Can you use whole milk in your radiator in an emergency? This guy did so you don’t have to.

Car owner and Redditor /u/Sqyare_Ad284 shared an interesting scenario that recently happened to him after a trip to his local grocery store to the /r/MechanicAdvice subreddit.

On his way home, his car started overheating. In the middle of nowhere (rural farmland,) he DIY’d a fix for his radiator hose but, with several gallons of coolant spilled, he needed something to replace it with.

Nowhere near a water source and not enough in his bladder to do…you know what into the radiator, he did the next best thing, he filled his radiator with two gallons of whole milk he just bought.

That’s right, not 1% or 2%, regular ol’ whole milk.

Check out his thread posted below.

Had to use milk to fill my coolant system
byu/Square_Ad2484 inMechanicAdvice

OP describes how a blown radiator hose was the culprit.

Using zip ties and duct tape, he was able to bandage the radiator hose good enough for the trip home.

But whole milk?

As his caption reads, he made it out OK.

“It sounds disgusting but I made it home without it getting too hot. I drained it the next morning and it reeked like hell but it worked. Flushed everything and replaced it.”

His question was,

“Will this cause any long term damage?”

While no one gave a definitive answer, no one said he’d do permanent damage either, and I agree with that.

There was, however, plenty of advice.

“Flush the h*** out of it like 3-4 times. Change the thermostat and hope for the best. When I was younger, I used beer and urine in the radiator to get home,” /u/guyonsomecouch12 commented.

“I would fill with water, run to temperature and drain, and continue to do so until it drains clear. After it drains clear, fill with coolant,” /u/Djwaffletop suggested.

The fact of the matter is that whole milk is just 87-90 percent water, making it the largest component of milk.

The other 10-ish percent is proteins, fats, carbs, minerals, and vitamins, in other words, organic compounds.

I’d bet that, even if he didn’t flush his radiator, and he lives in an area that doesn’t get extremely hot or drives in overly demanding conditions, his engine would be just fine, at least for a little while.

If he used the heater, rancid milk would flow through his heater core, and it’d probably smell awful.

The worst that can happen is, since milk doesn’t have lubricating properties or rust inhibitors, his cooling system would begin to rust and eventually gum up. After how long? Your guess is as good as mine, maybe a year…or two?

But, in an emergency situation, especially a life or death sort of thing, liquids that are mostly water (like milk or fruit juice without pulp) would be fine to fill your radiator with if you’re overheating.


  1. As a mechanic of 40yrs I’ve seen and used lots of tricks to get my trucks home. As long as you flush it good shouldn’t affect anything.

  2. Using whole milk in your cooling system would probably be ok on the short run, most definitely would be better to drain the cooling system once arrived home immediately before the vehicle cooling system cools down so you don’t have cottage cheese buildup in your radiator and water pump, thermostat and small coolant hoses and heater core as well but I’m pretty sure milk would help remove rust in the cooling system but have it drained immediately so your cooling system doesn’t develop cottage cheese! Milk has no lubricating ability so depending how long the drive was so I would have to say that the water pump will be the victim really soon since the bearings were wiped out of lubricating agents in ethylene glycol so think again and replace that water pump before you end up repeating last night’s episodes.

  3. Lmao…This takes me back when am old friend of mines.We were coming from somewhere..And the car had over heated…We barely made it home It was a bucket in the yard and it .had put some kind of tan liquid water substance I’m guessing the bucket was used to Wash out some paint brushes and rollers…..He quickly poored it in the car to cool it down. I was like what are you doing…I learned that day that it was a quick temporary solution to prevent any further damage to the engine block ..That was back in 1989..????


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