Engine Overheating

AJMackey · 10-12-2018, 07:43 AM

Any suggestions? My car is overheating. There’s plenty of coolant with no leaks. I bled the system so the water pump is working but my fan only seems to come on when the AC is working. So the fan is working, but is there some sensor somewhere that tells the fan to come on when the engine gets hot? If so, where and what is it? Or can it be something else? Can the thermostat have something to do with this?

Boland01 · 10-12-2018, 08:03 AM

Have you tried pulling codes? That may help.

TemjinX2 · 10-12-2018, 11:29 AM

maybe just try bleeding the system again with the water pump method. I know some people have said they needed to do it twice to get all the air out of the system.

ewicky · 10-12-2018, 11:39 AM

How do you know the engine is overheating? Is the oil over-temp? Is the coolant over-temp? Does it overheat idling or do you have to be driving? Or does driving help? Does turn on the A/C help or hurt? The coolant system is self-bleeding so there's no real need to bleed it like most people on this forum seem to obsess over.

Typically the fan works in conjunction with the water pump to only use as much electricity as necessary to keep the coolant at the temperature desired. This is all run by the computer.

AJMackey · 10-12-2018, 11:42 AM

When I drive it, I get the yellow temp warning, then it turns red and goes into limp mode. Sometimes it goes a few miles, sometimes it'll go 10 or more so I haven't been using the car. I just replaced the ECT sensor and that didn't seem to help. There's no codes from the auto store reader, so the next step is to take it to a BMW repair shop so they can run their diagnostics. I've bled the system a couple of times just to be sure that wasn't part of the problem.

Joebie · 10-12-2018, 11:44 AM

Just because you hear the water pump during the bleed procedure doesn't mean that it's actually working to capacity when it has to get rid of all the heat the engine makes during actual driving.

If your water pump and thermostat have never been replaced I'd bet good money that that's the problem, but like someone before me said, pulling codes would probably give you a definitive answer.

From lurking here, the answer to pretty much 99% of all overheating problem is just replace the water pump and thermostat and all is well again for another 100k miles. BMW water pumps notoriously fail around the 100k mark, its just part of owning the car. Not much else ever goes wrong with the cooling system.

Good luck!

AJMackey · 10-12-2018, 11:52 AM

Joester, thanks for the reply and that's most likely the route I'm going as the car has a bit over 100k. The only thing that concerns me is the fan not coming on when the engine heats up. I don't want to replace those items and have it not be the issue. I don't understand why the fan comes right on as soon as I switch on the AC, but if the AC is off, it doesn't come on at all.

Pladi · 10-12-2018, 11:54 AM

water pump.. almost 100 %

techwhiz · 10-12-2018, 01:12 PM

Quote:

Originally Posted by AJMackey

Joester, thanks for the reply and that's most likely the route I'm going as the car has a bit over 100k. The only thing that concerns me is the fan not coming on when the engine heats up. I don't want to replace those items and have it not be the issue. I don't understand why the fan comes right on as soon as I switch on the AC, but if the AC is off, it doesn't come on at all.

It's the water pump.
Unless you have a hose burst, yellow then red, then limp is a water pump.
Mine did that about two months ago. Water pump.

Joebie · 10-12-2018, 01:20 PM

Quote:

Originally Posted by AJMackey

Joester, thanks for the reply and that's most likely the route I'm going as the car has a bit over 100k. The only thing that concerns me is the fan not coming on when the engine heats up. I don't want to replace those items and have it not be the issue. I don't understand why the fan comes right on as soon as I switch on the AC, but if the AC is off, it doesn't come on at all.

The fan comes on when you enable the A/C because without the air flow through the condenser, the refrigerant would not be cooled from its hot state to be able to cool your car. So if your car isnt moving, you pretty much NEED to have a fan blowing air over the condenser in order to get cool air from the A/C. This is actually a great way to test your fans on most cars if you put the A/C on full blast and the fan(s) don't come on, the fan is probably bad.

While I'm not sure if its normal for the fan to not come on when the car is overheating, my guess would be that from an engineering perspective, it shouldnt ever be necessary to cool the car with the radiator fan under normal operation without another failing component being the cause, so why put the feature in there in the first place? If the fan came on to cool an overheating car, it'd just be a band-aid for a different problem, if that makes any sense. You shouldnt really ever need the fan for engine cooling if the car is working right, so why ever have it come on? That's just my guess I dont know for sure if that's the reason. I wouldn't overthink this if I were you, BMW engineers work in mysterious ways.

2008 with a bit over 100k miles is overheating? Pretty much guaranteed to be water pump and thermostat time, without fail. Every time. Dont overthink it.

Best of luck to you!

mweisdorfer · 10-12-2018, 01:22 PM

Quote:

Originally Posted by AJMackey

Any suggestions? My car is overheating. There's plenty of coolant with no leaks. I bled the system so the water pump is working but my fan only seems to come on when the AC is working. So the fan is working, but is there some sensor somewhere that tells the fan to come on when the engine gets hot? If so, where and what is it? Or can it be something else? Can the thermostat have something to do with this?

Check to see if you can hear the water pump come on after you do an air purge sequence (84 degrees on level 1 and then hold the gas pedal down about 10-15 sec.). If you can hear the water pump come on, then :

It's the Thermostat most likely.

If your water pump has over 75,000 miles on it, change that "while your in there" or you will be stranded and stuck with a $100.00 towing bill (or more) to your house; not to mention paying overnight shipping for the new water pump.

Also, change the U shaped connecting hose as well.

catcher22 · 10-12-2018, 03:11 PM

You need to replace your water pump and thermostat.

juld0zer · 10-12-2018, 07:30 PM

On mine, the thermostat failed in the shut position and the coolant pump also has a speed deviation fault logged just before it went into limp. Not sure if the thermostat killed my pump but thermostats don't log faults for mechanical failures in the shut position. Activating the bleed mode confirmed a stuck pump due to the sound and lack of flow.

118k km.

When you change the pump, rotate the impeller by finger and you will notice the notchy feel of failure.

Papibmw328xi · 10-17-2018, 06:01 PM

I've been having the same issue. My car started overheating so I changed the water pump and thermostat, and still the same thing I took it to BMW and they said it was a faulty water pump so I bought another one and this one works, and I have done the bleeding process as well and I still have the same problem. Do you think it could be the radiator? Maybe the Fan? I've also changed a couple sensors on my car as well and checked that the fuse for the pump is good and it is. I need some help please

ckanderson · 10-17-2018, 08:05 PM

Quote:

Originally Posted by Papibmw328xi

I've been having the same issue. My car started overheating so I changed the water pump and thermostat, and still the same thing I took it to BMW and they said it was a faulty water pump so I bought another one and this one works, and I have done the bleeding process as well and I still have the same problem. Do you think it could be the radiator? Maybe the Fan? I've also changed a couple sensors on my car as well and checked that the fuse for the pump is good and it is. I need some help please

Easy way to test for a a clogged radiator is an infrared heat gun.

Papibmw328xi · 10-17-2018, 08:08 PM

Quote:

Originally Posted by ckanderson

Easy way to test for a a clogged radiator is an infrared heat gun.

Thank you I'll look to see if it is clogged tomorrow! I've been wondering if maybe it's the fan because I only see the fan coming on when the overheating sign comes up on my dash

BM3Rrrr · 10-17-2018, 11:22 PM

Stop denying the truth...its the water pump for sure...

ckanderson · 10-18-2018, 08:20 AM

Quote:

Originally Posted by Papibmw328xi

Quote:

Originally Posted by ckanderson

Easy way to test for a a clogged radiator is an infrared heat gun.

Thank you I'll look to see if it is clogged tomorrow! I've been wondering if maybe it's the fan because I only see the fan coming on when the overheating sign comes up on my dash

It could also be used to make sure hot coolant is running through the pump....

Papibmw328xi · 10-24-2018, 06:28 PM

So I have checked my radiator and all seems well. so i still don't know what to do with my car. When i try and bleed the system or at least try to the water pump does not budge. it wont bleed the system at all which leads me to think there may be an air bubble in the system and thats why it's overheating. What else do you think i should do? the new water pump works because when i left the bleeder screw open a whole lot of coolant started shooting all over my engine bay.

BM3Rrrr · 10-24-2018, 07:28 PM

Quote:

Originally Posted by Papibmw328xi

So I have checked my radiator and all seems well. so i still don't know what to do with my car. When i try and bleed the system or at least try to the water pump does not budge. it wont bleed the system at all which leads me to think there may be an air bubble in the system and thats why it's overheating. What else do you think i should do? the new water pump works because when i left the bleeder screw open a whole lot of coolant started shooting all over my engine bay.

Did you replace the thermostat?

Papibmw328xi · 10-24-2018, 07:37 PM

Quote:

Originally Posted by BM3Rrrr

Quote:

Originally Posted by Papibmw328xi

So I have checked my radiator and all seems well. so i still don't know what to do with my car. When i try and bleed the system or at least try to the water pump does not budge. it wont bleed the system at all which leads me to think there may be an air bubble in the system and thats why it's overheating. What else do you think i should do? the new water pump works because when i left the bleeder screw open a whole lot of coolant started shooting all over my engine bay.

Did you replace the thermostat?

Yea I have replaced the thermostat along with the water pump when I changed them out. I even replaced the engine temp sensor and I was also going to replace the coolant temp sensor but I could not find the coolant sensor so I returned it

nsjames · 10-24-2018, 08:08 PM

the reservoir is the highest component, so the system will bleed air no mater what as long as the coolant flows.

do you have any diagnostics software?
You've spent a lot of money on parts, but have you actually tried to diagnose the issue before parts shotgunning?
If you know that the pump and thermostat are working and it keeps overheating, I woudl test the coolant for combustion byproducts. You may have a popped head gasket.

10-12-2018, 07:43 AM	#1
AJMackey Registered 0 Rep 3 Posts Drives: 2008 BMW 328xi Join Date: Oct 2018 Location: Parkland Florida iTrader: (0)	Engine Overheating - Need Opinions... Any suggestions? My car is overheating. There’s plenty of coolant with no leaks. I bled the system so the water pump is working but my fan only seems to come on when the AC is working. So the fan is working, but is there some sensor somewhere that tells the fan to come on when the engine gets hot? If so, where and what is it? Or can it be something else? Can the thermostat have something to do with this?
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10-12-2018, 08:03 AM	#2
Boland01 Lieutenant 149 Rep 460 Posts Drives: 2010 535ix, 2008, 2007 335i Join Date: Sep 2013 Location: Magnolia, TX iTrader: (0)	Have you tried pulling codes? That may help.
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10-12-2018, 11:29 AM	#3
TemjinX2 Major 521 Rep 1,485 Posts Drives: 2008 335xi e92 Join Date: Dec 2009 Location: Socal OC iTrader: (0)	maybe just try bleeding the system again with the water pump method. I know some people have said they needed to do it twice to get all the air out of the system.
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10-12-2018, 11:39 AM	#4
ewicky Lieutenant 204 Rep 525 Posts Drives: '07 335xi 4D AT Join Date: Jan 2017 Location: Seattle, WA iTrader: (0)	How do you know the engine is overheating? Is the oil over-temp? Is the coolant over-temp? Does it overheat idling or do you have to be driving? Or does driving help? Does turn on the A/C help or hurt? The coolant system is self-bleeding so there's no real need to bleed it like most people on this forum seem to obsess over. Typically the fan works in conjunction with the water pump to only use as much electricity as necessary to keep the coolant at the temperature desired. This is all run by the computer.
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10-12-2018, 11:42 AM	#5
AJMackey Registered 0 Rep 3 Posts Drives: 2008 BMW 328xi Join Date: Oct 2018 Location: Parkland Florida iTrader: (0)	When I drive it, I get the yellow temp warning, then it turns red and goes into limp mode. Sometimes it goes a few miles, sometimes it'll go 10 or more so I haven't been using the car. I just replaced the ECT sensor and that didn't seem to help. There's no codes from the auto store reader, so the next step is to take it to a BMW repair shop so they can run their diagnostics. I've bled the system a couple of times just to be sure that wasn't part of the problem.
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10-12-2018, 11:44 AM	#6
Joebie Grandmaster 768 Rep 798 Posts Drives: 2018 ///M2 6MT Join Date: Dec 2014 Location: St. Louis iTrader: (0)	Just because you hear the water pump during the bleed procedure doesn't mean that it's actually working to capacity when it has to get rid of all the heat the engine makes during actual driving. If your water pump and thermostat have never been replaced I'd bet good money that that's the problem, but like someone before me said, pulling codes would probably give you a definitive answer. From lurking here, the answer to pretty much 99% of all overheating problem is just replace the water pump and thermostat and all is well again for another 100k miles. BMW water pumps notoriously fail around the 100k mark, its just part of owning the car. Not much else ever goes wrong with the cooling system. Good luck! __________________ Daily - 2018 Alpinweiß ///M2 6MT Exec Rain/Snow/Winter - 2011 328i 6MT Sedan - Black on Black, Sport Package Sold, But Not Forgotten - 2009 135i 6MT - Black on Black, M-sport, JB4
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10-12-2018, 11:52 AM	#7
AJMackey Registered 0 Rep 3 Posts Drives: 2008 BMW 328xi Join Date: Oct 2018 Location: Parkland Florida iTrader: (0)	Joester, thanks for the reply and that's most likely the route I'm going as the car has a bit over 100k. The only thing that concerns me is the fan not coming on when the engine heats up. I don't want to replace those items and have it not be the issue. I don't understand why the fan comes right on as soon as I switch on the AC, but if the AC is off, it doesn't come on at all.
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10-12-2018, 11:54 AM	#8
Pladi Lieutenant Colonel 718 Rep 1,753 Posts Drives: 2011 335i xdrive Join Date: Nov 2017 Location: Waterloo, ON Canada iTrader: (0)	water pump.. almost 100 %
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10-12-2018, 03:11 PM	#12
catcher22 Captain 294 Rep 922 Posts Drives: 2008 335xi Coupe Join Date: May 2008 Location: Virginia iTrader: (2)	You need to replace your water pump and thermostat.
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10-12-2018, 07:30 PM	#13
juld0zer Lieutenant Colonel 480 Rep 1,600 Posts Drives: Prev 135i 7DCT, Now 130i 6sp Join Date: Jul 2016 Location: 2153 iTrader: (0)	On mine, the thermostat failed in the shut position and the coolant pump also has a speed deviation fault logged just before it went into limp. Not sure if the thermostat killed my pump but thermostats don't log faults for mechanical failures in the shut position. Activating the bleed mode confirmed a stuck pump due to the sound and lack of flow. 118k km. When you change the pump, rotate the impeller by finger and you will notice the notchy feel of failure.
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10-17-2018, 06:01 PM	#14
Papibmw328xi New Member 0 Rep 6 Posts Drives: 2007 Bmw 328 XI Sport E90 Join Date: Oct 2018 Location: Shillington, PA iTrader: (0)	I've been having the same issue. My car started overheating so I changed the water pump and thermostat, and still the same thing I took it to BMW and they said it was a faulty water pump so I bought another one and this one works, and I have done the bleeding process as well and I still have the same problem. Do you think it could be the radiator? Maybe the Fan? I've also changed a couple sensors on my car as well and checked that the fuse for the pump is good and it is. I need some help please
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10-17-2018, 11:22 PM	#17
BM3Rrrr Davy Jones, Giant Squid 271 Rep 913 Posts Drives: a Pirate Ship Join Date: Jun 2015 Location: The Isle of Tortuga iTrader: (0)	Stop denying the truth...its the water pump for sure... __________________ 2010 e90 335i LCI - xHP - Mishimoto - BMS - CPe - Turbosmart - MHD - Eibach - Koni - VMR - LUX
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10-24-2018, 06:28 PM	#19
Papibmw328xi New Member 0 Rep 6 Posts Drives: 2007 Bmw 328 XI Sport E90 Join Date: Oct 2018 Location: Shillington, PA iTrader: (0)	So I have checked my radiator and all seems well. so i still don't know what to do with my car. When i try and bleed the system or at least try to the water pump does not budge. it wont bleed the system at all which leads me to think there may be an air bubble in the system and thats why it's overheating. What else do you think i should do? the new water pump works because when i left the bleeder screw open a whole lot of coolant started shooting all over my engine bay.
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10-24-2018, 08:08 PM	#22
nsjames Brigadier General 2440 Rep 4,331 Posts Drives: 08 328xi Touring Join Date: May 2017 Location: ohio iTrader: (0)	the reservoir is the highest component, so the system will bleed air no mater what as long as the coolant flows. do you have any diagnostics software? You've spent a lot of money on parts, but have you actually tried to diagnose the issue before parts shotgunning? If you know that the pump and thermostat are working and it keeps overheating, I woudl test the coolant for combustion byproducts. You may have a popped head gasket.
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