It is normal for the Porsche engines to exhaust white smoke on a cold start-up. This is caused by moisture burn-off. In more serious situations it is caused by oil or coolant burn off. Unfortunately one of the most common failures in the Porsche Boxster is the AOS which causes mass volumes of white smoke to emit from the exhaust.
A puff of white smoke that quickly clears is normal of the flat-six design. Don’t sit and let the car idle to warm up. Start it. Drive it. Keep the revs below 4,000 till the coolant and oil come up to temp (180-ish).
LexVan@rennlist.com
Porsche Boxster Exhausts White Smoke Only on Cold Starts?
You should be fine if you only experience white smoke on cold starts and the white smoke dissipates when the engine is warm. Make sure that you have done your regular yearly maintenance on your MAF.
If your Porsche Boxster emits white smoke that persists beyond engine warm-up then you need to investigate deeper into the root cause of the issue.
Porsche Boxster Exhausts White Smoke – What to Check?
1.0 Check your Oil Level
Overfilling your oil can cause white smoke and damage your AOS. An oil overfill or an AOS not doing its job causes extra oil to end up in the air intake.
Be careful that you never overfill your oil in your Porsche Boxster.
If you (or your mechanic) overfilled your oil, you must remedy this ASAP. Overfilling your oil can cause many short and long-term issues including the premature failure of the AOS.
2.0 Check Your AOS
Check the vacuum on the oil filler cap. Remove the oil cap with the engine idling (running.) If the vacuum is really strong and it takes a bit of force to pull the cap up then you might have a bad AOS. If the oil filler cap is easy to lift then you’re fine.
2.1 What is the AOS?
The Air Oil Separator (AOS) is part of the Positive Crankcase Ventilation (PCV) system. The AOS extracts minute amounts of oil mist from the crankcase, by liquefying the oil mist and returning it to the crankcase. The clean air is then sent through the air intake.
As the AOS ages and fails, it cannot separate the oil from the crankcase oil mist and send oil directly into the air intake resulting in a large amount of white smoke. It only takes a few drops of oil in the air intake to create a lot of white smoke from the engine.
If your Porsche Boxster spreads white smoke regularly it is a telltale sign of the failed AOS. Address a failed AOS ASAP.
A failed AOS can cause liquid oil to enter the combustion chamber of your engine, this causes hydro-lock and may cause terminal damage to your engine.
Oil entering the air intake will also cause your spark plugs to foul and cause your catalytic converters to fail.
The AOS should be part of your maintenance schedule every 6 years or 75,000 miles (120,000 km), whichever comes first. Make sure that when you are replacing your AOS you also replace the hoses and lines used by the AOS.
2.2 Example of a Failed AOS in Action
This video depicts the amount of white smoke drivers will experience when their AOS is failing (or failed.)
2.3 Replacing your AOS
Replacing your AOS is covered in PROJECT 9 in the book 101 Projects for Your Porsche Boxster .
- Used Book in Good Condition
- Dempsey, Wayne R. (Author)
- English (Publication Language)
- 312 Pages - 01/08/2011 (Publication Date) - Motorbooks (Publisher)
When replacing your AOS, make sure to get a new Porsche AOS Boot Clamp Assembly”. This item comes with a compression clip for easy installation, otherwise, you will need to source a spring clamp removal tool .
- Genuine Genuine part that fits your specific vehicle
- Air Intake Hose
- Part Number: 999 512 630 00
- Manufactured to meet specifications for fit, form, and function
- Pliers can be locked, feeing up your hands and making your job easier and faster.
- Long reach hose clamp plier with wire flexible wire shaft.
- Convenient for working hidden areas and long distance
- For replacement of fuel, oil, and water hose.
- For the removal and locking of clamps into open position.
Porsche AOS Replacement Parts
- Genuine Porsche part that fits your specific vehicle
- Engine Oil Separator
- Part Number: 996 107 023 04
- Manufactured to meet specifications for fit, form, and function
- Genuine Porsche part that fits your specific vehicle
- Oil Separator
- Part Number: 99610702601
- Manufactured to meet specifications for fit, form, and function
AOS Porsche Part # 996 107 023 04
| Year | Make | Model | Trim | Engine |
|---|---|---|---|---|
| 1997 | Porsche | Boxster | Base Convertible 2-Door | 2.5L 2480CC H6 GAS DOHC Naturally Aspirated |
| 1998 | Porsche | Boxster | Base Convertible 2-Door | 2.5L 2480CC H6 GAS DOHC Naturally Aspirated |
| 1999 | Porsche | Boxster | Base Convertible 2-Door | 2.5L 2480CC H6 GAS DOHC Naturally Aspirated |
| 2000 | Porsche | Boxster | Roadster Convertible 2-Door | 2.7L 2687CC H6 GAS DOHC Naturally Aspirated |
| 2000 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
| 2001 | Porsche | Boxster | Roadster Convertible 2-Door | 2.7L 2687CC H6 GAS DOHC Naturally Aspirated |
| 2001 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
| 2002 | Porsche | Boxster | Roadster Convertible 2-Door | 2.7L 2687CC H6 GAS DOHC Naturally Aspirated |
| 2002 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
AOS Porsche Part # 996 107 026 01
| ear | Make | Model | Trim | Engine |
|---|---|---|---|---|
| 2003 | Porsche | Boxster | Roadster Convertible 2-Door | 2.7L 2687CC H6 GAS DOHC Naturally Aspirated |
| 2003 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
| 2004 | Porsche | Boxster | Roadster Convertible 2-Door | 2.7L 2687CC H6 GAS DOHC Naturally Aspirated |
| 2004 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
| 2004 | Porsche | Boxster | S Special Edition Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
| 2005 | Porsche | Boxster | Roadster Convertible 2-Door | 2.7L 2687CC H6 GAS DOHC Naturally Aspirated |
| 2005 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
| 2006 | Porsche | Boxster | Roadster Convertible 2-Door | 2.7L 2687CC H6 GAS DOHC Naturally Aspirated |
| 2006 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
| 2007 | Porsche | Boxster | Roadster Convertible 2-Door | 2.7L 2687CC H6 GAS DOHC Naturally Aspirated |
| 2007 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
| 2008 | Porsche | Boxster | Roadster Convertible 2-Door | 2.7L 2687CC H6 GAS DOHC Naturally Aspirated |
| 2008 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.2L 3179CC H6 GAS DOHC Naturally Aspirated |
AOS Porsche Part # 9A1 107 042 02
| Year | Make | Model | Trim | Engine |
|---|---|---|---|---|
| 2009 | Porsche | Boxster | Roadster Convertible 2-Door | 2.9L 2893CC H6 GAS DOHC Naturally Aspirated |
| 2009 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.4L 3387CC H6 GAS DOHC Naturally Aspirated |
| 2010 | Porsche | Boxster | Roadster Convertible 2-Door | 2.9L 2893CC H6 GAS DOHC Naturally Aspirated |
| 2010 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.4L 3387CC H6 GAS DOHC Naturally Aspirated |
| 2011 | Porsche | Boxster | Roadster Convertible 2-Door | 2.9L 2893CC H6 GAS DOHC Naturally Aspirated |
| 2011 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.4L 3387CC H6 GAS DOHC Naturally Aspirated |
| 2012 | Porsche | Boxster | Roadster Convertible 2-Door | 2.9L 2893CC H6 GAS DOHC Naturally Aspirated |
| 2012 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.4L 3387CC H6 GAS DOHC Naturally Aspirated |
| 2013 | Porsche | Boxster | Roadster Convertible 2-Door | 2.9L 2893CC H6 GAS DOHC Naturally Aspirated |
| 2013 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.4L 3387CC H6 GAS DOHC Naturally Aspirated |
| 2014 | Porsche | Boxster | Roadster Convertible 2-Door | 2.9L 2893CC H6 GAS DOHC Naturally Aspirated |
| 2014 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.4L 3387CC H6 GAS DOHC Naturally Aspirated |
| 2015 | Porsche | Boxster | Roadster Convertible 2-Door | 2.9L 2893CC H6 GAS DOHC Naturally Aspirated |
| 2015 | Porsche | Boxster | Roadster S Convertible 2-Door | 3.4L 3387CC H6 GAS DOHC Naturally Aspirated |
From Youtube
Other Concerns for the Cause of Exhaust Smoke:
The primary reason for white smoke in your Porsche Boxster will be a failing (or failed) AOS. That being said we will also outline various other and more serious issues for the white smoke. We have seen all of these issues many times before during track days.
1. The Dreaded MAYO
When you are testing your AOS using the Oil Filler cap and looking for suction from your engine, do a thorough examination of the underside of the cap. It is not uncommon to see a yellowish creamy emulsion form (referred to as Mayo) under the oil filler cap of Porsche Boxsters and Caymans, particularly after short journeys during cold weather.
Unfortunately, the formation of Mayo is very indicative of coolant mixing with your oil. When this happens you will see a lot of white smoke during acceleration. The primary cause for this is a blown head gasket.
This is a prevalent event on Driver Education Days or Open Lapping Nights and virtually the entire track knows that you missed a shift and blew your head gasket.
2. Damaged Cylinder Head
A damaged (cracked or warped) cylinder head will cause your engine to lose compression and misfire because there is too much heat. The excessive heat build-up will cause the cylinder head to crack because engine components have warped.
3. Cracked Engine Block
If your Boxster is emitting white smoke continuously, you may have a cracked engine block.
4. Blown Valve Stem Seal
If you see blue or grey smoke after sitting at a stop for 30 to 60 seconds and then beginning to throttle. The valve stem seal regulates the amount of oil applied to lubricate the stem. Bad valve stem seals nearly always show an intermittent problem of oil burning. However, the smoke will eventually disappear after long engine operations or during long periods of hot weather
5. Failed Piston Rings
If the smoke coming from the exhaust during strong acceleration is a blue or grey color it is more probable that oil is leaking directly into the combustion chamber as a result of a failed piston ring(s). NOTE: worn piston rings and valve guides will burn oil and smoke during all times of engine operation and never disappear.
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