Here is my 185 which has the block heater installed on the RH side of the engine left of the fuel filter.  The tractor was delivered new to our farm in 1975 with the block heater installed, probably by the dealer.  Not a great close up pic of the area, but you can see the electric cord hanging down just in front of the starter

Hope this helps with your project

Thanks.  I will never forget the day it arrived at our farm, on the Dealers truck.  Over time, rear tires replaced, new seat exactly the same, front tires upgraded from 7.50 and rims reversed, paint job and decals, every thing else factory (a few filters/muffler along the way).

Paul Samwel

I can see the access port you are planning to use.  The block heater will cause convective flow in the coolant passages to warm up the engine metal everywhere the passages go.  The engine metal will conduct the heat really well in all directions.  One port location might be slightly better for overall heat transfer result, but the top of the engine, and the combustion chambers should warm up plenty to achieve a good starting condition.

Other readers might have more info to share on best location for the heater element

My experience with block heaters, like the one on my 185, and the external tank type on my D17 III Diesel, is they work very well, heat the engine up to very very hot (close to operating temp) so starting is like a hot day in July!!!

Good luck with your install

Thank you

DougG, Dr Allis

Thanks for the tip.  I need to tell the story of the muffler..........(not trying to derail this excellent thread on block heater).  

We had the dealer install a Year-Around Cab on the 185 in the fall of 1975.  The dealer welded an extension to the muffler stack so exhaust would clear the top of the cab.  The stack extension also served as a guide for operators who forgot about the cab height when going under a tree limb!!!..........numerous close calls

My father replaced the original muffler with the current and used the original OEM Nelson muffler stack (larger diameter sleeved over the new Stanley stack) and welded the pieces together - kind of a farmers solution.  It looked like ###%%% but got the job done!!..........good from far, but far from good

I removed the cab a few years ago and trimmed the muffler stack down to the current height to fit (barely) my garage door.  The extension is in my garage 

The muffler works ok, but is a reminder of my father's attempt to manage costs 

My brothers comment on the muffler every time they visit, comments not always favourable!!

Thanks for reading my rant about my nostalgic muffler