My BMW has been overheating, but it's not leaking anything, and I made sure it had antifreeze. It doesn't overheat until i've been driving for 20-30 plus minutes. The battery has been going dead randomly as well sometimes after it overheats and I turn it off. Any ideas?

If your engine is overheating, Try this procedure: Dirt and debris can get lodged in the radiator air flow paths. This can block the radiator and cause your engine to overheat and damage the engine. The thermostat can be stuck close. If you feel the upper hose very hot and the lower hose cooler than normal, it may be a stuck thermostat. Make sure the radiator and the overflow bottle are filled to the proper levels. Bleed air from the coolant system:This is best done by running the engine with the radiator cap off until you see when the air bubbles stop coming up. Check the radiator fans: The easiest way is to turn on the cars air conditioner and turn up the A/C fans. Both radiator fans should come on when the A/C starts Make a pressure test by using a pressure testing tool (available at most auto parts stores). Use the pressure shown on your radiator cap. Most cars are 16 PSI or less, so don't exceed that pressure. Replace the radiator cap if it doesn't hold the pressure.

Posted on Aug 08, 2012

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Why is my car overheating?

My BMW has been overheating, but it's not leaking anything, and I made sure it had antifreeze. It doesn't overheat until i've been driving for 20-30 plus minutes. The battery has been going dead randomly as well sometimes after it overheats and I turn it off. Any ideas?

2 Answers

danoyachtcap

BMW Master 2,907 Answers
Posted on May 09, 2015

danoyachtcap

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If your engine is overheating, Try this procedure:

Dirt and debris can get lodged in the radiator air flow paths. This can block the radiator and cause your engine to overheat and damage the engine.

The thermostat can be stuck close. If you feel the upper hose very hot and the lower hose cooler than normal, it may be a stuck thermostat.

Make sure the radiator and the overflow bottle are filled to the proper levels.

Bleed air from the coolant system:This is best done by running the engine with the radiator cap off until you see when the air bubbles stop coming up.

Check the radiator fans: The easiest way is to turn on the cars air conditioner and turn up the A/C fans. Both radiator fans should come on when the A/C starts

Make a pressure test by using a pressure testing tool (available at most auto parts stores). Use the pressure shown on your radiator cap. Most cars are 16 PSI or less, so don't exceed that pressure. Replace the radiator cap if it doesn't hold the pressure.

Anonymous

Expert 224 Answers
Posted on Aug 09, 2012

Anonymous

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Joined: Jul 11, 2012

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You might have a clogged radiator. If so replace the radiator. I would first replace the thermostat as it might be bad. When they go bad they usually stay stuck in the closed position. When closed there is no flow of water to or from the radiator. You can check the thermostat by removing it, it is located on your upper radiator hose, the return hose. To check it boil a pan of water and and using a pair of pliers hold the thermostat in the hot water. If the thermostat is bad it will not open. Hope this helps.

5 Related Answers

Anonymous

1 Answer
Posted on Jul 06, 2009

SOURCE: overheating

overheating bmw ...no sign of water in oil..no water from exhaust .. over heats in minutes ..ok when moving ?? please help ..

Anonymous

1 Answer
Posted on Nov 12, 2008

SOURCE: 1994 bmw 318i

Where is the water pump on 94 BMW 318, Is it behind the Fan or a seperate unit. is it easy to replace?

Anonymous

1214 Answers
Posted on Feb 03, 2009

SOURCE: 98 328IS OVERHEATING AFTER CHANGING THERMOSTAT

Are you putting the thermostat in correctly? It it will not work backwards.

And to confirm that there isn't a different problem, take the thermostat out all together and see if it overheats.

Engine not fully warming up is not usually caused by the thermostat. Stats usually fail closed, not open.

You will want to check the water temperature sending unit or gauge after verify the water temperature with an external calibrated thermometer. You can attach and insulate the external thermometer to the housing where thermostat is located.

Reply back what you figure out. I will be happy to help you further.

Anonymous

147 Answers
Posted on Mar 29, 2009

SOURCE: I have a coolant leak on my 2000 BMW 528i and now it overheating.

Pressure test cooling system to determine origin of leak. Radiator and coolant reservoirs are common problems. Vehicle is very difficult to purge air from cooling system and may take multiple times of idling until thermostat opens. Sometimes help to rev engine to about 2500 rpm 5-8 times to help build heat and move coolant through system. Must have heater on while performing this task.

Greg Mills

497 Answers
Posted on Aug 10, 2009

SOURCE: overheating

Sounds like a cooling fan are not turning on. Assuming you have an electric cooling fan. It could be something simple like a fuse or a relay which is stopping the fans from working, or it could be something as bad as the motor burning out on the fan.

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Hello,

I understand being new to cars, but that is ok. I am hear to help you. Some cars run hot, that is normal in a lot of cars. As long as it does not go into the red or way over the half way point your ok. But this is what I would do, this will make sure that car water temp/engine temp is working properly. First of all check your engine oil and make sure it is full at the dip stick. And then do the same with your radiator, make sure it is full with antifreeze. Also, you can have the antifreeze checked, they can test it, to make sure the right mixture of antifreeze and water are proper mixture. If not enough antifreeze compared to water ratio is off, then that can cause some over heating or possible over heating issues. So, in conclusion: first things to check is engine oil level and antifreeze level and mixture. I hope this helps you, thanks mike, expert fix ya man.

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Aug 02, 2011 • 1992 Honda Prelude

0helpful

1answer

My car started overheating. I was almost out of antifreeze, but my reserve tank still had antifreeze. Put a sealant in the radiator believing there was a leak, as well as the 50/50 mix, but it still ran...

Not likely water pump unless pump is leaking. You need to figure out where the antifreeze leaked out. Can you see anything leaking with radiator full and engine running? I have some tips at http://www.fixya.com/cars/r5929960-s_thermostat if you want to troubleshoot. Let me know if you have questions.

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Sep 10, 2010 • 2004 Chevrolet Impala

0helpful

2answers

Overheating after replacing radiator & thermostat in my 94 318I

check sensor
check actual temp with non-contact thermometer

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Jul 01, 2009 • 1996 BMW 318

4helpful

1answer

2000 bmw 528i overheating

The only way a heater core can cause overheating is if it's leaking and the engine is low on antifreeze. To check it for leaks it would help to use a cooling system pressure tester.

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May 23, 2009 • 2000 BMW 5 Series

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