Door latch assembly locking mechanism freezing up - WD40 good or bad idea?

[sehaare]

It is darn cold in chicagoland right now and the driver's door latch assembly lock mechanism appear to be freezing up. When I try to unlock all the doors with the key fob, everything else unlocks but I have to climb in from the passenger side and use the interior handle on the driver's door to open it. When I pull on the handle it forces the lock knob up and the door opens. When I then tried to cycle it with either the fob or the unlock buttons on either front door the actuator tries to lock and unlock it but can't move it (knob won't go up or down).

After I drove the SUV with the heat on and the interior of the car warmed up the latch worked fine again and I cycled the crap out of it to exercise it, but the next morning after sitting out in the cold the door would not unlock remotely again.

I suspect that it is simply a matter of some water getting into the latch assembly a freezing up. Normally I would hit something freezing up with WD-40 to displace the water, but if I remember correctly the latch interior was greased and I'm afraid that if I hit it with WD-40 I might just dilute the grease and do more harm than good.

So, should I hit it with WD-40 or not?

I'm not sure if there is a right answer but I figured I'd give the group a shot at it.

thanks in advance

 

[EB4X]

Probably on the brink of needing replacement but I'd try some White Lithium Grease on it.... availabe in spray cans now.
Probably not the case, but check the door jamb first where the lock actuator is riveted to and make sure the metal there is still intact / rivets still securely intact, the constant force of door actuator on my rear door caused the cheap thin metal to bend outward causing inconsistent functioning / lack of solid base to function properly.

 

[sehaare]

Probably on the brink of needing replacement but I'd try some White Lithium Grease on it.... availabe in spray cans now.
Probably not the case, but check the door jamb first where the lock actuator is riveted to and make sure the metal there is still intact / rivets still securely intact, the constant force of door actuator on my rear door caused the cheap thin metal to bend outward causing inconsistent functioning / lack of solid base to function properly.

I replaced this one about 10 years ago, so it is the newest one that I've got, but I'm sure I didn't replace it with a ford part and probably went cheap.

 

[donalds]

Sounds like a broken door latch spring

Google Search

 

[Jason94sport]

Happens with my passanger door. Only when it gets cold. Which is not often. When I hit the unlock on the FOB, I hear the passange side kinda grind. Still unlocks though.

 

[MakinJeepsWeep!]

I use fluid film on all that kind of stuff myself. Gets all over but works great and is safe for electronics.

 

[J_C]

I'd suspect that it's not water as much as just old, hardened grease due to the cold temperature. I've also had this issue with my garage door track, needed to thin the grease out or else there was more resistance than if it had no grease at all.

WD40 would help but be a temporary fix, mostly evaporates away leaving the old hardened grease the same viscosity in cold weather. I wouldn't spray so much in that it flushes all the old grease out, would take a lot of WD40 to do that in cold weather.

For this reason you should use a small amount of spray oil, and work the mechanism several times immediately to mix the oil in with the old grease. It'll mix even better if in a warm garage or heated mildly with a hair dryer or heat gun.

However, as Donalds mentioned you probably have a broken spring, too. Sometimes lubing is enough, sometimes not. It wasn't enough on my driver's door but was on my rear driver's side door... same spring broke too, but the rear still works. Lubing will also increase the interval till the spring breaks.

You might've used a Ford part 10 years ago, these used to only cost $40 when I bought one from the local dealership... not sure about today, but I wouldn't consider the Motorcraft especially high quality either, since they didn't chamfer the stamped metal edge that spring sits on, causing it to prematurely wear through and break, nor did they use a thicker spring wire to make it last longer.