Suggestions for best engine test? 2002 996 3.6
04-17-2013, 07:51 PM
#1
Racer
Thread Starter
Suggestions for best engine test? 2002 996 3.6
Just got a 2002 996 Targa with 3.6 engine, Tiptronic.
It has about 165,000 miles on the entire car -- no rebuilds, but a one-owner car, brought to THE SAME Porsche dealer and THE SAME MECHANIC for all maintenance (and even at the recommended intervals!) for its ENTIRE LIFE (10+ years).
Well, the PO tells me that one day at 158K miles, the car suddenly spewed white smoke. He took it to his mechanic who stated that it was "head gasket," and recommended that he sell it and just get another car. The price for a fix did not make sense for a 158K mile car. (It really sounded like an AOS failure.)
He sold it at dealer auction about one year ago, 158K miles.
I got it a month ago, now with about 165K miles -- auction purchase. Of course, I did not know about the "head gasket" problem (I was lucky to track down the PO, and he was gracious enough to tell me the car's history.) The car drives well, with good power (better than my 3.4 996). IT handles very tightly, brakes great -- everything's too good to be true.
However, I can see tiny flecks of copper in the radiator overflow tank.
In addition, occasionally the service engine yellow light comes on. The code checker says that it is burning lean. After zeroing out the codes, the car does not pop an SEL for several more days (we drive about 80 miles a day).
I cannot see any obvious evidence that the head/s were removed, so I wonder if Stop Leak was the solution for the car's "head gasket". Maybe the problem really was the Air-Oil Separator, and that was replaced. I don't know.
HOWEVER, I AM WORRIED WHETHER PROBLEMS LOOM AHEAD OF ME due to the past history and the occasional SEL. Can it be an AOS that is going out? Possibly a cracked head that someone's Stop Leak temporarily fixed?
Are there any recommendations for testing that I should perform on the car to proactively figure this out before it becomes catastrophic?
The condition of the car, both interior and exterior, is exceptional. Truly exceptional. The owner drove 100 miles a day to work, and kept it garaged both at work and at home its entire life. In fact, he stated that it was likely that the car probably spent more time outside when it was at the factory and at the dealership for scheduled maintenance, than when it was in his possession for 10 years.
I'd like to hear some ideas.
Thanks in advance.
It has about 165,000 miles on the entire car -- no rebuilds, but a one-owner car, brought to THE SAME Porsche dealer and THE SAME MECHANIC for all maintenance (and even at the recommended intervals!) for its ENTIRE LIFE (10+ years).
Well, the PO tells me that one day at 158K miles, the car suddenly spewed white smoke. He took it to his mechanic who stated that it was "head gasket," and recommended that he sell it and just get another car. The price for a fix did not make sense for a 158K mile car. (It really sounded like an AOS failure.)
He sold it at dealer auction about one year ago, 158K miles.
I got it a month ago, now with about 165K miles -- auction purchase. Of course, I did not know about the "head gasket" problem (I was lucky to track down the PO, and he was gracious enough to tell me the car's history.) The car drives well, with good power (better than my 3.4 996). IT handles very tightly, brakes great -- everything's too good to be true.
However, I can see tiny flecks of copper in the radiator overflow tank.
In addition, occasionally the service engine yellow light comes on. The code checker says that it is burning lean. After zeroing out the codes, the car does not pop an SEL for several more days (we drive about 80 miles a day).
I cannot see any obvious evidence that the head/s were removed, so I wonder if Stop Leak was the solution for the car's "head gasket". Maybe the problem really was the Air-Oil Separator, and that was replaced. I don't know.
HOWEVER, I AM WORRIED WHETHER PROBLEMS LOOM AHEAD OF ME due to the past history and the occasional SEL. Can it be an AOS that is going out? Possibly a cracked head that someone's Stop Leak temporarily fixed?
Are there any recommendations for testing that I should perform on the car to proactively figure this out before it becomes catastrophic?
The condition of the car, both interior and exterior, is exceptional. Truly exceptional. The owner drove 100 miles a day to work, and kept it garaged both at work and at home its entire life. In fact, he stated that it was likely that the car probably spent more time outside when it was at the factory and at the dealership for scheduled maintenance, than when it was in his possession for 10 years.
I'd like to hear some ideas.
Thanks in advance.
04-17-2013, 08:00 PM
#2
do you have a Porsche indy shop nearby? have a compression/leakdown test done for starters.
Good read on AOS here: http://www.pelicanparts.com/techarti..._Separator.htm
Good read on AOS here: http://www.pelicanparts.com/techarti..._Separator.htm
04-17-2013, 08:29 PM
#3
Racer
Thread Starter
Ref. compr and leakdown test, ok. Any particular reason it should be a Porsche mechanic? Can this be done by any mechanic, or is there something peculiar to Porsches?
04-18-2013, 09:31 AM
#5
The metal flakes indicates Bars Leaks was dumped in like KK says.
If the car is running better then your other 996 I would suspect there isn't any compression loss. Any signs of oil/coolant intermix in the oil or coolant? Any air bubbles in the coolant tank while it is running?
It's a tough one, based on what the PO said and the evidence in the coolant I would think a temporary repair has been made. Can you tell if the AOS has been replaced? If not, I think the leak in the motor has been sealed up with the stop leak.
If the car is running better then your other 996 I would suspect there isn't any compression loss. Any signs of oil/coolant intermix in the oil or coolant? Any air bubbles in the coolant tank while it is running?
It's a tough one, based on what the PO said and the evidence in the coolant I would think a temporary repair has been made. Can you tell if the AOS has been replaced? If not, I think the leak in the motor has been sealed up with the stop leak.
04-18-2013, 10:41 AM
#7
Racer
Thread Starter
Cosmo,
No coolant in the oil; none on dipstick; did an oil change and none in the oil change.
No oil in coolant; no air bubbles.
Is Bars Leak that good??
I haven't closely examined the air-oil separator, but there was a "dealer prep" on the engine, so everything glistens with that stuff they spray to make things look new. It has been about a year since the PO sold the car, so I'm thinking that its appearance might have been equalized out with a few thousand miles of road grime.
Any suggestions what to look for when checking if a new AOS was installed?
Kromdom,
Thanks for the link to Pelican's AOS replacement for 911's. I had only seen their instructions for Boxsters.
I think I'll pull the plugs this weekend to see if there's any telltale signs of bad acting going on. Otherwise, will take to P-Indy to do compression and leakdown. The anxiety is bugging me, although I should just drive the car until it breaks -- which typically occurs at the most inopportune time, huh.
BTW, contrary to my classical thinking, I can't help think about the Renegade LS conversion if the present engine goes.
No coolant in the oil; none on dipstick; did an oil change and none in the oil change.
No oil in coolant; no air bubbles.
Is Bars Leak that good??
I haven't closely examined the air-oil separator, but there was a "dealer prep" on the engine, so everything glistens with that stuff they spray to make things look new. It has been about a year since the PO sold the car, so I'm thinking that its appearance might have been equalized out with a few thousand miles of road grime.
Any suggestions what to look for when checking if a new AOS was installed?
Kromdom,
Thanks for the link to Pelican's AOS replacement for 911's. I had only seen their instructions for Boxsters.
I think I'll pull the plugs this weekend to see if there's any telltale signs of bad acting going on. Otherwise, will take to P-Indy to do compression and leakdown. The anxiety is bugging me, although I should just drive the car until it breaks -- which typically occurs at the most inopportune time, huh.
BTW, contrary to my classical thinking, I can't help think about the Renegade LS conversion if the present engine goes.
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04-18-2013, 12:36 PM
#9
Three Wheelin'
I think I'll pull the plugs this weekend to see if there's any telltale signs of bad acting going on. Otherwise, will take to P-Indy to do compression and leakdown. The anxiety is bugging me, although I should just drive the car until it breaks -- which typically occurs at the most inopportune time, huh.
BTW, contrary to my classical thinking, I can't help think about the Renegade LS conversion if the present engine goes.
BTW, contrary to my classical thinking, I can't help think about the Renegade LS conversion if the present engine goes.
LS swap is always a good option.
04-18-2013, 01:07 PM
#11
Racer
Thread Starter
One more thing that I forgot to mention...
ON STARTING THE CAR, THERE IS A VERY HIGH PITCHED WHINE THAT SEEMS TO COME FROM THE LEFT REAR CORNER OF THE ENGINE COMPARTMENT. It goes away after a few minutes, when the car warms up.
Macster -- I believe you mention a high pitched sound in one of your posts on the other Porsche forum. ...due to leak from manifold under internal crankcase pressure. However, why would this sound disappear after a few minutes warm up?
Early AOS failure?
ON STARTING THE CAR, THERE IS A VERY HIGH PITCHED WHINE THAT SEEMS TO COME FROM THE LEFT REAR CORNER OF THE ENGINE COMPARTMENT. It goes away after a few minutes, when the car warms up.
Macster -- I believe you mention a high pitched sound in one of your posts on the other Porsche forum. ...due to leak from manifold under internal crankcase pressure. However, why would this sound disappear after a few minutes warm up?
Early AOS failure?
04-18-2013, 02:03 PM
#12
That whine is the air pump pushing air into the cats during warmup. That is normal, if it gets really loud it will have to be cleaned/lubed or replaced. KK has a thread on how to do it.
04-18-2013, 02:50 PM
#13
Racer
Thread Starter
04-18-2013, 03:54 PM
#14
Three Wheelin'
Probably a vacuum or similar unmetered air getting in, check that top intake plenum is sealed up and no air can't get it other than the maf.
I don't see how radiator stop leak would in any way help a head gasket failure; probably bad AOS as you mentioned.
How much did you pay, if you don't mind me asking?
I don't see how radiator stop leak would in any way help a head gasket failure; probably bad AOS as you mentioned.
How much did you pay, if you don't mind me asking?
04-18-2013, 06:39 PM
#15
Rennlist Member
These engines do not have head gasket failures.
I'm guessing: Waterpump failed. Then either engine was low on coolant & developed a local hot spot in a head & cracked a coolant passage or water pump impeller broke & sent pieces into the head coolant passage leading to a crack. Liquid crack filler added to coolant later & stopped up the coolant leak into combustion chamber.
Get the oil anaylized & check the sparkplugs, replace plugs that look suspect with new. Drive the car if you aren't doing further harm, accept that you need to have the heads rebuilt sometime, but with that mileage just drive it until you have to do any major repairs. Don't turn the radio up too loud.
I'm guessing: Waterpump failed. Then either engine was low on coolant & developed a local hot spot in a head & cracked a coolant passage or water pump impeller broke & sent pieces into the head coolant passage leading to a crack. Liquid crack filler added to coolant later & stopped up the coolant leak into combustion chamber.
Get the oil anaylized & check the sparkplugs, replace plugs that look suspect with new. Drive the car if you aren't doing further harm, accept that you need to have the heads rebuilt sometime, but with that mileage just drive it until you have to do any major repairs. Don't turn the radio up too loud.