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Accidentally poured oil in antifreeze reservoir. Safe to drive short distance after siphon?

Ok, was inspecting my antifreeze in my reservoir because my heater has been blowing cold air. Looking to see if it was dirty or anything. It was brown. Decided to check the oil on the dipstick to see if it was milky. I noticed the oil was low so I also took the cap off of it and went to get a quart or oil to top it off. Came back, was talking on the phone to my mechanic friend and paying no attention at all and put 300-500 ML of oil in my radiator reservoir NOT cranked and hasn’t been cranked yet. Now my biggest problem is that my car i mini cooper so I have to take it to a dealer and since I’m in the middle of nowhere that means a 60-80 mile drive. So my question is, since the oil is lighter than antifreeze and is not in the system yet can I siphon out the oil or oil and antifreeze and be safe to drive it to the dealer? I can’t just drain the hose either for several reasons

I can’t speak to the effect on your own car of doing that of course, but if that happened to my 25+ year old Corolla that’s what I’d do, just use a turkey baster to suck as much of the oil out as I could from the top of the radiator. I’d error on the side of sucking too much out rather than too little. This presumes the engine was never started of course. If it was started, then there would be no doubt, I’d drain and flush the entire cooling system. The biggest problem with oil into the cooling system I’d guess is that it might degrade the hoses, and perhaps even the internal gasket material.

It was not started. I sucked out everything I could (oil and antifreeze) with a giant syringe. There was still some stuff in the very bottom but I think it was mostly all antifreeze. Normally I would bite the bullet and test my luck but I literally just got this car less than a week ago lol

I wonder if you could find someone local who was knowledgeable about car repairs enough to simply drain out the coolant from the radiator, and put fresh coolant back in. That might be a better alternative to remove most of the oil, and not a technically difficult job.

You can still slowly add in diluted antifreeze or distilled water to ‘float’ the oil back up within the reservoir to improve your syringe efforts. And after it is pretty empty, see if you can wipe the inside walls of the reservoir if oil is clinging there.

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I agree. It wouldn’t be a hard job to just removed the hose leading to the radiator to flush out the reservoir and maybe wash it out but I don’t have a floor jack or anything here. Also this is my first European car (god just saying that makes me sound like such a douche) and everything in there is so tight!

But I think you’re right I just need to ask around. I’m just not from here and don’t know who to trust yet. Also I have to go to work everyday so I NEED my car! Haha

Did you pour the oil in the radiator or in a remote plastic tank? If is the remote tank, just remove it , pour everything out, put some detergent and hot water in, shake it up good and rinse it out.

If the coolant is brown, then I assume that means you’ll be replacing it. If so, then sucking out as much oil as you can for the drive seems safe to me.

I’d remove the reservoir, flush it out well, and start over.

I assume your reservoir looks like this:


Filling with 50:50 antifreeze and driving to the mechanic will be no problem.

I flushed it out and washed it out best I could. I’m taking it to have the whole system flushed yes. Side note, in the bottom of my reservoir I noticed some buildup of something. Brown/tannish. Looks like mud. Kind of has the consistency of mud. Do you guys think that is rust or oil?

Probably a little rust or some material used at the time of engine assembly that has settled out. Absent other symptoms, I wouldn’t worry about that. I think my truck has a little brown residue at the bottom of the coolant overflow tank too.

Thank you. Scared me a little bit. I still haven’t figured out what’s wrong with my heater though. That’s the whole reason I started this mess

This is what colpr my coolant was too.

Whether that’s good or bad depends on what it looked like when the cooling system was originally filled. Cooling systems should be drained out and re-filled with new according to the owner’s manual service schedule. I do it every 3 years on my vehicles, some folks here say every 2 years. Others say longer, esp if they use a long life coolant. If you’re not sure when it was done last, that’s something you can have done at the same time the dealership figures out what is wrong with your passenger compartment heater. On newer cars the posts we get here about heater problems, it turns out usually a vent door isn’t actuating, not that the heater core isn’t working.

Yuck…the previous owner dumped a turkey on you.

Driving with a low cooling system for a long period of time can really foul up the condition of the coolant.

This problem has now been followed up in a new thread about brown mud in the coolant reservoir.
I suggest we proceed with future comments on that thread.

To the OP, I suggest that in future you keep a thread intact. All of the information gleaned is important, and starting a different thread on the same problem disjoints the information.

@cdaquila could we get two threads merged together?