Hi
Been riding my E55 for a year now. But it has problems.

Its taking cooling water.

Cant find any leaks. Doesnt smoke from tailpipe. Has driven ok but takes a whopping gallon every 500 miles.

Since last month it has been acting up. Throwing up codes like issfire on 5,6,8 cyl and random missfire code.
My dealer says they dont think it the head gasket as they are bulletproof. But I really cant find any outside water leak.

How would I diagnose it correctly? Dont want to tear down the engine in vain.

I have a new oil cooler bought but not fitted, but its not mixing water in the engine oil. But i have some tiny sludge in the water container.
It doesnt shoot air boubles in the water container and its so little oil slugde in the water container i really wonder .No water in transmissionoil either.

Is my left head gasket dying and how would I diagnose it correctly?

Car has not overheated and it run fine until a week ago when it started to run rough from one day to another. (Engine light on sometimes since July but running fine even then)

//Peter from Sweden.

 

Engine leak down tester and an air compressor.

Example here:

Note this is NOT a standard compression tester; this one indicates how bad the leak is and you just go to the exhaust pipe, air intake, coolant reservoir, or oil fill cap and listen for leaking air.

 

Do a proper coolant flush and change the coolant reservoir cap. Id start there.


Never heard of a m113 developing a head gasket issue.

M104s are notorious for this

 

check the window washer fluid tank I have heard of coolant leaking there.

 

Frankly at about 160K miles my E55 developed a similar "issue" - and I would have to top off the reservoir every 3-4 weeks.

I have a full complement of MB tech's - and they couldn't find the coolant loss either - and they are all under 35yrs old.

Before I went to tear down - I called Franz - my MB buddy - who has been a MB tech for 40yrs.

"Yep" - he recommended using 2 "Bar's Leak Tab's" in the coolant reservoir - NOT Bar's powder and NOT anything else - and drive for 2-3 weeks - and Franz said the loss would either go away 100% or reduce substantially.

You put them into the reservoir cold - and drive immediately for 1/2 to 1 hr to give good time at operating temp right away - nothing abnormal at all.

Yep - 2/3 weeks later the loss had reduced substantially but had not gone away entirely.

I called Franz again - and he said "use 2 more and no more than that"

2-3 weeks later the leak was totally gone... and in 40K miles since then has never reappeared.

It worked fine - I have changed my coolant on schedule twice since then - no issues whatsoever.

Whatever works - costs next to nothing - again Bars Leaks Tabs:

 

IF you have a head gasket or cracked component leaking internally, 99% of the time it will end up one of two places: engine oil or a cylinder. A borescope will usually show evidence of coolant in a cylinder, or bank, in that the pistons, valves, intake runners, etc. will be much cleaner where the leak is, even a small one. Not fool proof, but I have found many small leaks from HGs and cracked heads this way, even when I couldn't smell it in exhaust or see steam from a tailpipe. Simple oil analysis will tell you if there is coolant in oil, even if it does not appear to have sludged up.

 

Never seen a head gasket issue with the AMG V8 - and I shared my personal experience on the like $5-$6 solution to try... can't really hurt - right ?

 

Curious as to whether you ever successfully located the source.