Thoughts on Block Heaters
 

Block Heaters...Good addition in cold weather or unnecessary accessory that will increase chances of a coolant leak?

d24 block heaters
 

I think it is a great feature and a nice retro touch... but I am wondering: if you have access to electricity then there`s a chance that the car is already parked in your garage and needs the heater less than if it was parked outside! :)

I imagine it is a great idea for cars that are mostly parked in driveways for overnight.
They work by the way. If it keeps the coolant just -let`s say- 20degrees warmer, then it is already a substantial difference for your engine (less wear at start-ups).

I have one installed in my spare d24t and this Winter I will do an experiment on how many degrees it can increase the coolant temps in certain temp ranges.
Hopefully I`ll have the time. I think last time I plugged it in it needed about 20minutes to show substantial increases in coolant temperatures. Also, I was using digital thermometer on the surrounding areas and they showed a good amount of increase in temps relatively quickly.

I believe they really are able serve the purpose they were designed for.


Canada drivers will send their replies here, I am guessing. And maybe some Upstate NY diesel owners. These heaters also came factory on certain vw models in Europe, I remember seeing them as late as the late 90`s or so.

The O-ring can be a risk factor if the unit is "very old", even if you found a `new` NOS one that has never been installed on a vehicle. Probably easy to size it and replace with modern rubber.

In theory it could leak..... but so could anything else on the engine that seals with an O-ring.

Maybe the block heater would need the O-ring replaced once every 20 years or so? Doesn't seem like a big issue to me compared to the advantages.

I know Tom B argues this point about potential for coolant leakage. He's not wrong that it is theoretically possible (though even frost plugs leak sometimes too). But, his premise is that rather than using a block heater as a starting aid, you should instead tear down your engine, rebuild it with new rings and pistons and an overbore, install a custom-homebrew extra thin headgasket, and then if necessary hook up a big battery charger and crank the engine for up to 3-4 minutes on the starter continuously, risking damage to starting components and creating massive amounts of smoke ---- and that that is the correct way to start the engine in extreme cold, in lieu of a block heater. I have no doubt whatsoever that the method works for Tom and I respect the goal that a truly perfectly optimized diesel might be able to start using only its own systems even in the most unforgiving conditions. BUT I will also say that for most of the rest of us who are living with engines that may not be freshly rebuilt and with less confidence/desire to push the absolute limits of equipment we depend on daily, plugging in a block heater does seem like an easier route all around.

Living in a cold climate area, I will attest that block heaters are definitely an asset especially if you park outdoors, though if you're in a garage it may matter less as RedArrow pointed out. But if outside, it can make the difference between the engine starting vs not starting in extreme weather, but maybe just as important, makes it nicer to use the car on cold days. It starts quick and easy with the preheat, and your interior heater and defroster are working right away rather than taking the first 10 minutes to start to warm up. Much less wear and tear on the engine internals, plus starter, glow plugs/relay, and battery as well. Extreme cold starting is hard work for all of those components. Less smoke for you and your neighbors too if you are preheated.

The coldest I have started my D24T Volvos without block heater assist is around -15F (at 5000' elevation, which does make it more challenging also). They started but with difficulty and complaining and as I recall it took a few attempts. I tried my wagon one day at -35F and it didn't even think about starting, just cranked and smoked until I gave up out of mercy. I have block heaters in both of them and use them all winter long and when plugged in they start fast and smooth regardless how cold. Great improvement in the quality of life for the car and for me as well. :)

There's a reason every heavy diesel that operates in cold weather has a block heater. It's the best way to get a diesel going in serious cold.

Under normal usage and adequate maintenance, most of the wear on an ICE occurs during cranking and startup (insufficient oil pressure to "float" the bearing surfaces). Block heater can reduce this in cold environments, even when not cold enough to cause difficult starting.