I got the dash and instrument cluster out and I was able to eventually pry the top portion of the heater box apart and wiggle out the heater core. How did other members get their heater core out? There seems to be a large black bar running across the lower portion of the heater box and attached to it are several wires and vacuum lines. I haven't ordered the new one yet, but my options are BEHR and NISSENS.

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1990 190E 3.0L

If its anything like the W124, there should be (4) nuts holding it on at the sides. You will need to remove it. For the heater box, use a 2x4 to help pry it off the firewall.
Make sure you change ALL the vacuum pods.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

You must be talking about the 4 nuts, plus, one center bolt, attached to the black bar. That sounds like a great idea, but won't prying at that thing almost certainly ruin a few vac lines and possibly tear or disconnect the wires? Everything is held together firmly on the bar by thick nylon zip ties, electrical tape, and vinyl wrap.

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1990 190E 3.0L

I completely removed my heater box to replace the core. There was antifreeze residue on everything in there, along with the ductwork.

2nd winter with the new core, and I'm very glad I did it myself.

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My first Mercedes Benz. 4/6/07.

1984 190E (201 024) 2.3L four.

Yeah, but HOW did you remove the heater box? And what year and model car?

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1990 190E 3.0L

'84 190E.

I disconnected the heater water lines, electric lines, vacuum lines, loosened the 4 bolts holding it to the firewall, and lifted it straight up.

I didnt have to use anything to pry it out.

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My first Mercedes Benz. 4/6/07.

1984 190E (201 024) 2.3L four.

When I order my new one I'll see if I can get it in first..What brand did you go with? and did you do your vacuum pods and cluster lights and insulation while you were there?

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1990 190E 3.0L

I did the green vacuum pod on top, and the defroster pod. The others were replaced at some other time. I also replaced all of the lightbulbs on everything in the dash, since I had it all apart, anyway.

The new core I bought from MB came with foam insulation to go around certain areas of the core. It's a Behr branded core, made in Austria.

Be sure you turn the new core so that you can insert the little square nuts that are there for the clamp that holds the water connections in place, and be sure that you replace the O rings. My new core came with these bolts, nuts, and O rings.

I also replaced all of the molded hoses, and the vacuum water valve, as all of mine were OEM and getting hard/leaky.

Also, I replaced the radiator and water pump. The radiator was OEM and had issues, as was the pump. I'm so glad I did all this. It gives me peace of mind that my car is OK.

I also got those little clips that are allover your heater box from a parts car at the junkyard. I also pulled the blower motor side of things, and found it full of water under the blower... the drain was plugged up. It's now fixed, too, and smells so much better. Several of the clips holding the fan assembly together were rusted through. I have better air flow now since I cleaned it all up.

I was going to post a picture for you, but its already associated with another thread here on PeachParts.

Good luck. It took me 2 full days to replace the heater core from start to finish. I had no parts left over, either.

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My first Mercedes Benz. 4/6/07.

1984 190E (201 024) 2.3L four.

use BEHR for your heater core. There is a difference between the two brands, BEHR, being OEM, has the correct number of "tubes" in the core vs. NISSENS who tend to not have the same amount of cooling tubes, same with the radiators!! You should really replace ALL of your vacuum pods while you are in there, it would be a bear if you had to go back in after getting everything done. A long handled pair of needle nose pliers can be bought at Harbor freight will come in handy. They also make a long handled needle nose plier with the end bent at a 90 degree angle, you will use that one also. VERY similar to a 124 heater core replacement.

If you look closely at the zip ties they should be reusable.

While I was in mine, I took the steering wheel off, and lowered the column. Made it alot easier to maneuver around the dash area. Also, I untangled the wiring rats nest that was behind the instrument cluster area.

I was also being aware of where the vacuum lines connected. Everything was labeled, and the ties were re-used.

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My first Mercedes Benz. 4/6/07.

1984 190E (201 024) 2.3L four.

I have heard great things about Nissens. My radiator is Nissens and it is great. I had a Behr one, which developed a leak, buy the Nissens seems to be doing fine. I have a pair of 90° needle nose pliers. I will try to replace as much as I can when I am in there again. Also I noticed there was a red nub on the back of instrument panel. I thought it was a bulb because it is the same nub as the bulbs on the left hand side of the cluster for high beams, brake light, etc., but when I took it off it was a weird fuse or something. Anyone know what it is and what it does?

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1990 190E 3.0L