Hi I have a 1999 528i. I can drive this car from Florida to California and not overheat ( as long as I don't stop ) I have to keep on bleeding the system and the car will be good for the day! I had a friend test the coolant for exhaust and thankfully there was none! I changed every thing in the cooling system except for the radiator, after work I checked the radiator with a tempature sensor gun it was showing about 200 degrees at the radiator upper hose connection and only 146 at the lower radiator hose connection, also the tempature from the clutch fan was about 156, does this seem right, and could a blocked radiator cause air locks?????
snosuxs
pls clarify your car's "problem".....
I'm not 100% certain I understand what your car's problem is: I am presuming from what you've written that the enigne is running hotter than normal when the car is either moving relatively slowly or at a stand-still (e.g. idiling at a stoplight). If that is the case, in my experience the most likely 'cause' is a mal-functioning fan clutch. I have seen these cars run at highway speeds for hours on end at 'normal' engine temperature even when the clutched fan is not installed! But stop that same car at a stop sign (now the airflow across the radiator is nil) and the car will begin to overheat. Obvioulsy the fan clutch is not the ONLY potential culprit, but it's the most likely one if what is happening is what I've described.
I am not aware of BMW's specs for heat transfer across the radiator, but obvioulsy from your measurements the radiator is cooling the liquid as you seeing a temp differential from inlet to outlet - as to whether it's 'in spec' I can't tell you.
Bleeding: can be a bit difficult, but after one or two iterations you should be able to get all the air out of the system; I've owned 3 E39's (I-6 motors) and never had too much difficulty bleeding after a coolant change, etc. If you're bleeding the coolant very frequently (as it seems you are) and getting air out EVERY time you bleed that seems a bit odd - I am at a bit of a loss to explain that one. Perhaps you need to add coolant SLOWER when bleeding - that is usually helpful in moving the air out of the system.
Best of Luck!
I'm not 100% certain I understand what your car's problem is: I am presuming from what you've written that the enigne is running hotter than normal when the car is either moving relatively slowly or at a stand-still (e.g. idiling at a stoplight). If that is the case, in my experience the most likely 'cause' is a mal-functioning fan clutch. I have seen these cars run at highway speeds for hours on end at 'normal' engine temperature even when the clutched fan is not installed! But stop that same car at a stop sign (now the airflow across the radiator is nil) and the car will begin to overheat. Obvioulsy the fan clutch is not the ONLY potential culprit, but it's the most likely one if what is happening is what I've described.
I am not aware of BMW's specs for heat transfer across the radiator, but obvioulsy from your measurements the radiator is cooling the liquid as you seeing a temp differential from inlet to outlet - as to whether it's 'in spec' I can't tell you.
Bleeding: can be a bit difficult, but after one or two iterations you should be able to get all the air out of the system; I've owned 3 E39's (I-6 motors) and never had too much difficulty bleeding after a coolant change, etc. If you're bleeding the coolant very frequently (as it seems you are) and getting air out EVERY time you bleed that seems a bit odd - I am at a bit of a loss to explain that one. Perhaps you need to add coolant SLOWER when bleeding - that is usually helpful in moving the air out of the system.
Best of Luck!
I agree with the above--the OP didn't pose the actual "problem" that needs resolving. If the car starts to overheat at idle could be fan clutch or water pump. Fan clutch is relatively easy to pinpoint--if you think it spins just not fast enough after idling a bit, forcing the electric pusher fan (in front of the radiator) to kick on high too often, you probably have what I've called "lazy fan syndrome," where the fan clutch is worn to the point that it does not sufficiently spin at idle or low speeds to regulate the coolant temperature sufficiently. Anyway, post more info....
Cooling issue like this one
I was driving this week and the car just suddenly jumps up in the gauge. I check the fluid and it is low, but it was full prior to this incident. Let air out of the bleed screw and it is steaming. I grab the upper hose and there is no water pressure in it.
It starts to steam when at Idle too long. Coming from by the expansion tank. Could not see source of the liquid.
So, after i overheated, not up to the red area before I stopped, I turned on the heater and full heat at 90 degrees. Then it all seemed to stabilize.
What could be the cause of the issue. Clutch or water pump. Water pump has less than 40K on it.
Thanks for any input.
I was driving this week and the car just suddenly jumps up in the gauge. I check the fluid and it is low, but it was full prior to this incident. Let air out of the bleed screw and it is steaming. I grab the upper hose and there is no water pressure in it.
It starts to steam when at Idle too long. Coming from by the expansion tank. Could not see source of the liquid.
So, after i overheated, not up to the red area before I stopped, I turned on the heater and full heat at 90 degrees. Then it all seemed to stabilize.
What could be the cause of the issue. Clutch or water pump. Water pump has less than 40K on it.
Thanks for any input.
Do not drive any BMW that is overheating. The needle isn't an accurate display***8212;the electronics move the needle only at 117°C or higher, which is already way too hot.
It could be the thermostat, a leak, fan, or the most likely reason, a busted expansion tank (leak points here). Cooling overhaul is due. Might as well do the water pump as it's 1/2 way through its life.
It could be the thermostat, a leak, fan, or the most likely reason, a busted expansion tank (leak points here). Cooling overhaul is due. Might as well do the water pump as it's 1/2 way through its life.
I thankyou all for your input, but I just replaced the water pump, clutch fan, and the thermostat a week ago! I have no leaks of coolant. This past saturday I drove the car 35 miles on 95 at about 80 mph, I drove alittle in town in some stop and go traffic and all was well( I was gussing that all those new parts paid off!! ) I retuned home on 95 driving about 80 mph and got close to my house only to get caught in some long traffic lights the temputure started to climb, if I put the car in neutraul and bring it to a hige idle the tempature will immediatly come down!! I just feel that if the engine temputure is 200 degrees the moving air off the radiator should be quite warm, is it possible that the radiator can't rebound from be under such a load, and can it cause air pockets???
Auxiliary fan or a bad fan clutch. There's been reports of bad clutches out of the box from BMW.
Now I understand it.
Since you just replaced the water pump, clutch fan, and the thermostat a week ago....
Yes a partially clogged radiator will have diminished cooling capacity.
Let's say brand new radiator has 100% cooling efficiency
A 10-yr old/100K mile radiator has about 70% cooling efficiency.
Usually not a problem because there is safety factor built in from factory with extra cooling capability until it is down to 60-70% efficiency.
Then it will manifest exactly as you described: Stop-and-go traffic in hot weather will bring the boy out of a man.
So, yes change the rad, it is cheap compared with a new engine.
Since you just replaced the water pump, clutch fan, and the thermostat a week ago....
Yes a partially clogged radiator will have diminished cooling capacity.
Let's say brand new radiator has 100% cooling efficiency
A 10-yr old/100K mile radiator has about 70% cooling efficiency.
Usually not a problem because there is safety factor built in from factory with extra cooling capability until it is down to 60-70% efficiency.
Then it will manifest exactly as you described: Stop-and-go traffic in hot weather will bring the boy out of a man.
So, yes change the rad, it is cheap compared with a new engine.
I also have a similar cooling problem
I also have a similar cooling problem. I have a 1998 528i. The car has never overheated during normal driving, but if it sits at idle for a time (about 5 min.) its starts to overheat. Once I start driving, the needle quickly move back down to its normal position. I am not a cooling expert, but from what I've gathered fromvarioust threads, this is most likely a fan clutch. Does this sound correct?, and is replacing the fan clutch and easy DIY, or should I have it done by a shop.
I also have a similar cooling problem. I have a 1998 528i. The car has never overheated during normal driving, but if it sits at idle for a time (about 5 min.) its starts to overheat. Once I start driving, the needle quickly move back down to its normal position. I am not a cooling expert, but from what I've gathered fromvarioust threads, this is most likely a fan clutch. Does this sound correct?, and is replacing the fan clutch and easy DIY, or should I have it done by a shop.
The only time that I had these same symptoms I had a leak and was low on coolant. When I replaced the lost coolant and properly bled the system the problem went away. As it turns out the leak was coming from the new Bosch water pump which was installed along with a new o-ring 2 months earlier. Just to check my supposition, I swapped out the new pump and o-ring with the original old ones and the leak stopped. Not sure if the cause was o-ring or water pump, but I will replace the water pump and o-ring again at 200K or before, but not with a Bosch.
I know its been a while, I just wanted to fallow up. After ordering the wrong fan clutch, I finally got the right one and got it installed today. I ended up having to make my own tool to hold the hub as none of the automotive stores arround here had a wrench that would fit on the BMW hub. After installing it and letting the car idle for 20 minuets it was fine. Thanks for your help and Merry Christmas.
Hey I'm going thru the same thing. I changed my water pump pulley, fan, thermostat, and now I'm getting a water pump and a radiator. I'm hoping that will do the trick. See if your pulley have any damage and change the water pump not that expensive off line. I need help also I'm hoping that's the problem
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