[RoRosBimmer]

I just got my water pump and thermostat changed at an Indy shop. Once I got it home, I tried to vent the air out of the cooling system by using a very helpful DIY by ENINTY (http://www.e90post.com/forums/showthread.php?t=565770). I started the process but couldn't hear the water pump. I tried about 3 times with 5 minute intervals between each trial. My guess is that the shop did something wrong. Thanks for your help.

[shadowx360]

Is your car an e90? It could be that you don't hear your water pump going. You can check by checking the voltage on your battery before and during the flush and you should see a drop in battery voltage from the draw. Multimeter, if you don't have one, is free from Harbor Freight with any purchase

[RoRosBimmer]

Originally Posted by shadowx360

Is your car an e90? It could be that you don't hear your water pump going. You can check by checking the voltage on your battery before and during the flush and you should see a drop in battery voltage from the draw. Multimeter, if you don't have one, is free from Harbor Freight with any purchase

Thanks! I will try this once I get a multimeter

[PA66400]

Not sure of the instructions that you read, but here is how I do it (works every time): get in car, shut door, put key fob in ignition, press start button with foot OFF the brake, turn heat to highest temperature, with fan on lowest setting, then press and hold accelerator for 10 seconds. You will then hear the waterpump start to circulate and it does this for ~8-10 minutes. NOTE: if you open the driver's door, the whole procedure stops. To prevent this (and allow me to continue to work while it is venting) I usually start the procedure standing outside the car, with the driver's window open and I press the accelerator pedal with a broomstick.

[Efthreeoh]

Why did you try and vent the cooling system once you got the car back from the shop? If the Indy did not perform the vent procedure upon installation of the pump, once the engine was run and it did not overheat initially then you can assume the air was bled from the system and all is needed is to open the reservoir cap to let it out and top off the system.

The instructions from Eninty's DIY are correct and you can get out of the car once the pump starts running.

[RoRosBimmer]

Originally Posted by PA66400

Not sure of the instructions that you read, but here is how I do it (works every time): get in car, shut door, put key fob in ignition, press start button with foot OFF the brake, turn heat to highest temperature, with fan on lowest setting, then press and hold accelerator for 10 seconds. You will then hear the waterpump start to circulate and it does this for ~8-10 minutes. NOTE: if you open the driver's door, the whole procedure stops. To prevent this (and allow me to continue to work while it is venting) I usually start the procedure standing outside the car, with the driver's window open and I press the accelerator pedal with a broomstick.

Ohhhh I had the drivers door open. LOL. Thanks

[RoRosBimmer]

Originally Posted by Efthreeoh

Why did you try and vent the cooling system once you got the car back from the shop? If the Indy did not perform the vent procedure upon installation of the pump, once the engine was run and it did not overheat initially then you can assume the air was bled from the system and all is needed is to open the reservoir cap to let it out and top off the system.

The instructions from Eninty's DIY are correct and you can get out of the car once the pump starts running.

Ok. I'm not sure if they did it or not. Will it hurt if I try again?

[PA66400]

Originally Posted by RoRosBimmer

Ok. I'm not sure if they did it or not. Will it hurt if I try again?

No, you can do it as often as you like. Twice is usually enough. Watch for the drain on your battery - best to hook up the underhood battery boosting posts to at least a 6-10 amp charger while running the flush cycles. Don't hook directly to the battery, as you can harm the car's electronics (potentially); always use the underhood +ve and negative posts.

If the indy shop did not do this procedure, I would not let them work on the car anymore, as not doing this clearly shows that they do not know current BMW's and/or do not read manuals available to them for service work, such as Mitchell's.

[Efthreeoh]

The purpose of bleeding air out of the cooling system is to prevent overheating of the cylinderhead upon initial startup of the engine once the system was drained and refilled. Generally the highest point in the cooling system is the cylinder head and the fastest heating part of the engine is the cylinderhead, so it's a bad combination. Air gets trapped at the highest point in the cooling system, so air can get trapped in the cylinderhead, and depending upon the design and severity of the amount of air in the system, cause blockage of coolant flow through the head, which can allow the head to overheat.

I don't see this as much of a risk in the N52/H54 design. The coolant reservoir tank (and bleed screw) is pretty much at the same level has the cylinder head, so if the cooling system is filled properly, meaning refilled with the bleed screw open, there is very little trapped air in the head when the system is refilled. Of the four times I've drained and bled the system, very little air escapes from the reservoir when opened to top off; only a few more ounces of coolant is required to top off the system. If you check the coolant level in your car (when it is cold!) and find it is full, then there is no air trapped in the head.

If you drove the car home from the shop and it did not overheat, then you don't have an issue. If the coolant reservoir is full, then you don't have an issue.

[Three_thirty_I]

Originally Posted by RoRosBimmer

Ohhhh I had the drivers door open. LOL. Thanks

It makes not difference if the door is open or closed, at least it hasn't with my car. With the ignition on, simply set the fan speed to the slowest setting and the temperature on both sides of the climate control to max, and then press the throttle down to the floor for 10 seconds. You will immediately hear the pump start its purging cycle.

It's not very loud, so best is to stand on the left front side of the engine (if you are standing in front of the car), you will hear the pump come on and speed up/slow down, gurgle (if having to bleed air out) etc. The entire process takes roughly 12 minutes to complete, so it does put some strain on the battery, but I doubt enough to deplete it. It is however recommended to run this purge process at least twice and as such it does make sense to keep an eye on the battery. But with that said, my car's battery is already at the end of its life but is able to still cope with two of these purge procedures back to back - just very important to take the car for a good drive afterwards.

[RoRosBimmer]

Originally Posted by PA66400

No, you can do it as often as you like. Twice is usually enough. Watch for the drain on your battery - best to hook up the underhood battery boosting posts to at least a 6-10 amp charger while running the flush cycles. Don't hook directly to the battery, as you can harm the car's electronics (potentially); always use the underhood +ve and negative posts.

If the indy shop did not do this procedure, I would not let them work on the car anymore, as not doing this clearly shows that they do not know current BMW's and/or do not read manuals available to them for service work, such as Mitchell's.

Thanks

[RoRosBimmer]

Originally Posted by Efthreeoh

The purpose of bleeding air out of the cooling system is to prevent overheating of the cylinderhead upon initial startup of the engine once the system was drained and refilled. Generally the highest point in the cooling system is the cylinder head and the fastest heating part of the engine is the cylinderhead, so it's a bad combination. Air gets trapped at the highest point in the cooling system, so air can get trapped in the cylinderhead, and depending upon the design and severity of the amount of air in the system, cause blockage of coolant flow through the head, which can allow the head to overheat.

I don't see this as much of a risk in the N52/H54 design. The coolant reservoir tank (and bleed screw) is pretty much at the same level has the cylinder head, so if the cooling system is filled properly, meaning refilled with the bleed screw open, there is very little trapped air in the head when the system is refilled. Of the four times I've drained and bled the system, very little air escapes from the reservoir when opened to top off; only a few more ounces of coolant is required to top off the system. If you check the coolant level in your car (when it is cold!) and find it is full, then there is no air trapped in the head.

If you drove the car home from the shop and it did not overheat, then you don't have an issue. If the coolant reservoir is full, then you don't have an issue.

Thanks for the information

[GoRomeo]

If the Indy shop know what they are doing, they should ve done this as part of the job. Ask them if they did, if they did not, take car back and have them do it. Simple as that...

How much did you pay for labor?

[RoRosBimmer]

Originally Posted by GoRomeo

If the Indy shop know what they are doing, they should ve done this as part of the job. Ask them if they did, if they did not, take car back and have them do it. Simple as that...

How much did you pay for labor?

$400 because he replaced the thermostat first and found out it was the water pump after he closed everything up and test drove the car. I paid $900 total with parts and labor.

[Efthreeoh]

Originally Posted by RoRosBimmer

$400 because he replaced the thermostat first and found out it was the water pump after he closed everything up and test drove the car. I paid $900 total with parts and labor.

No offense to your Indy, but you may want to look for another one. The T-stat will not cause the engine to overheat. The T-stat fails safe in the open position, and what causes the need for a T-stat replacement is the heating element in it will fail, which triggers a Service Engine Soon (SES) light. The T-stat is part of the control system that reduces cold-start emissions, so if it is not working properly it throws a OBD II trouble code.

The water pump on the other hand does not throw an OBD II fault code (SES light). The water pump will throw fault codes in the ECU that can be picked up by a BMW scan tool. The Indy should have scanned the car for water pump fault codes as part of his diagnosis of the overheat symptom your car had.

[RoRosBimmer]

Originally Posted by Efthreeoh

No offense to your Indy, but you may want to look for another one. The T-stat will not cause the engine to overheat. The T-stat fails safe in the open position, and what causes the need for a T-stat replacement is the heating element in it will fail, which triggers a Service Engine Soon (SES) light. The T-stat is part of the control system that reduces cold-start emissions, so if it is not working properly it throws a OBD II trouble code.

The water pump on the other hand does not throw an OBD II fault code (SES light). The water pump will throw fault codes in the ECU that can be picked up by a BMW scan tool. The Indy should have scanned the car for water pump fault codes as part of his diagnosis of the overheat symptom your car had.

Damn! I need a new mechanic. Thanks for the information.