Coolant glow plug effectiveness

caveman · Post by **caveman** » Sun Jan 18, 2009 1:33 pm

Looking at my friend's 98 TDi that i sold him a couple of years ago. He thinks that it's taking too long for there to get heat inside. I never noticed a lack of heat [and i need the heat] so decided to check the 3 glow plugs in the flange on the side of the head. Got voltage going to them but no current, so either the 3 GP's are burnt or some other issue. Just wondering if anyone has any experience with them working/not working to tell me how far i should go to fix them i.e. whether they will make a difference.

Post by **Fatmobile** » Sun Jan 18, 2009 11:15 pm

If you have voltage but no current the glow plugs are burnt out.

caveman · Post by **caveman** » Sun Jan 18, 2009 11:21 pm

That's what i figure. my question is how effective are they ? Do they make a big difference in heating the interior. I would of course imagine that it helps get the motor up to operating temp sooner.

archebald23 · Post by **archebald23** » Fri Dec 04, 2009 12:57 am

According to Beru.com, "The diesel engine dissipates very little heat due to its high efficiency, this results in the usage of water heating during the cold season of the year for improved driving comfort. This warms up the interior and the engine more quickly.

In modern diesel engines with little heat dissipation, Glow plug with post-heating are used for pre-heating the cooling water."

So Glow plugs does make a HUGE difference in heating diesel car's interiors.

caveman · Post by **caveman** » Fri Dec 04, 2009 8:18 pm

They do make a difference especially in a TDI that produces so little heat . Early last spring my friend that i sold my 98 jetta to a couple of years ago seemed to think that it wasn't as warm as it used to be. Checked the usual including the coolant GPs . The wires from the relay to them were burnt. Replaced the wiring and changed the fuse on the relay. Fixed and now has lots of almost instant heat. Next time i need to open my cooling system [ i have a vanagon and bleeding the system can be a pain] i will be installing a TDI flange with the glow plugs and trigger one or two relays when it's real cold. Not only are you heating the passanger compartment, you are helping to bring the motor up to operating temps sooner.