Activa & V6 coolant changes.

[Deanxm]

http://www.evanscoolants.co.uk/#

There you go sir, some glossy marketing propaganda for you.

D

[Mandrake]

Why would i have waterless? because i can stick it in and it will do the job for 20 years,

Not to be cheeky, but is a coolant life of 20 years without changing it, at roughly 10x the price of normal coolant worth it for a car that's already 20 years old ? Are you planning on keeping your XM until it's 40 ? Because I'm not planning on keeping my Xantia that long.

In that regard such a long life at such a high cost (assuming it really can last 20 years, which I'm dubious of) is only going to leave you out of pocket as the car will either be scrapped long before you made back the money or you will be subsidising the running cost of the next owner. (Assuming they don't just dutifully dump and replace the coolant after 2 years not knowing that it has magical coolant in it!)

Also if it can really last that long without any changes I would have thought car manufacturers would be falling over themselves to supply it in new cars - it might cost more on the sticker price of the car, but they could reduce regular services costs and use that as a carrot to attract buyers. I can see the slogan now - "Sealed for life" coolant systems! Yet we don't see this happening.

i can run the system as open vented so no more popping expansion tanks and stressing hoses and seals,

But is it a good idea to run it open vented even if boiling isn't a risk ? An open vented system exposes the inside of the cooling system to a constant fresh supply of oxygen which can promote oxidation, whereas a sealed system has a small quantity of oxygen in the expansion chamber but once that is "consumed" no more can get in unless the cap is removed.

This is similar to the shift from open vented central heating systems to sealed pressurised systems - one reason the sealed system is preferable is that once the the system is filled and air has had time to bubble out and be bled no more oxygen is being added to the system all the time, while an open vent system allows a small but steady amount of oxygen to find its way into the system.

and if a the blurb is to be believed when im done i can tip it down the drain rather than run it down the tip for disposal. I wouldnt leave out the cost in this decision as if they were the same price i would say those benifits are worth it, as prices stand i dont think they are.

All the considerations you've mentioned still overlook the low specific heat capacity of pure Propylene Glycol - if its only 65% as good at transferring heat as water (and about 75-80% as good as ethylene glycol + water) then you are sacrificing cooling capacity of the system. Whether this is an actual problem or not depends on the margins designed into the system and whether you do any high stress work like towing, but I certainly don't like the idea of paying so much money to have something that fundamentally doesn't remove heat as well as conventional water based coolant mix.

Propylene Glycol mixed with water would seem to be a decent option though, certainly from the non toxic point of view, but then it's not a waterless coolant, and presumably still rather expensive...

[Stickyfinger]

I would never run an open system as it will oxygenate the water...this will upset the ph levels with the resultant effects on the different metals.

The above in addition to the cooling effects etc of sealed systems.

[white exec]

Thanks for the Evans link, Dean. Now reminds me that I have read into this before.

There is oodles of stuff on the web, looking into Evans' claims for their "waterless" product.
Their MSDS sheets are interestingly not available on their own site, but are (a legal requirement) available republished on other users' sites.

The product actually contains ethylene and propylene glycol, plus corrosion inhibitors - the principal constitutents of standard industry coolant/antifreeze.
Their mainly ethylene glycol but 'waterless' mix is heavily criticised for
- having a lower specific heat (heat absorbing/conduction ability) than a water-glycol mix
- being significantly more viscous than water
- causing the engine to run hotter (even Evans' user text says that temp gauge may show higher).

There are dozens of articles on the web critical of the product claims.

I think you've already clocked that this is a marketing ploy, with the aim of selling an essentially low-cost brew at a high price. Close to snake oil, maybe, inasmuch as immediate engine damage will probably not result, so keeping the company in business and out of obvious trouble. Reminds me of the flurry of excitement about Silicone Brake Fluid - everlasting and non-hygroscopic, but also with extremely poor lubricating properties: a good deal of machinery and many brake systems creaked almost to a stop when using it.

[Deanxm]

Not to be cheeky, but is a coolant life of 20 years without changing it, at roughly 10x the price of normal coolant worth it for a car that's already 20 years old ? Are you planning on keeping your XM until it's 40 ? Because I'm not planning on keeping my Xantia that long.

I can assure you, my grandchildren will bury me in this car
photo(96) by Deanxm, on Flickr
photo(35) by Deanxm, on Flickr

But is it a good idea to run it open vented even if boiling isn't a risk ? An open vented system exposes the inside of the cooling system to a constant fresh supply of oxygen which can promote oxidation, whereas a sealed system has a small quantity of oxygen in the expansion chamber but once that is "consumed" no more can get in unless the cap is removed.

Water and oxygen is required, like the fire triangle you only need remove one but no i would run it with the cap on as it doesnt seem to pressurise anyway.

This is similar to the shift from open vented central heating systems to sealed pressurised systems - one reason the sealed system is preferable is that once the the system is filled and air has had time to bubble out and be bled no more oxygen is being added to the system all the time, while an open vent system allows a small but steady amount of oxygen to find its way into the system.

Its actually more about stopping kettling and noise in ever smaller, thinner and more efficient heat exchangers and lowering instal cost, time and limits placed on heating system design by having to have header/expansion tanks.

Chris, it is true, the marketing is strong with this one and it is said the louder someone shouts, the less they have to offer. I still cannot help but wonder about cooling with something more suitable than water, i mean a transmission cools with oil just fine.
Would be interesting to eliminate the water, oxygen and expansion while using a cooling medium with a higher boiling point. At the moment the XM runs pure OAT coolant with zero water in it and it cools very nicely, ive noticed no difference at all between a 50/50 mix and pure additive although on engines paired with poor or closely matched cooling capacity to engine output i would guess proplems could arrise.

D

[white exec]

'Pure OAT coolant' contains a very high proportion of water, even if it's ready-to-use and hasn't been diluted by the user. '100% xyz' only means there aren't any other active/significant constituents present: the same applies to emulsion paint, tomato puree, malt whisky, etc. Essentially, if it feels wet, it contains water (organic solvents excepted).

The reason why water is used so extensively in cooling systems (along with additional protection) is its excellent ability to
- flow
- rapidly absorb heat energy
- rapidly release heat energy
- mix with other additives at low cost.

Oils are less good in all these respects, but have to be used in certain applications, where lubrication or bearing-load is required.

Products undiluted with water, but liquid in nature (eg glycol, and the Evans product), are also normally less good than water in shifting heat.