996 sunroof issue . Stuck from sitting ?

Bought a 99 C4 996 last year with dead engine . Prior to me buying the car sat for a year with the previous owner . I had a 3.8 built and car now running great . So now I am slowly going through the car to fix little issues . One is the sunroof . When I push the open button or the button to slide open I hear the motor running but the sunroof doesn't open . I decided to push up on the sunroof while pushing the center button and pop the rear pops open . So now when I push the center button the rear of the sunroof opens . Push it again and it closes . Progress 😁 But the sunroof doesn't slide back . The motor sounds like it is laboring and then just closes . So what's the next step ? Should I pop open the back and spray WD40 on the tracks ? If the front of the sunroof is " stuck " from sitting what's the best way to " unstick " it ? I have done a search but all the problems I found being discussed were about timing or retiming. All advice appreciated .

I contacted the previous owner and he said the sunroof was working fine before the engine died and the car sat . So I am going to assume the sunroof is stuck on gasket at the front .

Was able to play around with the sunroof for about 15 minutes today . So it consistently goes up into vent position and back down . And now it will pull open about an inch and then stall . I think lubrication is the key . I will have more time tomorrow to dig into this .

Interested to know what you find. I have a 99 as well with a non working sunroof and would like to fix it.

Didn't have time today and I work tomorrow . Hope to attack it on Wednesday . Going to start slowly with either WD40 or silicone spray on the slide rails the best I can get to them . Hopefully it's just old dried up grease and I can free it up . Will update when I know more .

Well I didn't have to work today so decided to attack the sunroof . I popped the sunroof open to the vent position . Then carefully sprayed WD40 on each side to hit the rails on each side . Did that three times then let it set for 15 minutes . My thoughts were maybe the WD40 would break down any dried up grease . After 15 minutes I tried to open the sunroof rearward . With each attempt the roof would open a little further . After about 6 tries it fully retracted . Success !!! 😋 . With the roof fully retracted I hit both sides again . Took her for a drive and opened and closed it several times . Everything works the way it should . I got lucky . Now I need to find out what the right lube is for the tracks and apply that . I assume it's a lithium grease . I might even try Fluid Film as it is an excellent lubricant . Hopefully my post can help someone else . ​​​​​

I have used some white lithium grease on the rails. Works for years.

The right stuff is Krytox GPL 205, or VW special lube (probably same as GPL205) VW part# G052141A2 or VW sunroof lube VW part# G00045002. Clean as much of the old hardened junk out of the tracks as you can.

^^^ Appreciate you providing those part numbers . I am heading to local Harbor Freight this morning to pick up a few items . I see they stock Super Lube synthetic silicone grease and doing some research last night there are lots of positive reviews . It's also a dielectric grease and safe for o-rings . So will use that on my sunroof rails and see how it goes .

Nice. Thanks for the update. can cleaning out the old stuff and applying new grease be done without removing headliner etc?

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Assuming you can open the sunroof then yes . With the sunroof fully retracted you have access to the rails . When cleaning obviously you have to be careful not to go crazy and soil the headliner . A shop vac , a tooth brush and a rag go a long ways . To apply the grease I plan to put small dabs on my finger and smear where needed .

I got lucky and bought the VW Sunroof grease referenced above by intuition. I will be lubricating my tracks once I get my C4s back from my Indy for a spring refresh, will post how that goes!

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Thanks. I'll give this a try. My sunroof won't open with the motor (gets stuck) but I will take the motor out and try to open it manually with the allen key. Hopefully that gives me access to the tracks.

^^^ Does your sunroof pop open at the rear to the " vent " position ? If it does you can spray WD40 or similar in from there .

Got the sunroof open by using the allen key but it's very stiff. Is this (red area) where the grease needs to be applied?

^^^ Yes

Cool. I've ordered the grease. Should be here tomorrow. I'll try it and report back. Thanks.

While you wait for the grease to arrive clean the rails if they are dirty . Shop vac along with a toothbrush and rag with some WD40 will do the trick .

It�s always nice when a fix like this turns out to be just a little common sense, basic mechanical knowledge and persistence. Nice job! Who know what it would have cost you if you brought it to an �expert��

So I added the grease and sunroof works again - kinda. It's not stopping in the correct positions when I open or close. Also it won't open all the way. I did replace the sunroof motor when I first started troubleshooting this problem so perhaps it needs to be retrained. Will try that next.

So the limits are now set correctly again via re-teaching but the motor is really struggling to get the roof open. I'm guessing that the tracks in the rear part of the sunroof under the headliner needs to be lubricated. Do I just spray WD-40 in there as best as I can? Seems like I may be on my way to taking the whole sunroof out to lube everything up.