Do I need to run 100% coolant if I start my car/drive once a week?

BaLleRz68

Founding Member
Oct 9, 2001
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Im on my second radiator after busting the first one and was wondering if I need to run 100% coolant and a electrolysis cap. I talked to a local mustang shop and they recommended me to do this in order to prevent the radiator from leaking again? I only drive my car on the weekends or start it if i dont have time to take it out for a drive. Any thoughts are appreciated. Thanks.
 
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It sounds like the first radiator was just plain crap. I feel the same way about your shops advice.

100% antifreeze will be hard on the rubber hoses and will not cool very well. Use the standard 50/50 antifreeze/distilled water mix and, if you want, add some additional corrosion inhibitor. Antifreeze already contains some.

I am not familiar with the cap that you suggested, but suppose it wouldn't hurt anything to try.
 
Read the temp ranges for the different mix ratios and you will come to the conclusion that pure anti-freeze is lunacy. Run 50/50, this gives the widest heat range. If you are concerned about small leaks use the Prestone liquid sealant for cooling systems. I've used it for 20 years with very good results. Also, pure coolant is so slick it will find a way out where 50/50 would stay in.
 
NEVER use 100% antifreeze. it is less efficient to do this, you actually do a better job heating, cooling with the 50/50. i would talk to your local shop again about that suggestion running 100%
 
Agree with the 50/50 advice.

I do use an sacrificial anode-equipped radiator cap, and it is slowly disappearing, which tells me something. With iron block, aluminum heads, and copper/brass based radiator, there is some ionization going on and I'd rather the cap anode dissolves instead of more expensive bits. Make sure your engine block is well grounded too, or you can be slightly energizing your coolant and accelerating electrolysis.
 
To add to what's been said, the more coolant that's in the mix, the faster it becomes acidic. This is an issue in diesels as they are artificially heated in the winters and the coolant goes acidic faster, we change the coolant every 2-3 years in the 6.5TD.