Changing Engine Coolant

Posted by: Calum F on 10 February 2014

I need to change the engine coolant in my Honda Accord. Does anyone know, should I be using De-ionised water with the antifreeze or is filtered tap water OK?  Thanks
Posted on: 10 February 2014 by Mike-B

The "right" answer is de-ionised water.  

But some will say it depends were you live & if in a real soft water are its OK to use that 

Safest of all is to buy ready mixed

 

Make sure you have the right type of antifreeze for the engine, alloy engines generally need  a different type from iron/steel engines - again check with the makers specs 

 

Posted on: 10 February 2014 by Bruce Woodhouse

Agree with Mike. Pre-mix is probably the way to go as you can then be sure you have the right dilution. Definitely check your manufaturer specs re OAT and non-OAT types. There are multiple brands and types and in general they should not be mixed (they can react and solidify) so if it has been main dealer serviced in the past i'd ask what they use. if not give the system a good flush with a hospipe before the refill.

 

I'm a bit of an expert on this. I own a Triumph Stag, a car with a somewhat notorious cooling system

 

Bruce

Posted on: 10 February 2014 by Mike-B
Originally Posted by Bruce Woodhouse:

...............   Definitely check your manufaturer specs re OAT and non-OAT types. There are multiple brands and types and in general they should not be mixed

 

A story to underscore the problems over mixing antifreeze types .....

In my past life I was director of service for a refrigeration system manufacturer & we used diesel engines very similar to a car in self powered units.  We had a heat exchanger across the engine coolant & refrigeration systems & as such the coolant needed antifreeze & it had to be spec'd for -40'c. 

We had thousands of units around the mideast & india & trying to teach these guys about the importance & the complexities of antifreeze was not easy, especially so when the modern non-glycol mixes started to appear.  Needless to say much did not get followed & all sorts of disasters ensued;  the worst was a fleet of engines in India, they had cast iron heads & blocks & I got called in when all the heads had been eaten away & attempts to run the engines had punched holes thru from the combustion chamber into the water jacket,  The negotiations to replace 50 engines is another story. 

The message is don’t mix antifreeze, what you could get away with a few years ago ain’t good these days with the many types & formula around.

Posted on: 10 February 2014 by Calum F
Thanks gents. The car is 14 years old and I know it takes a traditional ethylene glycol type A/F, blue in colour but it has never been changed but Honda recommend change at 10 years then every 5 thereafter. Did not realise the technology of A/F has changed so much, no idea what this OAT is all about or why and when it came in
Posted on: 10 February 2014 by George J

Ask the Honda dealer to recommend the best antifreeze for your application. If they don't know then no-one does ...

 

ATB from  George

Posted on: 10 February 2014 by Mark Dunn

Hi Calum,

 

When you ask the Honda folks about which antifreeze to use be sure to find out if you need a silicate free type. Honda had a period around the time your car was built where you had to use silicate free other wise the water pump seals failed in short order.

 

Regards,

Mark Dunn