Coolant under the carpet.

[Mdriver]

Only a slight leak on the driver's carpet and I guess this means the classic heater core/heater valve/O-ring replacement job.

Where is the cheapest place to buy all three?

Also, at Maximillians website, which one of these is the O-ring you are supposed to buy and replace?

http://bimmer.com/epcvsoapimc.epc?co...lientid=bimmer

Thanks,

Gabor

[M3 Mitch]

You might try to see where the leak is coming from (if you can, I know it's hard to see anything inside the dash).

Check the hoses that go to the heater core, if you are lucky maybe a hose clamp is loose or those hoses are othewise leaking.

Might as well try the easy fix first.

As hard as heater core replacements are, and I know the M3 is not the worst, but still, I would be more interested in getting correct factory parts and not sweat the price so much. Max has been a reliable supplier of correct parts for a long time, probably not the cheapest of all suppliers but you can count on getting correct parts from him.

IMHO, if the heater core is leaking and you will replace it, it's a good time to drain and refill the cooling system with 50-50 BMW coolant and distilled (or better) water (another place I would advise against trying to save a buck- I will cheerfully ante up for the BMW coolant just as cheap insurance...but your mileage may vary..)

[d2a4]

Actually, to replace the core is quite easy.

[TooTall]

Actually, to replace the core is quite easy.

Agreed, I did this just a couple of weeks ago. The heater valve had started leaking. I replaced the valve, the heater core, and the two heater hoses under the hood. My car had the pressure relief valve fitted to the heater hoses so the stock hoses were cut to fit the relief valve. I got parts from Bav Auto and they included the O-rings with the valve and the heater core. There are two types of heater valve and heater core. If you are just ordering the valve you will have to know which type it is. One trick, after disconnecting the two hoses from the firewall, flush plain water through the heater core and then, if you have it blow compressed air into the top pipe to get as much of the water/coolant out as possible. That way there will be very little to spill into the interior when you take the valve off the heater core. I am told that coolant will cause you carpet to disintegrate.

Cheers,

Kurt

[UNHCLL]

I line the entire foot well with plastic, and have a large roll of absorbant pads nearby to collect any drips/spills.

Once you've removed the center console, you can tuck the plastic up under the heaterbox to ensure none gets down onto the carpet.


HTH,
C

[Mdriver]

Update: I went home at lunch to take some pictures of the leak.

Here are my findings.....







When i run tha car with the heater I can see coolant dripping from crack in the last picture.

So what does it look like I am dealing with?

- gabor

[UNHCLL]

Wasted heater valve. replace it.
I'd say replace the core too since you're there and you're already draining a good amount of coolant.

drain the radiator before starting the process, also remember to loosen the cap on the coolant res. before starting.

You also now know which type of heater core you have, so you can order the correct one.

[d2a4]

Haha, the valve leaking badly huh. My was leak at the o-rings (a little down from the valve). I replaced the o-rings last month but still smell the coolant, I guess I have to open it up again :(

[Mdriver]

One quick question!

It looks like I have the aluminum heater core but what type of heater valve to I buy?

There are two heater valves,

http://replacement.autopartswarehous...Valve&dp=false

which is the correct valve?

Thanks for the help guys. I will order my parts!

- gabor

[TooTall]

My heater valve failed in the same place. I think I caught it sooner, as I didn't have near as much residue built up. From this point on its not hard. Disconnect the heater hoses, flush and/or blow out as mush coolant as possibe. Take out the screw holding in the heater core. Remove the screw and clip that hold the two pipes up close to the firewall. Take out the three screws holding the heater valve to the heater core. These screws thread into square nuts that slot into the flange on the core, don't lose them! Pull the heater core out of the heater box a little bit (1/4 to 1/2 in.). You should then be able to push the heater valve towards the firewall and seperate it from the heater core. It will take some finaggling but it will come off. Once the valve is out, the heater core slides straight out. Look at the two metal tubes that go through the firewall. Mine had pinholes corroded through the ends where the heater hoses lapped over them. Probably wouldn't have leaked but I replaced them anyway. They were cheap (at least for M parts!) from the dealer.

Cheers,
Kurt

[Mdriver]

The screws on the water valve that connect to the heater core are impossible to get off. I can't even get a rachet/socket combo on the upper and lower screws, the space is too small. Already, I was able to drain out a lot of coolant via the broken water valve.

What tool works best for these guys?

Also, do I have to reemove the bumper to gain access to the radiator drain plug?

- gabor

[d2a4]

No, no need to remove bumper to drain. You need the 8mm wrench to remove those 3 screws and lot of patient

[Mdriver]

HELP! I cannot for the life of me get the two screws (uppermost/lowermost) off the connection between the water valve and the heater core. I used a small cresent wrench and no matter what I do, I cannot get a hold of the screws because of the water valve housing getting in the way! What special tools can you recommend I use to remove this water valve from teh heater core?

Looking at 'TooTall's' post above he mentions "Take out the screw holding in the heater core". Is this the answer? To remove the heater core screw first? IS this a job where certain parts need to be removed in a specific order?

- gabor

[d2a4]

The other way is using the 8mm socket and swivel joint. If you don't have one, let me know.

[TooTall]

I used both a 1/4" drive socket with a swivel and an 8mm wrench. I have a set of small ignition wrenches and may have used one of those. The tubes from the heater valve extend into the heater core openings about 1/2 inch so when you do get the screws out, the heater valve has to be pushed away from the core toward the firewall to remove it. I found that if I removed the crews holding the core to the heater box and pulled the core out a little I had a little more room to swing a wrench on the bottom screw, that's why I mentioned it.

Where are you in SoCal?

Kurt