normal. I don't think the whole engine overheated (didn't seem terribly hot), so I think there was just a hot air pocket around the sensor (driver's side of head). In the 617 engine, driving will eventually move air bubbles to the reservoir. Driving the front up on ramps helps, though probably not sufficient until the T-stat opens.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Thanks, Bill. Just jacked the front up again and burped it for 20 minutes with the DEF on full blast. Topped off a tad. Was already very close to the line from a previous top up. Brought the idle up. Took IR readings every which way. The needle on the gauge stayed relative static just above 80C once warm. The readings with my IR around the temp sensor between the cylinders on the portside of the block read around 78 - 80C. Same where the hose from the heat core meets the block. The vents in the car were blowing a staggering 68C (again, in DEFROST mode on full blast). Pleased with all the IR readings. Starting to think maybe it was a little air and, or (as it could be both) a jumpy gauge or bad sensor. The damn car itself seems to be solidly where it should be with the IR.

Same thing ... Needle suddenly jumps up from 90 to 100 while driving. I hop out and measure with the IR on the side of the road. 82C on the block by the sensor. 77C at the thermostat housing. Hoses all reading fine.


But the weird thing is the starboard side of the block (under the thermostat housing, on the opposing side of the injectors and temp sensor). There's one spot that does read about 105C. Is that just part of the circulatory system? Any ideas? Again, this is on the opposite side of the block from the temp sender and injectors.

Really feelling like a buggy gauge though. I smack the dash, and it drops back down. I smack it again, it pops back up. IR readings say all is well.

Uhhh ... I just realized the one hot spot I was finding on the starboard side of the block is near the turbo. Duh.

Anybody got a part number or good suggestion for a replacement temp sender?

Smacking the dash and the gauge changing means the trouble isn't in the sender.....

I'd take the binnacle out and clean all the connections , usually it'll be a ground path issue .

It's a simple thing to add a brown wire from the gauge cluster to the unibody , ensuring perfect grounding in spite of poor solder joints etc.

__________________
-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