glow plug based coolant heater

[gone-ot]

Aren't glow-plugs designed for short-duration ON periods, unlike block heaters which are designed for long-periods of use?

[dremd]

Originally Posted by Old Tele man

Aren't glow-plugs designed for short-duration ON periods, not long-periods as block heaters are?

I run the coolant glow plugs in my TDI for as long as 15 minutes, they have been in service for 370,000 miles with no failures as of yet. That said, they are designed for the use.

[Piwoslaw]

I found one of these 12V coolant heaters, used, for a very good price. It was a bargain, since it not only came with all of the plumbing that connects it, but also with the fuse/relay box, with all cables still connected (not cut!). And the best thing: everything still works - the relays, the fuses, even all 4 of the glow plugs

I found a forum with the following info on this model:

I took mine out today and tested them. They should measure about 1.2Ohms across them, which I think works out about 30watts each.

So this device should give me either 60W or 120W of heat, depending on whether I turn on one pair or both pairs. My cabin ventilation has a 3x100W electric heater, which is hardly noticeable when used (no sense using it when it's warmer than -5C outside). The coolant heater will provide even less heat to the cabin ventilation, but at least whatever is not used will help heat the engine a bit faster.

Soooo, I got this installed - hooked it up to the coolant line which goes from the engine to the cabin's heating core, and to the manual switches I had for the 300W ventilation heater (no plans to use it any more). I've only had one drive since installing, but not enough feedback to know how much faster the engine heats up. I do know that with the engine off, each pair of glow plugs drops the battery's voltage by ~0.5 volt, and I can hear the coolant start to sizzle.

[oldtamiyaphile]

So it looks like my van has one of these heaters as standard. Unfortunately, it's mounted under the battery so not exactly easy to get to.

My question is, are these designed to help engine warm up, or just to provide cabin heat sooner?

Any idea on the activation and deactivation temps etc? Do they turn on only with the engine running, or with the glow plugs?'

My goal is to connect these to my solar panels to help with engine warm up beyond the factory parameters, but knowing those parameters would be a good start.