Hi all,

So i recently got an error code relating to the glow plug circuit in cylinder 4 (40 Tdi, 4 cylinder engine, error code P0674)

Car runs fine, no issue on start up and no lost fuel consumption or any big issues so assuming just maintenance. 

However, what would everyone expect a rough cost would be for the 4 plugs to be changed plus labour? Bosch plugs I checked are around 18 euro so make that 80 for parts (mechanic will probably charge me 100) and 2 hours of labour (if issues).

Appreciate any help!

 

 

For context what mileage and age of vehicle?

though the common conception is glow plugs never need to be changed until broken this is not true from a mechanics opinion.

 

the constant hot and cold expansion as well as metal on metal corrosion can cause them to seize in place. Rule of thumb for most cars is every 120,000km (100k miles) or 5 years to avoid large repair bills.

 

labour can and will vary but as a rough estimate I’d expect 1-2 hours plus parts. You should never replace 1, replace all 4.

it’s just common for running issues after this or the others to start playing up not long after if you don’t replace all at the same time.

If they don’t come out easily expect 3-4 hours labour.

 

 

Edited July 29, 2025Jul 29 by Optimus

@Optimus yeah, they would have been getting changed at the next maintenance as I am about to cross 100,000kms on the car. The car is 6 years old at the moment. Had the car serviced twice in the 1.5 years I've had it and no mention it and had everything checked over before I bought it. 

Yeah I was going to be replacing all 4 regardless, the bosch ones are roughly €18 a plug where I am from so I assume a mechanic will try charge me 25/30 per plug. The labour as you said I am expecting 1/2 hours at the moment if it is easy but hopefully not 3/4 hours! 

I am expecting around 275-300 at the moment as a conservative estimate 

Worth spraying PlusGas penetrative release on the glow-plug recess prior to dropping off. Actually better to work on them while car engine is warm, as tackling a cold and potentially seized plug is a world of pain if it snaps. A smear of ceramic grease on the thread before tightening too.