Author Topic: coolant glowplugs (Read 2348 times)

jimfoo · « **on:** January 09, 2008, 10:18:13 am »

Why do some, or maybe all TDI's as I don't know, have glowplugs in the coolant line? Just to help it heat up sooner or are they needed to keep it warm enough at low temps when idling? Since I'm converting my AAZ to a TDI I guess I better find out if they are really needed or not.

the caveman · « **Reply #1 on:** January 09, 2008, 02:13:14 pm »

TDI's are so efficient they don't produce much heat even compared with a IDI. I think i read that where a 6 cly. gas motor from the 80's was only 40-50 efficient [10-15 friction loss, 30-40 heat loss] a TDI is something like 60-70 efficient. which for us means more torque but less heat sweat.
Next year i'm going to install them in my 1.7l transporter so i can get more heat in winter and be able to switch over to wvo sooner. If they didn't have those glow plugs to heat the a-freeze you would be freezing.

jtanguay · « **Reply #2 on:** January 09, 2008, 11:37:27 pm »

only the 5 speed TDI's came with them. the automatics didn't get them because the tranny helps warm up the motor enough (also considering how the torque converter sucks power...). cars with the coolant gp's had bigger batteries and a bigger alternator (120 amp i'm assuming)

maybe 5 or so minutes less time to heat up the engine. i'm going to try to find a way to hook them up on my car. i'll probably use the circuit that energizes the glow plugs on cold start (and tells them not to turn on when the engine is at temp, so when the engine is at temp the gp's won't turn on) but my real focus is on getting one of those webasto heaters :wink:

if you were going to run them for an extended period, you would want to make sure you have a 140amp alternator to make sure you dont run into any charging issues.

the caveman · « **Reply #3 on:** January 09, 2008, 11:40:55 pm »

yup , i think i'll just use another glow plug relay and trigger it when i want.

jimfoo · « **Reply #4 on:** January 09, 2008, 11:47:26 pm »

I might see how it is without them first. My IDI warmed up really fast and I have 2 heaters in my car so maybe I'll be ok. If not I do have 4 new glow plugs and 3 old ones, and I don't think it would be too hard to make something to install some of them in, maybe even the aluminum pipe that goes to my heaters.