DrDoe

My eyes were on the temperature gauge and I didn't paid attention to AC error code 1000. Reset the AC and my coolant error also went away. I see coolant overflow from the intercooler low pressure system. Does that means the system is full or that doesn't mean anything?

DrDoe

Nick,
Well, I wasn't that lucky. That same coolant service message came back. Checked on the engine fan and it isn't spinning when temperature set to LO.

tusabes

check your AC refrigerant charge level

an undercharged AC system will cause fan not to work correctly

DrDoe

You are right. My AC system needs service. I was about to go into the fuses/relays module but I guess it's safer to address the AC system first.
I can't get to the dealer appointment until next week and I'm not sure if I want to go to the oil change place...

Welwynnick

The AC won't stop the cooling fan coming on - it just won't come on all the time the AC is on. The cooling fan control takes both the engine cooling and the AC cooling demands.

Does the engine tend to run hot when you're driving fast or slow or both?

If the fan has failed, there's a specific warning message on the dash.

Nick

DrDoe

It tends to run hot in idle mode and AC on. When heat on, it went back down to just above 80C.
I'm trying to search for voltage readings at at engine fan plug and so far no lucks.

tusabes

you can just go to the auto parts store and get the can of refrigerant with the hose and gauge attachéd. For $30 you can fill it yourself , it's super easy

DrDoe

I just researched AC replace procedure. Don't look hard so I went ahead and ordered vacuum pump, manifold gauge set, PAG 46 and R134a for $180. Going to be here by Wednesday 3/29.

With climate system OFF, the temperature keeps going up when I do city driving and only comes down with highway speed.

Here's a picture of the engine fan plug I found online. I think the top large pins get 12v from the battery and the bottom smaller pins get some voltage signals from the relays. I'm going to get some voltage readings for better clues.

DrDoe

Getting back to this thread... This looks to be a very small investment to ensure all air get out of the system
Thanks for the suggestion.

DrDoe

Coolant overflow yesterday from the intercooler circuit:
Not here today. Did they went back in?

DrDoe

Voltage readings at the plug


Any idea on how to get the fan to run beside AC on? I think I will have to go back to the fuses/relays panel...

ItalianJoe1

I had to replace a fan on my first CL for that issue, the Coolant-Visit Workshop message was due to an intermittently faulty fan controller or motor. I swapped the whole unit out, cost me about $300 for a replacement, not hard to change, solved the issue.

Sometimes, I would start the car and not have a/c until I was moving, so I knew the fan wasn't coming on. When moving I had freezing cold air. After changing out the fan it was good all the time.

My opinion: The fans get weak with age, the digital controller tries to compensate but is only so capable. After 10+ years the fans are due for replacement. It's not worth overheating your very expensive engine for the cost of a fan replacement.

DrDoe

It also sounds like a bad fan to me but it was totally fine before I worked on the radiator. It didn't overheat with the leaked radiator and leaked lower hose.
Coincident after Eurocharged TCU tuned?

ItalianJoe1

Nothing to do with TCU.

It's possible, the fan was only working partially, allowed the car to get hotter than normal and blew the radiator/hose.

Also possible it's just strictly a coincidence.

DrDoe

I mentioned TCU tune because I was in the compartment and removed the fuses/relays panel. I went back there the 2nd time to make sure nothing can fit this disconnected plug and it doesn't
Now I can move forward with troubleshooting the fan issues from recent radiator works.
I was trying to replace the radiator, the lower radiator hose, the radiator pump, the tandem pump and at the same time removing ABC dead weight. In hindsight, I should avoid doing ECU/TCU tune in the middle of the mess.

DrDoe

Thank you guys for helping me with the advice to look at the fan and the AC. The fan is spinning again after I get the AC compressor to kick in.

tusabes

so was it the low refrigerant keeping the AC off to protect the AC compressor , and resulting in the fan problem

DrDoe

Yes. You was absolutely right on this.
Thanks again.

tusabes

glad to help ! The Mercedes is one of the few cars where you need a correctly functioning AC system to have a correctly functioning cooling system

Welwynnick

Are you sure about that?


It's unbelievably absurd if it's true.


Nick

tusabes

this is the second time low AC charge has resulted in disabling both the AC compressor and the engine fan

DrDoe

I knew about the refrigerant problem but without tubsable's advice I would still be dicking around with the fan I think. With the voltage readings, it seems like there isn't a way to test the fan manually.
Here's another kicker: I worked with V12icpack and I'm certain that there are no issues with the VT or the coil pack but the local MB specialist Indy shop continues to tell me that I need both to avoid #7/left bank misfire.
The intercooler refill reduced the occurrences but the AC/coolant might have been the real fix as I haven't seen any today.
The previous owner replaced the radiator on 1-21-16 with Behr so I wasn't willing to pay for another Behr. I picked up JSD radiator for $58 shipped to test my replacement skills. I would be very happy if it lasts for 1 year.

ItalianJoe1

If you are getting misfires on hot restarts, check your fuel pump controller, if it's not the 5 bar one, install the updated one and pump/filter.

DrDoe

I looked it up while I was under the car for ABC lines removal. It's 5bar A2205402945 but it's old. I haven't replaced the pump either.
I think about the same line on possible fuel delivery issue but so far no misfire yet post coolant works. Still too strange to have the issue on one side for either fuel or coolant issue
In the past I was able to duplicate the misfire issue by getting a car wash. Took it on the car wash rails this morning and no misfire. Knocking on wood...

DrDoe

I disconnected the fan plug for ECU flash and I thought it would be interesting to look at the voltage readings again

They look different than before.
The voltage readings can help detect fan issues.