Sluggish start in cold weather: Battery, Glow Plug, or Other?

The weather in NJ lately gets down into the mid 20's overnight and early morning and then warms through the day into the 40's. I've found recently that when starting my car in the early AM when the temp is in the 20's, that it is very sluggish to turn over. Once the car has been driven extensively, or once the day has warmed up the car starts much better. Does this sound like a battery problem, a glow plug problem, or something else entirely?


I don't know if it's related but I've also had a number of occasions recently where the ESP warning light came on until I shut the car off. When I restart the ESP warning light would go off. This link makes me wonder if my problem is related to the alternator.


Thanks for any help you can provide.

I have a similiar "problem" for me its a combination of things. Supposedly VW mapped the engine wrong, so it could be chipped to "six" the problem". i am not so sure that I believe that or that i would bother. And I know the battery the previous owner put in is a bit undersized, so it takes a while to crank over. But with 173k miles on the car, who cares.

But if this is something new to your car, then its worth looking into.

If one of the glowers went bad, it would throw the check engine light. Keep an eye on your battery voltage, it could be weak. If so, a new one is easy, but make sure you have some jumpers in the trunk just in case. Knowing how to start the car on a hill isnt a bad thing either

How old is the battery?
+1 on checking the volts before starting & during (w/help).
I'd bet it drops below 10v while cranking.

If by "very sluggish to turn over" you mean the cranking speed seems slower than usual making for longer cranking period before an actual start, then thats a very good indication of the battery getting weak (especially if its still original or a generic replacement), or if the battery is known to be good (doubtful by the thread title) many of these cars are of the age when the starters are getting old/worn enough to need refurbishing/replacement.
If you meant it cranks over fine with good speed, just takes too long to fire off, then since its a PD and has a lift pump, make sure that's running when you turn the key on. Lift the rear seat cushion, turn the key to ON and listen for a short whirr sound for a second or two while it builds fuel pressure and shuts off.
I believe the '04's had the newer type/faster GPs, so you may not notice the difference in the "wait to start indicator" when the temps drop into the 20's, where as if its the older style GPs, you should see a few seconds longer glow time from when its warm. A defective coolant sensor will not tell the ECU to cycle the GPs long enough for the colder temp, making for longer/hard starts. If you had a GP issue you would normally have a CEL, not so w/bad sensor.

LahDeeDah said:

... it is very sluggish to turn over....

Click to expand...

Slow cranking is a battery that's not up to the task and if it's the original battery don't even bother getting a load test. Get a new battery. That slow cranking will eventually lead to a no start condition. This is one of the few items I don't mind going to the dealer for. The price is within market and you know it will be the right battery and fit properly ... provided you tell them repeatedly that you want a battery for a DIESEL engine TDI. Don't let them slip you the battery for a gasser.

I just went thru this. It's amazing how you don't notice it over time and once new batt is in it'll zing over like new. In my experience this morning, advance and autozone both wanted $166, the specs on one of them didn't even seem high enough (cca's) and VW dealer sold me one to match my VIN for $125! I really wanted a VW batt anyhow...orig is 8 yrs and 260k miles into its service!

Thanks everyone for the replies. Yes, the battery is the original battery so it's reasonable for it to be ready for replacement.

One other thing I noticed when I started the car today is that while it was sluggishly getting to turn over all the dash lights came on, including having one of the turn signals flash, even though the turn signal switch wasn't flipped. Don't know if this indicates anything but I thought I'd bring it up.

Thanks again and have a wonderful Thanksgiving.

The day mine didn't start the dash lights and both turn signals did what you described. Also, the horn made a faint bleep. Later that day when it warmed up the car did start and I replaced the battery the following day. Happy thanksgiving to you, as well and good luck!

I vote for a new battery.

Yeah, probably the battery. And as noted this is one place that the stealer usually doesn't rob you.