Block Heater / Freezer Plug

[SerratedFrond]

CAR: MK1 4spd Diesel 1982

I recently replaced the block heater.

Here is the type I use:


Here is a diagram:


So, I installed a new one and had it pretty snug in there, and now its coming out again. I have never had to replace one before So I am not sure as to how the freezer plug hole should look.

Here is a picture of the freezer plug hole:


Do you see that ridge on the inside of the engine block? Is that supposed to be there? Is it supposed to go all the way around? Is this what those wings press against? I tried to line the wings up so they would grab onto that ridge, apparently I failed.

If so, then I guess my only option is to put a freezer plug in there right?

Thanks for any help.

[stevethefolkie]

From the picture I can't tell if that's a ridge or part of an old freezer plug still stuck in the block - but I don't recall there being a ridge - but its been quite a while since I looked into a water jacket on a VW ... is that where the old block heater was located? (depth perception in a photo can be tough - but it doesn't look like you've got enough clearance in the water jacket for the heater - again - though - this may be fore-shortening due to the camera angle or something) -
On the last one I installed (maybe 10 years ago) - I had to clean the living hell out of the hole to get a decent seal - I had to seat the heater as fully as I could and then tighten the internal expansion bolt (which, if yours is like the one I did, should cause the ring supporting the rubber gasket to expand a bit) - I think those fingers SHOULD tighten against the inside of the block - by the way - so perhaps you just didn't have the heater shoved far enough in OR perhaps the bolt backed off a bit from vibration allowing the heater to come loose.

[Dunchie]

The 2.0L 16v I just took apart had a ridge just like that behind the freeze plugs, it only had the bottom one, not the top but I'm pretty sure those ridges are ment to be there.