9-3 Aero Problems - Missfire - Failed Compression Test

[Max M4X WW]

Hi,

A mate came round the other day with his W-Reg 9-3 Aero which is miss firing, we pulled the plugs out and noticed that one was a bit oily but put some new Bosch items in anyway - no luck - miss-fire still there. On removing the plugs again we noticed that there is a bit too much oil in cylinder 3, he says its been using a little more than usual as well.

There was an engine light lit, before we disconnected the battery for 10 minutes which cleared it but he hasn't had any codes read.

Today it failed a compression test on the oily cylinder, so I'm guessing rings or head gasket? The car has done 98k, its been serviced to schedule I think but not by Saab. I did it once a couple of years ago probably around the same time that I had my Aero with ~130k on it.

Any ideas what could of caused this or what the car is worth as it is?

Cheers, Max

[Prof Beard]

Well, sadly, I suspect in its current state it is worth spares money. I'm surprised this has happened - those engines are pretty bullet-proof if maintained...

[John D9395]

I am no mechanic, but 3 things give you compression (assuming you have a spark plug in the hole!), piston / rings, inlet valves and exhaust valves.

Given that the valves don't connect to the sump, my guess would be piston rings?

Fix that, and the car will be worth more than the Prof is indicating!

[Max M4X WW]

John D9395 said:

Fix that, and the car will be worth more than the Prof is indicating!

Problem is we cant do this ourselves and paying someone could be expensive.

The only reason I can see for this having happened is lack of oil changes, wrong oil or being run low on oil.

[K321]

check DI cassette

my car is 1999 , 160k, not even been servided properly..and soon driving 1000 miles across europe in it, only time its misfired is cos of DI cassette,
i had another one ..w regd about 4 years ago and the one time it misfired and went in safe mode was when i had blown up the turbo, i got a new one from neo broa

[Max M4X WW]

Don't the DI cartridges fail more on Trionic 5 engines?

Its failed the compression test anyway..

[K321]

i thought the Di cassettes fail more on on trionic 7 (black engine cover)

if i was your mate, i would sell the car to an independent specialist for around 300 quid, then buy another one for £1000 but with red engine top


its odd why it would fail compression test and what would cause it...

go to uksaab forum as they are saab nerds there