My son accidently poured some antifreeze into the place where the oil goes now the car runs with ticking when its idle

  • 1
    Did you drain all the old (well, the oil/anti-free mixture), flushed a bit more oil down to clean it and then refilled with clean oil? or does it tickle with the original polluted mixture? – Hennes Jul 24 '14 at 17:53

You need to drain the oil (let it drain as completely as possible) and put new oil inane run the engine. If you see it come back as a "chocolate milk" looking mixture, you need to change the oil again. This may take several tries (two or three) to get it all out. You need to change the filter with each attempt as well. The reason this is important is because the water in the oil will cause corrosion on the bearings, which will degrade them and ultimately allow them to fail. The sooner you get this done, the less damage you'll do to your bearings. The corrosion does take some time to happen. If it just happened and you get it done soon, you shouldn't run into any issues.

  • I agree about what to do in this case, but its not because of corrosion. Antifreeze is not water, and consist propylene glycol, that prevent corrosions. The things why you use antifreeze and not water is: lower freezing point, lubrication and to prevent corrosions of radiator (steal and aluminum). But antifreeze do not lubricate as good as oil and you can damage you engine because of strong heat and fast wear and tear of your engine parts. – Watsche Jul 25 '14 at 7:08
  • @Watsche ... The problem with your premise is two fold. First, coolant is anywhere from 30-50% water (or should be). Secondly, while antifreeze does work well against corrosion in the radiator, its not so good in the crankcase. Bearing surfaces are made of babit (sp) which doesnt play well. – Pᴀᴜʟsᴛᴇʀ2 Jul 25 '14 at 20:50

I've worked at automotive dealerships for over 30 years. Bearings are made of soft metals such as copper and babbitt so that they will not damage crank journals if contact is made. In earlier days, having coolant in the oil was an inconvenience. You may want to run a few quarts of ATF through an engine, then change the oil twice, in quick succession. Over the last 20 years, many engines have bearing materials that will not tolerate coolant. A chemical reaction can occur which will destroy the bearings. Before you do a lot of work on a car with, for instance, blown head gaskets, find out if your bearings are going to be adversely affected. It may be more prudent to simply replace the entire engine.

  • +1 on making sure the engine is still viable. Easily could have ate up a bearing with water in there – DatsunZ1 Jan 4 '19 at 15:28

The best solutions is to drain the oil and replace the oil filter to prevent damage to your car. Then fill it with new and clean oil. As antifreeze is harmful for the engine and can cause lots of smoke and can overfill the oil capacity in engine.


Lexus/Toyota have a machine that flushes all of the lubrication system. It is fitted to the vehicle by a hose and adaptor placed at the sump plug hole. A second adaptor is placed in place of the oil filter, again with hose. When connected up and running it flushes the system with fluid, then gas, and then oil. It was devised primarily for their hybrid vehicles, because of their particular engine usage. Other non-Lexus/Toyota prestige garages sell the flushing operation as part of a service enhancement.

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