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A very bad day yesterday...

1176 Views 6 Replies 5 Participants Last post by  Atomulese Vlad

Yesterday it was a bad day for my SLK. :crying:
First... a week later the "check cooler" message showed up on my display... I stopped and filled the cooler tank with about 800ml antifreeze and kept going fine until yesterday. I drove about 1000kms in this time.
Yesterday the engine management light came on... after going for 20kms the "check cooler" message showed up again, and when I stopped I had a "rough" idle of the engine.
So I went to a local repair shop to find the error codes.
I attached 2 pictures with the error codes, maybe someone can shade some light and give me an ideea what's happening.
Also the antifreeze has a weird color... like mud or clay(forgot to take a picture). The antifreeze is "D" type. It doesn't appear to be engine oil in it.

I don't think the "check cooler" and engine management light are related after reading this topic.
I hope to have an easy fix, also.

Also considering in replacing the "thermocouple"(is this the right therm?) for the antifreeze problem, maybe the antifreeze turned in to steam as I didn't find any signs of leakage.

Any help is appreciated :)


P.S.: Sorry if I don't make sense. English is not my native language.


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Seems like your MAF is the problem. If the MAF is bad your fuel mixture will be affected. With the coolant could be a leak. If you have a bad thermostat your car temperature will be low or high again you will not loose water.

Daca vrei mai multe detali PM am avut un slk 200 2 ani de zile si nu am pierdut deloc apa.
Your english is fine, except what is a "thermocouple"?

Muddy coolant could be automatic transmission fluid due to a failed radiator too. How do you know it's not motor oil?

You should do a compression test first, then check for coolant in the exhaust. These tests require specialized equipment.

I don't think I would drive the car until you've resolved the missing coolant and mixture problem.
If you do a compression test you need a special tool. Not cranking from the key. Cranking with the key will give you false reading.
don't drive it anymore

I had it too with my SLK 230 AMG 1999. Cooler water was leaking into the automatic transmission. Don't drive it before you are sure. Automatic transmission repair is expensive.
I had it too with my SLK 230 AMG 1999. Cooler water was leaking into the automatic transmission. Don't drive it before you are sure. Automatic transmission repair is expensive.

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So... finally I have time to share my experience...
After almost 6 months I found(hopefully) from where is all this oil in the water...
In december I had the cylinder head gasket replaced as it was damaged(and thought that from there is the oil in the water, also there were burned gases leaked into the water). Had also to grind the cylinder head with about 2mm(if I recall correctly).
The job was a succes, thankfully. Until this week I discovered again oil in the water when I was changing the supercharger oil and the crankcase gas hoses.

In the first post I mentioned a ”thermocouple”, this week I found that the correct term is oil cooler.
As the supercharger was off the engine the mechanic checked the oil cooler(one of his first thoughts in december), he discovered that the gaskets where affected and the oil cooler metal case was ”eaten” enough to allow engine oil get into water.
One of the previous owners also put some ”radiator sealing dust” in the water, the oil cooler was filled with these dust...
Tomorrow all the parts are ariving and the mechanic can finish the job. I pray that after this, I will not find oil in water again...

I have to mention that I am a ”bad” driver and I don't check the water/oil/etc. So from december until now(16.000km) I didn't checked the water not even once, I'm lucky that things didn't got worse... Please don't be like me... And under no circumstances put ”radiator sealing dust” in the water.
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