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Huge amount of blow-by.

2K views 9 replies 3 participants last post by  timthemechanic 
#1 ·
Vehicle started hunting a little on the way home one night (thought it was a batch of bad fuel as I’d only just filled up), but when I got to work the next morning I had reason to open the bonnet.

Oil everywhere, mainly from dip stick, thought it was coming from the cracked dip stick top, so made arrangements to pick up a new one on the way home.

Replaced the dipstick and travelled home (about 50kms), by the time I got there grey smoke was coming from the engine bay.

After making a few calls (& text messages), talking to a couple of SAAB “experts”, the feeling is that my 9.5 AERO might have a cracked piston.

Does anybody want to buy a much loved well maintained 2003 turbo, auto SAAB at a very reasonable price?

I ask, because Keith, the well respected SAAB mechanic from Bayswater/Ashfield tells mehis once great all time mechanic that could replace pistons “quick smart” has moved away from being on the tools.

Unless of course someone can refer me to someone trust-worthy to carry out the work.

If I was a little younger and had a workshop, I’d take the job/project on myself, as I’ve really enjoyed owning and driving this quality Europe automobile.

The vehicle has reasonable new tyres all round on it, the rear rotors and pads were replaced recently and the battery would only be 18 months old, leather is great, paint is very reasonable and it’s licensed until September next year.

Located in Brigadoon
 
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Discussion starter · #4 ·
The belief is that with a broken/cracked piston the compression that being forced into the sump is being released out through the dip stick filler system.
Have you any experience with happening?
 
Discussion starter · #7 ·
Okay, your crankcase ventilation is fully sealed, has an oil trap on the back of the engine connected via a hose the remove oil in the gases. At low engine loads, when the pressure in the manifold is negative, the gases are led from the oil trap, up a connection on the throttle body. The gases are mixed with the intake air and combusted in the engine. THE CONNECTION IS AFTER THROTTLE BODY. The line has a check valve that prevents charge air from entering the oil trap when the pressure in the manifold is high, since that would pressurize the crankcase.
At high engine loads, when there is overpressure in the intake manifold, the check valve in the hose to the throttle body shuts. The gases are instead led via a hose from the oil trap to the turbocharger intake pipe. The gases are mixed with the intake air and then combusted in the engine. The hose is inserted in a connector that secures it to the turbocharger intake pipe. The hose extends into the airflow producing an injector effect, which effectively draws the gases from the oil trap. Since the oil trap is located at the back of the engine, it is kept warm, preventing the formation of ice. In the event of leakage such as a hose in the system, it lists trouble codes - 7 of them which must be corrected continued diagnosis.
As stated in Alldata manual.
Okay, your crankcase ventilation is fully sealed, has an oil trap on the back of the engine connected via a hose the remove oil in the gases. At low engine loads, when the pressure in the manifold is negative, the gases are led from the oil trap, up a connection on the throttle body. The gases are mixed with the intake air and combusted in the engine. THE CONNECTION IS AFTER THROTTLE BODY. The line has a check valve that prevents charge air from entering the oil trap when the pressure in the manifold is high, since that would pressurize the crankcase.
At high engine loads, when there is overpressure in the intake manifold, the check valve in the hose to the throttle body shuts. The gases are instead led via a hose from the oil trap to the turbocharger intake pipe. The gases are mixed with the intake air and then combusted in the engine. The hose is inserted in a connector that secures it to the turbocharger intake pipe. The hose extends into the airflow producing an injector effect, which effectively draws the gases from the oil trap. Since the oil trap is located at the back of the engine, it is kept warm, preventing the formation of ice. In the event of leakage such as a hose in the system, it lists trouble codes - 7 of them which must be corrected continued diagnosis.
As stated in Alldata manual.
I really appreciate your input here. You are very knowledgeable.
A while back I was having a little trouble with the engine smoking and leaking a little on the ground.
Originally my service mechanic tried to tell me he thought it was a possible leaking rear main seal.
I did a little homework via Google and the like and it was recommended that because at around the 200 km mark the 9.5 Aero developed a bit of a blow-by issue and there was an aftermarket crankcase ventilation system that could be purchased. I did purchase this from either England or Sweden, it wasn’t super expensive (around the $300 mark from memory).
I had the mechanic fit (it included a new dip stick holder box and quite a few other parts, pipes and a couple of PCV valves).
The engine ran better, the oil leak stopped and the fumes also disappeared. The crankcase pressure was a thing of the past.
That would of been 10-15,000kms ago.
Over a period of two days (less than 100kms), the engine has become had to start, it has spat 1-2 litres of oil out of the dip stick filler (with dip stick installed) and with dip stick installed the last time I started the engine, it took two or three attempts to start, it started rough and it chuffed white/grey smoke from the dip stick filler, so much so that I haven’t wanted to start it again without having a knowledgeable SAAB mechanic on hand.
Any thoughts would be totally appreciated.
I’ve checked the two large PCV valves and they appear to be working fine.
 
Discussion starter · #9 ·
You have an '03, I have an '01 which is before the did the upgrade. You have a tube going over the valve cover from the vent canister in the back of the engine. You can't see the hose connections to oil trap. Or the short hose that goes from the trap to the block. The drawings given in the manual I have are simple and don't show as having pcv valves in the system. It show a check valve in the hose going to the throttle body. I would verify vacuum at hoses attached to the oil trap. Remember it has to have vacuum from both the throttle body and turbo inlet all the way to the trap, and then a sealed un blocked hose connection to the block. Also make sure the oil is not overfilled because it could fill the trap and block exit for pressure. Mine has the dipstick on the filler cap and locks down.
Hello Tim

I’m not sure if you’ve ever dealt with a cracked piston issue at all.

But the amount of oil getting pushed out of the dip stick filler (with dip stick in place and locked down), along with the very poor idle, I’m sure it’s not just a blocked PCV value or pipe.

How Specialized are the tools to actually remove the head?

I ask because if I can’t get someone knowledgeable to visit and diagnose (not for free), then maybe I’ll either advertise it for a Tonkin offering or attempt to pull the head off myself to see if it is a crack piston or not.

To think that you might be located in Perth, Western Australia would be a long shot, but if you were or knew someone here, I’d be totally blown away.
 
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