Engine Advice/Guidance

[questforbalance]

I need some advice/guidance. I have a 2002 Porsche Carrera C4s with Tiptronic. The car just hit 100,200 miles. From the first day I bout the car with 56,000 miles it consumed a little oil; usually about 1/2 to 3/4 of a quarter every 750 to 1,000 miles. It appeared to consume a little more during the winters. The car is a daily driver and parked outside everyday. The car runs fine. I used to use Mobil 1 0W40 but switched to Mobil 1 5W50 about 10,000 miles ago. The car has a ticking sound coming from the engine. I noticed this sound 20,000 miles ago. The sound may have gotten louder.

 

Over the last month the car has been consuming more oil than usual. I usually check the oil every weekend. I put in 3/4 of a quart last week and one full quart this weekend. SO now I am trying to figure out what to do about this.

 

What do I do? How do I diagnose this? Can I diagnose it? Is the car heading toward being junk? Is an engine rebuild in my future? What would that cost? Or is it something else? At what cost? Should I take it to Porsche dealership or an independent Porsche mechanic to diagnose? Is it worth investing any more money into this car? (Note, we do like the car a lot. So an additional reasonable investment is certainly possible.)

 

Some thoughts, advice and guidance from people who had experience with this would be greatly appreciated.

[JFP in PA]

I need some advice/guidance. I have a 2002 Porsche Carrera C4s with Tiptronic. The car just hit 100,200 miles. From the first day I bout the car with 56,000 miles it consumed a little oil; usually about 1/2 to 3/4 of a quarter every 750 to 1,000 miles. It appeared to consume a little more during the winters. The car is a daily driver and parked outside everyday. The car runs fine. I used to use Mobil 1 0W40 but switched to Mobil 1 5W50 about 10,000 miles ago. The car has a ticking sound coming from the engine. I noticed this sound 20,000 miles ago. The sound may have gotten louder.

 

Over the last month the car has been consuming more oil than usual. I usually check the oil every weekend. I put in 3/4 of a quart last week and one full quart this weekend. SO now I am trying to figure out what to do about this.

 

What do I do? How do I diagnose this? Can I diagnose it? Is the car heading toward being junk? Is an engine rebuild in my future? What would that cost? Or is it something else? At what cost? Should I take it to Porsche dealership or an independent Porsche mechanic to diagnose? Is it worth investing any more money into this car? (Note, we do like the car a lot. So an additional reasonable investment is certainly possible.)

 

Some thoughts, advice and guidance from people who had experience with this would be greatly appreciated.

 

Some oil consumption is not uncommon on the M96, but yours sounds excessive.  First thing to check is the AOS, try removing the oil fill cap while the car idles; if it is very hard to remove, you are sucking oil in through a bad AOS, which you can change out.  The M96 is also known for wearing the cylinder walls on the thrust side of the pistons; if yours has gone that way, a total rebuild is the only cure.  You can usually detect cylinder scoring with a simple compression test, or by using a bore scope.

[Ahsai]

This is less likely but have you also checked if there's any oil leak and oil in the coolant?

[Ahsai]

If you want to check simple stuff you can at least check the oil filter for metal shavings and debris. Just remove the filter. You will lose about 1 qt of oil.

You may want to shoot a video of the ticking noise here for feedback.

If it's determined that your engine is terminal, a roller is only worth a few thousand. A used/rebuilt engine with install should be ~$15k all in.

[AWDGuy]

I also have a 02 C4S....

Hate to say it but sounds like you have some scoring going on. Is one side of the exhaust tips darker than the other? My left hand side was black from burning so much oil.

My symptoms are worse though. I burned through 5L of oil in 1000km (all short trips) and after the engine is warm, I can hear a loud engine ticking/tapping noise. Ocassionaly, My car would spew out blue smoke on start up also.

If I didn't have oil burning and engine tapping noise, you'd never know...car drives perfect.

Edited February 16, 2015 by AWDGuy

[questforbalance]

Thanks for the comments. The oil filter is clean, the coolant is clean also. I recently changed the coolant reservoir. The symptoms of white smoke bellowing out the exhaust at start up in the mornings and in evenings after sitting parked after work, the burning of oil leads me to believe it maybe the air oil separator, but I need to confirm that. I will run the car later, warm it up a little and while idling I will twist off the oil fill cap. I have been doing research on changing the air oil separator and based on its location looks like I will have to remove the intake manifold on the left side. Does anyone know if I can avoid doing all that if I just lower the engine? Will lowering the engine provide enough space to get at the air oil separator in the back of the engine?

[JFP in PA]

Thanks for the comments. The oil filter is clean, the coolant is clean also. I recently changed the coolant reservoir. The symptoms of white smoke bellowing out the exhaust at start up in the mornings and in evenings after sitting parked after work, the burning of oil leads me to believe it maybe the air oil separator, but I need to confirm that. I will run the car later, warm it up a little and while idling I will twist off the oil fill cap. I have been doing research on changing the air oil separator and based on its location looks like I will have to remove the intake manifold on the left side. Does anyone know if I can avoid doing all that if I just lower the engine? Will lowering the engine provide enough space to get at the air oil separator in the back of the engine?

 

Lowering the engine makes the AOS much more accessible.

[Ahsai]

Check out my MkII AOS thread here

http://rennlist.com/forums/996-forum/851947-mkii-aos-diy.html

It may be helpful. Also, you can rig up a simple manometer using the oil filler cap and some clear tube filled with engine oil. You can also get a digital manometer for $50 from amazon http://www.amazon.com/gp/aw/d/B005FU5HFI/ref=mp_s_a_1_1?qid=1424033536&sr=8-1&keywords=digital+manometer&dpPl=1&dpID=41aIijLgVpL&ref=plSrchπ=AC_SY200_QL40

Edited February 15, 2015 by Ahsai

[questforbalance]

After much thought, reading comments on this and other forums, I decided I would replace the air/oil separator. Mine is an MKII version. I have removed the throttle body (no big deal at all), the front intake manifold plenum (a little challenging), and I have wasted a few hours trying to remove the rear plenum. that plenum just will not come out. Getting to the strap bolts was a night mare, but I finally loosen up the straps. I lowered the engine as far as I could, but that rear plenum just does not come out. I tug and pull and twist, but no luck. How do I get that bugger out? Boy, I am not looking forward to tackling the hard part....the removal of the manifold and the air/oil separator...but I will persevere... So, can someone tell me how to get that rear plenum out? Much appreciated.

[Ahsai]

There's no need to remove the rear plenum BEFORE you remove the left intake manifold. Please, just read the link I sent above for this exact reason (to save people time). The rear plenum will come out with the left intake manifold in step 16.

[Ahsai]

The rear plenum rubber sleeves are designed to LOCK the rear plenum and they won't shift left or right no matter how hard you try to twist them as long as both the left and right intake manifolds are still bolted firmly on the engine.

[questforbalance]

Thanks Ahsai. I did notice that in your write up, but the Bentley book said to remove the rear plenum first. So I figured I would take the rear plenum out first. I will follow your advice/guidance since you did this already. BTW, how did you fit your hands up from under the car to access the AOL separator hose and allen head bolts? I can barely fit one hand up from underneath. I lowered the engine up to the center support. I was able to reach down from the top and can feel the AOS hose and by touch found the allen head bolts. But I am not sure if I will be able to get a tool down there. Did you try accessing them from top and found that it did not work and thus finally accessed them from the bottom? Thanks

[AWDGuy]

If your removing the intake manifold, try and take a peak or cell phone pic of inside the Intake plenums. the heads on cylinders 1-3 were super clean. Cylinder #6 had oil pooling in the valves. If you see oil in there, you found your problem and replacing the aos won't do anything.

[Ahsai]

Thanks Ahsai. I did notice that in your write up, but the Bentley book said to remove the rear plenum first. So I figured I would take the rear plenum out first. I will follow your advice/guidance since you did this already. BTW, how did you fit your hands up from under the car to access the AOL separator hose and allen head bolts? I can barely fit one hand up from underneath. I lowered the engine up to the center support. I was able to reach down from the top and can feel the AOS hose and by touch found the allen head bolts. But I am not sure if I will be able to get a tool down there. Did you try accessing them from top and found that it did not work and thus finally accessed them from the bottom? Thanks

That's correct. I wasted a lot of time going from the top with some success (I got one of the hex allen bolts of the AOS from the top) but it's not a reliable way. Regarding getting the hands there, you can't especially if you have big hands. You prwtty much have to work with your fingers. When down there facing the rear of the car, try to slide your right hand (fingers) from the side above cyl #3 to reach the bottom aos hose and the most difficult hex bolt.

Let me know if you have more questions and good luck!

[Ahsai]

Btw, the Bentley manual is a joke on this one and most of the detailed instructions on the web is for mkI. I couldn't find good mkII instructions or I found some but they did'nt work for me.

[questforbalance]

 

Thanks Ahsai. I did notice that in your write up, but the Bentley book said to remove the rear plenum first. So I figured I would take the rear plenum out first. I will follow your advice/guidance since you did this already. BTW, how did you fit your hands up from under the car to access the AOL separator hose and allen head bolts? I can barely fit one hand up from underneath. I lowered the engine up to the center support. I was able to reach down from the top and can feel the AOS hose and by touch found the allen head bolts. But I am not sure if I will be able to get a tool down there. Did you try accessing them from top and found that it did not work and thus finally accessed them from the bottom? Thanks

That's correct. I wasted a lot of time going from the top with some success (I got one of the hex allen bolts of the AOS from the top) but it's not a reliable way. Regarding getting the hands there, you can't especially if you have big hands. You prwtty much have to work with your fingers. When down there facing the rear of the car, try to slide your right hand (fingers) from the side above cyl #3 to reach the bottom aos hose and the most difficult hex bolt.

Let me know if you have more questions and good luck!

 

Hello Ahsai, I started this project and PITA project is an understatement!!  I got the intake manifold off, got the plenums off, even got both allen bolts holding the AOS off, but cannot get the bottom vent off the AOS. I tried for hours to get at it from the top, from the bottom, but cannot get enough room to press the hose connection off. I cannot get my fingers up high enough to get a grip on that vent hose connection on the AOS. I have the engine lowered to the center support, but still there is not enough room. I even had my wife try to get at it, but that failed also. Did you push the engine over to the passenger side when you did the job? I am thinking that I will try that, but I want to ask first.

[Ahsai]

I hear you. With the left intake removed and the AOS pushed up, I was able to remove it from the top using my left hand reaching deep down. Later I was testing something and I was also able to remve it from the bottom. It's very tight at the bottom and if you have big hands, it will be impossible.

No, I didn't push the engine. Mine is an '03 C2 and I wonder if your C4 tip is different and tighter.

[Ahsai]

It would definitely help if you can push the engine to the right. I never tried that and you probably will need to slide your jack in from the side so the jack is more free to move the engine left and right.

[questforbalance]

Thanks Ahsai. I plan on trying to move the engine over this weekend.  Also, I do not know if you had it on your car, but on my car there is a metal angle that is bolted to the side of the car that has supports the 2 inch coolant metal pipe as it heads downward. That angle severely restricts my hand accessing the lower vent clamp and does an excellent job of cutting and bruising my left hand. I am going to either unbolt that angle or bend the angle up. I am sure that will help a lot.

[Ahsai]

I don't quite remember whether I have that bracket but it felt like a lot of metal around that area. I didn't have much trouble undoing that lower vent hose from the top once I lifted up the AOS a bit with all the other lines still connected. Are you sure you squeeze the plastic rings pretty good to disengage the ring lock before trying to pull it out?

[questforbalance]

Well, I want to thank everyone who provided great advice. This was the biggest PITA job I have ever done. I used every small tool I had and finally got it done. I still puff out some white smoke at start up in the morning, but not as much as before. I still have a tapping sound coming from the engine at all times. I am not sure what it is, but i heard someone with a Boxster on Youtube who had the same exact noise and identified it as sticky hydraulic lifters. Has anyone used Liqui Moly hydraulic lifter additive or Rislone Engine treatment to solve the problem? Or is this a hydraulic lifter replacement in my future? Thanks

[JFP in PA]

Well, I want to thank everyone who provided great advice. This was the biggest PITA job I have ever done. I used every small tool I had and finally got it done. I still puff out some white smoke at start up in the morning, but not as much as before. I still have a tapping sound coming from the engine at all times. I am not sure what it is, but i heard someone with a Boxster on Youtube who had the same exact noise and identified it as sticky hydraulic lifters. Has anyone used Liqui Moly hydraulic lifter additive or Rislone Engine treatment to solve the problem? Or is this a hydraulic lifter replacement in my future? Thanks

 

Porsche uses hydraulic cam followers with rather small oil passages in them that are prone to blockage and varnish like build up as they form a kind of "dead end" for the oil passages.  I have not seen an additive that would help with that problem.

[Ahsai]

I think to tell whether the noise is from a lifter or from a scored cylinder, Jake Raby suggested using a stethoscope to listen on the cam cover and on where the engine block meets the head. If the latter is louder, it's a scored cylinder.

 

John, any reco for distinguishing lifter noise and scored cylinder knocks?

[JFP in PA]

I think to tell whether the noise is from a lifter or from a scored cylinder, Jake Raby suggested using a stethoscope to listen on the cam cover and on where the engine block meets the head. If the latter is louder, it's a scored cylinder.

 

John, any reco for distinguishing lifter noise and scored cylinder knocks?

 

You really have had to hear both to sense the difference, lifters make a sharper "tick" while bad cylinders tend to make a duller sound.  Jake's description of where to place the stethoscope is a good one as it would localize the sound.

[questforbalance]

Great information. I will use my stethoscope tonight. can you provide the link to Jake Raby's article on how to listen to the sounds? Also, I read somewhere that loose spark plugs can also sound like bad lifters. I replaced the spark plugs a year ago with the OEM Bosch plugs. I torqued them to 28 NM because the spark plug box said to torqued it to that, however, Wayne's book and the bentley book said to torque them to 30 NM. Do you have any thoughts on this? Thanks so much for the assistance.