Car overheating a bit and other observations - PeachParts Mercedes-Benz Forum

Ceristimo · #1 05-05-2015, 12:52 PM

So, yesterday I got my oil cooler brackets and all exhaust doughnuts. I put it all on the car, called my insurance company to put in on my insurance plan, grabbed the keys and took it for a lengthy spin. For the first time since I bought in three months ago!

Yes! It still badly needs a wash though. And new windscreen wipers...

Can't say that it was a very relaxing drive. I'm watching the dials like a hawk, and am listening for any weird noises constantly. I'm hoping that feeling will go away as I cover more miles in Ol' Betsie.

So, here are some observations, and I was hoping some of you fine folks could give me some answers. I'll try to be short.

1) Temperature is at 100C. It's on the line between 80 and 120. I'm sure this is way too hot. So I guess a Citrus flush (found a how-to on this website), would be in order? As are a new thermostat, gasket and all that good stuff. Anything else I should do to make the car run cooler?

2) There's a high pitched whistle noise when I'm driving. It's very noticeable in the cabin when going 60 miles an hour and disappears when I let go of the throttle. Is this the turbo, or do you normally don't hear those on these W123's?
3) How much engine braking do these automatics do? I've ever only driven stick shifts, and the first (and only) automatic I've ever driven is my wife's boring Camry. When I let go off the throttle on that thing it just coasts without barely slowing down. Letting go of the throttle on the Benz results in heavier engine braking then my Mazda does. Normal? I would guess it is, what with the high compression on diesels, but figure I'd just check.

Other observations:
I've noticed the car shifts a tiny bit too early perhaps, so I might have to tighten up that bowden cable just a hair. When I first got it it shifted at almost redline, since the bowden cable was too tight, so I loosened it up, but guess I did it just a hair too much.

I might have some electric gremlins. The car stereo just looses power randomly. It seems to be the only thing that looses power though, so it might be the 30 year old radio that's dying. Again, no biggie.

And ehr....These W123's aren't exactly quiet, huh? When cruising 60 mph it isn't that bad, but when you accelerate that big ol' diesel certainly makes it's presence known. I kinda love it, to be honest...

I FINALLY figured out how to lower the seat, so it's nice my head isn't touching the head liner and I don't have to cradle that ridiculous steering wheel between my thighs anymore...

I had planned to take it to work today, but I need to get the engine temperature sorted out first. I guess technically 100c isn't overheating yet, but it's a little too hot for comfort, especially considering it was only 50F out when I drove it last night...

Ceristimo · #2 05-05-2015, 02:40 PM

OK. Just bought a new thermostat, gasket, upper and lower radiator lines and expansion tank cap.
I also bought new copper/ceramic fuses.

My wife hates me now and despises the car... I spend over 500 in parts in less then two months, and still can't drive it. There's nothing as expensive as a cheap Mercedes...

Hopefully I'll get all parts in before this weekend, so I can flush and drain everything and finally start driving it next weekend!

rscurtis · #3 05-05-2015, 03:44 PM

Wait until we have an EMI attack or a large solar storm and your car will be the only one running. See how much she likes it then.

connerm · #4 05-05-2015, 03:47 PM

"My wife hates me now and despises the car"

My wife hates me from time to time, but she's always hated my 85 TD. Everytime it needs a repair, she's hoping it will be a big job and then we can just get rid of it. Silly woman. Any way you can stop letting her know how much you spend on it or just lie? I do both.

That temp doesn't seem hot to me. I'd be happy with my 85 and 95 running there.

Ceristimo · #5 05-05-2015, 03:47 PM

@rscurtis
Well, if that ever were to transpire, I'm sure there would be a few other things to worry about...

@Connerm
Really? 100C doesn't look hot to you? Aren't these engines supposed to run at 80c? I mean, 100c on a flat road going 60 mph with 55f ambient temp. I don't want to know what is going to happen when it has to climb a steep hill when it's 85f out....

Before I bought this car I didn't have any kind of 'hobby' I ever spend any money on. I haven't spend money on anything for myself for years. So I don't feel too bad about it, honestly.

And yeah, she hates the car, but she's not the only one. Apparently not everyone likes these old Mercedes. A good friend of mine called Betsie an "ugly, white old turd". But then he did help me put the drive shaft back in, so it's all good.
My father-in-law was drooling over it though. I stopped by his house last night. He always wanted an old Mercedes. He said: "Oh, it's an 84 huh? yeah, I personally always wanted an '78 300D". I didn't tell him those are the same...

t walgamuth · #6 05-05-2015, 03:50 PM

82 C is normal for these cars. It could have a higher stat in it or the stat could be malfunctioning. Have you checked the coolant level? Looked at the fins in the rad for dirt? Fanbelt tight?

renaissanceman · #7 05-05-2015, 03:59 PM

My '87 runs at about 82-85C under steady highway conditions with the ambient between 30-85F. With the A/C on, it will run a tad hotter, maybe 85-87C. Hit a grade and the temp will climb to near 100C if I'm romping it with the A/C on.

Summer will be telling on cooling system performance. I have a new fan clutch and 11 blade plastic fan installed, and have yet to have the mechanical fan kick on. I just replaced the aux fan temperature switch to the one that will make it come on at 100C (vs 110 stock -- waaaay too hot for my comfort)

Are you up near Fairbanks? The new thermostat may help, just keep an eye on it! I have the 80C one in my engine.

cfh · #8 05-05-2015, 04:00 PM

I recently had whistling on my '83 300SD - same OM617 engine - and it turned out the u-tube to the inlet side of the turbo was a little loose. Tightened it up with 10mm socket on an extension (rather than a screwdriver). No more whistling.

Phillytwotank · #9 05-05-2015, 04:03 PM

Quote:

Originally Posted by renaissanceman

I just replaced the aux fan temperature switch to the one that will make it come on at 100C (vs 110 stock -- waaaay too hot for my comfort)

Can you share your source for that?

renaissanceman · #10 05-05-2015, 04:34 PM

For my W124:

006 545 42 24 (used in M102-3-4 and OM602 engines) 100ºC/110ºC with red top

Parts purchased from Pelican.

Ceristimo · #11 05-05-2015, 04:44 PM

Quote:

Originally Posted by t walgamuth

82 C is normal for these cars. It could have a higher stat in it or the stat could be malfunctioning. Have you checked the coolant level? Looked at the fins in the rad for dirt? Fanbelt tight?

Thanks for trying to help me out! I already ordered a new thermostat. I'm thinking it might be malfunctioning. The coolant level is fine, it's at the line. The radiator is a little dirty, I should probably clean that out a little. Fanbelt is tight. I think. It doesn't squeal.

Quote:

Originally Posted by renaissanceman

My '87 runs at about 82-85C under steady highway conditions with the ambient between 30-85F. (...)
Summer will be telling on cooling system performance. I have a new fan clutch and 11 blade plastic fan installed, and have yet to have the mechanical fan kick on.(...) Are you up near Fairbanks? The new thermostat may help, just keep an eye on it! I have the 80C one in my engine.

I'm very close to Fairbanks. I live in North Pole. What do you call the mechanical fan? The one that is driven by the belt? That one is constantly spinning on my car. I assumed that is what it is supposed to do?
I also ordered the 80C thermostat. I'll boil it in some water with a thermometer to see if the new one works OK, before I pop it in.

Quote:

Originally Posted by cfh

I recently had whistling on my '83 300SD - same OM617 engine - and it turned out the u-tube to the inlet side of the turbo was a little loose. Tightened it up with 10mm socket on an extension (rather than a screwdriver). No more whistling.

Thanks! Mine could probably be a little tighter. Couldn't get a could grip on the clamp with my screw driver, I'll use a socket and extension and tighten it up a little more. So the turbo should be inaudible for the most part then?

Thanks for the replies guys, really helpful. I'm hoping to do the coolant flush etc this weekend.
I have not been able to locate the Zerex G-05 coolant anywhere in town here. The only stuff I can get is the pre-mixed 50/50 stuff, but that won't cut it up here. It only goes down to like -36f, and it gets way colder up here, so I need the stuff you mix yourself. I usually mix it 65/35 (that's what I did on the Mazda and Toyota), which brings the freeze point down to -63f for the green antifreeze that I run in both those cars.

If I can't locate the Zerex G-05 at all (I'm gonna call the Ford dealer in town, see if they have it - some Fords apparently use it as well), then Ol' Betsie will just have to live with the green coolant that my Mazda runs with.

renaissanceman · #12 05-05-2015, 05:31 PM

Amazon.com: Zerex ZXGO51 G-05 Antifreeze - Gallon: Automotive

Same price as getting it locally in the lower 48.

Ceristimo · #13 05-05-2015, 05:42 PM

Yes, except they won't ship that up to Alaska... They can only ship those things with ground shipping. I had the hardest time getting Red Line 75-90 full synthetic transmission oil for my Mazda because of the same reason.

Ceristimo · #14 05-05-2015, 06:13 PM

Ha! Took up the phone again, called a whole bunch of stores...and I was able to find a store that carries the undiluted, full strength Zerex G-05 stuff. Nice! I'll pick up 2 gallons of the stuff and should be good to go for this Saturday.

dkr · #15 05-05-2015, 08:06 PM

Quote:

I'm very close to Fairbanks. I live in North Pole. What do you call the mechanical fan? The one that is driven by the belt? That one is constantly spinning on my car. I assumed that is what it is supposed to do?

The fan clutch is supposed to cool the engine down while idling on hot days in the absence of air flow from driving. I doubt it does much for you in Alaska.

Dkr.