1993 Mercedes 400e, Castrol Edge 10W-40, 5k miles

[userfriendly]

Thank you for that Hessam;

There is more than one empty 5 gallon pail of Delo 400 SAE 40
and it's red-headed step sister, Duron SAE 40 in my garage.

If you look at the add pack of the Delo flavor (as the French
describe choice) and Mobil 1600...WHAM
You see good old fashioned high saps.
None of this watered down CJ-4/SN,
"oh no !!" what about my particulate filter oil.

Another thought, because the above dogs ain't gonna hunt
on this board, is one of the many 10W40 MB 228.51 oils,
which are synthetic. So they must be better.

 

[hattaresguy]

The car is running hot because the radiator is likely original and inefficient.

You should run between 90-100, hitting 105 maybe once in a blue moon but that should be rare. At 105 the electric fans should be on full tilt, if it goes above that you have problems.

The M119 is a bit tight in the W124 engine bay so if your cooling system is not to spec you will see higher temperatures. The fan sensors on these cars can go bad. Make sure when you have the AC on the electric fans come on. Also the fan clutch can fail over time.


I'd recommend replacing the radiator with a new Behr, both hoses, coolant expansion tank and cap, along with the T stat. Flush and refill with Mercedes coolant. At 22 years I'd also replace the fan clutch as they get weak and can leak fluid out over time. If the belly pans are not in place install them, those aid in cooling as well.

 

[hattaresguy]

Originally Posted By: OVERKILL
Looked it up:

OP's engine has two pusher electric fans as well as one large clutched mechanical fan, so a very similar arrangement to a bimmer.

The M119 engine appears to have an air/oil cooler for the engine oil behind the front bumper:

Which is different than what BMW does. The above oil cooler is from an R129 (different chassis) but the same engine.


Yes on the OP's their will be a separate oil cooler, their should also be a T stat in the line if I remember correctly. This will cause an oil pressure drop/temp decrease when it opens.


Typically you will see slightly higher oil temps in traffic because either the oil cooler T stat is closed because your not generating much heat, or their simply is a lack of air flow over the cooler. Running on US roads at legal spends doesn't generate a lot of heat so the oil will cool.

 

[Hessam]

Originally Posted By: hattaresguy
The car is running hot because the radiator is likely original and inefficient.

You should run between 90-100, hitting 105 maybe once in a blue moon but that should be rare. At 105 the electric fans should be on full tilt, if it goes above that you have problems.

The M119 is a bit tight in the W124 engine bay so if your cooling system is not to spec you will see higher temperatures. The fan sensors on these cars can go bad. Make sure when you have the AC on the electric fans come on. Also the fan clutch can fail over time.


I'd recommend replacing the radiator with a new Behr, both hoses, coolant expansion tank and cap, along with the T stat. Flush and refill with Mercedes coolant. At 22 years I'd also replace the fan clutch as they get weak and can leak fluid out over time. If the belly pans are not in place install them, those aid in cooling as well.


That is a lot of work for a 23 year old car. I would just start with a coolant flush with G-05, or MB coolant, and change the thermostats. You can probably do that yourself for less than $50. If they radiator is not leaking, why would you just change it? I still have the original Behr radiator in my 240D, and don't plan on changing it until it starts leaking, or cracks.

 

[Pontual]

Originally Posted By: used_0il
The next time you are at the coin operated car wash,
hit the rad and oil cooler.

The butterfly effect, a math theory simplified;
Too many butterfly in rad make car overheat.

It is not my place to make an oil recommendation,
but if that was my car driving like you (and I)
in that heat, I would use Delo 400 SAE 40.



Butterfly effect Hahahaha

 

[hattaresguy]

Originally Posted By: Hessam
Originally Posted By: hattaresguy
The car is running hot because the radiator is likely original and inefficient.

You should run between 90-100, hitting 105 maybe once in a blue moon but that should be rare. At 105 the electric fans should be on full tilt, if it goes above that you have problems.

The M119 is a bit tight in the W124 engine bay so if your cooling system is not to spec you will see higher temperatures. The fan sensors on these cars can go bad. Make sure when you have the AC on the electric fans come on. Also the fan clutch can fail over time.


I'd recommend replacing the radiator with a new Behr, both hoses, coolant expansion tank and cap, along with the T stat. Flush and refill with Mercedes coolant. At 22 years I'd also replace the fan clutch as they get weak and can leak fluid out over time. If the belly pans are not in place install them, those aid in cooling as well.


That is a lot of work for a 23 year old car. I would just start with a coolant flush with G-05, or MB coolant, and change the thermostats. You can probably do that yourself for less than $50. If they radiator is not leaking, why would you just change it? I still have the original Behr radiator in my 240D, and don't plan on changing it until it starts leaking, or cracks.


A OM616 produces a lot less heat than an M119, the higher HP Mercedes are more sensitive to the cooling system not being right. My buddy went threw this with an S600 a few years ago, the old radiator just wouldn't cut it.

As radiators age the passages slowly get blocked and they lose efficiency, the plastic on the top tank also becomes brittle so eventually that will crack.

It doesn't matter how old the car is, if its in good shape, it can be brought back to factory specifications.


A new E550 is around $80k so spending a few bucks bringing an nice W124 back isn't a terrible investment. A 400E in proper shape still drives better than a late model Japanese FWD car.

 

[Hessam]

Yeah but it's not just the cooling issue... you could do all that work which is going to probably cost more than the value of the car itself, and still have other issues pop up with the car. I think with an older car before you do any work that's going to exceed the total value of the car itself, it's always wise to ask yourself how much more are you really willing to put into the car in terms of future repairs, and how much longer are you realistically expecting to keep the car?

I'm not arguing that old radiators don't become less efficient with time... but I have changed the radiator fluid in my 240D with G-05 every year, and I have not noticed any difference in the engine operating temps from 10, 15, or even 20 years ago. But what I do is after i flush the old coolant I put a running hose of water in the radiator opening with the drain plug out and turn on the engine and let it run for about 5 minutes, or until the water coming out of the drain plug looks as clean as it's going to get. After water looks relatively clean with no deposits, I turn engine off, plug the radiator back and add some fresh G-05. The radiator plastic looks aged on the outside, but inside the radiator it still looks very clean. I don't even see any rust/scales/sludge when I flush the radiator fluid every year.
I don't know if the OP knows the age of his radiator, but I think it's wise to start with the flush and thermostat change and see if that produces any positive results, then go from there. That might be a newer radiator he has, just in need of a some fresh coolant, as coolant does lose it's capacity to absorb and diffuse heat over time as well. I actually like the G-05 better than the MB coolant. I would go with that. Definitely get the OEM or at least OEM brand thermostats. those are cheap.