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I've noticed that at long stop lights, drive throughs, or whenever I'm idling the engine temperature is quick to rise. I don't know if thats a natural characteristic of benzes or if there is something wrong w/ my cooling system. It tends to freak me out when this happens and it happens a lot faster when I'm running the A/C.
Okay, if your thermostat and coolant have been maintained, the only thing left is your radiator. Since your car is a W124, the radiator is at least 10 years old. Some of its channels may be obstructed so that coolant isn't flowing freely. Can you consult a mechanic to see if the coolant flow can be determined? Also, what mix of coolant are you using?
I'm probably going to flush and refill the system since its so close to summer. I know you're supposed to use the pink coolant but the car had green coolant in it already so I'll continue using that. I don't want to switch because if you mix the pink and green stuff it causes it to gel. Even if it is pressure flushed I don't want to take the risk of clogging anything up.
In my W124 ('93 300E 2.8), the fan usually engages when the temp gets above 100 celsius. I get those temps if I'm in heavy stop and go traffic on a warm day. Is your car going above 100 in heavy traffic? Or is it happening at long stop lights?
Also, are you using straight coolant/anti-freeze or are you using a 50/50 mix of coolant and water (distilled or de-ionized, not tap water)? For summer use, I like a 60/40 or even 70/30 ratio of water to coolant.
A 50/50 mix of course. I work at an auto parts store and once in a while you'll be suprised at the reaction people get when you tell them you need to add water to coolant. It only occurs during really warm days while at a stop light or the drive through. Other than that she runs like a champ.
It only occurs during really warm days while at a stop light or the drive through. Other than that she runs like a champ.
Geez. So if you were stuck on the freeway, you'd peg your temp gauge? I'd find out what's really going on with the radiator. Also, you probably have that great composite radiator with the plastic ends. I only recently found out that the damn thing requires a neutral Ph coolant that only Mercedes dealers carry. Apparantly Prestone is Ph negative and can eat away at the composite part.
It doesn't really peg all the way. Its the next line above 80 celcious (100 celcius)??? Maybe I'm just paranoid. I might also add a coolant additive when I refill it after flushing. Thanks for the help. If you can think of anything else let me know.
that sounds normal to me. in stop start traffic and or hot days when idling ti can get ot the line above 80 which is 100 C. the fans should kick in. if it stays at 80 while driving then you should be ok.
Just make sure you are usuing the mb approved collant from the mb dealer, any other coolant causes corrosion.
The mb coolant is a pinkish color.
I use one gallon of mb collant and fillt he rest with water. never had a problem with it.
happens to my car too '95 e320.
it also happens to the dealership transports ('94 e320 wagons).
the temp gauge reads close to 100 when stopped, but goes down when the car moves.
note that this is when the airconditioners are on.
Oh sweet! And this whole time I thought something was wrong. Another question, does anyone know where the fuel filter is located on 124s? I normally see it on firewalls of other vehicles but I don't see it on my 260E.
Check your viscous fan.
MB radiators are expensive; don't change it unless you're SURE it's the problem.
When you change your coolant use MB stuff (MB coolant can also be green).
If the thermostat you put in recently had 87o on it then that's the temperature you'll get most of the time.
fuel filter is in a recessed firewall under driver side rear of the undercarriage. Jack up the rear driver side rear tire and there is a plastic housing that conceals the fuel filter, lines and fuel pumps. There are I think three screws that hold this "shield" in place. Once removed you have access to everything. I will tell you, changing the fuel filter without a lift is a dirty, sticky job that I would not do again if a mechanic can do it for $100. You've got pressuized fuel spraying/dripping on you and you're bound to get axel grease in your hair that doesn't wash out for about a week, but hey, that was my experience.
I really would consider flushing the coolant system and putting in the MB stuff. When I bought my car it had the green stuff in it, but I drained and flushed the system and refilled with MB brand. One year later and no problems. 100C w/ air on in stop and go is normal. Should come back to around 80 very quickly once moving though.
I think as they age and parts wear, they do start to run hotter. I replaced a lot of parts in my 300E, but the temp was always around 100C in still traffic. It would sometimes rise a little, and the aux fan would bring the temp down. The funny thing was that my car would hesitate and have rough idle when the temp got that high. I don't know what caused that to happen, but I tried everything to find the culprit. I sold it, and the new owner has NO hesitation or cooling issues. Yeah, I'm puzzled also.
My '91 rises above 100C too in stop and go traffic. I just replaced the fan clutch but it still rises. I read the manual and it says it's normal to rise but not to drive it while in the red...
I use Zerex which is supposed to be comparable to the Benz coolant.
I changed the fuel filter on my mb and it takes like 2 hours but you have to get jack stands! All you need to do is to wait till your tank is almost empty and jack up your car and then lower it on the safty stands remove the 3 plastic nuts under the rear passanger side and there is your fuel filter but what you need to do first is take off the line that is going from the fuel accumulator and put a bolt in it! or something to keep the fuel from leaking. Then and only then you can loosen the two bolt holding the fuel filter (do no take them off) remove the bolt from the front of it and let the fuel drain into a pan and now remove the line from the back of the fuel filter. after this is done install it how you removed it!
ABOUT ROUGH IDLE WHEN THE CAR IS HOT IT WAS PROBABLYTHE TEMP SWITCH
Last edited by YNVDIZW124; May 12, 2005 at 02:37 PM.
A general rule of thumb for cooling, with correct coolant level. Slow speed overheating, usually means lack of airflow.
Fan clutch, fan speed, obstruction(bugs, etc), plugged rad., worn impeller on water pump causing low waterflow at low rpm, slipping belt, thermostat.
High speed overheating, is usually lack of coolant flow (since you have good air speed at 75 mph.)
Plugged radiator, thermostat, slipping belt, suction hose collapsed.
Try 70% water and 30% coolant with some water wetter.
I did the resister mod for the high speed setting on the front fans to come on at 90C. It works awesome. Goes to show these cars have horrible airflow problems at low speed or idle. Im putting on a 16 inch electric fan 2100 cfm for 40 bucks brand new to improve the slow speed temps. The huge stock fan clutch takes up way too much room being so close to the radiator and motor to allow any good flow.
are you all driving with the ac on? mine ( when it warms up ) goes to 81/82 and stays there... but then again i don't like to use the ac as i want to get the most mpg that i can get
I also did a test and let my car idle w/ the A/C on. I noticed that I couldn't get the auxiliary electric fan to activate. What temperature is it supposed to turn on at? If this is my problem could it also be a fan switch or relay causing it or is it just a bum electric fan motor? Thanks for all the input so far.
I know this is an old post but i was just reading through my 1992 300E 4MATIC Owners Manual and found some useful information for this topic, it states right in the manual under coolant temp guage that "During severe operating conditions and stop and go city traffic the coolant temperature guage may rise to the red marking" so from that quote directly from the manual, i would agree that these cars just naturally run hot when at a stand still. Hope this helps anybody concerned or confused by the operating temps.
Check out earlier discussions here on how to lower engine temperature by installing a "cool harness" that forces the cooling fans to operate from lower temperature. https://mbworld.org/forums/e-class-w...l-harness.html
I installed this device for many years on my 1990 C124, and the one I picked (you have a couple of choices; the other device cuts in at 92 degree Celsius) helps keep my engine temperature below 85 degree Celsius, and you can hear the fans cutting in and out while in slow moving traffic.
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