Hi -

There's been some discussion about this 'pig of a job', eg https://www.fiatforum.com/stilo/286366-replacing-alternator-jtd.html but we haven't got a guide yet. I had to replace my alternator yesterday, and took a few photos - it's not enough for a formal guide article, but hopefully it will be helpful. There's no doubt it's a demanding job for a DIY'er, but it's not technically difficult - took me about 8 hours, working at a steady pace and stopping frequently to consult manuals etc.

Start by jacking onto axle-stands, removing driver's side road-wheel and inner wing linings. With a long spanner, turn the aux belt tensioner anti-clockwise and slip the aux belt off the pulleys :



Underneath the car, slip a piece of scrap wood as picture, this helps to absorb torque when you unbolt the front exhaust section :



With WD40 and attack weapons as preferred, unbolt the front and rear connections :





And drop the short flexi-section out :



From above (standing on the removed roadwheel helps), unclip the indicated electrical connection, and unbolt the dipstick upper mounting :



Unbolt the lower dipstick fixing (where it enters the block), unclip any attached wiring, and remove the dipstick tube :



Remove the stubby rubber tube to the coolant pressure tank (warning, there will be a spurt of coolant), disconnect the ECU plugs, and stuff all the ECU cabling round the back of the engine to get access to the alternator top bolt :



After undoing the top bolt, back underneath to remove the two electrical connections on the alternator, and undo the nut on the bottom bolt. Then remove the chassis bolts from the two engine reaction struts:





There's now a neat little rectangular space between the driveshaft and the bulkhead. Apply a lever to the reaction strut mounting, and pry the engine forward just an little, and the alternator will neatly drop through there:



Reassembly is straightforward - just put everything back where you found it.

General points :

- The chassis bolts for the engine mounting are incredibly hard work to remove. A long breaker bar, and patience. Clean the bolts and coppaslip them, and they go back in a lot easier.

- The lower alternator bolt came out through the wheelarch, but fractionally fouled on the inner chassis. I was near to hacksawing it off, but then succeeded by applying a crow bar to the top of the crankshaft pulley and levering the engine block down a few mills.

Coincdentally, just replaced my alternator today too. One thing I would add to the above for anyone doing this job is to disconnect the battery before using a spanner anywhere near the alternator electrical connections.

My original alternator is 105 Amp and came out from the bottom as you describe, but the replacement is 120 Amp and considerably bigger. The new alternator wouldn't go back with the driveshaft in place. I'm also fitting a new right driveshaft anyway, so it didn't matter.

Did you manage to get the top spacer back in OK? It usually falls out when you remove the alternator and gets lost. It's a pain to get the spacer back in, and manoever the alternator into place, and refit the bolt all at the same time. I hung the spacer in place on the end of a spare long bolt, then held the alternator in place and pushed the original bolt straight through, pushing the spare bolt out, but leaving the spacer in place.

I had the same problem with the bottom bolt fouling the chassis, so dropped the engine a little. I wouldn't recommend anyone using a crowbar on top of the crankshaft pulley. I tried fitting the bolt from the opposite end, but the threaded end would have fouled the auxiliary belt.

I still haven't got the driveshaft back in yet, local Fiat dealer didn't have any "Tutela MRM ZERO" grease for the tripod joint. Waiting for some to be delivered from a dealer in Canterbury.
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Davren said:

Coincdentally, just replaced my alternator today too. One thing I would add to the above for anyone doing this job is to disconnect the battery before using a spanner anywhere near the alternator electrical connections..

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Sorry, yes of course - I shouldn't have left that unsaid.

Davren said:

Did you manage to get the top spacer back in OK? It usually falls out when you remove the alternator and gets lost. .

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My heart just stopped. I don't remember a spacer...? Went and crawled around on the garage floor, no sign of it. Connected the USB borescope to my laptop and had a peek down the back of the engine, and there it was - held in place with a splodge of underseal or sikaflex. Probably done by the garage who changed the timing belt for me last year - they saved my bacon!

Davren said:

I had the same problem with the bottom bolt fouling the chassis, so dropped the engine a little. I wouldn't recommend anyone using a crowbar on top of the crankshaft pulley. .

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With the 'reaction struts' unbolted it was quite easy to push the block a little way, I moved it 2-3mm frontwards/downwards without exerting a lot of force. It did feel a bit crude and bodgy though - surely Fiat could've designed that arrangement better? A smaller hex-headed bolt, or a shallow dent in the chassis to allow it to be withdrawn? For reassembly, I put it back the other way - the nut and thread are well clear of the aux belt.