[ROVERNET - UK] Coolant choice

Tue May 30 21:04:25 BST 2006

Thanks Vern! I'll try the water wetter in my system then.

>From: Vern Klukas <vern at inkspotco.com>
>Reply-To: rovernet at lyris.ccdata.com
>To: rovernet at lyris.ccdata.com
>Subject: Re: [ROVERNET - UK] Coolant choice
>Date: Tue, 30 May 2006 12:55:32 -0700
>
>Here is an article I wrote a couple of months ago for the Roverview, about 
>coolants.
>
>
>Most car owners, when asked to describe the parts of the cooling system of 
>their car, list the radiator, water pump and hoses, and think of the 
>coolant itself as just the stuff in the radiator.
>In fact, the most important part of the cooling system is the coolant 
>itself. Using the wrong fluid or not maintaining the quality of the fluid 
>will lead to greater grief than a soft hose or a leak in the radiator will 
>(unless you are miles from anywhere, in the desert, when the leak is 
>discovered, that is).
>There are three tasks that any coolant must perform: First, it must act as 
>an efficient medium to transfer heat from the engine. Second, the coolant 
>must control corrosion and sediment within the cooling system. And finally, 
>the coolant must remain liquid at the environmental temperatures the engine 
>operates in, which in our context means it shouldn't freeze.
>All modern cars use glycol/water mixtures as coolant. This is more to 
>satisfy the third requirement of a coolant than the first two requirements. 
>And it does do that well, with a 50/50 ethylene glycol/water mix not 
>freezing until -37°C (-35°F).
>Until recently, ethylene glycols has been the glycol of choice. Concerns 
>about its toxicity and a sweet flavour that encourages animals and children 
>to sample it have led to more use of propylene glycols, which are lower in 
>toxicity but more importantly, does not have the sweet flavour. However, it 
>does not provide quite as good protection, as a 50/50 mixture freezes at 
>-32°C (-26°F).
>While the glycol coolants protect against freezing, they are relatively 
>poor at the first task of a coolant, transferring heat. In fact, water is a 
>superior coolant for two reasons. Most importantly, it has twice the heat 
>capacity of the glycols. That means that it takes twice as much heat to 
>raise the same quantity of water 10° as the same quantity of a pure glycol. 
>The second reason is that water is a quarter the viscosity of a typical 
>glycol. The lower viscosity helps heat transfer as the hot water mixes more 
>readily with the cooler water away from the engine surfaces, moving heat 
>away from the engine metal.
>Water freezes though, and so is impractical as a year-round coolant in our 
>cars.
>Water is also poor at corrosion and sediment control. Water can contain 
>dissolved minerals, and its solvent nature means that many corrosion 
>processes are enabled in a water bath. The glycols are pure materials so 
>have no dissolved minerals, but as they are mixed with water in use, must 
>have corrosion protection chemicals added.
>How this applies to our collector cars is explored next.
>
>Personally, I use 100% water during the warm months of the year and a 
>glycol mixture just sufficient to protect to the coldest weather I see 
>during the winter in my daily driver P6. Someone who only uses their car 
>during the warmer months could do the same, but simply drain the system for 
>the winter. Mind you, many heaters cannot be completely drained and an 
>empty radiator raises the specter of forgetting to refill come spring. The 
>twice-yearly change of coolant also performs the important task of 
>replacing the anti-corrosives in the system.
>But wait you say, didn't you just write that water fails to perform any 
>anti-corrosion duties by itself? That's true. I've been keeping something 
>from you.
>First, I use only distilled water. Distilled water (not deionized water, 
>which still contains minerals) is free from dissolved minerals, solving a 
>good part of the problem.
>Second, I add an product from Red Line Synthetic Oils, called Waterwetter. 
>We'll get to the "waterwetter" later,  here the point is that this product 
>has all the anti-corrosive additives you would normally find in an glycol 
>coolant.
>Okay, why "waterwetter"? The main purpose of the product is not corrosion 
>control, it to act as a surfactant, which is a substance that reduces 
>surface tension in a liquid. Surface tension is the force that makes a drop 
>of water bead on a waxed surface. If surface tension is reduced, the bead 
>collapses and wets the surface better. Hence, the "waterwetter" name.
>This is an important effect and it works just as well with glycol coolants 
>as water. It increases the ability of a coolant to transfer heat from the 
>engine this way: Heat from the engine causes the microscopic layer of 
>coolant next to the engine surface to boil. This vapour then condenses into 
>the next layer of coolant transfering the heat. Lower surface tension 
>allows the vapour to condense more readily into the coolant, increasing 
>efficiency.
>It is a win for everybody. If you use regular glycol coolant mixes in your 
>car, Waterwetter will improve the performance of your coolant close to that 
>of pure water. Using it with pure water will result in even greater 
>performance.
>Your car will have a greater ability to endure those long climbs in the hot 
>sun without overheating and will generally run cooler all the time.
>Never forget, however, that maintaining that performance means regular 
>coolant changes to renew the anti-corrosion properties of whatever coolant 
>you chose to use.
>
>
>Yours
>Vern
>
>>Hi Ali,
>>
>>I did a bit of searching on coolant choice this weekend, It's the first 
>>really hot weekend in NY, and the temp gauge on my 2000TC was just at the 
>>top of the green section and would occaisionnally cross the line into the 
>>low red. I think re-coring the radiator may be on the cards. The coolant 
>>quite clean, and I think the engine had been flushed before I bought the 
>>car last October.
>>
>>Anyway, apparently the antifreeze does stop corrosion in the engine, but 
>>also inhibits thermal conductivity (so I was wrong with my last email on 
>>this). So it doesn't cool as efficiantly as pure water.
>>
>>I did find a product called 'water wetter' from redline oils that's meant 
>>to improve the wetting abilies of coolant and thereby improve cooling by 
>>up to 30 deg F. I'll add some to the coolant in my car and tell you if 
>>anything improves. Has anyone else used this or a similar product? did it 
>>work for you?
>>
>>That's about it apart from the fact that I got my NOS carbs' fitted this 
>>weekend and what a difference it made. I kept thinking the engine had 
>>stalled when pulling up at the lights, and I'm not creating my own 
>>personal hole in the ozone layer any more.
>>
>>Take care,
>>
>>StevenD
>>
>>
>>
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>
>
>--
>Vern Klukas                             I'm a little . . .
>Inkspot Type & Design
>vern at inkspotco.com
>
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