How do you loosen up a sticky Heater Valve?

[Douglas]

Just did the dreaded heater lever job. Unfortunately, I forgot to bring my digital camera, so I have no pix to share. Frankly, there's not much to show in any event. It's pretty straightforward. As everyone says, it's just tedious.

The job took 5.5 hours. I made a couple of errors along the way, misplaced a couple of parts, etc that added about 30-45 minutes to the job, so I suspect I could've done it in closer to 5 hours.

When I got everything back together, I found that the heater lever on the driver side was stiff to the point of almost unmovable (The heater lever was completely broken before I started the job, so I had no previous experience with that lever.)

My first thought was that I had installed something incorrectly, but when I went to turn the heater valve on the firewall, I found that it was also extremely stiff when you tried to turn it with a pair of pliers.

Is my assumption correct? Also, has anyone here ever loosened up a sticky heater valve successfully?

I'm going to give it a good squirt of WD40 every day for a week or so followed by a healthy turn or two with a pair of pliers.

Anyone else have a better idea?

Douglas Kim
New York, NY
280 SL #016220

[Tom]

Doug,

Sounds like you've already opened the rubber plug at the top of the firewall in the engine area and lubed the linkage.  Also, make sure the flap closes all the way when the heat is off-if not, adjust the linkage.

I have also heard of adding a lubricant to the coolant tank to help lubricate the valve.  Here is an old post from Yahoo:

 
I was told by my mechanic to pick up some Stay Lube Soluable Oil and
add 1 cup to my coolant. Sounds odd, but he said that it actually
helps things like the heater control valves work more easily at the
heater core. I also believe he mentioned that it lubricates any
thing else in the coolant system that can stick and be a candidate
for corrosion over time.

By the way, he is a great mechanic and owns a 4.5 and has restored
many SLs, for any of you out there wondering if he is the guy at the
corner Shell. He is with one of the high end MBZ dealers here in the
Bay Area and is known as the knowledgable guy on the old cars.

Hopefully that helps anyone out there. It is one of those
preventative things that will never be known if it actually works.

P.S. I actually did this yesterday, and the heater control valves do
seem to move a bit easier. The bottle of Soluable Oil I got actually
gives guidance on how much to put in the coolant systems, I took
Walt's recommendation of 1 Cup.



1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
1970 280sl Deep Red (Project Car)

[A Dalton]

Both the valve body core and the heater core valve sleeve are
brass, so the best cleaner is carb/choke spray..
 I have also had good results with BP/Blaster .
 The trick is over night soak..
 WD is not a good brass oxidatrion penetrant, but OK after the fact..

[hands_aus]

Doug,
your best bet is to replace the heater valve O-Ring and when installing it lubricate it with a small amount of hi temp grease.
This has been discussed on here and the yahoo site, have a look at the Technical Articles also.
The discussions also covered the time frame of regular movement of all the levers to keep them from freezing.
I think someone recently had a thread on here about this very thing.

Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[rwmastel]

quote:Originally posted by Douglas

I'm going to give it a good squirt of WD40 every day for a week or so followed by a healthy turn or two with a pair of pliers.

Anyone else have a better idea?

Doug,

Remember, the "WD" in WS-40 stands for Water Displacer. It is not actually a lubricant.  I suggest using a product called PB BLaster.  I found it at NAPA.  It seems to get into stuck bolts and the like and makes them come apart much easier.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[ted280sl]

Doug,
  Congratulations on going where most fear to venture. My heater valve was very tight to the point where the flap linkage was broken. I removed the valve and used a dremel tool wire brush on the inside of the heater core body. This made a huge diference. Of course I also replaced the "O" ring. This can be done through the opening in the engine compartment but, it is much easier if you remove the hood cowl.
Regards,
Ted
PS: The valve must be aligned correctly or it will not function properly.

[TA250SL]

Here is an interesting removal technique from the personal website of a MB220SEb restorer.   http://www.220seb.com/heater.htm#Pulling the Valve Cores

Tom