how cold do you let it get before plugging in?

[libbybapa]

As others have said, using a block heater is more about saving wear and tear on the engine rather than ensuring the vehicle will start. A properly functioning VW diesel will start reliably down to temperatures below zero Fahrenheit. The TDIs will easily start at lower temps than that even, without any complaint. Instead, to save extra wear on the electrical system and extra engine wear from a cold start, a good rule of thumb (on gas or diesel engines) is to use a block heater any time you think you will be using the vehicle heating system for interior heat. I have an exterior outlet that is hooked to an interior switch and tend to switch the block heater on about 1 hour before driving if the temps are down into the teens and single digits °F. Less time if warmer. More if sub-zero °F.

A hose heater in the lower radiator hose of a VW is a waste of energy. It will heat up the radiator and not the engine block. The temperature of the coolant in the radiator does not affect the engine temp until the thermostat is fully open on a VW. Until then, the thermostat regulates the coolant inlet temp by mixing with the bypass coolant and does an accurate job of it when the coolant in the radiator is 20° or 150°. If you have used a hose heater and heated up the coolant in the radiator and then you drive away, all your heat will get dissipated by the air rushing over the radiator before the thermostat even opens. If you have the hose heater very close to the thermostat, then, if run long enough, the thermostat might get hot enough to open the thermostat enough to trickle a small amount of heat into the engine, but it's no harder to install a block heater and the benefits are much greater. If you just want faster comfort heating and don't care about the engine's cold start, then a hose heater in the heater circuit will heat up the heater core and give some comfort heating right away while the engine is still warming up.

[TylerDurden]

Hose-heater goes in the bypass hose. Warm coolant rises up to the head, then down through the block.

Easy-peasy, all from the top:

• Pull the hose and collect the coolant as it drains from the pump
  Remove an inch of the hose and fit the heater
  Replace the hose and the coolant
  Zip-tie the cord to any convenient locations.

My cord comes out under the center of the bumper.

[libbybapa]

Right on. That works.

[TylerDurden]

Works quite well... cylinder head temp by #1 injector was 108F this morning. Ambient was ~22F.

[TylerDurden]

Stumbled upon these thermostatic outlets:

The Thermo Cube is a unique, patented electrical device that plugs into a standard 15 amp electrical outlet and turns power on automatically according to outside air temperature, saving money by using power only when temperatures require heating or cooling. There are five models available with different temperature ranges to choose from.

Also found that $5 is a lot for a little plastic plug cover.

[82vdub]

The temp sensor outlet is something that will probably energize at something close to freezing. If your winter temps are like they are around here, it won't act any different then a standard outlet. Essentially, if it's colder then the temp setting in the device, it will pass power 24x7 until the temp goes above the set point. Good in theory, but it won't save any money in the cold winter months.

[texcl]

Yeah its below freezing for 6the months here lol. I like the idea would be perfect for more mild climates. I use a lawn ornament timer and the set it for one hour before we leave.

[82vdub]

I have a timer rigged up to power an extension cord that's left outside. I would have it come on 1-2 hours before I'd need to go somewhere as well.

[Corlebra]

towards the end of spring when out average overnight temp was in the upper 30*'s F I would plug it in just to eliminate any headache in the mornings. Last night i parked in the street w/o a plug in, came out this afternoon at a mid 20's and the car refused to start, pushed it close enough to the house to drag out the extension cord and 45 minutes later it fired up w/o the glow plugs.

So, 40 and below i better make sure to have an extension cord handy

[dirtroad]

I have a magnetic heater that sticks to the oil pan of my International 4900 tandem. Plug it in and it heats the oil up making it easier to crank over. I thought about getting one for the VW. I had to try cranking 4 or 5 times the other day when it got down to 20F. You can get them @ Tractor-Trailer type stores if anyone is interested.

[bbob203]

we use those on our equipment where I work. thought about tossing one on the jetta figured it can't hurt.

[texcl]

I've used them on tractors and cars and have found them to not be very efficent, block heaters are much better.

[bbob203]

Hose-heater goes in the bypass hose. Warm coolant rises up to the head, then down through the block.

Easy-peasy, all from the top:

• Pull the hose and collect the coolant as it drains from the pump
  Remove an inch of the hose and fit the heater
  Replace the hose and the coolant
  Zip-tie the cord to any convenient locations.

My cord comes out under the center of the bumper.

where did you get that heater? p/n?

[bscutt]

I got mine on Amazon. Google/search for Katts 1 inch hose heater. Should be about $30 shipped give or take a little.

Just hooked mine up to a kmart appliance timer ($11) rated at 1250 watts whcih iss plenty for a 400 watt heater. It should be nice and toasty tomorrow am.