Heater Core Replacement

[Dougy Fresh]

My heater core is leaky, im going to have to replace the s.o.b. before i really dig into i was just curious if there are any other common wear parts that i should replace while im in there?

[sacM3]

I just did this job and I did the heater core valve at the same time. I would also reccommend doing the down pipe that runs parallel to the valve as the end of mine was pretty corroded from 17 years of life. You'll have to take the entire center consol out to get to the core and valve. Its pretty tight quarters up in there to get it all out as well. Get a set of male torx sockets as you'll need them to get the core out. Also a 1/4" ratchet is about all I could fit up there to loosen things up. The good news is it slides out easily once the valve and down pipe have been disconnected. It is easier to do if you disconnect the two coolant lines in the engine compartment close to the firewall. Get a set of the o-rings that seal all of the different peices between the valve, pipes, and core. These are known to be the main source of leaks. I did not put my interior back in for at least a week after doing the swap and drove around with the heater on all the time so I could be sure nothing was leaking. I did not want blue carpet again.

Good luck!

[Audio4u]

SacM3,

Thak for the info, I am getting ready to do this as well.

Tyler

[Dougy Fresh]

thanks for the great info One last question, how many o rings are needed?

[D///M3]

The ETK shows 3 o-rings (2 on the heater core to the water valve & 1 on the water valve to the outlet pipe)- FWIR when I did mine, I ordered 4 total, just in case I needed an extra one- This is also a good time to check/ replace the coolant by-pass/ recall hoses along the firewall in the engine compartment. Check the water valve as well if it has any corosion starting on it, you might want to do that as well (you'll have everything apart already)- I know I would not have to do that messy job twice!

HTH-
Don

[Dougy Fresh]

thanks don, do you know the part #s for those recall hoses? im just going to replace everything i can while im down there. i dont wanna be back in there for a long time.

[D///M3]

Doug-

64-21-1-381-541 outlet hose $11.60
64-21-1-374-908 outlet hose $8.73
64-11-8-367-832 small t-connector $1.25
64-11-8-391-926 small t-stat $23.75
64-21-8-367-834 hose $4.75
64-11-8-377-824 o-rings .65 cents/ each (x4)
82-14-1-467-704 gallon of coolant $22-

All prices are US "list" prices.

Hope this helps-
Don

[AlpineRunner]

So does the actual heater core leak? Or is it usually just the plumbing?

[Dougy Fresh]

from what i understand usually it is the heater core, and when that leaks it means everything else around it is pretty beat up too.

You can tell if its the heater core if you pull up the carpet on the drivers side next to the console and it is a little damp. Also if when the heater is on you smell coolant, and if the front glass has a fog like filmy residue.

Don thanks for the help, your the man

[sacM3]

Just as an FYI, the symptoms below don't necessarily mean the core is leaking. Ask me how I know. The first time around (6 years ago) only my valve was leaky and I had the exact scenario you listed below. Unfortunately My core was doomed and it started leaking as well a few years later, probably got corroded from all the coolant leaking on it before. Because it is not a fun job to replace these things, I just did not use the heater for 3 years. (gotta love living in CA) Now that I am redoing my interior, I decided to change everything: Valve, pipes, o-rings, and core. Figured for a couple hundred $ I should be good to go now.

Oh yeah, when you are assembling everything be careful with the pipe and the valve when they go into the core. Both are notched and only seal completely if you line it up right. The metal on the pipe will bend easily as well if it is not lined up right or if you start forcing it. You'll see what I mean when you have all the parts in hand. HTH

Originally posted by Dougy Fresh

You can tell if its the heater core if you pull up the carpet on the drivers side next to the console and it is a little damp. Also if when the heater is on you smell coolant, and if the front glass has a fog like filmy residue.

[archie]

Can anyone guess what I will be doing the next couple of days?

[m000240]

Replacing your heater core?

[archie]

Replacing your heater core?

lol! Yep,how did you know?

Funniest part it blew no joke just as I turned onto my street just after I was going up the hill by my home next to a dude in an E46 M3 and to my right was a dude in an E39 M3.

[m000240]

I'd be interested to see how it goes, especially pics and any trouble you encountered, as this is on my "within the next 6 months" list. Glad you were at least close to home.

[Reelizmpro]

Hope you have small hands Archie. Oh yeah, mind as well change the heater valve and O rings too. It's actually not that bad, just tedious.