System which removes excess heat from liquid cooled internal combustion engine. It also helps maintain the engine temperature at a consistent level. The cooling system encompasses the radiator, water pump, thermostat, hoses, heater core, overflow reservoir, and anti-freeze (or coolant).

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15
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8answers
28k views

My car's coolant temperature reaches almost 100 C / 212 F in a fast pace

Today, after a very hot day, I saw that my coolant was almost reaching 100C/212, I pulled over, stopped and took a look over the hood. The very little water that remained in the coolant tank was all ...
13
votes
2answers
163 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 ...
12
votes
7answers
9k views

Can radiator cool down a car too much?

Recently they replaced my stock radiator with aftermarket one (at dealership, so I hope they knew what they were doing), and since then I feel that a car is not warming up enough. Even if I warm it ...
12
votes
5answers
868 views

Should Multiple Coolant Hose Leaks in a Short Time Worry Me?

Right after fixing another problem with one of my cars ( 98 Mazda 626 GF 2L ), I revved the engine and all of a sudden heard the tell tale hiss of a coolant leak: As you can see, this hose just ...
12
votes
4answers
150k views

Can I drive a car with only water and no coolant if it has a leak?

Recently, I was informed that a car I share ('02 Nissan Sentra) was close to overheating. I was told it gets close to the upper limit very quickly upon running the car. When I inspected the vehicle, I ...
11
votes
5answers
121k 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 ...
10
votes
1answer
116 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 ...
8
votes
5answers
315 views

Is it Safe to Drive With Low Engine Coolant?

I have a 2001 Chevy Malibu and have replaced the engine coolant in it twice in the last six months after the low coolant warning light came on, and the light has recently come on again. The climate ...
8
votes
3answers
1k 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 ...
8
votes
2answers
67 views

Ford Expedition Eddie Bauer 4.6 V8 2003 automatic rpm goes high

When driving, sometimes when I want stop the vehicle, I go to press the brakes, but that time engine rpm goes high, keeping brakes pressed hard, after 5 second engine becomes normal. It goes high when ...
7
votes
4answers
142k views

What happens if I drive without antifreeze in my car?

What happens if I drive without antifreeze in my car (no water / no antifreeze)? This is my main question. I've added some follow up questions that are specific to my situation but for the main ...
7
votes
1answer
116 views

What exactly is meant by “engine coolant”?

I know that engine coolant is a fluid in the engine used to dissipate heat spots and keep the engine cool in general as the moving parts generate heat. In this context, I would call the oil an "engine ...
7
votes
2answers
10k views

Why would my engine temperature raise from normal to high and drop back down again?

I have a Nissan Micra (UK, 51-plate, 2001 model) that I have been using to drive to work on a daily basis - 10 miles each way a day on a variety of roads - streets, main roads, main roads in traffic, ...
7
votes
3answers
3k views

Blocked water flow in engine?

My dad has a 1993 Subaru Legacy L 2.2L (no turbo) with a perplexing cooling problem. It overheats, and there doesn't appear to be flow through the cooling system. The upper radiator hose is extremely ...
6
votes
2answers
81 views

Why does my overheating car cool off on declines?

Thanks for your never-ending support! The quick and precise answers and suggestions that you all provide is priceless in its worth. After the timing belt change ( I skipped the water pump, it looked ...
6
votes
1answer
210 views

How can I test my thermostat?

How can I tell whether a mechanical thermostat works as it should? Is there a test that can definitively tell me if a thermostat is good or bad?
6
votes
3answers
1k views

Golf mk3 TDI has pressure in the cooling system

I have an interesting problem on my VW Golf MK3 TDI. Basically, sometimes the pressure cap on the coolant reservoir lets out some coolant. Here's what I know: It happens when the car is under ...
6
votes
2answers
25k views

Why does my car sometimes blow cold air while the heater is on?

This started about a week ago. I put the heat on and about after driving a couple of miles with the heat on it would randomly blow out cold air. Sometimes if I turned the heat off or switched it from ...
6
votes
1answer
109 views

Electric water pump control

Electric fans are now common on cars, both aftermarket and stock. The advantages in horsepower, faster warmup, and hence emissions are well documented elsewhere. The same reasoning can be applied to ...
6
votes
3answers
487 views

94' Honda Civic Cooling issues

Here's what's going on: The temperature remains constant on the highway. The temperature remains constant for short trips. The temperature generally remains constant when the car is not moving. (It ...
6
votes
1answer
39 views

How to test the function of a water pump?

Is it possible to test a water pump for proper function (ability to move a certain volume of coolant) without disconnecting it from the engine? If so, how would one do that?
6
votes
2answers
56 views

Coolant in engine… Head gasket going

I have an 05 Equinox, and while idling it sometimes overheats. We have to continously add coolant every week. If this was the only problem, I'd fix it, but, there's other issues as well, and combined ...
6
votes
0answers
28 views

Coolant expansion tank issue

My coolant tank is filled up to the correct level before driving off but I've taken a half an hour drive and it is very low and warning light comes on. Once stopped it cools down and the level rises. ...
5
votes
2answers
45 views

Will an engine overheat if it has no coolant recovery tank?

My wife's Mini has a leak in the coolant recovery tank, and she has been told by the dealer that her car is at risk of overheating without the coolant recovery tank.Frankly, I don't believe it. Cars ...
5
votes
2answers
10k views

Engine never warms up (actually: it cools down) at highway speeds

I have a 1997 Caravan (base model) and normally on my drive to work and my highway drives in rush-hour, the engine warms up just fine. I took a road trip for work, about an hour and fifteen minutes ...
5
votes
2answers
86 views

Why is antifreeze mixture not as stated?

To keep things short I poured 200ml of concentrated genuine ford super plus premium antifreeze (Ethylene glycol based) within a bowl. Then added 200ml of water to dilute the solution to a 50/50 ...
5
votes
2answers
90 views

Water underneath floor carpet - Mazda Protégé 2002

I just bought a Mazda Protégé 2002 and a few weeks later I noticed a damp spot on the back passenger side floor. Very wet and soaked. Later I noticed the smell grew larger and the vapor on the glass ...
5
votes
2answers
294 views

Ditch water in radiator

I lost a coolant hose going down the road and all my antifreeze was gone. I found a puddle along the road and filled my radiator back up after I fixed the hose. Will this cause electrolysis in my ...
5
votes
1answer
61 views

Min/max fill for coolant reserve/overflow tank in abscence of markings

I have a 2001 Honda Prelude SH. I am looking at the coolant reserve tank. There are no min / max fill lines visible, although the manual says there should be. I am just re-adding coolant after fixing ...
5
votes
1answer
496 views

Blazer overheating in cold temperatures

Sorry, this is going to be a bit wordy. I have lots of details... A few weeks ago, the temperature was in the single digits with a negative wind chill. I started up my 96 Blazer and let it run for 10 ...
5
votes
2answers
699 views

Strange cooling circuit problems in a 1997 vw golf mk3 tdi

Driving across Europe, i noticed the car was using water. I drove slowly and got to the destination. Since then, the symptoms have been getting stranger. The water loss is caused by excess pressure ...
5
votes
1answer
44k views

Getting the best results sealing head gasket leak with Blue Devil

The 1998 Subaru Outback I've been having cooling system problems with turns out to have a combustion gas leak into the coolant. I suspected this but couldn't get a test to turn up anything; taking it ...
5
votes
1answer
1k views

Should overflow tank be filled when replacing coolant?

I have recently fully rebuilt my engine, minus the block and pistons. All the gaskets were replaced, valves lapped, valve lashes tuned etc. I did it because I had an overheating problem and a head ...
5
votes
2answers
7k views

Overheating & coolant loss in 1998 Subaru Outback

I'm having trouble with this vehicle overheating, presumably from losing coolant. The problem is very similar to what's described here: ...
5
votes
2answers
2k views

Changed radiator, now have misfiring?

I have a 1996 Nissan Altima. I had to change my radiator recently because it developed some cracks on the top of the tank and I would have to refill the tank every few days. When I changed the ...
5
votes
1answer
1k views

2005 Subaru Forester XS overheating

While on a roadtrip, the car started overheating with coolant boiling out. We refilled the radiator with coolant, but it kept occurring. We managed to make it back home by having the heater on high ...
5
votes
0answers
44 views

AC Cooling stops at high speed

My car ac works very fine in normal conditions. But when I drive it for awhile longer, and often at high speed, it stops cooling. I can still hear the fan sound loud and clear but air flow decreases a ...
4
votes
2answers
124 views

Coolant boiling and smoke coming out of engine bay

I have a 1995 Toyota Camry SE that has 195,000+ miles that has started to develop some serious problems. Aside from what I believe to be an issue with the transmission, the car had been running ...
4
votes
2answers
821 views

Washing coolant system with dish soap to remove oil residue

Someone mentioned it is a good idea to wash the coolant system with dish soap to remove residue oil. I was wondering if that is true or can it have any side effects?
4
votes
2answers
95 views

Is it necessary to maintain antifreeze to water ratio?

I had my radiator cleaned and flushed yesterday. The mechanic who did the work advised that pure distilled water is better than using mixture of water and coolant. I checked the manual and it just ...
4
votes
2answers
11k views

Coolant spillover tank boiling but engine not overheating

After driving some time, is it normal that the plastic spillover coolant tank, usually attached to the fan housing, that takes boiling overflow, get so hot that you get bubbles boiling out of it even ...
4
votes
1answer
210 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
720 views

2015 STI White smoke

My 2015 Subaru WRX Sti is emitting white smoke from the exhaust. The smoke smells like burning electronics. When I pull over and open up the hood, I also see white smoke in the engine bay. The smoke ...
4
votes
1answer
19 views

1994 Dodge Dakota V8, Antifreeze leaking from water pump

Every time I put ether antifreeze or water in my radiator it immediately comes out from beneath the water pump? What could cause that to happen?
4
votes
1answer
6k views

Can a blown head gasket cause overheating, without losing coolant?

My 2006 Subaru Outback overheated when my wife was driving. I got to the car that evening and its radiator was pretty low. I refilled it, and the car ran fine for a week. Then it overheated again. ...
4
votes
1answer
38 views

Thermocouple vs Thermostat

Why don't modern engines use a thermocouple (electronic temperature sensor) instead of a (wax element) thermostat?
4
votes
1answer
43 views

Waterbottle cap still poping off

I have a 2008 Ford Fiesta 1.6i. The car heats up and builds pressure in the water bottle that causes the cap to pop open and boiling water to come out. I have taken it to Rord where they have done ...
4
votes
2answers
71 views

Replace Yamaha FZ6 radiator for two smaller ones

I bought the engine of a Yamaha FZ6. I want to use it to run a competition single seater car we are builiding in the university. The engine didn't bring the radiator with it. I would like to ...
4
votes
1answer
9k views

Engine's Normal Operating Temperature

I read in the Motor Oil University article on Bob the Oil Guy's websites that: The automotive designers usually call for their engines to run at 212°F ( 100°C ) oil and water temperature with an ...
4
votes
5answers
16k views

F-150, heater will blow hot, then cold

F-150, heater will blow hot, then cold and then heat gauge will rise to extreme high, will boil over then gauge will drop to normal. Just had it flushed and no change. After driving for about 10-15 ...