Finding the heater core, W108 - PeachParts Mercedes-Benz Forum

1christos1 · #1 07-15-2009, 10:33 PM

hi everyone,

Heater core has been bypassed. Car is running again. I have to admit though I feel like I'm letting my car down after owning it for 15 years. I don't need heat for several months so have time, but many years ago I instaleed the heater levers and I'll be damned if those levers don't do anything now.

I have access to a free heater core if I want to go ahead and take it out myself. Anyone here know what's the best way? I know its going to take a very long time to get to it but I will this summer. I've pulled apart and put together a few things on dashboard so I'm comfortable tearing things apart.

So, what tools should I bring? flashlight and screwdriver are the obvious ones. what direction do I start? what can I expect to be tough areas to take apart?

any tips are much appreciated. I'll be pulling it out of a 72 280se. Mine is a 280sel of the same year. I'm assuming the heater core would be the same, but I should make sure of that I guess.

Thanks in advance.

Christopher Nicolaides

JimFreeh · #2 07-16-2009, 06:01 PM

If this is anything like the W114/W115, the complete dash has to be removed, along with all the HVAC components.

Basically, you will strip everything back to the base of the windshield.

Not a fun job.

Jim

bwostosh · #3 07-16-2009, 07:09 PM

This job starts with removing the seats, then the carpet on the trans hump on the bottom.
Then start with removing the rear view inside mirror on top
Drop the steering column too.
Your experience with removing will be invaluable.
Watch for the little spring clips that go "twing" and vanish.

twinockchef · #4 07-16-2009, 07:29 PM

I have done this a couple of times. I do not think it is necessary to remove the seats. It would just another pain in the ass job on a already difficult job. Take the heater core to a radiator shop and have them preform a leak test. Make sure it is prefect. Better safe than sorry.
The below post is from last year.

I just did this last week. It only took me five hours. You will need to take your time with the process of removal and installation. Many of the parts may break. First order a new heater blower fan(replace it now instead of later) and rubber seals for the heater core valves.
1. remove the vent on the dash - two screws
2. remove the left and right covers, which cover the frame between the windshield and door - just pull them out
3. remove the wood dash bow - two screws in the middle under the vent on the dash (be careful not to break it.
4. remove the dash cap - four screws which are close to the defroster vents and then pull the cap off ( it is attached at the front with clips.
5. remove the main a/c vent - unplug the electrical connection on the right side. There are about six screw on the underside it. It should pull right off from the clips which attach it to the dash.
6. remove the a/c blower - two screws on each side
7. remove the evaporator - three bolts, one on the left side against the firewall. The other two are on the inside of the compartment behind the right wheel were the antenna is. Unscrew the a/c lines under the hood. it takes a lot of effort too get it out.
*The lower heater vents will need to come out. To get to them the center carpet has to come out.
8. Remove the center consul - three screws, two in the middle and one at the front also disconnect the window switches.
9.remove the center carpet and the carpet on the left and right side.
10. unscrew the vents which are of the floor - two screws each.
11. remove the vents which connect to the bottom of the heater box - one screw each.
12. remove the glove box door.
13. remove the glove box interior - two screws and about seven clips. Unclip the light and then pull out the interior box.
14. remove the ash tray front
15. unscrew the four screws which hold the ash tray holder. One of which is the switch four the glove box light.
16. remove the radio
17. pull out the instrument cluster - there is a plastic nut which holds the cluster in. To get to it you will need to reach up from under the dash (this is easier said than done). With the nut off carefully pull the cluster out. Disconnect the speedometer cable, oil pressure line, electrical plug and the shifter indicator (this disconnects close to the steering column under the dash. Move the shifter and you should see the linkage move back and forth). the temperature cable cannot be disconnected. I just rotated the cluster and taped it to the left side of the dash. *be careful not to scratch the wood on the dash with the back of the cluster.*
18. remove the heater controls (this is a pain in the ass). There are two 10mm nuts on each side which hold the heater control face plate on. Unclip each cable connection (label them), two of which require a screw drive from the top (through the controls) and the bottom. Don't lose the clips. They like to pop out and vanish into the black hole of the dash. There are also two electrical plugs on each side of the controls.
19. remove the a/c hose - this hose runs from the far left vent down to the left side of the main a/c vent. It is the hose which right behind the instrument cluster. Be careful it likes to break.
20. remove the three defroster vents - the left and right ones are secured with clips which are on top of the dash. Unscrew from the dash and then remove clips from the vent. The right vent will fall out but the left vent will just moved to the side (watch for the small hose at the left of it.). The center vent is removed by a single screw at the center of the dash under the dash vent.
21. drain the cooling fluid from the radiator.
22. disconnect the heater core hose connections - inside of the engine compartment on each side of engine.
23. unscrew the heater box - two 10mm nuts on each of the box at the fire wall.
24. disconnect the electrical plug from the heater box - it is right next to the valves on the right side.
25. there is a bolt which attaches the box to the dash - it is on top at the front of the box. There may also be a connection at the lower front of the box.
Now you can remove the heater box. First pull the box back to get the heater core pipes out of the holes in the firewall. Then slide the box to the right. It takes a lot of finesse. Rotating the right side up while at the same time pushing to the right (this will help in getting the heater blower fan to clear the top of the dash. Go slow and be patient. It will come out.
This list may appear overwhelming but it works. The order od operations works well too.
If I missed something let me know.
Good Luck
Twinoakchef

1christos1 · #5 07-16-2009, 11:33 PM

outstanding!

Thank you so much. I've done steps 1-4 and 12-18 already before. I am fully aware of the pain it is to pull that stuff out. But i actually got pretty good at it after awhile.

The a/c stuff seems a little daunting though, but I'll have to just figure it out.

Probably won't attempt this until mid august, but now I'm looking forward to it!!

Thanks again. I'll definitely post how successful I am.

Christopher

berfinroy · #6 07-17-2009, 09:26 AM

Jeez, what a job. Aren't there some pretty good radiator pin-hole leak sealers out there that are worth a try first?

twinockchef · #7 07-17-2009, 10:35 AM

The reason I had to replace the heater core was because of the use of a leak sealer. The radiator and heater core were 70% clogged.
I believe that when one thing needs repair it is always a good opportunity to go in and preform a lot of preventive maintenance. With the heater core replacement you could then replace the blower, rubber seals, clean and refurbish the heater controls.
If the A/C system has not been looked at in a while you could then clean the A/C blower and replace the expansion valve, hoses, dryer and then recharge with new freon.
I also removed the wood and repaired and refinished it too.
It might seem like a lot of work but the pay off is a functioning reliable car that looks great.
I would rather drive my 71 280sel than the a new car and my wife's car is a new 08 R320.

mbbuff · #8 07-17-2009, 03:17 PM

Twinockchef has obviously been there up to his eyeballs. The only thing I would add is, don't forget to rebuild the heater control valves too. This is a job you'll only want to do once.....no not really even once.

ABDow · #9 07-31-2009, 09:05 AM

Ensure that during the rebuild stage you tightly secure with zip ties everything that might rattle, especially electrical wiring. There is nothing worse than doing all this work and finding that you have a new, deep, inaccessible rattle - don't ask me how I know.