brano_co

already booked in for the head bolt replacement (car ate 0,5L of water in last 8 months) , this was on schedule already 2 weeks ago, but their best "engine" man over here is already 2nd week sick, so waiting , once he will be back in work, hopefully the after following week.

week ago as also today have to travel @ on highway not a far away, not in hurry set the cc to 100 mph / 160 kph and was surprised once the water was almost all the time running between 80-92 C, all the way up and down over and over

any idea why what can be wrong ? as there wasn’t any error code reading...

MagasC63

Lol not in a hurry at all. All jokes set aside sorry about what you are going through. Hopefully it's not a serious problem. I'm sure some of the MB techs will chim in on this one soon.

Critter

Low level of coolant or air lock inside of coolant chambers inside of the engine. If you select full heat on the controls does the heat also go up and down or very low heat.
Is the reservoir at proper level? does it require daily fills and is there a subtle pressure release when removing the reservoir cap when cold?


Are you saying .5 liters or 5 liters of coolant in the last 8 months, any sweet smelling exhaust and white billowy clouds out the exhaust


Also possible the temperature sensor is defective, But think it is a coolant level issue

brano_co

to be fair, didn’t checked the water level, as already twice happened that the message "low water" come on, in the last 8 months, so not checking the water level daily, just waiting for the bc to show off that’s there is something “wrong” (just few months ago find the head bolts issue here) so filled the water after that twice, in total 0,5 L not a 5L as using the same bottle of water. Due to head bolt issue I am not driving long trips last few weeks, till the bolts will be replaced. Once I set the heating to for example 24 or 25 C, yes the heat come on. No need for daily fills, going off from office in 10 minutes back home, so will try to remove the cap and see what’s the pressure & level.

last 1-2 weeks I think when I am in garage can smell something "other, different form normal" think since roughly the time, when I saw the temp on highway running up & down on highway first time, about the smoke not sure…

Do you think is better to park the car at MB dealer, and wait till the bolts will be fixed, and don’t trying the luck any more ?

Thank you for your help.

Critter

I believe that if you had head bolt issue you would be going through a lot more coolant than .5 liters in 8 months, this is negligible. Coolant entering combustion chambers will emit billowy clouds out the back and that will smell very sweet.
Head bolt breakage would cause a sudden lose of coolant, when the car is shut down then the 15 or 16 psi( pressure) that the coolant system runs under would push coolant into the offending cylinder, so large amounts of coolant would be needed, and also large clouds of smoke.
You are using anti freeze and not just plain water, right.

brano_co

I do have antifreeze in car, but toped up the 0,5L with distilled water only, as i didint know back then, whats going on, think it just need few dcl of water , and will be good.

I dead read the M156 head bolt issue thread ,as also searched for other threads like this, just this temp gauge last 2 times on higway really confused me...

hope the bolts will be replaced soon, and all will be good...

olszowa12

If you water temp levels are going up and down, check your water pump.
Mine died in November and the temps went up to 140 degrees C.
Fortunately it's all good now.

brano_co

the car do have just nearly 50,000 km, do you think it can die so fast ? but thx for the suggestion.

olszowa12

I was told that there is no rule for water pump issues - it can be at 30.000km or 150.000km.
For me, it was 165.000km and the guys at the shop said it was very long for a water pump in a heavily abused car.

AMG893

Dont say that! Just say that you "drive your car hard!"

brano_co

Ah I see, thank you for this info

Critter

A water pump consists of a pulley a shaft, bearing, seal and a impeller inside of a housing, the only way to raise temps to 140C would be to seize the bearing, tear out the seal and dump the coolant, just how would it make the temp go up and down as the Op has stated.
Did your impeller fall off? or pump seal leak out coolant and cause the overheat issue.
Your mechanic is blowing smoke. Did he also change out the thermostat with the water pump?

brano_co

just take the car from service last Thursday, the head bolts were replaced, at sat did about 350 km (220 miles) including lots of highway mileage, and all is well now, no water temp fluctuating, so don’t know what was that , its ok now

zcct04

Thanks for the update.
That's good news - congratulations!

brano_co

thx

Kejdi2000

the engine temp was going up and down very fast on the cruise control? i have the same problem and no errors on computer scanning

Critter

Air in coolant system, pressurized from leaky head gaskets which will blow the rad, cause large amounts of white smoke as well as driveability issues, or you have a bad sensor or loose connection on that sensor. Check level of coolant when cold in the reservoir, fill to proper level and recheck daily when cold again after operation.

Kejdi2000

i dont have problems with water or antifreeze, it still remains the same level. smth else i have noticed, when i have this temperature movements, sometime when i sot on the traffic lights the motor of the car go off. so i have to turn it again on. in some other moments of the temperature movement, i have smth like a bump from the engine. it happens always with the temperature movements (once per month)

Critter

The best advice I could give is to take the car to a shop to check for codes as to why the car will stall at the lights. Also at the dealership they could look into the history or previous events and give you answers to your issues. Possibly a tune up is needed or sensor issue is causing you grief. Good Luck

motoman

The fluctuating temp reading does sound like air pockets. Besides annoyance the air will accelerate corrosion of any headbolt at the shoulder and filet IMO. This after looking closely at some samples. Seems the coolant additive pak (really exist?) supposedly contains silicate for slow release protection of alum. The headbolts are on their own except for the galvanize coat.

Critter

Motoman this new guy has a C180CGI not sure if they have the same bolt in coolant setup.
To the OP can you be a little more specific about the temp rise, what is the actual temp when this happens. Is the check engine light on or does it come on then go off later when you drive.?