coolant replacement

[s4rap]

Hi all,thinking of replacing my coolant for some Evans waterless 180.Has anyone else done this?just wondering about flushing the system out with water before adding the stuff what flushes the water out.Going to get it done at a garage but wanted a bit of advise before hand,car is 2001 clk430,THANKS

 

[Frostytel]

When u have drained all the original coolant out you put in the water removing fluid you can buy off them, this then removes any remaining traces of water ready for the good stuff..... Will be putting this stuff in both my cars after xmas

 

[Dieselman]

Why? Water is one of the best coolants available, it has a very high specific heat capacity.

 

[brigadier]

The coolant you mention is not on mb 325.0 specification list, so I assume it's not mb approved. You can see the mb approved coolants here - MB 325.0 - Anticorrosion/antifreeze agents (Specification 325.0) - Mercedes-Benz Specifications for Operating Fluids
I recommend BASF Glysantin G48 or G05. afaik that's the same coolant MB sells in their packaging.

 

[s4rap]

Evans 180 is for classic cars or cars that are not used very often,my clk only does 1-2000 miles per year.Unlike water it doesnt overheat or boil,theres no pressure in the system so its easy on hoses and its got very good corrosion protection....or so they say.

 

[brigadier]

Water doesn't overheat - like DM said it's best for cooling (in fact 100% water has best cooling properties, coolant is added to protect from boiling, freezing and to protect cooling system). G48 I mentioned before has a boiling point of about 165C. It's approved by mb and therefore contains all additives to protect the cooling system. I wouldn't worry about low usage. Personally I would always use only fluids that meet correct spec for the car. Best to use distilled/deionized water to mix.

 

[markjay]

Cooling systems are pressurised in order to increase the coolant's boiling point.

If the special coolant does not generate as high pressure as water, there may be some benefit as it will be kinder to old rubber hoses as the OP suggested?

Also, water is corrosive, even with corrosion inhibitors, so potentially the alternative coolant is made of a less corrosive substance, and kinder to the more basic alloy cylinder heads of old?

 

[brigadier]

Lower pressure might be a good thing if the hoses look a bit shabby, but then I would replace them - I guess it's just my way of doing things. And corrosion is not an issue if good quality coolant is used and changed at recommended intervals.

 

[hotrodder]

I don't get the 'no pressure in the system' comments. Even if the rad cap is modified/changed to prevent the system from holding pressure parts of the system will still be pressurised when the engine's running... water pump creates pressure by pushing coolant around the system against the restriction that is the thermostat. This is one of the reasons why running without a thermostat is a bad idea, everyone knows about the running too cold/taking ages to warm up bit however the pressure in the system is not just about raising the boiling point. Coolant temps aren't taken adjacent to the combustion chambers where temps are MUCH higher and the pressure created by the pump helps prevent steam pockets from forming. Added to which anyone that's owned something vintage with an open system is familiar with them puking coolant when shutting off a hot engine- keeping the system pressurised is as much about reducing this as anything and switching from filling the radiator to a seperate header tank further improved things

From a quick play with google i'm going with snake oil... loads of forum threads about from (usual for car forums unfortunatly) comically ignorant to a bit more clued up and several identical MSDS sheets showing the stuff to be ~ 70% ethylene glycol... http://www.hrpworld.com/client_images/ecommerce/client_39/products/pdf_3415_3.pdf
They're at odds with what the evanscooling site says about NTG though...

NPG is recommended for racing engines that run on tracks or in series where there is a "NO Ethylene Glycol" rule

so may be the MSDS's are fake
Haven't read through it properly but instructions for the stuff... http://www.hrpworld.com/client_images/ecommerce/client_39/cat_header/683_4.pdf (which mentions propylene glycol at the top like the MSDS the other usual 'anti freeze' suspect)

 

[markjay]

Most of the pressure is generated by the water being warmed up.

This is a specific feature of the substance used - other substances (not water) might expand less when heated and will generate less pressure at the same temperature compared to Water.

 

[kth286]

providing Evans works OK and does NIL damage, then from a time and cost saving perspective, it seems you can fill and forget the cooling system for the next/forever years.

 

[hotrodder]

^^ There is that but google shopping suggests that i'd be looking at ~ £140 for enough of the stuff to do a coolant change on the w124. Ignoring labour that's around 5 coolant changes (G48 + deionised water) to get your money back or 10 - 15 years. Count your time/paying labour will improve things but the labour for the initial switch is gonna be higher than for straightforward coolant change

Most of the pressure is generated by the water being warmed up.

This is a specific feature of the substance used - other substances (not water) might expand less when heated and will generate less pressure at the same temperature compared to Water.

I was half asleep and so might have missed it but i could only find anecdotal claims of it's coefficient of expansion... some saying it was lower than 50/50 water/antifreeze which would fit with the lower pressure change as it's heat cycled, others that it was higher. Evans themselves say...

Use of a 7 lb. cap on “waterless” system is recommended for racing, street rod and performance enhanced
vehicles. For applications where 7 lb. cap is not available, standard cap may be used. All stock – factory original
computer controlled daily driven vehicles are coolant change only – no system changes are required.

and the impression that i got (still not read it properly) is that they're saying it has a higher boiling point at atmospheric pressure and so won't boil if the system isn't pressurised and coolant temps exceed 100

The MSDS sheet claims a specific heat capacity of 0.66 BTU/lb, a 50/50 mix of ethylene glycol in water is ~ 0.8 BTU/lb (neat ethylene glycol is 0.56, propylene glycol 0.6)...

 

[s4rap]

WOW very technical this coolant thing.I am going to keep the car for the rest of my life and on chatting to the guys at evans this seemed a good idea.Great feed back though thanks chaps!!

 

[Dieselman]

No anti-corrosion additive is going to last the life of the engine as they all break down due to heat, so my advice is use decent regular antifreeze and distilled or soft (rain) water and change it at the specified intervals.