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2001, 330CI, convertible, automatic trans
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15 Posts
Discussion Starter · #1 · (Edited)
Just bought a 01 330ci convertible. Was only driven 30 min a month for 2 years. Dude was topping off coolant with water. Starting to notice small pool on ground so I'm going to replace hoses, thermostat and expansion tank. As well as flush the radiator.
Question: Should the radiator just be replaced? Also, if I flush. Can I do this with water or should I use a flush cleaner?
Does anyone know if someone makes an expansion tank that doesn't crack?馃槄
 

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2013 X1 M-sport
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22,636 Posts
Most experienced folks on here know to do a full cooling system refresh.
I buy the whole set of commonly replaced/plastic parts, check the date codes on the ones I pull off and only keep the newer ones if they were replaced recently, then return the unused parts, if any.
No need to flush unless there is evidence of impurities.

You might be able to see the part date codes with a bright light and mechanic鈥檚 mirror.
 

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04/1999 328i 5MT
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125 Posts
I don鈥檛 know anyone that鈥檚 ever flushed a radiator with just water鈥
Personally, I like to run a flush before doing a refresh just to get all the mineral deposits out of the motor and then replace all the parts. Idk if you know the previous owner well and or trust that they used distilled water when topping off, but if it were me, I鈥檇 do the radiator and water pump as well. Better safe than sorry.
 

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Just bought a 01 330ci convertible. Was only driven 30 min a month for 2 years. Dude was topping off coolant with water. Starting to notice small pool on ground so I'm going to replace hoses, thermostat and expansion tank. As well as flush the radiator.
Question: Should the radiator just be replaced? Also, if I flush. Can I do this with water or should I use a flush cleaner?
Does anyone know if someone makes an expansion tank that doesn't crack?馃槄
The genuine BMW ET will probably outlive the car if you replace it now. I replaced mine a few months ago after 15 years of usage as PM.
  • don't forget the expansion tank cap. Personally I use the stock 2.0 bar cap, again genuine.
  • clean aluminum mating surfaces on the engine
  • Perhaps do the expansion tank bracket, especially if the expansion tank is stuck on it
  • New crush washer for the engine block drain plug
  • new bleeder screw (should come with the new upper hose kit)
  • lubricate o-rings with undilluted bmw coolant, makes them slide in place easier
  • lower radiator hose has temp sensor, get a new o-ring for that sensor
  • if the radiator is still the original, check it at the lower section if it's still straight. Also if the hose ends of the radiator feel that are about to crack, replace the radiator too.
  • What about the water pump? Ever changed? These have the bearing go or leak through the o-ring
  • hard coolant lines below intake? They also tend to rot and leak
  • auto or manual? different radiator drain screw that should be replaced too
  • Read and perform the venting process precisely to avoid overheats and other issues.
 

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2018 M240i
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12,432 Posts
The installation of aftermarket cooling system parts is strictly verboten. Go to www.realoem.com and enter the last 7 characters of your car鈥檚 vehicle identification number. Hit enter and bookmark the page. Cooling system parts are located in the engine and radiator sections. Get the part numbers and head over to FCPEuro. Enter each part number and you鈥檒l see a list of parts:
1. BMW labeled. ($$$$)
2. original equipment (OE) ($$$)
3. original equipment manufacturer (OEM) ($$)
4. aftermarket ($)

1. These are the same parts you buy at the dealer.
2. These parts were made by the supplier of these parts to BMW.
3. These parts were made by a supplier of parts to BMW, but does not supply these parts
4. Made who knows where.

I highly recommend that you buy parts made by the respective suppliers to BMW. That way you鈥檙e getting BMW quality at a reduced prices.
 

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2001, 330CI, convertible, automatic trans
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15 Posts
Discussion Starter · #8 ·
Awesome, thank you all for your advice. Yesterday I found dried coolant sprayed all on the top of the air filter box. Could the leak be from the expansion tank cap? Is there supposed to be an o ring on it?
 

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Yesterday I found dried coolant sprayed all on the top of the air filter box. Could the leak be from the expansion tank cap? Is there supposed to be an o ring on it?
Drive it to operating temp, then park and remove the air filter box, radiator fan, and look for where the pressurized coolant leaking. the cap has 2 o-rings and one flat gasket.
 

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2002 330i, 2000 323i
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1,041 Posts
Here is an easy way to discover the leak(s), rent a coolant pressure tester from any of the parts stores such as OReilley or AutoZone. Use it with the engine cold (it's easier and safer this way). Pump it up to about 15 lbs and look for the leak as your pressure gauge should also drop pressure.
 

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2002 330 Ci
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3,238 Posts
Drive it to operating temp, then park and remove the air filter box, radiator fan, and look for where the pressurized coolant leaking. the cap has 2 o-rings and one flat gasket.
Just let it idle in the driveway. Don't chance an expansion tank blowing while driving away from home.

Before starting....

Open up the cap and check the level. If low add some coolant or distilled water.

Replace the cap. Start up the car.

Leave the hood open.

Let it idle for 15 minutes or so.

If there are areas of the coolant system that are compromised you will see coolant leaking/spraying from the area.
 

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2001, 330CI, convertible, automatic trans
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15 Posts
Discussion Starter · #12 ·
Doing my full refresh kit tomorrow. Radiator was cracked at the top where it connects to the expansion tank.
Wish me luck I'm new to working on my own car. Managed to change my own spark plugs so I'm confident I can do this. Thanks all!
 

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Fantastic that you are tackling this job yourself. It's a big job and while not super difficult, some parts can be stubborn to remove like lifting the expansion tank upwards off the ET bracket and removing the lower hose off the radiator (if it doesn't want to budge, just cut the hose and take them out together).

If you run into a jam reach out here, there may be a fanatic near you who's experienced in doing a cooling system replacement and would be glad to help. The bleeding at the end is not tricky at all but you want to get it right.

Good luck!!
 

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2001, 330CI, convertible, automatic trans
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15 Posts
Discussion Starter · #16 ·
Thank y'all for the positive energy!
I'm glad to have purchased mangos overhaul kit from FCP euro. Was hoping to be done today..... but... I was being a little too confident, boy you weren't kidding about that lower hose and the expansion tank! Ran out of daylight and it started snowing. Gonna resemble tomorrow.
 

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Was hoping to be done today..... but... I was being a little too confident, boy you weren't kidding about that lower hose and the expansion tank!
Lower hose connected to Tstat and lower right of radiator? That should be like eating cake. Or do you mean the lower hose to the tank bracket? We don't call that smaller hose as "lower hose" which is reserved for radiator lower hose.
The whole thing might look easy, but not breaking things and no leak result is the challenge. Don't just try to pull the tank up off the bracket, as it can be hard and break your back, or the bracket. I used a falt screwdriver wedging between the tank bottom and the bracket to separate them.
Don't forget to lube the male part and the o-ring with grease before assemble together.
 

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2001, 330CI, convertible, automatic trans
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15 Posts
Discussion Starter · #18 ·
Well.
10 days later. All fully back together. No leaks or additional warning lights on the dash.
Learned allot about what I didn't have for this job.
Learned that you should be sure there's not cactus on the ground BEFORE you lay down.... and be patient, and gentle.

I did find something weird that maybe y'all can shed light on. This hose goes into the expansion tank. Pretty sure its not supposed to be split like that. What is it called and why would they do that?
Automotive fuel system Automotive tire Motor vehicle Bumper Automotive exterior
 

Premium Member
2005 330xi Auto, 2006 330ci Vert Auto
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2,203 Posts
Well.
10 days later. All fully back together. No leaks or additional warning lights on the dash.
Learned allot about what I didn't have for this job.
Learned that you should be sure there's not cactus on the ground BEFORE you lay down.... and be patient, and gentle.

I did find something weird that maybe y'all can shed light on. This hose goes into the expansion tank. Pretty sure its not supposed to be split like that. What is it called and why would they do that?
Looks to me like someone tried to save a few $$ and rather than replacing a failed hose, simply mend it with some sort of a coupler.
 
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