Overflow of antifreeze w124

[WDB124066]

Hopefully pretty good if the cap was the anode...!

 

[darreningram]

My coolant hasn't been changes in a long time and I just keep adding if it dips at all- rarely. I notice she runs a bit cold most of the time- 70- in normal use. Therefore I suspect the coolant/water ratio is a bit off. Is it simple to draw and refill the system and if so could someone give me a brief idea of how to do this? Thanks in advance

 

[hotrodder]

My coolant hasn't been changes in a long time and I just keep adding if it dips at all- rarely. I notice she runs a bit cold most of the time- 70- in normal use. Therefore I suspect the coolant/water ratio is a bit off. Is it simple to draw and refill the system and if so could someone give me a brief idea of how to do this? Thanks in advance

Low running temp is more likely to be a dead thermostat, especially if it takes a fair time to reach 70ish as it should only take a couple of miles to reach 80° even in the depths of winter

There are detail differences with different makes/models as some engines have bleed points for the cooling system but a generic coolant change procedure is typically...
Heater set to fully hot (don't need, or want, the coolant to be properly hot though) to ensure coolant can get in & out of the heater core easily
There's usually a drain tap on the rad, if not (or it's stuck) can undo the bottom rad hose instead. This'll typically allow ~1/2 to 3/4 of the coolant to escape with the remainder being trapped in the crankcase which'll have it's own drain tap. This is usually in an awkward spot to get at
Can flush the system through with clean water if what came out was properly manky or just close the drain points and refill with 40 - 50% antifreeze in water
Once the system appears full run the engine with the rad cap left off. As the coolant circulates and warms up most of the air will escape and the level will drop. Squeezing rad hoses can help 'burp' the system but vibration from the running engine is sometimes enough. Some engines have bleed points that need cracking to ensure air isn't trapped, others are pretty good at self bleeding... all depends if there's any areas that are higher than the rad/header tank that can trap air; this is why there's often a small hose from either the thermostat housing or top of the radiator that feeds back to the header tank.
Top up as necessary while the engine is running and once it's upto temp and the level is stable put the cap back on

20 Cooling System - M104 covers the cooling system for m104 engines. Go back to the main index and there's sections for the m103, m119 and several diesels

Anyone with a reasonably sized air compressor can take advantage of vacuum purge & fill kits which'll also confirm there's no leaks i.e. won't hold a vacuum if there is

 

[PobodY]

I've always gone with the running the engine to temperature with the cap off; then take it for a short drive and re-check it after you've let it cool again.

 

[darreningram]

Thanks guys, great information especially the step to step guide Hotrodder which is really what I need- I will review the thread to see what the conclusion was on type and brand of coolant to use and have a go next weekend- thanks again

 

[Bean]

With the new genuine Mercedes radiator cap fitted (I was able to do this myself!) the temperature has been fine. I still needed to replace the water I had been using with coolant. I decided to buy the coolant from halfords, and I thought I might as well replace the thermostat at the same time. I purchased a gates thermostat and an mb thermostat seal. Whilst flushing out the old coolant, putting in new coolant and replacing the thermostat all looks straightforward especially with the advice on this forum and others, I decided not to because of risk of wrecking one of the 3 'bolts' (I need to update my tools) Today I asked the local garage to flush out the old coolant, add the new coolant and replace the thermostat. The termperaturw is now running around 100 but the coolant is staying in the car. It would make sense this is due to the new thermostat? Annoyingly I was told gates was a quality product. Whilst it says on the sealed box 'made in the USA' on the part it says 'made in China'! Not happy but my fault for trying to save £30 not buying a genuine mb part but also probably not needing to replace it. Anyway, I'm tempted to put the old thermostat back in the car? Would I need a new seal?

 

[WDB124066]

Put the old one back in and see what difference it makes. Were you able to match the temps exactly with the replacement one...?

 

[Bean]

1 degree difference. Do I need a new seal?

 

[zipdip]

Yes I only posted a couple of days ago that buying a thermostat is a bit of a lottery,and has been for years,always boil a new one up in a pot to make certain it is opening properly.

 

[optimusprime]

You could come down a degree ot two , on the thermostat if need be .I was reading a post from a guy thats well up with mb engines .He said to do this would help the system start to circulate quicker.And help to keep temp down