Strange new exhaust smell

[Jason]

Unless of course its just a leaky line or your heater core going bad, which
is the case with mine.


Jason

----- Original Message -----
From: "Phil Payne" <quattro at isham-research.com>
To: <quattro at audifans.com>
Sent: Wednesday, January 07, 2004 4:23 AM
Subject: Re: Strange new exhaust smell


> > For about the past month, I have had a strange exhaust smell from my '92
100S. It smells
> like burnt coffee beans (not exactly the odor, but that's as close as I
can describe it). I
> originally thought it was just some sunflower seeds that mice had stowed
in the engine bay
> that I attempted to blow out and happened to get onto the exhaust or other
hot engine surface.
> But upon closer inspection, the smell is definitely coming from the
exhaust, and not the
> engine bay. I have changed the oil in that time period (from 10W30 Syntec
to 10W30 Quaker
> State Higher Mileage) to see if it helps my oil consumption issues (~1 qt
per 500 miles), so I
> was wondering if it may have something to do with it. I have used this
same Quaker State oil
> in a Honda Accord and Plymouth Voyager, and they do not have this odor.
Any ideas?
>
> Burning coolant.  A head gasket leak is favourite.  "Acrid" is the best
adjective, IMO.
>
> You need to do two tests:
>
> a) Pressurise the coolant system with the engine cold and leave the car
for a while to see if
> you have a minor leak.  Good idea to spin the engine with the plugs out
after this test in
> case you do get leakage into a cylinder that would otherwise cause
hydrolock.
>
> b) Once you're happy the system isn't leaking in general, top up the
coolant with pure
> additive (no water) and see if either the coolant level falls over time or
the smell gets
> stronger.
>
> These leaks are sometimes VERY minor.  It takes only a very tiny amount of
coolant to cause a
> noticeable smell.  I've known cars run like this for years.  The greatest
exposure is
> increased bore wear - you often find on stripping a car for this that the
factory
> cross-hatching is still visible in the cylinders that have seen no
leakage, and polished away
> in the ones that have.
>
> --
>   Phil Payne
>   http://www.isham-research.com
>   +44 7785 302 803
>
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