An alcohol based fluid that is miscible in water and used to remove heat from the engine. Also see [tag:cooling-system] for related components such as the radiator and water-pump.

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23
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8answers
150k views

Running with straight water as coolant in the summer. Is it fine?

I grew up flushing the coolant twice yearly. In the Spring, you drain the antifreeze and fill with straight water for the summer. In the Fall, you drain the water and put in a 50/50 antifreeze/water ...
8
votes
3answers
54k views

Oil in coolant - how much trouble am I in?

I have oil in my coolant reservoir. Could it just be the head gasket or is it almost certainly the entire engine or might it be something else entirely? Thanks in advance...
6
votes
2answers
28k views

Accidentally poured engine oil into the coolant reservoir

My 1990 Mazda 626 leaks oil like a sieve, so I regularly top up the oil. In a moment of stupidity, I opened my radiator cap instead of my oil cap while topping up my engine oil, and poured about 50-...
10
votes
1answer
148 views

Coolant Reservoir

Two questions, One, is there any reason why some coolant bottles are shaped in this way? Two, if this coolant bottle was placed on its side such as in the image below for example would coolant ...
11
votes
5answers
126k views

Why would there be transmission fluid in the water overflow reservoir?

The car is a '98 Buick Lesabre with the 3800 engine and about 170k miles. It appears as though some oil was in the radiator, but I haven't seen any signs of coolant in the oil. The water pump recently ...
7
votes
3answers
2k views

What actually happens when there is not enough coolant in a car engine?

I know that a lack of engine oil can destroy an engine, so I was curious as to whether it is just as bad to drive a car with a very low engine coolant. What is engine coolant? What exactly are all ...
4
votes
1answer
166 views

I've got oil in my coolant but no coolant in the oil - Ford Triton V10 Motorhome

I have a Triton v10 engine in my vehicle I have oil in my coolant but no coolant in the oil. What could be the problem?
2
votes
2answers
44k views

Using only coolant or mix of water for radiator?

Do I have to use only coolant for radiator or mix coolant with water, if so what percentage of coolant and water should be mixed?
18
votes
12answers
93k views

Is Prestone “All Makes/All Models” coolant *really* compatible with all models?

My car's manual says to use the blue Honda coolant: Always use Honda All Season Antifreeze/Coolant Type 2 [MSDS]. This coolant is pre-mixed with 50 percent antifreeze and 50 percent water. ...
13
votes
2answers
201 views

How do I troubleshoot the source of oil in my coolant?

I would like to know the step by step troubleshooting procedure for discovering the source of oil appearing in coolant. There are several different points of failure that can be the root cause for ...
9
votes
3answers
2k views

Car won't reach operating temperature

Here's a seemingly simple problem - I noticed that the temperature gauge of my mother's 2004 Opel Meriva 1.7CDTI won't ever climb above minimum. I checked the OBD readings to see if it was a defective ...
5
votes
1answer
9k views

Bubbling sound from coolant and increase coolant liquid level

I drive an old Daihatsu Charade 1993. Just 2 days ago, I heard a bubbling sound from the coolant when I turned off the machine. I didn't really care much until yesterday when the car got hot ...
4
votes
1answer
251 views

Flushing coolant after driving only with water in

If I drive my truck for 30 min with just water in my system, would it be equivalent to just flushing it stationary (the proper way to flush it)? IOW, if I just drive around with a clean water refill ...
4
votes
1answer
76 views

Is coolant testing necessary on modern vehicles?

My father in law continually reminds me to check my antifreeze when it starts getting cold. I get the squeeze tester out and it always shows everything is fine. We drive cars that are always less than ...
3
votes
2answers
3k views

accidentally placed oil in the coolant reservoir in a BMW 325i. How do I fix it and what is the cost?

I accidentally added oil to my coolant reservoir. I have a BMW 325i. The oil light came on and I figured my oil may be low. When the oil was added the oil light warning went off. However, the ...
3
votes
1answer
368 views

95 Corolla overheats, probable coolant leak or maybe thermostat, need more advice.

Vehicle is a '95 Toyota Corolla. Was driving yesterday for about 5 minutes and glanced at the temperature gauge which I noticed was running pretty high (weather has been around 90 degrees f lately)....
2
votes
2answers
163 views

Coolant disappears from coolant reservoir but no leak observed

I just replaced the water pump in my 2005 Ford Escape V6. I discovered that each time I fill the coolant reservoir with coolant and drive the car, by my next stop the coolant reservoir will be ...