W123 Heater Core Leak? smell/no see

[tqwrench]

Just got the car, embarking on the normal maintenance. Fixed a fuel leak, parts coming tomorrow for other stuff, filters, multi function switch, hazard switch, etc...

I noticed that maple syrup smell with the heat running after getting the car home. I think it's more on the passenger side than driver. No visible leaks or low coolant. Not overwhelming, just there when the heat is on.

Coolant is dirty. Too strong, looks like mud, drained it, recovered just under 2 gallons between the radiator and block. Starting the flush procedure. I noted no one sells heater core for one of these.

Any tips? Do the cores go bad on these, or should I look elsewhere (o-ring? valve?)? I did see this post: http://www.peachparts.com/shopforum/diesel-discussion/413157-last-thing-ill-bug-you-guys-about-coolant-flush.html

[Benzadream]

Pretty sure "cores go bad" on just about anything (depending on a lot of variables). Besides "W123", you don't mention "year, model, mileage, condition, etc". That info would influence which direction I would go, for sure. Also, possibly, how much other money I was gonna sink into the car. Is your car a "mint condition, low miles cream puff or a rusted out, high mileage beater"? More than likely, somewhere in between.
Changing the core in a 123 can be a daunting task (as would a core change in any MB ever made, I'm assuming). If MB has a major fault in their outstanding engineering, across all years and models, it would be the placement of evaporator and heater cores IMHO.
I'm probably gonna get crucified for this next statement, but, I'd put some "stop leak" in and see what develops (or doesn't).
I'm of the opinion that if your heater core is already leaking, and in a somewhat compromised condition, an aggressive flush treatment might make matters worse.
Fill 'er up with the proper mix, add some stop leak and drive it for a while. You may be pleasantly surprised (or not).
You could also drop the fan under the dash (easy job) and using an inspection mirror see how much fluid might be in there (and also gently flush that area with water, in the process). Make sure the "drain tube" is open and functioning.
You can always go all Rambo on a bunch of "balls to the wall" flush and fills at a later date if you feel it's prudent. If it were me, I'd "tread lightly".
Just one person's opinion......

[tqwrench]

Originally Posted by Benzadream

Pretty sure "cores go bad" on just about anything (depending on a lot of variables). Besides "W123", you don't mention "year, model, mileage, condition, etc". That info would influence which direction I would go, for sure. Also, possibly, how much other money I was gonna sink into the car. Is your car a "mint condition, low miles cream puff or a rusted out, high mileage beater"? More than likely, somewhere in between.
Changing the core in a 123 can be a daunting task (as would a core change in any MB ever made, I'm assuming). If MB has a major fault in their outstanding engineering, across all years and models, it would be the placement of evaporator and heater cores IMHO.
I'm probably gonna get crucified for this next statement, but, I'd put some "stop leak" in and see what develops (or doesn't).
I'm of the opinion that if your heater core is already leaking, and in a somewhat compromised condition, an aggressive flush treatment might make matters worse.
Fill 'er up with the proper mix, add some stop leak and drive it for a while. You may be pleasantly surprised (or not).
You could also drop the fan under the dash (easy job) and using an inspection mirror see how much fluid might be in there (and also gently flush that area with water, in the process). Make sure the "drain tube" is open and functioning.
You can always go all Rambo on a bunch of "balls to the wall" flush and fills at a later date if you feel it's prudent. If it were me, I'd "tread lightly".
Just one person's opinion......

Year and model in my signature (1983 240D 4-speed manual), condition is 7/10, mileage 225k. Thank you for the tips on the blower motor and drain, great ideas! Rest of it we are also aligned on, I get it.

[tqwrench]

I believe I have found a service part replacement core. Does this look familiar? I'm in a catch-22, the part comes from Australia, and my other option is to tear the dash out. Hoping to leverage some experience here.

[Benzadream]

DOH!! Sorry. I'm forever missing details, such as your tag line, on web pages.
It truly is hard teaching "old dogs" new tricks. Might have something to with the fact that I was born more than 25 years before our cars rolled off the assembly line.
I have the same car except an auto trans. 7/10 sounds pretty nice. Mine is nowhere near that condition (worse), but has about 10k less miles.
I recently noticed the dread coolant odor in the passenger compartment. Tried a little stop leak and it went away. Gonna "thank my lucky stars" and leave it alone.....for now.
FWIW, mine didn't need a flush and fill. The radiator fluid mix looked new and maxed out on the hydrometer. T-stat seems to be doing its job, as well.
Best of luck with yours. I'll be interested to follow along.