king_j

this is for E320's, specifically the I6 models.

my engine temp. was usually around 80. recently, its been around 90, and when warm outside ( 85-90 degrees f.) the engine temp. is sitting at 95.
is this normal, or is there something wrong with my cooling system?
the coolant is full, three are no leaks and all the fans seem to work fine.

the car currently has 77,000 miles. i had the headgasket replaced at 45,000 miles due to a coolant leak in cylinder # 6. since it was changed, i have not had any problems.

any ideas?

E-Klasse

Sounds normal if you are standing still or just sitting in traffic for the temp gauge to rise up. It should go down when you get moving. The thermostat should open at 88 deg. C. if I remember correctly so 90 + - 5 deg. is nothing to be scared of. The reading on the gauge has less of a delay than most other cars so changes are displayed faster. You should check the 2 cooling fans in front of the radiator. The second cooling fan turns with the first. Only the one on the drivers side is turned by a motor. The other one runs off of a belt behind both fans. If the belt has slipped off, then you are only running with one fan. With the engine off, spin the the one and see if the second one spins.

Musikmann

Yeah, that auxilliary fan that runs off the motored one could be an issue. My dealer discovered that my connecting belt was missing (no trace of it they said). The auxilliary fan supposedly only starts spinning once the engine reaches a certain temp.

I have since traded that car, but it's nice to know it is easy to check for this. To replace that $30 belt (at the dealer anyway) was going to be expensive, because you have to remove the fan housing to access the area. I think they wanted 1.5 hours labor, so approx $150 plus belt (and the fan if deemed necessary).

Good luck!

BostonC4S

My primary fan is operational however the belt has slipped off. The belt is not cracked and seems to be in good shape. Any DIY instructions on how to reinstall the belt? TIA.
Mark

E-Klasse

The belt may stretch and keep sliding off. To replace it you have to take them out and install it from the back. Takes about an hour or two but is a DIY job.

ccmbduong

My '96 E320 MB runs at 97-100 C when it's 100 C outside. During winter it runs at around 85-88 C

E-Klasse

If it was 100 C outside you would be boiling...

ccmbduong

Good Catch... hahaha... I meant 100F

patrick_y

I just had the same problem a few days ago, the outside temperature was 100F and the coolant was coming very close to 100C. Two days later (the car wasn't operated for two days), I popped the hood and opened the coolant tank cap and I looked inside. The coolant colour has faded, there are precipitates (solids) in the liquid, and it looks in pretty darn bad shape.

So, I consult my service manual and I read that the coolant should be replaced every 3 years, we've had the car for four, so it's about time.

Then I go look at my service documentation, the bloody dealer was supposed to replace the coolant at the last "B" service (which was performed less than 5000 miles ago). Does not look like that they did. However, on the work order, they supposedly did, as there is a check mark next to "Additional Work: Replace Coolant" on this long checklist.

Now, we have two cars in the family, one is a 2005 C230 which, like any car also has coolant in it. This car has 12500 miles on it. The coolant looks brand new. I used this to compare the coolant and its colour.

According to the service record, we were supposed to have the coolant replaced less than 5000 miles ago. I think the dealer (we take it to the dealer) forgot to perform this, although they do go through a check list and they did check mark it.

So, before I start pointing any fingers at the dealer, can someone tell me if my coolant does not look like it was replaced and I am likely correct that the dealer forgot to replace it?

This can be found somewhat upsetting, you take the car to the dealer to make sure things are done 100% correctly, yet, they aren't.

Richard / E320

Does this mean that this was work that was done in addition to other work already being done, or does this mean that work that needs to be done beyond what it was originally there for?

Either way, it should be easy to determine if it's not new coolant and should be changed at once.

patrick_y

Well, this is what I think, I think the dealer's mechanic forgot to replace the coolant, but checked the box that says "Additional Work: Replace Coolant" on the checklist even though he didn't.

So, either the mechanic lied or forgot. Either or. I'm pretty sure it's not new coolant because I have a car that's 18 months old that has coolant that looks newer than this car that's been driveen less than 5000 miles on its current coolant.

koskesh

At what temperature do the auxiliary fans come on? I've seen my engine get up to 115 C and haven't seen the fans come on yet. 1997, E320, I6