# Should I replace cooling parts BEFORE they break on a 2001 325ci?



## PatS (Jul 9, 2005)

I have a 2001 BMW325ci with about 76k miles. The car runs fine, but i have heard horror stories about water pumps breaking and that this year and model, many cooling system parts are made of plastic (water pump, thermostat.) Should i just bite the bullet and make the investment to replace the parts with aluminum ones, like the water pump? Which are the most important parts to replace?
I want to keep the car for as long as possible -- I really like the car and it has been basically trouble free so far.
Thanks!
Patricia:eeps:


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## Fast Bob (Jun 4, 2004)

Well....let`s put it this way....one instance of overheating can toast the engine, leading to either thousands of dollars in repairs, or rendering the car pretty much useless should you choose to not fix it. Replacing the cooling system *now* is a good idea (they ALL fail sooner or later), a fairly easy DIY, and it`s relatively cheap ($500-600) life insurance for your car.

P.S.: Get the Stewart water pump with the all-metal construction....it`s worth the extra cost....


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## Orient330iNYC (Jul 30, 2002)

+1
if the cooling system goes out, and you dont shut down RIGHT AWAY, you run the risk of warping the block.... and then its time for a new engine.

and do the full overhaul...
on my 330i, i just replaced the water pump since i was swapping out the alternator... my best guess is, the new pump pushed a bit more pressure, because the thermostat housing started leaking soon after...

ended up replacing the hoses, thermostat housing, and expansion tank. was only slightly more expensive, but i should have done it all at once to avoid having to do the job twice.

tischer bmw sells a full rebuild kit for 315:
http://www.trademotion.com/partloca...fo&PartID=774527&siteid=214672&catalogid=4462

Kit includes genuine BMW:


Thermostat w/ housing/gasket (11537509227)
Waterpump (11517527910)
Upper radiator hose (17127510952)
Lower radiator hose (11531436408)
Expansion Tank (17117573781)
Radiator Cap (17111742231)
Engine drain plug crush ring (07119963200)
Lower hose temp sensor (13621433077)
1 gallon BMW antifreeze (82141467704)

*Price includes Free Ground Shipping! (US only)

the OEM pump (2nd rev) lasted for 90K miles, but was starting to go south. the rev1 pump lasted 15K miles. i'm personally comfortable with replacing with current OEM parts every 50K miles or so.


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## bpbville (Jan 6, 2010)

*Coolant Leaking Out of Cap with No Cause is Sight? Help Please!!!*

I have a 2004 BMW 330i and have replaced all coolant related parts with the with the exception of the water pump. I have had done everything that I know to do, but still have coolant leaking out of the cap. I have no explanation for this. I have went as far as the replace the cap three times with all new BMW OEM parts, and put two new expansion tanks on the car. No one can find the issue that is causing this. I can drive the car at time for hours with no coolant issues at all, at others I can not get a mile without the car leaking coolant out the cap as if it is boiling over. I am so confused and do not know what to do. I know that it could be a cracked head or a blown head gasket, however I have no signs of that what so ever. Can the water pump cause this? Its the only coolant related item that has not been replaced. This site is great and has helped me beyond words can say, and I hope that someone out there can give me some advice. I can not afford to take the car to BMW as it is nearly 200 miles away from my home and I have already spent 2,000.00 on the replacement parts thus far. Please help me if you can. Any advice is welcome and desperately needed. Thank you for your time.


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## HeadRoom (Jun 3, 2009)

^^ You say everything in the cooling system has been replaced. The radiator has been replaced, correct? You never mentioned that.

Do you have oil in your coolant? Does the car put out white smoke at start-up? The next time the motor is warmed up, put your hand on the upper rad hose, and then the lower hose. The top should be warm, and the bottom should be cold.


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## bpbville (Jan 6, 2010)

*Yeah.... Everything but the Water Pump*

Yeah I have replaced everything except the water pump. When I check the hoses the upper hose is hot however the lower hose is not. I have been reading several posts on here and there are several that seem to suggest that their problems, which were similar to mine, were caused by the water pump.

To answer your other question, Im in Kentucky with a temp of 16 this morning, yeah I have a little white smoke upon start, but nothing more than any other car that is started in this weather. As for any milky oil, none. Nor any type of oil or discolored coolant can be seen in the expansion tank. The oil is perfect with no signs of water, or anything unusual.

I assume you are thinking as I was that it could have a blown head gasket or a cracked head, there just are no signs of that at all. The exhaust has no sweet smell, just can not explain this at all. I am new to BMW and I have found one local shop that are actually certified to work on the car, within a 100 miles of where I am and even they are lost for a explanation. They did not do all the work, I did have the expansion tank and radiator put in at another shop, but the car continued to have issues. This past time at the shop they were focused in on trying to stop the water from flowing out the cap of the expansion tank and against my better judgement I actually have bought a second new expansion tanks and now three new caps, because as unlikely as it is they thought one of the two could have been defective. The car will hold its pressure and will not leak out of the cap while just sitting, the heat works great while just sitting, then when you drive the car that is when the problems starts. However, I have drove the car as far as 50 miles(since the boiling out the expansion tank issue started) and had no coolant issues what so ever, and then again as little as 1 mile and have the coolant "boiling over" of the expansion tank cap.

Like I said the only thing left for me to change is the water pump, and I would have done that but the mechanic seem to think that it looked to be relatively new, however it housing does not determine what's actually going on inside of the actually pump. Thank you for discussing this with me because I am simply lost. I am ready to write this car off.

A couple notes that may be important, I bought the car two months ago and had a good months worth of driving until the expansion tank cracked and even then the car did not run hot. I was able to catch the problem, with the low coolant light indicator warning me, without allowing it to run hot. It has been in the red once, but for no longer than the time it took me to turn off to the side of the road, less than a minute or two at the very most. Any advice you can offer me would be so greatly appreciated. It helps just having someone who can relate at all. Im pretty lost with this thing right now. Thanks again.


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## Fast Bob (Jun 4, 2004)

bpbville said:


> Yeah I have replaced everything except the water pump. When I check the hoses the upper hose is hot however the lower hose is not. I have been reading several posts on here and there are several that seem to suggest that their problems, which were similar to mine, were caused by the water pump.
> 
> To answer your other question, Im in Kentucky with a temp of 16 this morning, yeah I have a little white smoke upon start, but nothing more than any other car that is started in this weather. As for any milky oil, none. Nor any type of oil or discolored coolant can be seen in the expansion tank. The oil is perfect with no signs of water, or anything unusual.
> 
> ...


Change the water pump, and **bleed the system thoroughly**....


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## injunmort (Aug 19, 2009)

it sounds like one of waterpump plastic blades is now in your cooling system causing a partial obstruction. change the waterpump and try to flush out the whole system. you might get lucky and retrieve the offending blade. there are threads on this site that will be more help with regards to clearing out your cooling system.


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## bpbville (Jan 6, 2010)

*Sounds Like Sound Advice*

That sounds like sound advice. Thank you all for helping me with this issue. It makes sense that the water pump would most likely be the most probable problem. I am just confused to as why the water pumps out of the cap like that. Has anyone ever had this problem before. I am trying to understand what would cause the coolant to flow out of the expansion tank cap so easily. Is it the fact that the coolant is getting hot and boiling over, or is it the fact that the water pump isn't pumping and the coolant simply has no where to go but out out the cap? I am just wondering if anyone has anyone ever had a leak coming out of the cap as I have described? Thank you all again it is great to have someone actually know what I am talking about after speaking with so many other who have limited experience with BMW. I am so grateful that this site exists.


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## QuoteWarz Insurance (Dec 17, 2009)

Yes, I would definitely suggest replacing it before something goes wrong. One very important thing you must do it bleed the entire cooling system. If there are air bubbles or pockets in the system then it will create a problem for you.


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## bpbville (Jan 6, 2010)

*It was bleed....*

It was bleed over the course of two days. I had to take it in to have that done I just could not get the bleed myself no matter what tricks I found in other threads on this site. After it was bleed properly it did have heat and worked great for about three hours, then the cap just started losing coolant like a waterfall. I am hoping that the water pump could cause this because I simply have replaced everything else in the coolant system. There is no signs of a blown head gasket or cracked head. I just don't know what else it could be.


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## injunmort (Aug 19, 2009)

if there is an obstruction in the system, and the coolant doesnt circulate smoothly, you will build pressure in the radiator which the path of least resistance to alleviate this pressure is the cap. when you change the pump be sure it has not come apart. i have heard of them disintegrating and depositing its remains in the system until blocks a passage. this causes all sorts of cooling problems. i would flush the system really well and also the radiator and themostat housing and all hoses and hope you can relieve the obstrution. you might want to flush the heater core too. it is a pia but is necessary if you are to restore the functionality to your cooling system.


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## bpbville (Jan 6, 2010)

*Thank you...*

Thank you very much, that makes perfect sense. I understand what you mean and this makes me think of something that I encountered when I changed the expansion tank. Someone prior to my buying the car tried to use "Stop Leak" for the radiator- apparently they were trying to stop the crack in the expansion tank from leaking, which obviously did not work. When I looked at the bottom of the expansion tank there was a collection of "crud" that had collected in the bottom of the tank that was blocking the water from entering the bottom of the expansion tank. I am wondering if there is another blockage similar to the one I already removed. I have taken the car in to have the system flushed but I am not sure if they have actually done it properly. Thank you all for the advice and I feel like I have a couple good leads to help me get the car back on its feet. Any additional advice is welcome and appreciated.


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## ECSTuning (Feb 25, 2009)

PatS said:


> I have a 2001 BMW325ci with about 76k miles. The car runs fine, but i have heard horror stories about water pumps breaking and that this year and model, many cooling system parts are made of plastic (water pump, thermostat.) Should i just bite the bullet and make the investment to replace the parts with aluminum ones, like the water pump? Which are the most important parts to replace?
> I want to keep the car for as long as possible -- I really like the car and it has been basically trouble free so far.
> Thanks!
> Patricia:eeps:


Its all depends on how much peace of mind is worth to you. It was worth the cost to me to repalce the entire cooling system on both my my E46s.

We have created all in one kits just for this. Because our E46s followed the pattern of weak cooling systems set by BMW in the late 80's. But it seems these models are excessively prone to overheating, causing huge repair bills. Due to a low coolant capacity once these engines enter the "Red Zone" on the gauge, thousands of dollars in damage is already happening.

Once these models have more than 60k miles they should be serviced, then every 60k miles there after. Water pumps begin to fail, thermostats housings crack, along with expansion tanks and begin to leak due to plastic construction.

We have Level I & II kits available

*Level I Includes:*
Water pump
Fan switch
Thermostat & housing
Sealing gaskets
Expansion tank & cap
1 Gallon Coolant
Upper & lower radiator hoses
*Click HERE to order or for more information.*


*Level II Includes:*
Water pump
Water pump pulley
Fan switch
Thermostat & housing
Sealing gaskets
Expansion tank & cap
1 Gallon Coolant
Upper & lower radiator hoses
Accessory drive belts
Radiator drain plug
Coolant level sensor
Level sensor clip

*Click HERE to order or for more information.*


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