Goofaroo

I was driving my recently acquired 94 E320 wagon today and parked it for about 30 minutes. When I came back out I noticed antifreeze on the ground under it. I took a quick look under the hood and the level in the reservoir was unchanged. I got back on the road and paid close attention to the temperature gauge. At traffic lights, the temp gauge was going up to the mark between 80 and 120 (whatever that is). It was also a bit sluggish and you could tell that both the electric and mechanical fan were fully engaged. I parked it again and got out and heard a gurgling noise coming from under the hood. I opened the hood and could find nothing leaking or amiss. Possibly just fluid returning to the overflow reservoir?

It was 104 degrees out and I had the AC on. I am not sure that the antifreeze puddle came from my car and I have seen no sign of a leak since. Does this sound like I should be concerned or would it be typical for the temp gauge to hit the mark between 80 and 120? I have been suspicious of the head gasket a couple of times due to an odd smell from the exhaust but I have seen no indication of oil in the antifreeze or antifreeze in the oil.

ptoro01

Coolant dries as a white stain, check around the coolant reservoir, they can crack. The cap is also a pressure regulator, thus could allow a certain overflow to occur.

Goofaroo

I drove it again last night and when I parked it, it started gurgling and coolant ran all over the garage floor. It runs perfectly and I verified with a respected local Mercedes shop that they replaced the head gasket on this car in 2009. I am planning to rebuild the suspension and do a thorough service on this car but now I am concerned about the cooling system. I don't see any cracks in the reservoir but there is a small leak in the overflow tube that comes out just under the cap. I could tell that the coolant was running out from there. As far as the temperature while driving goes, it seemed as though all was well during my drive and the temp never got anywhere near the red zone. Possibly a faulty cap on the reservoir?

It has no sign of oil in the reservoir. Both fans are kicking on and the mechanical fan clutch seems to be in good shape with slight drag when turned by hand.

I would really like to move forward with the suspension work but I am going to have to address the cooling problem first. By the way, it seems to get up to operating temperature very quickly. Is that a common trait of this engine or possibly a hint as to what the problem might be?

I am about ready to scrap my suspension plans for now and order a new radiator, reservoir, water pump, thermostat, hoses, etc. but I'm not convinced that I'm not overlooking an obvious and simple resolution.

Any ideas will be much appreciated.

Shoomakan

Your running temperature seems fine. When it's cool, it's at 80. When it gets hot, it goes up to the mark above it that you mentioned. Anything over that, you should be worried.

If your fan clutch seems fine and there's no water leak anywhere else, and all the coolant is still topped off, there's no need to replace everything. Just find the individual problem.

A good little mod though is changing the electric fans' temperature setup to engage slightly earlier, at around 84 degrees.

QVHK

I had the same problem before as well. Check if the plastic inlet of the reserviour bottle is not broken. If this looks OK, then it is easy fix - the tip of the black rubber tube may have aged and cracked, and/or the holding clip is loose. Replace or cut off the bad part. I do have another problem though. Temperature is below 80 during highway cruising, and just 85 or so in slow traffic. But normally after stopping engine and restarting after a short while, temperature shoots up to 95 and the two electric fans will kick in to cool it down. Temperature drops quickly back to normal after fans kick in, but this situation happens too often lately. I only replaced both electric fans six months ago, as one side never worked. And in the days when only one worked, temperature rarely shoot up as fast. For the peace of mind, I recently replaced the thermostat, but things remain more or less the same. Is this sign of a faulty fan clutch?

Goofaroo

I will definitely look into modifying the fans to kick on earlier. I've done that on a few of my motorcycles with good results. That still doesn't address the real problem though. Granted it is hotter than a habanero pepper fart here in Oklahoma right now but if I am going to make this car my daily driver it is going to have to learn to keep it's cool.

chlippo

make sure there is no air in your cooling system too. all small leaks should be checked and fill it again.

Quicksilver500

When you park it hot, it heat soaks and can cause excess pressure. There is a second coolant reservoir in the right front fender kind of a catch can. If you just filled the system maybe there was too much and its balancing the fluid level out. Could be a bad cap as well. Where is the puddle under the car? Maybe based on that we can give you some more things to look at.

-Mike

Saijin_Naib

With a blown headgasket and no AUX fans working, my car never saw north of about 85C while driving.

Goofaroo

The puddle comes out from somewhere under the right front. I only added coolant after it had already done this once and the level in the reservoir was low. Since I just purchased the car I don't have a history to go by of what is normal operating temperature for this vehicle. However, I also recently purchased my wife a very nice 99 E320 wagon and even in this heat the gauge goes up to a bit over the 80 mark and spends all day there regardless of the driving conditions or being stuck in traffic. Hers does heat up after shutdown and restart but very quickly returns to it's normal temp.

I'm kind of suspecting that maybe I need to do a very thorough flush of the engine in my W124 and possibly replace the radiator. I have no idea how the system has been maintained for the last 17 years although the vehicle in general appears to have been well cared for mechanically.

Shoomakan

I know how you feel. Mine runs fine in daily driving conditions, but when I drive it uphill and hard for 10 minutes, temps shoot all the way up.

It's really annoying.

ksing44

I purchased a coolharness for my car that worked great to keep the running temp lower. I purchased the coolharness from the link below. It simply turns on both fans at full speed at a lower temperature to never let the engine get too hot. I think it saved me from having to get the headgasket done. I went with the coolharness that tells the fans to come on 105 degrees.

Coolharness

Also, I had a bad radiator cap and I was getting a sucked in hose when the car cooled. I suspect something with the cap could lead to gurgling or overflow, since the sucked in hose clearly affected the reservoir level.

Goofaroo

Thanks for the tip about the Cool Harness. I ordered the CH-95, installed it last night, and so far it has worked beautifully. I purposely sat idling for a while with the A/C on and it never got all the way to the 100 mark. Before it would quickly rise above it.

RBYCC

I've had the CH-92 installed on my twin turbo C124 M103 for the past four years.
Performs well, even in 100F ambient temps stay below 90.

The mod can be done less expensive but the Cool Harness looks OEM.

Ed A.

ksing44

Glad it worked out for you. Now that you mentioned the CH-95, that is what I got too. The only small thing that bugged me sometimes, was on some very hot days the fans would not ever go off. That is until I turned off the car. Then I could restart the car and the fans would stay off until it heated up again for the first time and then stay on. Like I said, that was just on very hot days.

I think the temp would more or less stay at 95 and it just didn't drop low enough to let the fans go off on those very hot summer days. I figured the CH-92 would be worse in that regard, but it sounded like I may have been one of the only ones that experience the fans staying on. Don't get me wrong, the fans on was better than seeing the temp sky high.

I really think it did preserve my slightly leaking head gasket from going totally bust. I had the leak for at least 5-years with no issues and no oil in the coolant. I just had a little oil on the outside of the motor and with regular oil changes I never even needed to top off the oil.

zach1328

The mark between 80 and 120 is 100 degrees Celsius, or if you live in America that is 212 degrees Fahrenheit.
In 104 degree weather it is very likely the engine will be running at the 95-100 mark at traffic lights. There is not enough air running through the engine to keep it cool while stopped.

I live in Texas so I have the same deal. While I'm going along on neighborhood roads (30-40mph) it runs at about 90-95 Celsius probably because its slow speeds with tons of stop signs/traffic lights.

Once I get onto the highway (70-75mph) its running in the low to mid 80s. If I pick up the speed more, the temperature seems to drop 75-80 Celsius when I'm going over 85mph (I usually don't go 85 though).
Those temperature numbers are assuming its over 100 degrees outside. When its cooler outside my engine is almost always between 75 and 85.

I don't know what the problem is with the leaks, but I can tell you it is normal for it to run up to 100 Celsius at traffic lights. The W124 engines all run pretty hot compared to other engines.


EDIT:
After you fixed it was it still sluggish on acceleration? My car sometimes has that problem when its 100+ and really humid. When it gets really humid out the air is thin, which could make the car run a little more sluggishly.

Goofaroo

Mine only got sluggish when it got above the 100 mark. Last night with the temperature below that mark at all times it never lost power. I even shut it down for a few minutes to see if it would get hot at restart and it did get a bit hotter but it quickly cooled back down. I'm still planning a thorough service of the cooling system but I think that the harness is a great addition even to a healthy system. I didn't buy the CH-92 because I was afraid the fan would run all the time. I didn't drive it enough last night to tell if it was running all the time with the CH-95 but I figured that if it runs more that I want it too, I will just remove it in the winter.

ksing44

^^ I had no problem with the fans staying on in the winter. It was only on very hot days in the peak of the summer heat. It is true that the combination of cooler temps and keeping the car moving will turn off the fans no problem. It is a good mod. It has to be, Ed has one too!!!