Heater Core Related Question 300D - PeachParts Mercedes-Benz Forum

tobybul · #1 01-22-2010, 01:30 PM

Has anyone ever had dirty heater core issues (causing marginal heat)... and what did you do clean it out?

tangofox007 · #2 01-22-2010, 01:47 PM

It is incredibly easy to backflush the core with a garden hose. That will tell you very quickly if you have an obstruction or not.

snookwhaler · #3 01-22-2010, 01:55 PM

I have not had any marginal heat. But, when I replaced the rad. I back flushed every hose I could find to remove. When I back flushed the heater core, a bunch of orange crud came out of it. I'm not sure if the performance improved though? I could not really tell a difference.

Cr from Texas · #4 01-22-2010, 04:48 PM

Odd. I read the question differently. I thought he was asking about the fins being blocked with lint, hair, etc. I know that can happen to the AC evaporator.

dogguy · #5 01-25-2010, 01:06 PM

Quote:

Originally Posted by snookwhaler

I have not had any marginal heat. But, when I replaced the rad. I back flushed every hose I could find to remove. When I back flushed the heater core, a bunch of orange crud came out of it. I'm not sure if the performance improved though? I could not really tell a difference.

I'm planning on replacing the original radiator and hoses in my '85 300CD-T.

Could you please elaborate a bit on how you did the back flush? Sounds like an excellent idea when doing a rad./hose replacement.

Thanks-

snookwhaler · #6 01-26-2010, 04:15 PM

I basically did what the DG tutorial specifies with the shout, only I did a little more and did it a few more times because of the amount of orange crud that was coming out. I also DID NOT do the Citrus flush.

Reversing the flow out of the heater core and the hose on the side of the head is where the most crud came out.

It runs at about the same temp's and nothing really changed. But, when I drained some coolant to repair my vacuum pump and take a peek at the monovalve, the coolant was beautiful instead of a cruddy mess.

Murkybenz · #7 01-26-2010, 04:28 PM

If you pull the garden hose out of the heater hose every now and then it introduces some air into the system and this lets the water agitate the crud better and loosen it up inside the matrix.

Then go and flush in the normal direction of flow and do the same and then reverse and repeat introducing air all the time

I find this gets a lot more out.

tobybul · #8 01-26-2010, 09:12 PM

Any thoughts about introducing muratic acid in the core like maybe for about a minute and then flushing it?

Eric · #9 01-26-2010, 09:30 PM

the crud is dirt on the outside, not inside.

Cr from Texas · #10 01-26-2010, 09:32 PM

Quote:

Originally Posted by tobybul

Any thoughts about introducing muratic acid in the core like maybe for about a minute and then flushing it?

The metal of the heater core is more likely to react with the acid than the crud.

cdplayer · #11 01-26-2010, 09:34 PM

PM sent

dieseldan44 · #12 01-28-2010, 02:29 PM

toybul,

I took my heater core out of the '82 because I was replacing the evaporator. The new heater core does make a big difference, at least in my case. The fins were not blocked. The evaporator had enough dirt to plant a garden.

Things to check -
- unplug monovalve electrical connection - bad monovalve = lukewarm heat
- check aux pump and make sure its doing its thing

To be fair, at the same time I replaced my heater core I replaced my water pump and radiator, so my experience is not completely scientific.

BUT, it too the car heat from lukewarm to burn your face off...passengers beg for mercy.

tobybul · #13 01-28-2010, 07:57 PM

Quote:

Originally Posted by dieseldan44

toybul,

I took my heater core out of the '82 because I was replacing the evaporator. The new heater core does make a big difference, at least in my case. The fins were not blocked. The evaporator had enough dirt to plant a garden.

Things to check -
- unplug monovalve electrical connection - bad monovalve = lukewarm heat
- check aux pump and make sure its doing its thing

To be fair, at the same time I replaced my heater core I replaced my water pump and radiator, so my experience is not completely scientific.

BUT, it too the car heat from lukewarm to burn your face off...passengers beg for mercy.

Thanks, dd. How easy was the heater core to replace? Can u give us a run down? Also, where did you get the new heater core? Thanks

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode