regclown124

Hi guys, I recently took my car into my indy for service (85k miles). Needless to say, I will not be going back as he missed some critical things (brake squeal and brake fluid is dirty) which I was hoping he would pick up on. I have been using him for a while and he does great work, but maybe there were some changes I was unaware of. He did mention that I do have an active coolant leak (I will upload photos shortly). At first, I thought he was bluffing, however I did recall that in December of last year the coolant light came on. I topped it off with about 4-5 oz of Zerex purple coolant and it has not come back since. There were and still are no leaks under the car and the engine temp has always stayed at around 90C when fully warmed up.

Today on my way back from the grocery store I noticed a slight fluctuation in temp, the thermostat dipped to 80 for a minute then went back up to 90. The car has 85k miles and I will be replacing the thermostat and waterpump as recommended after a pressure test. A few questions:

1. How serious is the leak because the car has been operating normally ever since.
2. Is this normal wear and tear after 10 years and 85k miles (bought it brand new in 2014)
3. Indy quoted me $1450, other shops quoted me $1200 and change. Is this a fair price for parts and labor.
4. I am not driving the car long distances but plan on getting this addressed by the end of next week after I return from work.

regclown124

Attaching pics

chassis

What country/region are you located?

Photos are not good, sorry to say. Please post larger photos.

Fluctuating temperature gage is not "operating normally". You have issues with your cooling system.

Better, larger photos will help people to offer suggestions.

gearFX

I agree that larger photos will help, and I almost always agree with Chassis in general. However, I have noticed that the W166 temperature gauges do not appear to be damped (or as damped?) like many modern vehicles where the needle stays pegged at a specific temperature once the engine is warmed up and barely ever moves unless something serious is wrong. Maybe it's just my car, but I definitely see the temp gauge needle on my W166 make small movements throughout a drive. I will have to check to see if it's in the 80-90 degree range the OP described though.

chassis

The temp gauge normal needle position is 50% of full scale. Note this is not in the "middle" of the white zone.

Many posts on this site asking "is my engine overheating" because of MB's chosen nominal indicator needle position vis-a-vis the red and white colored zones.

Normal operation means the needle fluctuates very little, or not at all. And not rapidly.

gearFX

OK, that is consistent with what I have observed too. Mine moves more like the hour hand on a clock, not the minute or second hand, if it moves at all (within a small range on the dial, except during warmup of course).

regclown124

Thank you all. I did notice some coolant sitting on top of the block near the belts. I called a few places and they all quoted me around $1500 give or take a hundred. Turns out I have multiple leaks so I decided to get it replaced. Is this normal wear/tear for 10 years 85k miles?

Œuvre

Sorry, but what exactly is it that you are getting replaced (e.g., just the thermostat?) and what parts and service are the quotes for? Did you (or anyone else) narrow down the origin(s) of the coolant leaks? Multiple plastic lines and fittings around the engine (including this one...this is one of my Mercedes techs up here in New England), the plastic thermostat housing, and seams on the plastic parts of the radiator itself have been known to develop leaks at around that age (and even more on the turbo-charged variants of those engines)...

chassis

Gasoline or diesel engine?


The photos are of no use.

regclown124

Its a gasoline engine. Turns out I also had a leak in one of the hoses that runs to the heater core. All in all it was about $6xx for parts (Water pump, hose, thermostat, coolant and looks like he replaced the belt too) and about $7xx for labor (He had the car for a day and a half)

Œuvre

Yes, to answer your earlier question, it's not at all uncommon for those coolant lines and plastic fittings going to the firewall to develop leaks/crack at around 10 years. In another discussion, I had mentioned talking to my mechanic a few months ago about a list of those items I wanted replaced (along with the thermostat, coolant reservoir/expansion tank, and coolant flush) when I get my 10-year service (including belt, idler pulleys, and tensioner and 4MATIC fluid changes) at the end of this year. Based on the description of the work done to your car, reputable independent Benz/European specialist shops with master techs would have charged around twice as much for the labor up here in eastern New England...

efi dart

Guys,
My ML 400 was using water and i could never trace it........!
leak #1 After i added x2 small food dye bottles to the cooling system, i diagnosed the heater core Y piece (engine bay side of the firewall) had a hairline crack
Leak#2 Then a few months later the water pump took a dump..........

Rattle on start up is next on my hit list,,,,,,,,,ughhhhh