SL55 AMG overheating issue

[zoros]

Many thanks.

 

[Alex]

Alex - thanks. Not sure what you mean by 'split system'. I don't think I have. The OEM pump was replaced by this (done by a MB Indy last month):
https://www.amazon.co.uk/dp/B00W22IIEE/?tag=amazon0e9db-21
But much cheaper price (£108+vat).

The original design relies on a single header tank for both, engine and supercharger cooling circuits. A lot of people prefer to separate the two to prevent unnecessary mixing of colder and hotter water thus reducing the cooling effect. The OE circuit is not self-bleeding (unlike in a CL55K) so by changing out the pump you've introduced the air in to the system. I was only asking to see if your system is different to the OE or if you've used an aftermarket pump instead of the OE. I'd try to bleed the system as suggested above or another thermostat if bleeding doesn't cure it.

 

[zoros]

Alex - thanks for your advice. If I may, I'd like to take it further -
I have just the one single header tank as per OEM.
The replacement pump for the supercharger intercooler circuit was a Bosch (ending in 010). It was an aftermarket item highly recommended by MB forums.
Now, with regard to self bleeding- I have been told that unlike the last video in my recent post where you see the sytem being bled back into the header tank, manually - my car has a bleed nipple (coming off the supercharger pipes) which leads to the header tank (see link below) and this bleeds the supercharger system automatically.


Assuming this to be the case - and my car auto bleeds the supercharger circuit - can I now eliminate the option that it is still an air lock and proceed with my main suspicion which is the relay/fan module requiring a new cooler fan?
Could there be a problem using an aftermarket pump??

 

[Alex]

Sure, seems like your car purges the air same way as the CL55K does. Aftermarket pump (not genuine Bosch?) could be a problem but it doesn't kick in on the tick over anyway so not really an indicator for the rising temps. The ECU activates the relay which in turns powers up the pump when the IAT temps reach the limit.

Is cooler fan = radiator fan? If it is, I don't see being a problem either as you say it kicks in at about 85-90C.

It could be a faulty coolant temp sensor or the wiring issue. Replacement sensor is inexpensive. I'd test the wiring too. It's only a two wire harness - with one being ground and another (red/green) signal wire. Both go into a 26-pin plug on the ECU. Signal wire is pin 5 on that plug, ground is pin 9. I would do a continuity test between those to pins on the ECU harness plug and the corresponding wires that go in to the sensor.

 

[E55BOF]

I had a fan problem on one of my diesel 211s, and the message "Check Coolant Level" came up; that is the message you get if there is a problem with the fans - there is no "Radiator Fans Faulty" message in the OBD.

The problem is with your radiator cooling fans. Serviceable fans run up to a fairly high speed and stay there until the coolant temperature drops. They do not slow down after a second or two, and they do not make rubbing noises.

 

[Baldbloke]

I had a fan problem on one of my diesel 211s, and the message "Check Coolant Level" came up; that is the message you get if there is a problem with the fans - there is no "Radiator Fans Faulty" message in the OBD.

The problem is with your radiator cooling fans. Serviceable fans run up to a fairly high speed and stay there until the coolant temperature drops. They do not slow down after a second or two, and they do not make rubbing noises.

Exactly. They should be on until the water temp drops.
You earlier said that both main hoses were hot so not a circulation issue, unless the rads compromised, but you have said there’s fan issues.
Sensor or the fans themselves [emoji1303]


Sent from my iPhone using Tapatalk

 

[zoros]

I'm inclined to go for the cooler fan/ in built sensor, then.

Now can someone point me to a nice man who sells dirt cheap cooler fan assemblies please?