Cooling system fault

[Brian48]

Hi, I have a mercedes benz c200 w202, p reg. One of the pipes had On my way! Away and I lost a lot of water, but the car ha been cutting out or the last few days. I managed to refit the pipe and refilled the coolant, but I ran it for 20 mins with the cap off, but the car only blows cold air.

But when I put the cap back on, the overflow pipe starts to release ai like a valve blowing out air, this happens every 4-5 seconds.

Any help would be greatly appreciated.

 

[Dieselman]

Possibly the head gasket has blown.

 

[Brian48]

Thanks, I have checked the oil and at present there shows no sign of water in the oil, I didn't know if there was a specific way to bleed the system. I have checked both top and bottom hose and they get warm

 

[Dieselman]

Leave the cap off and keep squeezing the bottom hose. It can take a long time to fully purge the air.

Alternatively, wedge a funnel into the filler neck and use it as an extended header tank. The air will purge through the water in the funnel. If it just keeps bubbling continuously, the head gasket has gone.

If really unsure, purchase a Block Tester, which the dye changes colour on Co2 passing through it.


Mine in action on a badly blown gasket.

 

[Brian48]

Thanks diesel man, I will go and re do it now and update shortly

 

[Brian48]

I've filled it with water and ran it, but it starts to bubble out, the temp in the car is just over 80 but it blows cold air out. I think it is the head, if anyone else can think of an alternative

 

[Brian48]

Just a thought, could a worn or faulty water pump cause this issue ?

 

[grumpyoldgit]

Hi Brian, I don't really understand this bit in your initial statement - One of the pipes had On my way!
Are you saying the hose had come off and that you just put it back on and refilled the system? That you didn't replace it with a new hose?

If that is the case then it points to the hose being blown off due to internal pressure, which as Dieselman has said, points to a blown head gasket.

Does it release water from the overflow pipe with the cap on when it is cold?

Doubtful that it's the pump.

 

[Brian48]

Yes sorry, the pipe that connects to the heater matrix had come off, I re-connected it and filled the coolant back up. But even when you try and drive the car and accelerate, there is no power.