[nuke21]

So I am doing a coolant flush on my BMW. I was going to drain it, fill it with distilled water, drive it around till operating temperature, then drain and repeat a few times. Someone told me to add a gallon of 5% distilled white vinegar then fill rest with distilled water, drive around for 2 days, then do the distilled water drain and filles a few times. They said this will help get some gunk out since this car has 160k miles and assume this wasn't done by the previous owner. My question is will the distilled white vinegar eat up the rubber seals in our cars if left in there that long or is this just an old wives tale?

[eljay]

I wouldn't risk it with vinegar.
Just use coolant flush and replace coolant.

[Efthreeoh]

From Wikipedia:

Cleaning
White vinegar is often used as a household cleaning agent. For most uses, dilution with water is recommended for safety and to avoid damaging the surfaces being cleaned. Because it is acidic, it can dissolve mineral deposits from glass, coffee makers, and other smooth surfaces. Vinegar is known as an effective cleaner of stainless steel and glass. Malt vinegar sprinkled onto crumpled newspaper is a traditional, and still-popular, method of cleaning grease-smeared windows and mirrors in the United Kingdom.

Vinegar can be used for polishing copper, brass, bronze or silver. It is an excellent solvent for cleaning epoxy resin as well as the gum on sticker-type price tags. It has been reported as an effective drain cleaner.

The use of vinegar in dishwashers and washing machines can cause damage to their rubber seals and hoses, leading to leaks. According to testing done by Consumer Reports, vinegar is ineffective as a rinse aid and in removing hard-water film while used in a dishwasher. According to Brian Sansoni, chief spokesperson for the American Cleaning Institute, vinegar "isn't very useful with stains that have already set into clothing, including food stains and bloodstains." Other household items and surfaces that can be damaged by vinegar include flooring, stone countertops, knives, the screens of electronic devices, clothes iron water tanks, and rubber components of various small appliances. Common metals that can be damaged by vinegar include aluminum, copper, and lower-quality grades of stainless steel often used in small appliances.

I'd suggest it is not necessary.

[M-technik-3]

I use it once a year to do my tile floors in a 25/75 ratio 75 being water. It is good at cleaning out old food in your under sink incinerator. Makes the smell go away.

Car wise windows is as far as I would use it.

[nuke21]

Even at only 5%? Doesn't this mean the entire gallon of distilled white vinegar only has 5% of it is vinegar and the rest is distilled water?

I mean I'm definitely too scared to use it now from what you guys are saying but that is crazy to think 5% can do that kind of damage!

[M-technik-3]

I personally would not do it as I don't know how it would react with a Magnesium block. Cast Iron and I was younger and cars were extremely cheap back then sure I would have tried it. These days with sensors and seals and alloy engines I am very unlikely to try.

[Efthreeoh]

Originally Posted by nuke21

Even at only 5%? Doesn't this mean the entire gallon of distilled white vinegar only has 5% of it is vinegar and the rest is distilled water?

I mean I'm definitely too scared to use it now from what you guys are saying but that is crazy to think 5% can do that kind of damage!

I really have no idea what your concerns are. My car has 423,000 miles on it. I've never "cleaned" the cooling system. I replaced the radiator at 350,000 (after a deer strike on the front end - it wasn't leaking). I (unnecessarily) replaced the original set of coolant hoses at 8 years and 236,000 miles. Those hoses are still on the car 9 years and nearly 200,000 miles later; I did the Mickey flange at 378,000 in 2019. I'm still on the original coolant tank. In 2011, the T-stat failed at 134,000 and the WP at 149,000; those replacement components are still on the car nearly 14 years and 283,000 miles later. I've changed the coolant 3 full times (with no flush) just drain and refill. Throwing in acetic acid and letting it cook inside the aluminum/magnesium engine and plastic cooling system seems sort of pointless (stupid IMO) and just asking for trouble. BMW does not call for it, so why do it?

[eljay]

Exactly as Efthreeoh said above: your goal shouldn't be to dislodge every speck of debris in the cooling system as you may get trapped in the water pump etc. Just flush the coolant and be done. If you want factory clean engine, take it out, disassmble it, clean the crap out of it and re-assemble.

[StradaRedlands]

When you drain the coolant, a LOT of debris comes out with it. Just drain and fill a few times to increase your percentage of new coolant and you should be good. But if you really want to flush because you have known contamination, do it right

[lobotomy]

What all above have said is true. You must confront whoever gave you this advice, and let them know it is detrimental to any coolant system in any vehicle! Worst advice I have heard so far this year, and probably for the next 11 months as well!
Acidity is the #1 attacker of a cooling system. It occurs naturally as the coolant /water mixture ages. This acidic buildup causes deterioration to components as already mentioned. Why you would ever want to flush a coolant system with an acidic mixture is beyond my comprehension!

[NZE90]

Originally Posted by nuke21

So I am doing a coolant flush on my BMW. I was going to drain it, fill it with distilled water, drive it around till operating temperature, then drain and repeat a few times. Someone told me to add a gallon of 5% distilled white vinegar then fill rest with distilled water, drive around for 2 days, then do the distilled water drain and filles a few times. They said this will help get some gunk out since this car has 160k miles and assume this wasn't done by the previous owner. My question is will the distilled white vinegar eat up the rubber seals in our cars if left in there that long or is this just an old wives tale?

No, i wouldn't bother with this person's advice to you. Seems like a ridiculous idea.

[TriumphTim]

I would not flush with vinegar solution.

What have kind of vehicles is the "someone" working on, maybe ok for some old cast iron block thing with all rubber hoses.

Not a good idea for a modern car with a mix of metals and plastics.

[nuke21]

Thank you all for the great advice. I will just drain and refill a few times with distilled water and consider that a good enough flush.

[crashoverride]

Heck you can flush with tap water. But driving without coolant is ill advised.