ST220 (2003) - Advice on potential Alternator problem

[Bacon_VII]

Hi guys,

Just thought that I would pick the brains on here about an issue I'm having with my st220.

At the beginning of Feb, my ST220 burst a power steering hose that ran around the back of the engine, which sprayed the fluid just about everywhere including the exhaust manifold - It didn't half smell horrible. Anyway, my mechanic fixed this and cleaned up the mess and all is well. However he did say that the alternator got covered in power steering fluid, and whilst he's cleaned it out, he didn't know what the long term consequences might be.

Fast forwarding until the end of April, whilst I was re-gassing the aircon (hence car idling for about 30-40 minutes with the air con on full) I noticed a faint acrid smell. I looked around but could not see anything amiss. So I finished the job in hand and took the car for a blast, and the smell disappeared. So I just put this down to to what I though may have been a little leak of refrigerant.

However, last week whilst waiting at a drive-through for some not so fast food, I started to get get the same acrid smell, but much stronger, and I thought I same a whiff of smoke. I took the car home (gently) and had a look around - again I could not see anything wrong. So I left it at the garage to be looked at.

The garage had the car for 2 days, but whilst they could smell the same smell (as described by my mechanic as like melted insulation of wires), they could find nothing wrong. They could not locate anything getting hotter than it should, no hot or obvious wiring culprits. Their only advice is that it could be the alternator (as it had 'form' from the power steering burst), but having measured the output, they could not be sure it was the problem. Not sure enough to justify a £250-300 part as a possible culprit.

Anyway, I picked the car up and had a look around it this weekend, and I too am stumped as I cannot see anything wrong. The car runs OK, plenty of power, no strange noises, nothing.

Going down the alternator route, I measures the following voltages, but I'm not to sure is this is telling me that the alternator is on its way out. Perhaps you guys may have an opinion;

Battery voltage (ignition off) = 12.3V
Battery voltage (engine running, but heavy draw ancillaries off) = 13.5V
Battery voltage (engine running, Blower, heated front/rear screens, heated seats, headlamps on) = 11.8V

Whilst running these test the acrid smell is still there, it seems to be independant of whether the air con is on or not, but is far more pronounced with the blower running. I did notice that the smell is present in the engine bay, and is strongest on the drivers side (which is the same side as the alternator). Also, during these test, with the car just idling after about 30 minutes the revs dropped and it did stall all by itself. It happily started again and ran smoothly for another 20 minutes.

I have driven the car for about 50 miles (without any issues) the smell is still quite strong with the blower on. When I parked it up I had a smell under the bonnet and the smell is hardly there, but what there is is strongest on the drivers side of the engine bay.

Any advice or theories welcomed. I'm happy to get the alternator replaced if its more than likely the cause, but I don't want to spend a few hundred quid to swap something that isn't the cause.

Thanks in advance of any replies.

[philmots]

On another car i once had a plastic bad melt itself to the exhaust which resulted in a similar smell. I scraped off what I could but it took a month or so for the smell to fully go as some still remained there.

There may be something stuck to the engine block/manifold that starts to melt when it gets hot. If it's under the bonnet it will only emphasise the smell when the blower is on as this is where it takes the heat from?

Re the alternator readings, i'm not an expert but it sounds correct.

[Bacon_VII]

Thanks for the input.

I did have a good look around but could not see an obvious signs of such and neither did the garage. Mind you, that's not to say that it wasn't a poly-bag that has since come off and its just the after smell.

I've driven the car another 100 miles or so with little-no evidence of the smell. Hopefully it was just a one off.

Thank.

[djone101]

The package between the back of the alternator (which has a plastic housing to help air flow of the diodes in the back) and the exhaust manifold (cat exit cone) is very tight. There should be a heatshield in between the two. If that's damaged or missing you'll quite possibly get heat damage to the back of the alternator or duct which would give you a nasty smell. Difficult to see all of this in the car - best view is from underneath though.

Good luck.

[Bacon_VII]

Sounds like something worth looking at - also would not necessarily be conspicuous by its absence.

I'll have a look tonight/tomorrow.

Many Thanks

[Kidders]

Check the sump gasket, they drip oil onto the exhaust and it bloody stinks. Curiously mine has got better since running fully synthetic oil.