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MG MGB Technical - Heater Woes

Driving down to MGB60 at the weekend, I noticed that my heater was blowing cold.

I managed without it, despite the misty windows.

Thinking that my new (4 years old) heater tap may be faulty, I disconnected the hose from it, only to find it blocked with a crystalline substance.

I've always been a fan of Bluecol antifreeze, but if I remember rightly, I struggled to find it when I recommissioned my car and used an antifreeze from Euro Car Parts. I'm guessing that this is what is blocking my hose, as I can't think what else it could be.

I have some Millers ethylene glycol antifreeze to put in it, but what is the best way of getting rid of what is likely to be in my cooling system at the moment?

Any recommendations for cooling system flush?

The car doesn't overheat, so I'm hoping there isn't much blocked, and the radiator was re-cored three years ago.





Dave O'Neill 2

Dave-
That looks like crystalized silica to me. Whatever water was mixed with the antifreeze, it sure wasn't distilled water! Purchase a good plumbing flush for hot water heater systems, follow the directions on the bottle, and make sure that you flush it out completely afterwards. If you have an aluminum core, be sure that the flushing agent is compatible with it. Refill with a mixture of quality antifreeze and distilled water only. Be warned that the premixed antifreezes that you can purchase at auto parts stores are made with tap water, not distilled water.
Stephen Strange

I think this is the antifreeze that I used.

https://www.eurocarparts.com/p/triple-qx-blue-antifreeze-coolant-5ltr-523770471

The specification doesn’t actually give much information.

I found another antifreeze being sold by Halfords, which is silicate based. I wonder if it is similar?

https://www.halfords.com/motoring/engine-oils-and-fluids/antifreeze/hal-silicate-antifreeze-rm-5l-600423.html

The water used was from the dehumidifier in my garage, so I would have thought it was fairly pure.
Dave O'Neill 2

Found this on the web:

Triple QX Blue Antifreeze Concentrate is an ethylene glycol based engine coolant concentrate formulated meeting BS6580 for use in all engines including those constructed from aluminium alloys. It employs established inhibitor technology and is nitrite, amine and phosphate (NAP) free and includes borate and silicate. Triple QX Blue Antifreeze provides up to 40,000 miles of service in passenger cars. It is advised the coolant is replaced when the above mileage have been reached or a period of 2 years, whichever is sooner.
Mike Howlett

That crystalline substance looks exactly like what happens when you mix old-fashioned glycol-based (IAT) coolant with modern OAT coolants, as in the attached.

G11 is supposed to be an inorganic acid technology and glycol based, the implication being that what was in there previously was OAT.

Why they jumped in the jargon bandwagon and came up with IAT which can be easily confused with OAT when you are trying to remember which is right for your car instead of sticking with 'glycol-based' beats me. Like using 'DOT5.1' for something that is compatible with DOT4 but not DOT5!

All I can suggest is trying things that will dissolve those crystals you can get out, then making sure whatever works is compatible with your engine, heater and cooling system.


paulh4

There shouldn't be any OAT in there. Prior to re-commissioning, it was last on the road in 1999, at which time it would have had Bluecol.
Dave O'Neill 2

Dave-
Water from a dehumidifier will contain whatever pollutants are in the air. Many years ago my father kept a dehumidifier running in our basement, and it was my responsibility to empty out the collected water. Believing that the water was fairly pure, I gave some of it to my pet dog. The dog got sick, vomited in our living room, and had diarrhea for a day or so.
Stephen Strange

Dave-
Perhaps I should make myself clear-
in light of the above previous experience, I consider the water that is condensed by a dehumidifier to be a somewhat questionable alternative to distilled water.
Stephen Strange

Stephen
Thanks. I picked up some DI water today. I will refill with that, once I've given it a good flush.

I used to live in an area with soft water and never had any problems with using tap water with anti-freeze. We now have harder water, so I didn't want to risk using that.
Dave O'Neill 2

This thread was discussed between 30/09/2022 and 03/10/2022

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