Webasto heating antifreeze

[MHS]

Going back on board this weekend, and want to check the antifreeze level in the central heating.

 

Webasto recommend Glycol, so I presume if it needs topping up I can use normal car antifreeze with rust inhibiting properties.

 

Am I right in remembering its best not to mix colours of antifreeze?

[cuthound]

According to several car forums mixing red and blue antifreezes can result in it forming a chewing gum like substance, so best to flush with water after draining if changing colours.

 

The blue antifreeze needs changing every 2 years, red every 5 unless its the Ford premium antifreeze, which lasts 10 years. I recently changed mine to Ford premium.

Pre-mix the coolant to a 25% solution for the Webasto or it may not conduct heat to the top of the radiators.

 

If changing the antifreeze for the engine use a 50% mix.

 

ETA to clarify the bit about flushing if changing colours

Edited December 2, 2014 by cuthound

[Harvski]

I recently bought some red antifreeze for my webasto heating circuit, I was informed the the chap at my local autospares that red and blue are both glycol based and quite safe to mix. So far so good after a few weeks.

[raymondh]

Before doing anything check

 

Does the solution freeze ? put some in the freezer 100% accurate check

Does it allow corrosion ? put sample metals in the solution and see if things rust or corrode - may take a while

 

In all the tests I have done my solution has been fine ie car, van, boat all 7 years or older

 

Works for me and the environment

 

Ray

[Chalky]

I recently bought some red antifreeze for my webasto heating circuit, I was informed the the chap at my local autospares that red and blue are both glycol based and quite safe to mix. So far so good after a few weeks.

 

The Red / orange is based on organic acids and is fundamentally different to the ethylene glycol used in the blue.

 

I've been advised not to use the red in older engines with soldered radiators because of issues with it attacking the soldered joints in the radiator however I've got no evidence to support this.

[Drayke]

I think Webasto recommend a mix of antifreeze at 40-50%, that’s what I have always put in mine. Don’t know about mixing different colours though.

[cuthound]

I initially put a 50% mix in my Webasto heating circuit, as recommended in the Webasto manual, only to find that the top half of the radiators remained cool, despite bleeding.

 

I initially tried heating the tops of the radiators with an electric heatgun (as used to strip paint). This was temporarily successful, as it restored heat circulation to all of the radiator surface, until the heating was turned off.

 

In the end I had to bite the bullet, drain down again and refill with a 25% solution (as recommended by NMEA and Tony Brooks of this parish).

 

Moral of the story - listen to acknowledged experts :)

[mango]

The component of antifreeze that protects against freezing is usually ethylene glycol or propylene glycol. These don't lose their antifreeze properties unless diluted with water when the system was topped up. Cheap antifreeze used to use methanol which could evaporate and become less effective, but I have not seen methanol-based antifreeze on sale for years.

 

The reason we need to change antifreeze is because the corrosion inhibitors become ineffective, rather than the antifreeze itself. The reason that different types of antifreeze should not be mixed is because the corrosion inhibitor components rather than the antifreeze components are not compatible.

[NMEA]

Possibly a vehicle manual? the marine install manual gives a mix of 25% glycol, the old 50% stipulation was for where the engine coolant was used, so as not to be in conflict with the vehicle manufacturers requirements. A 25% mix is a good compromise between frost protection and heating efficiency. Best of all for heating efficiency is water and inhibiter, but then you are left with no frost protection unless you use a frost 'stat.

I initially put a 50% mix in my Webasto heating circuit, as recommended in the Webasto manual, only to find that the top half of the radiators remained cool, despite bleeding.

[Sea Dog]

I initially put a 50% mix in my Webasto heating circuit, as recommended in the Webasto manual, only to find that the top half of the radiators remained cool, despite bleeding.

 

 

This issue is (also?) caused by poor mixing. The anti freeze concentrate should not be added separately to the water whatever the concentration ratio as it won't mix itself well in the heating system. Maybe alternate small quantities will be ok, but preferably mix it thoroughly at the required strength before it is introduced to the system. NMEA's 25% in UK climate sounds good to me.

[cuthound]

This issue is (also?) caused by poor mixing. The anti freeze concentrate should not be added separately to the water whatever the concentration ratio as it won't mix itself well in the heating system. Maybe alternate small quantities will be ok, but preferably mix it thoroughly at the required strength before it is introduced to the system. NMEA's 25% in UK climate sounds good to me.

Yup,

 

I premixed both the original 50% and the replacement 25% mix in 20 litre containers, before filling the system. NMEA's 25% mix sorted my heating issues.

[J R]

We replaced our Webasto water/antifreeze this year with a 50/50 mix. Have heard a 25% antifreeze mix will work but have not tried it. Never add/top up with a different colour antifreeze as mentioned above. When you do a drain down and refill there will be air trapped inside the system. Its a devil to get out and demands a certain amount of runnning the system, bleeding valves and topping up the header tank. It is not caused by the water mix added, just trapped air in the pipes. Any thing added must be well pre mixed. Adding the antifreeze and then water will cause problems with the circulation. We change ours every couple of years to be on the safe side and get the anti freeze from the local motor factors as its saves a lot from buying from a high street out let or petrol station.

[Neil Smith]

How do you calculate exactly how much the heating circuit takes.

 

Neil

[NMEA]

22mm tube is about 0.31 litres per metre, rad capacity should be published by the maker.

[blackrose]

On 27/12/2014 at 15:16, cuthound said:

Yup,

 

I premixed both the original 50% and the replacement 25% mix in 20 litre containers, before filling the system. NMEA's 25% mix sorted my heating issues.

 

Did you mix it with tap water? I know hard water contains minerals which can cause scale, but it's a finite amount going into the system. I've read websites which say that distilled water is not correct either and softened water should be used.

 

Edit: Hella actually state that tap water is used.

 

https://www.hella.com/techworld/uk/Technical/Car-cooling-system/Refilling-coolant-2708/

 

 

 

Edited September 26, 2021 by blackrose

[cuthound]

1 hour ago, blackrose said:

 

Did you mix it with tap water? I know hard water contains minerals which can cause scale, but it's a finite amount going into the system. I've read websites which say that distilled water is not correct either and softened water should be used.

 

 

 

I used tap water. The water where I live is reasonably soft, and the deposits only drop out once until the system is refilled.

 

As I use Ford 10 year long life antifreeze I won't be changing the antifreeze often, so the amount of scale introduced will be minimal.

[GUMPY]

I think used deionized water it's cheap so why not?

[ditchcrawler]

9 hours ago, blackrose said:

 

Did you mix it with tap water? I know hard water contains minerals which can cause scale, but it's a finite amount going into the system. I've read websites which say that distilled water is not correct either and softened water should be used.

 

Edit: Hella actually state that tap water is used.

 

https://www.hella.com/techworld/uk/Technical/Car-cooling-system/Refilling-coolant-2708/

 

 

 

We use to use deionised water on out generators but they ran vented cooling systems so often required topping up