I have read with interest many 2.4 owners especially 210 versions, having cold starting issues may I share my findings.
I recently posted a thread entitled white smoke/diesel smell, a failed Glowplug had been replaced, but not made a scrap off difference, I have discovered why this was, my car is a 2.4 20v (210) sportwagon reg jan 08, the drivers door jam says this plus Q4 designation is tagged onto the end off it, I've had Alfas 30 years 1975 Alfasud N 1186cc was my first, I know the Q4 means 4 wheel drive ala 155Q4 a great car, my 159 is definately not a 4/4, just front drive, however as I've discovered the Q4 designation is very immportant, as it appears to throw up correct part No's on german motor factors websites.
I decided to replace all five glowplugs on my car, hence local motor factors yielded NGK YE07's from reg No plate, duly fitted they failed to start completely, exactly the same happened with Bosch 0 250 203 001 recomended by alfashop, I measured original Beru's at 156.5mm tip to tip compared to the others at 151.9mm tip to tip, every uk factors/internet car parts, did'nt recognise the Beru Pt No or dimensions, Alfa Romeo dealers recognise the Beru part from the FPT//55208177 No but this No has to be quoted as the chassis No does'nt tell them this, having been shocked by the Alfa price of theese Gplugs, I contacted Beru Borg Warner by e-mail in Germany, after supplying chass/eng No's was e-mailed back telling me Beru's equivalent + revision No's also saying this part was specifically fitted to 4Wheel Drive 159, astonished by this thought my car is unique. having contacted Beru's U.K. distributors G.S.F/eurocarparts I've been told they cannot purchase individual orders from Germany, they only supply bulk orders. however I've found suppliers that can + cheaper so hence mine have been ordered, arriving in due corse.
The Gplug instrument panel light bears no indication as to the ammount off time the plugs are actually on for, I've timed them at 7-10 seconds from stone cold, I took my plugs out off engine & connected them with individual earths to all five via jump leads to battery negative having been carefull to ensure the hot tips don't burn anything, while partner inserts the ignition key you can observe which ones glow the brightest for the duration.
With this knowledge on-board I now have a technique, I get in put on ignition/put on seatbelt/ wind down drivers window all the way down then after this elapsed time car starts allmost emediately considering only 4of the five are doing anything this is'nt to bad & I'm happy with this untill I get my new plugs. my cars done 115,000 miles so if they hav'nt been done before they've lasted very well, the more I drive this Alfa the more I love it, went on holiday to north Wales recently, the car ran perfectlly, as it has done since purchased in June this year, very surprised to learn that entire length off Wales only has 1 dealer in Cardiff "only Welsh Alfa dealers are in Cardiff". very poor to add insult some ex Alfa are now Hyundai & Kia, if this is only choice in future I'll top myself, have you noticed how the most reliable cars are allways the most boring/ugly e.c.t, why do jap & Korean/chineese spring to mind ! why do people buy those horible contraptions, is it the first signs that your losing your marbles. Regards from an Italian car lover.