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).

learn more… | top users | synonyms

3
votes
3answers
6k views

Pros and cons of using straight antifreeze

I've heard from some people that they use straight antifreeze in their cooling systems and not 50/50. What are the pros and cons of doing that? E.g. does it reduce exposure to corrosion?
7
votes
1answer
124 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 ...
3
votes
2answers
2k views

How does the heater core work?

How does the heater core work? What are the inputs to the system? What are the outputs of the system? What are some common ways that it can fail?
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 ...
1
vote
1answer
33 views

2000 Vw passat 1.8l oil is in radiator

I have a 2000 VW Passat GLS 1.8l and it has oil in the radiator reservoir. and my Oil light says oil compression low. i flushed the radiator and found oil in it again, (the radiator overflow) it ...
3
votes
7answers
57k views

The mysterious overheating honda civic

This is a tale that goes back about a year when I found my very first car. I needed it to commute back and forth to school. When I bought the car it worked great, everything I could have wanted. ...
5
votes
2answers
109 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 ...
6
votes
1answer
343 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?
1
vote
1answer
20 views

1978 Ford 302 is using a lot of water

My 1978 Ford 302 is using a lot of water. There is no oil in the water or no water in the oil and I cant find any leaks. What can I do?
15
votes
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 ...
4
votes
1answer
147 views

Car is heating while Coolant Temp Sensor is normal

I bought a BMW 318i and the car heated twice so far while the coolant temperature sensor is normal. If we exclude the possibility that the sensor is malfunctioning, what problem would cause the ...
7
votes
2answers
11k 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, ...
2
votes
2answers
149 views

1996 mazda 626 leaking coolant

My mazda 626 was leaking coolant. I replaced the radiator for there is clearly a hole on it. It worked fine for about a month. Then I see some leakage again. And this time it is around the right side ...
5
votes
2answers
100 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 ...
1
vote
2answers
115 views

2005 Honda Civic - Oveheating [closed]

So my car has been overheating for over 1 year. It overheated during summer or when I went 80mph only. I recently saved up enough money to get the car fixed. I brought it to my mechanic and informed ...
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 ...
2
votes
2answers
123 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 ...
2
votes
2answers
7k views

Bent radiator fins — how many is too many?

Hi I thought I fixed some previous overheating problems but I only helped them. My car was running fine when it was 95F or so over the weekend but now it's 110F(yes, hell, I know) outside and my cars ...
3
votes
0answers
160 views

E46 rough idle with coolant light on

The car is 2001 BMW 330i. I have changed ignition coil, spark and IAC. Last week, my car experienced rough idle. Then I changed the coolant temp sensor today. After adding coolant and bleeding, the ...
12
votes
4answers
157k 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 ...
7
votes
3answers
4k 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 ...
2
votes
1answer
46 views

Engine oil going into the coolant

My 2005 Saturn Relay got a hole in a water hose and suddenly overheated, so I shut it down immediately. Found the crank case empty and the coolant full of oil. Replaced the hose and put oil in it, ...
5
votes
1answer
45k 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 ...
3
votes
2answers
138 views

1.6 Petrol engine overheats intermittently

I have a Vauxhall Vectra 1.6 (2007). The cooling system operated perfectly (a few kms after starting the engine the needle was pointing to optimum temperature without the slightest waver). 2 weeks ago ...
0
votes
1answer
97 views

Does using heat in the car SAVE gas?

Its well known that using heat in a car is almost free (see for example here). It is also known that using the heat can reduce the engine temperature which otherwise needs to rely on water cooling. ...
2
votes
2answers
286 views

Mazda 626 with Unknown Coolant Leak

I'm looking at a 98 Mazda 626 2 liter with an unknown coolant leak from the area in the back of the engine. Seller says a mechanic that quickly looked it over said he thinks it's either the head or ...
5
votes
1answer
2k 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
0answers
168 views

2002 Dodge Ram 1500 overheating

I have a 2002 Dodge Ram 1500 two wheel drive with a 4.7 liter engine. It's been overheating so I replaced the whole cooling system: I replaced the condenser cooling fan because its not coming on ...
2
votes
0answers
79 views

Changing Freeze Plugs on a Mazda 626

On a 98 Mazda 626 4 cylinder 2L engine where are the freeze plugs and how hard is it to replace them?
4
votes
2answers
107 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 ...
1
vote
2answers
2k views

Can you drive a 1999 Dodge Ram 1500 when the heater core is bad?

I am thinking of purchasing an older Dodge Ram; the listing on craigslist says that the vehicle is in good condition but the heater core is busted. I'm willing to go without heat/AC till I get around ...
3
votes
3answers
715 views

Do cowl hoods actually help with engine cooling?

I've read that cowl hoods used to be the method for air induction for older vehicles with carburetors and that the only purpose they serve for vehicles with fuel injection is for looks. However, I ...
3
votes
1answer
6k views

Flushing built up Rust and Mineral Deposits in Cooling System

The previous owner ran tap water in the cooling system for few years, and we have very heavy, mineral rich water locally. When I bought the car about six months ago, I drained the water, and put a ...
1
vote
1answer
37 views

How to test if heater core is causing cooling malfunction?

My 2007 V6 Tacoma is overheating, I have done just about any test imaginable, replaced the thermostat, water pump, did many other checks, incl. chemical test for gas residue in the coolant system etc. ...
4
votes
3answers
6k views

How to test if head gaskets are blown?

Is there a definitive way to test whether head gaskets in most engines are blown, without actually reaching for the gaskets themselves (at which point you might as well go ahead and replace them) ...
4
votes
1answer
226 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
7k 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. ...
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 ...
3
votes
1answer
2k views

Should I remove the thermostat when doing a cooling system flush?

I am going to do a cooling system flush and after some reading and watching some youtube videos I noticed that people take different approaches. So I have the following questions: I understand that ...
1
vote
0answers
46 views

Best way to control engine cooling? [closed]

Should I control engine temp with a thermostat or with a cooling fan temp sensor for on/off of cooling fan? I am installing a Tri cross flow alum radiator with full alum shroud and a special 16 inch ...
4
votes
1answer
749 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 ...
3
votes
5answers
49k views

Cooling fans not running

Update This question seems to be attracting a lot of views, so I guess a lot of people are having the same problem. Just to be clear, the problem with MY fans specifically seemed to be caused by my ...
4
votes
1answer
10k 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 ...
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 ...
1
vote
1answer
180 views

After car runs with temp normal it drops to tempature reading cold

My car temp reads normal but after warming up the tempature drops showing on the gauge engine is cold and the heat in the car gets cool
-1
votes
1answer
51 views

When pouring in anti-freeze why does choking the hose allow it flow better

Just wondering what exactly is going on there. When I pour in antifreeze and choke the the hose the antifreeze flows a lot better through. Any idea why this is? Thanks
1
vote
1answer
371 views

Camry 01 loosing coolant

I've camry 2001 LE, with 149K on it. Recently, I noticed coolant leak from the radiator and replaced the radiator. I still was loosing coolant little bit, so performed coolant pressure test. The upper ...
1
vote
1answer
89 views

Oil in the cooling system

I have a 2003 Chrysler GT, PT Cruiser with less then 60000 miles. It is a four cylinder 2.4L, that is turbo charged, and is automatic. I had a hole in the over flow tank and had it replaced with a new ...
2
votes
1answer
317 views

Changed thermostat but now constant leak around thermostat housing

I went to flush my cooling system and change the thermostat on my Mk1 Golf. All went fine until I put the new coolant in. There is a pretty steady leak from the thermostat housing. I've tightened ...
0
votes
1answer
190 views

Motor Oil in Coolant Reserve [duplicate]

2004 Mercedes E500 - Yes, I am sure of it. In a moment of stupidity, I added about 8oz of motor oil to the coolant reserve. I have heard nothing will happen and I've also heard it can mess up the ...