# Cooling System DIY E46 - Any advice?



## flat6fan (May 11, 2005)

I just bought my first BMW, it is an 01 - 330i with 79K - automatic. I have searched this forum and others to get a better understanding of the car. The car has stalled in parking lots three times in about a month - previous owner had plugs & intake CPS replaced by dealer. I just ordered exhaust CPS from oembimmerparts.com based on my research into this problem.

I have some of the service history but there is no mention of cooling system service. I am going to tackle this DIY in about a week. I have purchased the Bentley manual.

Here are my questions going into this DIY:

How much of the cooling system should be replaced as a preventive measure?
I was initially thinking of doing the water pump, thermostat, hoses and belts. The more I read it sounds like the radiator, expansion tank, fan clutch, tensioners and pulleys should be replaced. This obviously increases the cost of the project.

Any recommendations on parts suppliers? 
Pelican & oembimmer both have kits but I am not sure if that is the way to go.

What water pump to get?
I have seen various threads and it is confusing: metal impeller better vs. metal causing bearing failure. OEM = plastic impeller vs. OEM = composite impeller

Antifreeze?
$20/gal BMW vs. Prestone 
Will 1 gallon do it?

Can anyone post a drawing of the special tool used to hold the pulley while taking the fan nut off?
I would like the dimensions (hole size, spacing, length) to see if I can make my own.

Thanks!
:thumbup:


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## lukeeesteve (Sep 2, 2006)

flat6fan said:


> Antifreeze?
> $20/gal BMW vs. Prestone


BMW brand.


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## Nick325xiT 5spd (Dec 24, 2001)

E46 cooling systems seem to be pretty solid. I wouldn't bother.

It's pretty easy though - the E46es are self bleeding.


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## flat6fan (May 11, 2005)

That is the first I have heard of the E46 cooling system being solid. I am doing this DIY based on just the opposite - cooling system is a known weak point and should be replaced as a preventive measure to prevent potential overheating and related issues.

I will need to order parts soon so I am still looking for feedback on suppliers. My CPS just arrived today from OEMBIMMERPARTS - good delivery (Mon. order - Fri. delivery - standard ground).

Just bought the 32mm wrench from BIG LOTS based on another thread $6 :thumbup:

I am leaning towards doing the full system. Anyone have experience changing out the radiator (and/or expansion tank) - tips ?


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## WAM (Jan 30, 2002)

I would recommend the water pump and thermostat housing. Take a look at the hoses and if they look ok, you can defer that. My indy mechanic says hoses generally are fine for 8 years or so.

You might have a metal impeller pump. I did, Sep 2000 manufacture, 01 325i. However, the water pump and thermostat were both leaking. I got my pump from oembimmerparts, it was German one, metal impeller.

Get BMW coolant. I gallon, 3.78 liters, should be enough, when mixed 50:50 with distilled water.

Might as well change the V belt and the A/C belt at the same time, they might be the original ones.


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## FalconGuy (Sep 27, 2002)

http://www.autohausaz.com

The Water Pump on the E46 is probably one of the poorest designed parts I have ever held in my hand, that's saying a lot for a guy who handled a lot of parts as an aviation Tech. That said, Autohauz had a Graf (Sp?) for 50 bucks, OEM couldn't hold a candle to it when compared side by side. I have read here and elsewhere that the plastic impellers were no longer used, but my 2003 had one when I yanked it out. The dealer is still selling them and installing them as well, when I bought my coolant they saw my pump, tried to tell me to use only OEM. We put them side by side, the parts guy is a pretty cool guy and he openly admited he would choose the one I had even if it cost more, it doesnt, in fact its a whole lot less......

The belts may run 24 bucks, your taking them off anyway, it would be silly not to change them. The same goes for the thermostat, around 30 bucks with the Oring. Its an easy as can be DIY. The bad part, since you have an Auto, you must remove the fan, if you take one thing away from my post, please remember the fan bolts are reverse threaded, if you try to use the old left loosey logic, snap, for the 4 bucks I ordered new bolts anyway. I also would highly recommend you replace the Idler pulley, its going to screech anyway, its maybe 30 bucks? Plus its a real straight forward DIY, one bolt...

One other tidbit, the Bentley Manual is wrong when it tells you to relieve tension on the belts by turning the torx ( T50 on my 325) just be careful, try one direction, if you dont feel a spring being compressed and the belts loosen up after a 1/8th turn, your going the wrong way. Its an easy thing to snap that bolt. Do a search here and see how many have made this error.

I would say get the BMW coolant. I gallon tops, I bought two, didn't even use one and I drained the system and used distilled water to achieve the proper mix with no minerals to leave deposits.

The one silly thing I say get is the little plastic rivets that hold the intake cover and radiator shroud on, its a horrible thing to do this job and then discover one or two are missing. My local dealer gave them to me free when I bought the coolant at the parts counter, nice touch, when you consider how they are raping you on a gallon of coolant its a small token...

Given the age of your car, this is not something that may fail, this is something that WILL fail. It can all be completed in an hour or two, first time you may take double, then sit back and say I could do that in 30 minutes next time. If you need the tools to remove the fan ( one holds the fan, one is used to remove the bolts) if your willing to pay shipping you are welcome to borrow mine. Though I thing I paid 20 bucks on Ebay for them... Our DIY sponsor also sells the tool, it can be home made. Being a mechanic with a large tool collection, I couldn't resist buying another tool.

Too bad your down south, I would be happy to help you do the job for a cold beer. I bet some other member will step up to the plate and offer, at least I would hope.

At the dealer this could easily run a grand, in my garage, on a Saturday afternoon, taking my time, the pump ( get slightly longer bolts to aid in removing it by threading them into the empty threaded holes around the pump) This effectively pushes the pump out, in some cases its not needed, the bolts are under a dollar. For the entire job, Pump, Thermostat, belts, no hoses since they are one of the things that is well made in the cooling system, idler pulley, waterpump pulley, bolts, coolant misc items it was near, maybe slight over $150 with free shipping.

I would highly recommend you head over to Pelican Motors DIY section for some good DIY's with pictures. Also Madrussian.net has some good info.

Please feel free to email me if you have any questions, this is something that at this time of year, particularly if your down south, I would not put off. This is a great car, sadly this is not one of the great systems in the car. But the upside its very easy to work on, even if your not a mechanic or a do it yourself guy. Just search, read, take your time. Don't start on a Sunday night... start on Friday, take it slow. Hopefully you have garage. The only thing that needed me to get under the car was the Air conditioning Belt and to double check everything when done.

Good Luck


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## flat6fan (May 11, 2005)

I appreciate the advice and the offer to borrow the fan tool. I will check ebay first.

I have decided to do a major cooling system overhaul. I ordered the parts from Autohausaz and oembimmerparts. I also picked up the coolant from the dealer today.

I have next week off to finish the job and should receive the parts no later than Tuesday. Hopefully I will be posting a successful install after that and any tips beyond what is already documented. 

I am also replacing the exhaust CPS, oil change, air filter & cabin filter. My wife is trying to figure out why I am spending so much after just purchasing the car.  I'm just glad that you can actually work on the car at least for most common items.

One point that I have not read much about is the thermostat gasket. Does this require scraping the old gasket off and using a gasket sealer on the new item?

The E39 full system DIY recommends a 1/16" hole be drilled in the thermostat. Is that required or recommended for the E46?

Any additional tips on radiator removal/install or the hydraulic tensioner? I have not read much about these two items.

Thanks!


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## FalconGuy (Sep 27, 2002)

The gasket is an O ring, rubber, like the one on the oil filter. Wet it with coolant, your done.

That is by far the easiest of the job, good luck and let us know if you need any help


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## jj0n (Jun 15, 2007)

After reading this, I am a bit worried.
I have never had any problems (the temp gauge always stay right in the middle), but I do have 155,000 Km on my 99 323i and only change the coolant every two years or so.
Does this mean I should do a complete overhaul?
Does anyone know of a good parts source for Canada - southern Ontario?
Thanks


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## flat6fan (May 11, 2005)

Several factors lead me to this point:
1. Research - plenty of recommendations to replace at least some of the cooling system.
2. Failure Cost - I have had cars overheat before without any damage to the engine. I get the impression from my readings that the BMW engine is more prone to damage when overheated.
3. Time - I have next week off and some help if needed.
4. Weakest link theory - I figured since I had the time it would be just as well to replace the major components and not worry about them for a few years. I would hate to replace the waterpump and then have the fan fly apart.
5. Long distance driving - I will be making weekly trips of 200 + miles. Do not want to be stranded.
6. No cooling system information in service history.

You may never have an issue and this full overhaul is not cheap (close to $1K). I owned a 97 Dodge Caravan and everyone told me that the transmission would go at 60K miles but I sold it at 145K without ever having a problem. I am hoping this BMW keeps going strong well beyond 145K.


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## FalconGuy (Sep 27, 2002)

I replaced my waterpump, belts, pulleys, two tensioners, themostat and coolant along with the Idler pulley ( be sure to do that, its already overdue by your model/year. All on one day, for under $200? 

A lot under 200 too, with Good, ( read Better than OEM) parts in most cases.

No offense but where did the 1 Grand number come from?


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## flat6fan (May 11, 2005)

*Install Complete!*

Okay - I am back from a week's vacation at the lake which included my DIY. Having plenty of time and help from my nephew = :thumbup:, being 75+ miles from a dealer = :thumbdwn:. No probems after 100+ mile drive today!

I am attaching a PDF with part numbers, suppliers and costs. In response to Falconguy the ($1K) was closer to my total DIY (Bentley, ramps, tools, CP sensor, oil, filters, etc.). There are already good DIY's with pictures but I may post a few.

Cooling Parts Purchased:
The majority of the parts were purchased from Autohausaz.com. I have also purchased from oembimmerparts.com. I received excellent customer service from Paul & Max respectively and all items arrived on time and in good condition.

Radiator (Nissens)
Exp. Tank
Rad Cap
Thermostat
Upper hose
Lower hose (temp sensor leaked - removed and reinstalled old hose)
Waterpump (Graf) - Old pump (assuming OEM had metal impellar and looked great)
Pulley Waterpump
Drive Fan Blades (MTC)
Fan Clutch (Sachs)
Drive belt
Idler pulley
Belt Damper Hydraulic Tensioner (Not installed - it had mechanical)
BMW Antifreeze + Distilled water (I premixed it before pouring)
Belt tensioner pulley 70mm (for hydraulic set-up: did not fit mechanical tensioner)
Shroud rivets
A/C Belt
Thermostat for ATC (broken during installation - not part of original plan)

Lessons Learned
Note: Entire install was done while car was on ramps (Rhino).
1. The drain plug to the engine block is difficult to reach. The Bentley manual shows a bolt but my engine had a hex head mounted flush. I was not sure about this so I did not remove the block plug.
2. The fan pulley nut was a breeze with my $6 Big Lots wrench although it barely fit due to the thickness. My $30 Special fan pulley tool was not used or needed in this case. Overall fan removal was easy.
3. Automatic Transmission Cooler (ATC): There is not much documented on this removal. Bentley first instructs to removes ATF lines with alternative to disconnect entire cooler. We disconnected the entire cooler by pulling up on a clip at the top. Quite a bit of collant poured out during the disconnect (it was after draining radiator).
4. Radiator removal - After removing the expansion tank it took some inspection to see exactly what hoses are connected to the radiator assembly (A/C hoses are close by but not connected). The lower radiator hose would not come off radiator side so we left it on during removal. It took some twisting and turning to finally get it out. Note: Keep old parts handy until everything is working properly - see below.
5. Water pump and thermostat installation were straightforward and I like the O-ring gaskets. Also took this time to install an exhaust cam position sensor (5 minutes) due to stalling problem. Installed idler pulley.
6. Hydraulic or Mechanical? - I guessed on this one and purchased the hydraulic set-up. Lesson learned - purchase both set-ups and return the other after install. The first clue was that the new tensioner pulley hole was a different diameter (much smaller).
7. Install radiator - There is a plastic strip on the old radiator that must be transferred to the new radiator in addition to the plastic assembly for attaching the expansion tank and ATC. Positioning the radiator was not easy because there is not much to support or align it from below. We had to unbolt after the first try because the bottom was to close to the engine.
8. Expansion tank - We are moving right along at this point and just putting things back together. My nephew is below the car helping align and clip the tank and I am pressing on it from above. I did not take time to see what was below and it cost me ($69.01 and two days to be exact ). The large hole on the bottom of the expansion tank fits over the ATC thermostat. As I pressed down to seat the expansion tank the ATC thermostat housing broke (more plastic!). I ordered the part from the closest dealer and even though UPS or the dealer had no idea where the shipment was, it did arrive on time. Now back to the expansion tank install. I carefully  aligned the tank over the holes and pressed down. The clip did not hook properly so I applied more pressure until it finally slipped down into position -  time for a break!
9. I installed new fan blades and clutch. The only thing needed from the old assembly were the three hex screws to attach the fan to the clutch. During the fan install we realized the long torx screw supporting the radiator on the passenger side had to be removed and reinstalled with the fan shroud. It was tricky getting the radiator repositioned when reinstalling the screw.
10. Fan nut - this took a little time to get started but was not too difficult. My 32mm wrench ran out room and it was only hand tight until the engine completed the tightening.
11. Refill system (slowly) with BMW coolant and distilled water (heat setting 91 & blower on low). Drip, drip, drip  - the lower hose is leaking around the temp sensor. This is one part I did not replace so I am using the old sensor and the O-ring looks fine. Coated O-ring with vaseline and tried again with on luck. No time left to get a part at this point so we decided to use the old hose (still on the old radiator - wow was is it stuck on!). Put old hose (still in good shape) back on and tried again - No Leaks:thumbup: I am not sure if it is a defective hose or if it will work with a new sensor.
12. Completed oil change, air filter & cabin filter replacements.

This was a pretty big DIY but with the forum information, Bentley and a good helper it wasn't that bad. I will keep an eye on my lower hose and hopefully it will be okay until my next coolant flush. I may also change the mechanical tensioner out at that time.

One DIY begats the next DIY. I noticed a power steering fluid leak while under the car.

I will review my pics and post a few if they look helpful. Thanks all!


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## refugee (Jan 30, 2006)

Do you have a link to the Pelican Motors DIY for the water pump/belts?

Thanks



FalconGuy said:


> http://www.autohausaz.com
> 
> The Water Pump on the E46 is probably one of the poorest designed parts I have ever held in my hand, that's saying a lot for a guy who handled a lot of parts as an aviation Tech. That said, Autohauz had a Graf (Sp?) for 50 bucks, OEM couldn't hold a candle to it when compared side by side. I have read here and elsewhere that the plastic impellers were no longer used, but my 2003 had one when I yanked it out. The dealer is still selling them and installing them as well, when I bought my coolant they saw my pump, tried to tell me to use only OEM. We put them side by side, the parts guy is a pretty cool guy and he openly admited he would choose the one I had even if it cost more, it doesnt, in fact its a whole lot less......
> 
> ...


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## flat6fan (May 11, 2005)

*Broken Part*

Here is a picture of the part that I broke while installing the expansion tank. I glued it and put some epoxy on it just in case a replacement was not available in time. I am not sure it would have held because the broken plastic had to hold the spring in the picture under compression.


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## Lbert (Oct 6, 2006)

flat6fan said:


> Here is a picture of the part that I broke while installing the expansion tank. I glued it and put some epoxy on it just in case a replacement was not available in time. I am not sure it would have held because the broken plastic had to hold the spring in the picture under compression.


When I replaced my radiator, this auto transmission thermostat was also broke on the exact same spot as shown on your picture. I'm not sure if I broke it during the removal or if it was already broken to begin with. The BMW parts counter person said the breakage is common. Without describing the part and merely giving him the part number, he knew what I'm looking for. He did not even use the computer to look it up. The sad thing about it, the replacement part was an exactly the same. The weak black plastic cap was identical. The cap could have been redesigned or remanufactured with a different material by now. If you are replacing your radiator, this auto transmission cooler thermostat is most likely old, brittle, and weak so it is a good idea to have one handy when you tackle the project.

If you are not able to pull the radiator hose straight out, the best way to dislodge the connector is pry it out. Place a screwdriver in between the connector and plug, and gently twist the screwdriver to push the connector out. The idea is to move the connector parallel to the plug housing. Work the screwdriver also on the opposite side of the hose to equalize the pressure until it comes loose.


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## ride365 (Dec 19, 2001)

i just wanted to say thanks for this write-up. i'm considering this DIY and the information here is very helpful. it also helps to put things in perspective when a mechanic says "no problem, easy DIY." thanks to FalconGuy as your info was very helpful as well.


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## FalconGuy (Sep 27, 2002)

Glad we could help


Don't forget if your taking the fan out its reverse thread...

Also when moving a belt tensioner, go lightly, if you dont feel a spring compressing there is a good possibility you are going the wrong way.

Lesson I learned here as well.


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## jettek (Mar 11, 2008)

Hi FalconGuy, You work at Falcon Jet? I used to work there, I'm also a Aircraft Technician.


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## FalconGuy (Sep 27, 2002)

Jettek, I work with Falcon's, started out as a Tech at TEB, Still at Teb but now I train pilots on the 50/50EX/900EX/900C. I do miss the maintenance side of things, looking to do a little on the side but a new baby is making it hard to find time to change my own brakes at 100 bucks, never mind a 900EX at 160K a set..

Are you still in the industry?

Falcon Jet moved just about all of their Maintenance out of Teb a while back, now its all in ILG. My guess they couldn***8217;t compete with the labor in the markets of places like Duncan and Garrett (Now landmark)

I swear on every board I am a member of I get at least one PM or post a week thinking my name is the old Ford Falcon, asking me for parts or advice. This must be the second time ever anyone put the name with the right product.


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## ruzzosplinter (Apr 3, 2007)

What exactly is this part? I took out my expansion tank and didn't notice this thing until it was on the floor and had no idea where it came from. After trying to put it back together the most logical way seemed to be with the pin going inside the hole and then the spring with that black cap on top. The black cap seemed to have a perfect fit for the spring so it seemed right to do this. I then installed the expansion tank on top of this assembly, is this correct? I am not really sure what it is that u broke and I am wondering if mine is broken also.

Thanks


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