1984 300DT turbo diesel - does block heater fit into freeze plug hole?

[HuskyMan]

I have located a block heater that MAY fit this car, says it fits a "33mm threaded freeze plug hole.". Will it work?

[Do D Do]

http://www.peachparts.com/shopforum/diesel-discussion/240529-definitive-block-heater-coolant-plug-removal-thread.html
Check out post #5 on the above thread. It looks like according to this particular engine/thread that the block heater is a 38mm.

[Do D Do]

https://www.pelicanparts.com/cgi-bin/ksearch/pel_search_2016.cgi?command=show_part_page&make=MBZ&model=3392&section=engman&page=2&bookmark=6&part_number=900-203-48-95-INT

check link?

[HuskyMan]

Question: What, exactly, does the block heater attach to? Does it fit into the threaded freeze plug hole?

[Diseasel300]

It threads into a dedicated hole in the side of the block below the exhaust manifold. You probably already have a heater present and just need the cord. Crawl under the car and look for it, it may have a cap over the plug to keep out water and debris.

[Simpler=Better]

If you don't have one, that plug is a nightmare to remove.

[HuskyMan]

A few years back, I did something which caused the block heater to fail. I can't remember exactly what it wasI did (left it plugged in too long, etc.). As a result, the car needs a new block heater. I have seen several different types for sale.

I guess I need to crawl under the car and take a look so I don't buy the wrong one......

[dogguy]

Originally Posted by Simpler=Better

If you don't have one, that plug is a nightmare to remove.

I missed a tremendous opportunity when I didn't have a picture taken of me doing a removal on a 1983 W123 after the plug had been in the same spot for around 25 years:
> All sorts of parts removed to enable access.
> BIG Allen wrench in the plug. Mine's bigger than yours, LOL.
> Heavy caliber and long pipe on the Allen wrench.
> Me standing over/straddling the engine.
> Be sure we are 100% certain which way is counter-clockwise

I won.

I still have that plug...keep it on my desk as a reminder about life's little challenges.

[Do D Do]

Originally Posted by HuskyMan

A few years back, I did something which caused the block heater to fail. I can't remember exactly what it wasI did (left it plugged in too long, etc.). As a result, the car needs a new block heater. I have seen several different types for sale.

I guess I need to crawl under the car and take a look so I don't buy the wrong one......

I did the same thing...block heater just stopped working. I had been plugging it in for long periods, and it must have had enough. I tried a lower radiator hose heater for quite some time, and it did work for the most part but NOT like the block heater. I couldn’t find a proper block heater locally so had to use the lower hose heater type to get by for the rest of the winter. I ended up installing a used block heater from a spare turbo 617 engine I had. I did the swap (6 +years ago)when I had the turbo off the following summer when it was nicer out. I still plug my old swapped in block heater for long periods and it’s still fine. We regularly get stretches of -30 Celsius or colder up here and the block heater is the way to go. I actually still have that lower hose heater installed so I could probably use both but I have never had a problem with just the block heater.

[Do D Do]

If I was to do it again, for the extreme cold we get... I would not waste my money or time on the lower hose heater and go straight for the replacement block heater. While I was checking out the size of threads for your block heater... I noticed that it is used in several different Benz engines? I’m not sure though so maybe someone could say for certain... in which case... your dealer might stock it if your lucky.

[Simpler=Better]

Remember, in a pinch a 100W lightbulb does a great job. Just keep it in a cage away from anything flammable.

[vstech]

The bulb will help start in cold weather, but NOTHING like the block heater will.