Freezing locks 300d and 300td
 

First snowstorm of the season in Denver yesterday and today. When my wife got off work at 7:00pm yesterday, the locks on the 85 300td were frozen. Key would not go in all the way. Had to take the light rail home. I tried the locks on the 77 300d this morning. Same problem.
Anyone run into this problem before? What is the most effective solution? I've had frozen locking mechanisms on other vehicles, but they never inhibited the key from going into the slot. I'm thinking that heating up the key with a cigarette lighter might work but I'd like to know if there is another solution people have used.

Move south Kerry :)
I have never had this type of problem but suspect it should not be model specific. The cig lighter trick sounds like it should work.

I always spray graphite into the locks, and i never have problems with them freezing up. The only drawback, is that i have found I need to do this several times a month.

I was considering the graphite solution. When my wife got to work today (with a cigarette lighter) she was able to open the passenger door. The janitor at the school then shot wd-40 into the lock saying it would stop the problem. I am always reluctant to put oily substances in locks since they attract dirt, but if that lock stays unfrozen, I might try it on another.

Mine did that and I panicked. My friend walked by and told me to spray some cologne, or alcohol... well temporary solution I guess but it worked.

I was talking to my mechanic today and he drives a 1985 635Csi - Very beautiful car, and he bought a lock and found out that it's actually heated....

heated door locks on an 85 635.. neat...
Love these 6-series and 126 Coupes... I'd love to have either one.

Have done these in various stages of desperation/frustration:
1. Lit matches on key (nope).
2. Lit propane torch on key held by vise grips (yep).
3. Hair dryer (nope).
4. Electric heat gun (yep, but the paint!).
5. A shot of WD-40 in the fall before freezing weather (yep).
There are little aerosol cans of lock de-icer at most stores, but it seems to me that it wouldn't work too well laying in the glovebox of an iced vehicle. Some say WD-40 isn't good for the locks but it works for me and I've never had a lock failure. They also get a shot immediately after washing and before leaving the heated building.

Alcohol and WD-40 have both worked for me. They temporarily purge or displace the moisture in the lock tumbler that is freezing up. Actually, the WD-40's effects lasted and made the lock action really really smooth.

Alex

Frozen locks
 

Coming from the Great White North freezing locks are an almost every day occurance, often many times a day. THe door locks in my 123 freeze only when there has been sleet or rain followed by serious cold. I carry an aerosol container of lock de-icer in the pocket of each of my coats. They are about the size of a cigarette lighter and cost a couple of bucks.
I find that the freezing problem only happens with the doors not the trunk lock. I keep a small hair drier in the trunk. I use the block heater extension cord from the plug in to power the drier. Its amazing what a human can adapt to, i don't even consider this an inconvenience anymore.

to revive this thread, this year more than any so far ive sprayed something like 3 bottles of deicer into my lock tumblers due to endless frozen lock issues, what with wet, then freeze, ect.

Im pretty sure that enough alcohol has traveled through those locks now that there is no lube left, and the problem is recurrent pretty much daily.

Reading on here people have sprated WD40 in there to negate the problem for a short time, any other lubricants that are ice resistant? I just had to steal the wifes car this morning as I was out of my bottle of de-icer, and her bottle had no charge, though full.

I use the phone book magnets cut into circles. place one on the drivers lock before water gets in the lock... no water, no problem. the magnet keeps freezing rain/dew/etc from collecting on the keyhole...

I was thinking along the same lines. Instead of fixing the problem after the fact, why not prevent it from happening in the first place? I was going to make a velcro-ed rubber band (bicycle inner tube) strap to cover the key hole that can slide back and forth to keep water out and allow easy key access. I have not tried my idea yet. I will try your idea- seems easier to fabricate.

I had a couple of incidents of frozen locks alreadu this year. One time I was able to use a hair dryer, the other time (no hair dryer) and got in via passenger door which luckily did not freeze.

As I recall from taking apart door lock tumblers, there is an o-ring in there to keep water out. Locks that are very freeze prone may have a worn o-ring. I am not going to take the lock apart now to see if the o-ring is bad, not sure if a replacement is even available.

Another idea (yet to be tried) is to make a key insert with a nichrome heater that is powered by your cell phone battery. The heated key insert will have an LED to show when it's powered and is kept in the wallet all winter. When needed, insert key in frozen lock, take cell phone battery out, make contact with key so LED illuminates, and wait a minute or 2 for tumbler to thaw, insert real key to get in.

edit: It's probably easier to heat the lock with the car battery. But that only works on a car that has the mod whereas the heated universal key insert would work in any lock.

this actually works? the magnet doesn't fall off in cold and weather?

it works.

I have never had a door lock apart to know what is supposed to keep the water out, I never recall my parents having to deal with frozen locks on their 240D, so I may take one apart to see if they can be fixed so I do not have to deal with it any more on my 300D

I decided as long as water can get in, I might as well work with it ,and just inject a small amount of RV antifreeze in the lock to keep the water from freezeing, and it doesn’t freeze up. I would much rather just not have any water in there in the first place though..

Hmmn is the phone book magnet some sort of special magnet? I tried an Alnico magnet on my 85 door lock and my magnet did not stick. I was a little skeptical at first since I didn't think Mercedes would use anything that is magnetic that is prone to rust on lock harware. My skepticism was right.

ps. I just took a brake cleaner spray straw, stuck it in the door key hole to keep the flap open and blew in there with a leaf blower. Lot's of water came out of the driver's lock but none from the passenger lock. It rained yesterday but has been dry for the last 12 hours and the car is parked on a level driveway. The water seal on the driver's lock is not working as well as the the passenger side and that is the reason why my driver's lock is the one that freezes.