A20DTH — Hard Cold Start / Slow Cranking in Cold Weather
Engine cranks 4-5 times before firing on the first start of the day, especially in cold mornings after sitting overnight. Once warmed up, starts instantly every time. Glow plug warning light shows no error. Problem gets worse as temperatures drop. Feels like a weak battery but battery is fine.
On the A20DTH, this is almost always the starter motor. The bushings (copper sleeves) inside the starter wear oval over time. When cold, the metal contracts slightly and the armature shaft binds against the worn bushings, causing the starter to crank sluggishly. This means lower cranking speed, which means the fuel rail takes longer to build pressure, which means the engine takes several rotations before it fires. Once everything is warm and expanded, the starter spins freely and the car starts instantly. That's why it only happens on cold first starts.
Everyone chases glow plugs first. Don't. If your glow plug light isn't showing an error and the plugs test at 0.7 to 0.8 ohm resistance, they're fine. The real giveaway is how the starter sounds. If it sounds lazy, like the battery is dying, but your battery is good, it's the starter bushings. Plenty of owners go through an entire winter thinking it's the battery before figuring this out. Watch out for cheap rebuilds too. Most shops only replace the solenoid and carbon brushes but don't touch the bushings. The starter works great for a couple of weeks then the same problem comes back. The actual fix is replacing all three bushings inside the starter, not just the electrical parts. Most rebuild kits only include two bushings and skip the middle one. That's the one that wears first because it takes the most lateral load, and on some versions it should actually have a needle bearing instead of a plain bushing.
Check battery voltage and condition first to rule it out. A recent battery in good condition is not the problem, but confirm it anyway.
Check glow plug resistance with a diagnostic tool or multimeter. Should read 0.7 to 0.8 ohm each. If all four are in spec, move on.
Listen to the cranking sound on a cold morning. If it sounds slow and labored like a dying battery but the battery tests fine, the starter is binding.
Remove the starter motor. Inspect the three bushings for oval wear. Check if the armature shaft has copper residue baked onto it from the worn bushings.
Check the housing for the middle bushing. Some versions use a plain bushing where a needle roller bearing should be. If yours has a plain bushing there, consider sourcing a housing with the needle bearing version for a permanent fix.
Remove the starter motor. Disassemble and replace all three bushings. Clean copper residue off the armature shaft. Be careful with the housing bolts during disassembly, they commonly seize and snap. If bolts break, you'll need a replacement housing. Search for your specific starter part number at any major European parts retailer to find individual rebuild components. If doing a full rebuild, also replace carbon brushes and solenoid while you're in there. After reassembly the starter should crank hard and fast even in freezing temperatures. Upgrade option: the newer Insignia B starter is 2.2kw instead of 1.9kw with 11 teeth instead of 10. It bolts in and cranks harder, worth considering if your engine has some wear and needs extra cranking force.