Coolant Issue - Help.
Thread Starter
Newbie
Joined: Aug 2023
Posts: 13
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C63 W204
Coolant Issue - Help.
Hey everyone, i’m back with another issue.
i bought an 09 w204 a month or so ago, i noticed it was losing coolant very quick and i thought maybe my headbolts have gone - Its 95k km’s driven btw - I went to a mechanic to get it pressure tested and we found that the thermostat was leaking, keeping in mind i live in Pakistan where we dont have any official MB dealership or mechanics, i found a used thermostat and we put that on my car and the leakage stopped, meanwhile i thought i’d order a new from Uae or Usa that would take around 15-20 days to arrive.
In the mean time i’ve been driving my car and i have noticed that it is still losing coolant around 150ml every 100km’s, there are no visible leaks but they were no visible leaks when the thermostat was leaking but we found out after taking the covers off and when we pressurized the cooling system.
i just wanted a suggestion that how can i test that my headbolts are gone or maybe i still have a minor leak somewhere that i cannot see, i have ordered a block tester but that would arrive in 15-20 days aswell, could it still be a bad thermostat as what we installed was a used one, the car runs absolutely fine - The water temp is normal and oil temps are normal too even during hard driving the max i’ve seen is the temp rise to 122 keeping in mind i live where the temp is almost 40+ degrees and alot of humidity these days.
My oil level is fine too, no milky oil cap, but losing water is what bothers me, i’ve been running water in my cooling system as i thought i’d flush it out with coolant again when my new stat arrives.
sorry for such a long paragraph, i’m a newbie with very less knowledge and this is my first ever car, help would be appreciated.
i bought an 09 w204 a month or so ago, i noticed it was losing coolant very quick and i thought maybe my headbolts have gone - Its 95k km’s driven btw - I went to a mechanic to get it pressure tested and we found that the thermostat was leaking, keeping in mind i live in Pakistan where we dont have any official MB dealership or mechanics, i found a used thermostat and we put that on my car and the leakage stopped, meanwhile i thought i’d order a new from Uae or Usa that would take around 15-20 days to arrive.
In the mean time i’ve been driving my car and i have noticed that it is still losing coolant around 150ml every 100km’s, there are no visible leaks but they were no visible leaks when the thermostat was leaking but we found out after taking the covers off and when we pressurized the cooling system.
i just wanted a suggestion that how can i test that my headbolts are gone or maybe i still have a minor leak somewhere that i cannot see, i have ordered a block tester but that would arrive in 15-20 days aswell, could it still be a bad thermostat as what we installed was a used one, the car runs absolutely fine - The water temp is normal and oil temps are normal too even during hard driving the max i’ve seen is the temp rise to 122 keeping in mind i live where the temp is almost 40+ degrees and alot of humidity these days.
My oil level is fine too, no milky oil cap, but losing water is what bothers me, i’ve been running water in my cooling system as i thought i’d flush it out with coolant again when my new stat arrives.
sorry for such a long paragraph, i’m a newbie with very less knowledge and this is my first ever car, help would be appreciated.
Thread Starter
Newbie
Joined: Aug 2023
Posts: 13
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C63 W204
The car runs fine, no white smoke, oil colour and level is fine, the only issue i had is like when the car is hot and i try to start it up it sometimes misfires for 8-10 seconds then gets normal, the idle is a bit lumpy sometimes maybe i need to change my 02 sensors - But otherwise the car is fine it recently threw a code that Bank 1 and Bank 2 are running too rich.
Junior Member
Joined: Mar 2021
Posts: 62
Likes: 10
From: Goldfields, WA
AMG C63 W204
one of Tasos videos customer bought car in & had small coolant leak, some good tips here. I think if it was head bolts it would have become fairly obvious by now , but hey maybe I'm wrong. I think towards end of part 1.
C63 with 125k km check up (part 1)
C63 with 125k km check up (part 2)
MBWorld Fanatic!
Joined: Mar 2010
Posts: 5,894
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From: CH = Land of mountains, cheese, chocolate and watches
12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG + Ultima Can-Am sold)
You can see the start of the leak at around 26:30 of part 1
Thread Starter
Newbie
Joined: Aug 2023
Posts: 13
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C63 W204
Any other way to check the gasket or bolt issue? I’m unable to sleep like this, though the car is running great no issues only rough startup sometimes when the car is hot. Otherwise its only loosing coolant but I can’t see any visible leaks, we pressure tested the cooling system to 15psi the pressure dropped 5psi or so in like 10 mins but we couldn’t see any coolant dripping from the top or on the rear tray, haven’t opened the rad though.
can please anyone tell me how can i confirm if my bolts are bad or not my block tester will arrive in 15 days and I can’t wait for so long its just bothering me so much.
i have no white smoke, oil level is fine, no milky cap, car runs amazing on Wot and everything and i’ve driven it around 700-800kms now with topping up the coolant every other day by 100-150ml.
can please anyone tell me how can i confirm if my bolts are bad or not my block tester will arrive in 15 days and I can’t wait for so long its just bothering me so much.
i have no white smoke, oil level is fine, no milky cap, car runs amazing on Wot and everything and i’ve driven it around 700-800kms now with topping up the coolant every other day by 100-150ml.
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Joined: Jan 2014
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From: Republic of Texas
'99 and '05 E55 AMG
First, is the gasket on the reservoir cap good? Bad gasket allows coolant to evaporate very slowly when hot. Any residue around the base of the cap is good evidence of bad gasket. Happened to me a couple of years ago and to a friend's vehicle a few weeks ago. Reservoir caps are cheap. Also, try rolling the edges of the coolant reservoir between finger and thumb. If small pieces of plastic crumble off, the reservoir is bad and will allow slow coolant loss in the early stages of failure. Been there, done that, got the T-shirt...
MBWorld Fanatic!
Joined: Mar 2010
Posts: 5,894
Likes: 324
From: CH = Land of mountains, cheese, chocolate and watches
12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG + Ultima Can-Am sold)
First, is the gasket on the reservoir cap good? Bad gasket allows coolant to evaporate very slowly when hot. Any residue around the base of the cap is good evidence of bad gasket. Happened to me a couple of years ago and to a friend's vehicle a few weeks ago. Reservoir caps are cheap. Also, try rolling the edges of the coolant reservoir between finger and thumb. If small pieces of plastic crumble off, the reservoir is bad and will allow slow coolant loss in the early stages of failure. Been there, done that, got the T-shirt...
Purchased a new cap at the dealer for peanuts, topped up the expansion tank and never had a problem again.
Last edited by DRBC43AMG; Sep 12, 2023 at 10:15 AM. Reason: Completed post
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Junior Member
Joined: Mar 2021
Posts: 62
Likes: 10
From: Goldfields, WA
AMG C63 W204
yeh there has been heaps of those coolant expansion tanks go bad (brittle) and explode or crack on 'Tasos Moschatos' channel. However i guess as he is located in the UAE where the environment is hot
all year this is perhaps more common issue.
all year this is perhaps more common issue.
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12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
I don't know what the hell kind of plastic they used to use, but you can buy an early 90's benz with original plastic expansion tank and it is all yellow and working mint and these new ones last about a decade and explode.
