Joseph_H

In my 95 E420, the temp gauge runs over the 100 mark when the outside temp is over 90F -especially when I use the A/C. This is my first time owning a benz and was told that Mercedes (in general) read high temps on the temp gauge. Japanese cars I’ve owned barely go to the 1/4 the way on the gauge during the hottest weather (I live in Houston).
Just had the cooling system flushed at the MB dealer. I also made sure the coolant mix is at 50/50 ratio.

Any advise or recommendations will be greatly appreciated.

patrick

Maybe it is your A/C-condenser that needs to be cleaned (it gets too hot and then your radiator too), or maybe your extra A/C cooling fan(s) do not work?

Joseph_H

The Aux fans do kick in once the temp gets to the 100F mark.
I didn't know that the AC condenser could cause radiator heat.... I'll check with dealer on that. The temp goes up at times even with AC not on. It just happens sooner with AC on.
Thanks.

patrick

Just make sure that the space between condensor and radiator is free from dust and dirt.
Does the radiator fan work properly?

pocholin

Time for a cooling system clean up, change fluids, etc.

Joseph_H

Yes, the radiator fan seems to work fine. It runs when engine is running! I will make sure things are clean between the condenser and radiator. Thx

a2aa

CHECK THIS WEBSITE OUT.. MOST 94 AND LATER MODEL 8 CYL heat up in normal driving conditions. The earlier suggestions are great but, if these things are all checked out and still the temp goes over 100-105, Jim F has the perfect solution for you. I do have extra resistors if you are interested. Go to it first and read it carefully. I have a 1994 sl500 which doesn't take long to heat up here in texas. With the resistor inplace. cool as cat baby!!

click here: http://pages.prodigy.net/jforgione/MB_S500.html


Regards

a2aa

GO TO ARTICLE 17: auxiliary fan
on jim F's page
good luck!

Joseph_H

Thanks...
Did you try the Cool Harness yourself? Which model did you get (CH-92, 95 or 98??)

I've read the article and with my previous experience as a technician, i can make the modification myself once i get the correct resistor. The only "concern" I have is that during summer time, the temp stays well in the 90s which means the aux fans will very much stay on almost all the time or at least the most of the time.

mdp c230k

The 92 in the part number refers to degrees celcius.

Joseph_H

I realize that... I meant that once the weather temperature is in the upper 80s or in the 90s and with the A/C on, the temp gauge will be well up in the 100C range... with stop-n-go traffic it could get close to the red. with the modification in the article above, the aux fans suppose to kick in around 92C or so (for the CH-92 model) which means with the above hot environment, the fans will work much longer and extra hard... this may not be a big deal, but just a concern on what the work duration these fans were made to last.

mdp c230k

It's a trade-off, very expensive engine vs much cheaper fan. The fan should last many years running every time the car is turned on. If mtbf is a very low 5000hrs and you drive 2 hours every day it will last over 6 years!

Joseph_H

I agree 100%. There are many ways to look at it. Bottom line.... heat is your engine's enemy... my friend just bought a 2000 S430 and he complains about his temp gauge going close to the 100C mark in a relatively nowadays cool weather. makes me wonder why MB don't do something about that... I read somewhere that they claim it is okay for the temp to get up there...sorry not in my book... High temp = low engine life besides all that plastic and hoses in the engine compartment…. I guess MB don't think of their cars driving in areas like Texas where we get temp in the upper 90s (sometimes 100's) and equal humidity levels. Maybe Germany is much colder place and thus the mind set... other than that I love the car.

a2aa

92...

I have an SL 500 and I have the 92 degree resistor..because it will still try to creek up there to about 99 -100 then it kicks in... then it goes down to 93-94. Works like a charm. If you are good in soldering, you can do it yourself for less than $5.

Regards

vinceC

100 degC will not harm this vehicle. However, the auxiliary fans should come on and stabilize the temp at around 100 degC. If they do not, or if the car runs hot on the road (where there is plenty of airflow) then it could be a problem with the radiator. JimFs mods do drop the temps a few degrees, but the effects on hoses and wiring are insignificant. JimFs site will help you check the cut-in temps (and pressures on the A/C highside) of the fans.

darkLCD

I would like to throw my 2 cents into the conversation. This does not apply to to older Mercedes since I have no first hand knowledge of them, but only to the newer Mercedes that I've seen...2002 E320, a 2002 E55, and 2003 E320. It seems that Mercedes is intentionally running the engine temps higher in the newer cars. From what I can discern, it seems that the engine temps have been hovering around 100 - 105 degrees regardless of outside ambient temperature. My E-class hovers around a 100 degrees even when the outside ambient temperature is 56 degrees F. I've had 2 MB Tech's including a service manager look over the vehicle on the 1st day of pickup since I wasn't used to such a high engine temp and all said that the temperature was fine and normal. Fan's were operational and kicking in when necessary.

Discussing this issue with a tech (not a MB tech), we speculated that that the new advances in engine materials (various alloys, etc) are allowing MB to run the engine hotter for better efficiency with no loss of performance. If the engine ain't overheating, there really isn't a problem (which is the truth). Messing with the engine temp when it was geared to operate at that temp could actually decrease performance...especially since everything was calibrated for that temp. Yes, generally heat is bad, but running a cold engine ain't good either. People just ain't used to seeing the needle above the halfway mark. The car isn't overheating...and by overheating I mean the red zone.

In addition, messing with engine temp by making the fan kick in all the time could wear out your fan prematurely...not to mention the additional noise of the fan going all the time. Sure it may assuage your psychological fears, but there is really nothing wrong with the car. Maybe if Mercedes redid the temp gauge so that the 100 degree mark would be the halfway mark, that would put more people at ease.

darkLCD

Check out 2114me's 2003 E-class in the W211 forum with Engine Temp at 99 degree C with outside ambient temp at 77 degree F. Obviously, there's no flaw by MB with the engine temp (Last Pic on the page):

https://mbworld.org/forums/showthrea...0&pagenumber=2

a2aa

I've been to alot of forums discussing this issue. I opted to choose the cooler version of this coin. Why? I like feeling "cooler" when I look at my gauge. I don't care if MBZ did it the way they did. If I see the gauge over 100c my heart thumps a bit harder due to production of adrenalin. More adrenalin, more sweat. Therfore, cooler gauge reader, the calmer I get. Increased fan usage? So WHAT?? Use the darn thing. All connectors in that engine are plastic and rubber. They will get BRITTLE/HARD with continuous temps of over 100c.
I know because when I replaced the CTS(coolant temp sensor) connector, it literally crumbled. Together with the hood pad's premature deterioration, it's obvious that excessive heat is not good for the engine. That's me. My SL500 responds better when it's cooler. Am I hallucinating?? Maybe or maybe not... heat controls timing. Whether it advances or retards, it sure takes off better when cooler. NOT COLD........ but cooler

On the "fan" side of this converation, I have 2 other MBZ that are more than 12 years old , and have friends that have vintage and classic mbz...NONE of us have replaced a fan YET. And if it goes out??? I'd rather replace one component of an engine than to play detective trying to fine components that have prematurely deteriorated due to excessive heat. That's me. Ciao

Stay cool

patrick

You are right!