108 heater core valve removal

[mbgingerbread]

I need some assistance to figure out how to remove the heater core valves in my 280se. Do they just pull out or is there some twisting trick involved?
Currently, neither one of the valves will will move-they are stuck tight. The PO disconnected the cables-I figured this out as I was wondering where the two missing cables were which I was looking to disconnect from the lever assembly.
Thanks,
MBG

[ja17]

Hello.

Let the engine warm up before atempting to the repair. The heat of the engine coolant will help with the valve removal. Remove the slotted screw, the plate below it can be removed after the cylinder is pushed slightly downward. Next, you can invert a spark plug and thread it into the theaded hole where the slotted screw was. The spark plug makes an excellent handle to extract the cylinder valve. when the cylinder valve is removed, it can be cleaned and polished. Use a little plumbers grease on it before installation.

[twinockchef]

Don't forget to remove the snap ring which holds the valve in place.

[nhdoc]

Originally Posted by twinockchef

Don't forget to remove the snap ring which holds the valve in place.

Yeah, that would certainly help.

In my W108 there was nothing I could do to get one of the valves out, nothing. It really didn't matter too much since I needed to replace the blower so I ended up replacing both the blower and heater core at one time.

If you are lucky enough to get it out they still make the seals you will need to repair them as a kit...cheap and easy once they come out.

[mbgingerbread]

Thank you for the information.

I tried the usual today-spark plug in the valve etc.. I did fashion a small puller made from 1/2" pipe and made several attempts to pull the valve with it but to no avail. So, I am at the stage where I have to admit the fact that I will have to go all the way to the firewall and pull the heater core so I can get a better grip on things. I will essentially restore as opposed to repair but that's how I am approaching this project-do it right without regrets. Are there any tricks to continuing with blower removal and the like?
Thanks,
MBG

[nhdoc]

It's a big job. I tackled it with 2 experienced techs and to R&R the heater box took us a long day (10 hours with 2-3 guys working it). Basically everything has to come out before you can remove the heater box. If you have A/C that means the evaporator has to come out (you'll need to recover the refrigrerant).

You might try twisting the valve cores before pulling them. If you can break them free from being stuck by twisting them they will pull out. Try to fashion some sort of tool to grab the square edge.

If you do R&R the box you might consider finding a NOS blower and replacing yours. When the blowers go out, and they do, you need to do this job over again.

[twinockchef]

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 that parts may break. First order a new heater blower (nhdoc is right, 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.
If I missed something let me know.
Good Luck
Twinoakchef

[nhdoc]

Was it 5 hours just to remove it or did you put it all back together in 5 hours too? If you could do the complete R&R in 5 hours and do it alone you ought to do this for a living

It took me a good hour just to disassemble and reassemble the core and blower from the heater box with all the little clips and flaps!

[twinockchef]

This last time was the third time on this car.
The first time it took me about 12 to 15 hours to do the whole job.
While you have the heater core out take it to a radiator shop and have them clean it and pressure test it. Even if it work well before. It should only cost about $25, if that.

[mbgingerbread]

Twinockchef;
Thank you for the in depth and detailed list of steps to get to the heater core and blower motor in my 280se. I am almost half-way there. As far as the heater control levers are concerned-I had rebuilt the assembly with only one minor glitch on the top left lever-a screw was tightened a little too tight and broke so I used a little hot-glue medicine for reinforcement.
After reading your list I felt a little intimidaded; however, when I print this out and study it for awhile, it should make more sense.
I'll give everyone a full report thru this thread after the job is finished-might be a few days!
Thanks,
MBG

[nhdoc]

Originally Posted by twinockchef

This last time was the third time on this car.
The first time it took me about 12 to 15 hours to do the whole job.
While you have the heater core out take it to a radiator shop and have them clean it and pressure test it. Even if it work well before. It should only cost about $25, if that.

OK, that makes more sense...I know I was working slowly but could not imagine I could do it in 5 hours, however if I had to do it again it would have taken less time the second time.

[twinockchef]

While you have the heater box out check all of the cables for ease of movement. If the levers don't move smoothly usely it is the result of the inner wire having a bad bend. Just pull it out and straighten it out.
Also there are two rubber seals in each valve of the core. Add a little grease on them when you put them in.
Good Luck

[mbgingerbread]

So far my quest for the heater core is proceeding smoothly-well, about as smooth as can be expected. The condensor removal was made a little easier by drilling the heads out of the studs which protrude into the space where the antenna is. Further, I put a liitle grease on the condensor line fittiings which helped to make the removal easier as well.
Is there a better way to remove the instrument cluster nut? I am having some heartburn trying to get to the nut. Is this area accessible thru the outside by way of the fresh air intake at the base of the front windshield?
I am looking at each component as it is removed very carefully-so far the lower vents directing air to the rear seating area have been full of leaf bits!.
Thanks,
MBG

[twinockchef]

For me the instrument cluster nut is very difficult (and painful) to get at. Using a flash light locate the nut (somewhere between the streeing column and the parking brake. This is also where I put my hand. You can't see while you have your hand up behind the cluster.
Try feeling for the horizontal bar that goes along the back of the cluster. There is a treaded post attached which the nut is attached to. The nut is about one inch round. It was painful for me to reach up that far. The parking brake is what makes it hurt. It really dug into my arm.
Good Luck
Britton

[nhdoc]

I was lucky in that the nut was already gone in my car, and, in fact I don't think I have ever seen one still installed. I bet yours has never been off if it is still there because once you get it out will you ever put it back again? Most techs don't, they just stuff the cluster back into the hole it came out of and call it a day.