The other day I noticed a bit of an odd hot / coolant electrical smell in the car while driving but put it down to the car in front. I did have a quick look under the bonnet but there were no leaks or any other signs. I've been away for work and the car sat in mid stay at Stanstead (35 miles from home) for 3 nights. Drove back today and the steering was a little heavy in the carpark but nothing else and it was OK on the road. Got home OK. I then had to go to an appointment a couple of hours later and I got 100m down the road and the alternator (battery symbol) came on. I turned around and took the wife's Focus. Some checking in the dark later indicates a dead alternator, probably a failed rectifier. This is a known weakness on Cromas and Vectras. There are a few other threads on here about it. I started a new one as those are pretty old. So I've ordered a rectifier (£16) and looks like I'm changing it at the weekend. Seems like most the work is removing other kit (scuttle trim, fuel filter, glow plug controller for starters).
Not what I was planning on for the weekend.
I might try replacing the rectifier in-situ if access allows.

Robert G8RPI.

Well that job is done. Only took 20 minutes to repair the alternator
Then there were the 8 hours getting it out and back in again
It comes out from the top as described in eLearn but it's pig of a job,especially single handed. Being a right hand drive 16V my Croma is one of the trickier ones. You have to remove all the plastic trim below the windscreen (wipers off too), move the fuel filter and glowplug control to one side. Remove the filter and control unit brackets and unplug any connectors and unclip cables / pipes in the area including the bracket for the big multipole one on the top right of the block (battery already disconnected of course). Disconnect the two wires on alternator. I also removed one of the coolant pipes to the left of the alternator (the forward/upper one). You will need a new hose clip for this, get a narrow/ compact one about 25mm. I had minimal coolant loss from this disconnect, about 100-200ml.
Next remove the front right wheel with that side of the car supported on an axle stand. Remove the access panel in the lower part of the wheel arch. Using a 15mm ring spanner on the aux belt tensioner bolt turn it clockwise to release the belt tension an pull the belt off the alternator pulley. While under there remove the lower alternator bolt (E18 reverse Torx and you need a standard, not deep, socket or a spanner for this location) Next undo the the two upper alternator bolts (E18 reverse Torx) and the link plate. Note the alternator will drop when you undo the lower (long) bolt. Now the tricky bit, wiggle the alternator up between the block, scuttle, pipes and wires. After that bit of cussing, repair the alternator or get your replacement ready.
Th most useful thing I did was tie a pair of narrow (25mm) flat web straps to the alternator. One with a noose areound the pulley and the other around the body between the upper lugs. I was able to tie these to the block lifting lug and scuttle bracket respectively. This took most of the weight and allowed a little manovering. Two people one below and one above would be easier. Manover into place and refit bolts - easy :bang:. I put it roughly in position and looselt fitted the lower bolt first. Note if you do the upper bolt first, the lower alternator lug must be in-line or above the bracket on the engine as it can't rotate past it with the upper bolt in. At the top put the link plate on the long bolt and fit through the alternator lug and bolt into bracket, don't tighten yet. Rotate link and fit top (short) bolt. tighted all up. Fit belt back on. Due to access I found it easier to pull the belt of the large dual-mass pully on the crank, run the belt round the alternator pulley, wind up tensioner and put belt back on big pulley. double check all pulleys for correct belt location. Put everything else back together.

The actual alternator fault was a failed rectifier as suspected. The diodes seem to use a soft silicone seal rather than hermetic glass (replacement has glass sealled diodes). It was a negative diode that failed. These have a smaller aluminium heatsink plate and less airflow but it's bolted to the end frame. I used heatsink compound (Dow Corning 340) between the new rectifier and end frame to improve thermal conductivity. I used a rectifier that was listed as for a Vectra / Saab Denso 140A alternator ebay item www.ebay.co.uk/itm/132388475089.
This fitted fine. Note you should bolt the rectifier down before soldering the stator wires so you don't put stress on the joint. The cover over the brushes slides off making it easier to refit with out damaging the brushes. the cover then slides back on.

Robert G8RPI.

That sounds like a horrid job , thanks for writing it up.

It is a horrid job. I did mine a few years as I managed to source a brand new alternator with no exchange for around £100 or less. I had the help of another pair of hands as opposed to straps

My alternator had not failed but was struggling to get 100Amps out of it instead of the rated 140A so decided to replace it before it actually failed when going on a 3 week trip to Italy towing a caravan and all extra loading (fridge, charging, lights) that would be demanded.

I did look at changing the rectifier without removing the alternator but could not get one of the regulator/brushpack screws out in-situ. It took a screw extractor to get it out with te lternator removed. Even without that issue, it is not practical to do it in place, for starters you still have to remove everything except the wheelarch access panel.

Robert G8RPI.