99 996 six month report

[dr7966]

I have owned my 99 for about 6 months and thought some of the potential buyers would be interested in the issues encountered.

Started with 81k and now have 85k miles. I knew it would be a project and wanted to do as much work as possible myself.

Bought for 25k from Phoenix dealer and had it shipped to me in So Cal. Add another 2k for Cali tax.

CEL went on immediately with a P0605 error and it cost $800 for an ECU replacement. If you search P0605 I have a long post describing this.

Dealer refunded $500 (lucky my wife is a lawyer)

Replaced drivers side inner fender myself $180 from Sunset, cleaned radiators.

Bought extra key from Sunset $120 dealer programming $80 in woodland hills.

Changed trans fluid $30 oil and filter $70 all Mobile 1

Changed pre cat oxygen sensors $200 from Pelican (tried generic o2 sensors and returned, should use oem part for this)

Purchased a bosche starter for $200 because it was turning slow when hot but have not installed yet.

The engine runs good but uses oil with Mobile 1 10-30. I have added some 10-40 and Lucas additive and it has improved.

No leaks and the cooling system and electrical is ok. The AM radio is bad and FM is not much better.

The trans was very hard to shift when cold and has improved since the fluid change. 2nd gear syncro is not 100 percent

I was getting a CEL for a air leak in the emissions but it has not returned since I replaced the 02 sensors.

Next will probably replace tires and get alignment. I am fairly pleased so far with these issues and I know it could have been worse.

This site has also been great.

[KevinMac]

xx

Edited May 5, 2008 by KevinMac

[KevinMac]

I have owned my 99 for about 6 months and thought some of the potential buyers would be interested in the issues encountered.

Started with 81k and now have 85k miles. I knew it would be a project and wanted to do as much work as possible myself.

Bought for 25k from Phoenix dealer and had it shipped to me in So Cal. Add another 2k for Cali tax.

CEL went on immediately with a P0605 error and it cost $800 for an ECU replacement. If you search P0605 I have a long post describing this.

Dealer refunded $500 (lucky my wife is a lawyer)

Replaced drivers side inner fender myself $180 from Sunset, cleaned radiators.

Bought extra key from Sunset $120 dealer programming $80 in woodland hills.

Changed trans fluid $30 oil and filter $70 all Mobile 1

Changed pre cat oxygen sensors $200 from Pelican (tried generic o2 sensors and returned, should use oem part for this)

Purchased a bosche starter for $200 because it was turning slow when hot but have not installed yet.

The engine runs good but uses oil with Mobile 1 10-30. I have added some 10-40 and Lucas additive and it has improved.

No leaks and the cooling system and electrical is ok. The AM radio is bad and FM is not much better.

The trans was very hard to shift when cold and has improved since the fluid change. 2nd gear syncro is not 100 percent

I was getting a CEL for a air leak in the emissions but it has not returned since I replaced the 02 sensors.

Next will probably replace tires and get alignment. I am fairly pleased so far with these issues and I know it could have been worse.

This site has also been great.

Think only 0w- 40 Mobil 1 is the Porsche recommended oil. Some folks use the 15W-50, but the longlife BMW and Porsche certification is on the 0w-40. The 15W- 50 should not be used in cold climates per other discussion boards.

Mobil1 GL5 has limited slip properties. If you do not have limited slip, you may want to try RedLine 75w-90 NS. This may help your syncros work better and take care of your gear complaints.

Make sure you take your car to an alignment shop that knows these cars!

[Flyer007]

Sounds pretty good.

What made you "know it was going to be a project"?

It is great to be able to work on these cars. I have been loving mine for the last 2 months. Only put about 1k on her due to weather.

[perryinva]

Mobil 1 GL5 75w-90 LS is for both limited slip and non limited slip. That said, though, I'd still use the (and will use when I do it) http://www.lufteknic.com/Merchant2/merchan...Code=lubricants

Luckily, they are, literally, almost in my backyard, so it's easy for me to get!

[KevinMac]

Mobil 1 GL5 75w-90 LS is for both limited slip and non limited slip. That said, though, I'd still use the (and will use when I do it) http://www.lufteknic.com/Merchant2/merchan...Code=lubricants

Luckily, they are, literally, almost in my backyard, so it's easy for me to get!

Limited slip additives are a friction modifier that allows limited slip clutch pacs to slip. If there is no friction modifier in the LS axle they grab and cause either clunking when making tuns, or clutch packs locking up with grabbing on turns.

Syncros require no slippage when gear changing and are designed to line up the input to driven gear. Friction modifier can cause this to slip and cause a shift feel that seems to grind slightly or seems to have more resistance. So with that said M1 has a friction modifier already in it causing the feel as complained about.

Per Mobil1:

"Mobil 1 Synthetic Gear Lube LS 75W-90 contains special friction modifiers designed for limited slip-type differentials. In most applications, the addition of special LS (limited slip) additives is not required. For axles requiring the highest level of limited-slip performance, OEM specific LS additives can be added to this fluid. "

[perryinva]

Mobil 1 GL5 75w-90 LS is for both limited slip and non limited slip. That said, though, I'd still use the (and will use when I do it) http://www.lufteknic.com/Merchant2/merchan...Code=lubricants

Luckily, they are, literally, almost in my backyard, so it's easy for me to get!

Limited slip additives are a friction modifier that allows limited slip clutch pacs to slip. If there is no friction modifier in the LS axle they grab and cause either clunking when making tuns, or clutch packs locking up with grabbing on turns.

Syncros require no slippage when gear changing and are designed to line up the input to driven gear. Friction modifier can cause this to slip and cause a shift feel that seems to grind slightly or seems to have more resistance. So with that said M1 has a friction modifier already in it causing the feel as complained about.

Per Mobil1:

"Mobil 1 Synthetic Gear Lube LS 75W-90 contains special friction modifiers designed for limited slip-type differentials. In most applications, the addition of special LS (limited slip) additives is not required. For axles requiring the highest level of limited-slip performance, OEM specific LS additives can be added to this fluid. "

Seriously, without trying to be offensive here, I'm not sure what your point is. At Mobil's site, http://www.mobiloil.com/USA-English/MotorO...e_75W-90LS.aspx

It clearly states that LS is for both conventional and limited slip. For highest performance LS diffs, ADDITIONAL modifiers may be added. Also says so on the bottle. That said, I stated I will use what is the Delvac replacement factory fill, per the above mentioned website. I am assuming of course that they are correct about the Delvac as a replacement for Porsche factory fill. It is NOT for LS....additional LS modifiers MUST be added. I have always been under the understanding that LS rated hypoid oils can be used in either conventional OR LS, but, you CAN'T run regular hypoid in an LS diff. I do not have a LS diff in my car.

Now, I saw where you said "Mobil1 GL5 has limited slip properties. If you do not have limited slip, you may want to try RedLine 75w-90 NS. This may help your syncros work better and take care of your gear complaints."

and you may be right, I had good luck with Redline in my LS BMW, improved smoothness over the factory fluid. My point was that Mobil 1 75W-90 LS is supposed to be OK as well, according to Mobil. For non LS use only oil, Redline is not on the Porsche list AFAIK, but the Delvac is.

Edited May 5, 2008 by perryinva

[KevinMac]

My only point was he was complaining of some gear roughness, after changing over to Mobil1 75W-90. I am not saying that the Mobil 1 is not compatible with Porsche trans axles. Just that Redline NS or any other non LS lube being that it has no LS friction modifiers that it could possibly make the gearbox smoother due to the abscence of the friction modifiers. No one is debating if it is compatible, just that that a gearbox that has some mileage on it my do better if not LS to have no friction modifiers.

Edited May 6, 2008 by KevinMac

[dr7966]

Sounds pretty good.

What made you "know it was going to be a project"?

It is great to be able to work on these cars. I have been loving mine for the last 2 months. Only put about 1k on her due to weather.

I should rephrase to "I was prepared for it to be a project" mostly because I didnt know the previous owner(s) and it had 80k miles. There is a high percentage chance that something needs to be repaired.

I also dont mean "project" in a bad way. Before I bought the car I went through this and other forums and realized that these cars can be maintained and repaired by owners with some mechanical and troubleshooting skills. There are also alternatives to the dealer for parts. I get alot of enjoyment from repairing things myself that the dealer would charge big money for.

[perryinva]

I get alot of enjoyment from repairing things myself that the dealer would charge big money for.

+1000....amen!

[dr7966]

I have owned my 99 for about 6 months and thought some of the potential buyers would be interested in the issues encountered.

Started with 81k and now have 85k miles. I knew it would be a project and wanted to do as much work as possible myself.

Bought for 25k from Phoenix dealer and had it shipped to me in So Cal. Add another 2k for Cali tax.

CEL went on immediately with a P0605 error and it cost $800 for an ECU replacement. If you search P0605 I have a long post describing this.

Dealer refunded $500 (lucky my wife is a lawyer)

Replaced drivers side inner fender myself $180 from Sunset, cleaned radiators.

Bought extra key from Sunset $120 dealer programming $80 in woodland hills.

Changed trans fluid $30 oil and filter $70 all Mobile 1

Changed pre cat oxygen sensors $200 from Pelican (tried generic o2 sensors and returned, should use oem part for this)

Purchased a bosche starter for $200 because it was turning slow when hot but have not installed yet.

The engine runs good but uses oil with Mobile 1 10-30. I have added some 10-40 and Lucas additive and it has improved.

No leaks and the cooling system and electrical is ok. The AM radio is bad and FM is not much better.

The trans was very hard to shift when cold and has improved since the fluid change. 2nd gear syncro is not 100 percent

I was getting a CEL for a air leak in the emissions but it has not returned since I replaced the 02 sensors.

Next will probably replace tires and get alignment. I am fairly pleased so far with these issues and I know it could have been worse.

This site has also been great.

Its a year later and here is a 1.5 year 92k mile update. I have a Jeep for my DD so it keeps the miles down on the Pcar.

Changed the slow turning starter and cracked oil tube

Stopped using synthetic oil in the engine. Tried various weights of Mobil 1 and Castrol and it always used oil. Had some white and blue smoke at startup. Switched to Castrol high mileage 10w-50 and there is no smoke and it stopped using oil.

Removed the Mobile 1 75w-90 synth trans fluid and replaced with non synthetic petroleum and the shifting got much smoother. Still has a slight intermittent syncro roughness in 2nd but it is much improved. Plan on changing it again to get rid of all the synthetic. It does not have limited slip.

Replaced tires with Sumitomo HTR 2's

Installed a DUAL HD radio. Need to upgrade speakers. Reception is still not very good.

Installed a smoked LED third brake light.

Still working on the P0455 emissions leak CEL. Thought I fixed it but it came back.

With the smoother shifting and the oil use problem gone the car is much more enjoyable to drive. :rolleyes:

[phillipj]

Get ready for the oil guys to beat up on you now.... According to Porsche you have sinned...They are very sensitive about lubricants.. :lol:

[dr7966]

Get ready for the oil guys to beat up on you now.... According to Porsche you have sinned...They are very sensitive about lubricants.. :lol:

Expecting to be taken to the woodshed over the use of petroleum. Will not go to Porsche heaven either :o

Had to do something before the cats, 02 sensors, and plugs got fouled up with oil and needed to be replaced. Its no surprise that the car has more power and idles better without oil in the combustion chamber.

As far as the trans oil goes it was recommended by some earlier posts here to try oil without friction modifiers.

It was a great suggestion. The trans is quieter and shifts smooth for the 1st time since I bought it. :)

[phillipj]

What oil did you end up putting in the transmission?

[phillipj]

Mobil 1 GL5 75w-90 LS is for both limited slip and non limited slip. That said, though, I'd still use the (and will use when I do it) http://www.lufteknic.com/Merchant2/merchan...Code=lubricants

Luckily, they are, literally, almost in my backyard, so it's easy for me to get!

How do you know if you have "limited slip" or "non limited slip?" :huh:

Phillipj

[dr7966]

Mobil 1 GL5 75w-90 LS is for both limited slip and non limited slip. That said, though, I'd still use the (and will use when I do it) http://www.lufteknic.com/Merchant2/merchan...Code=lubricants

Luckily, they are, literally, almost in my backyard, so it's easy for me to get!

How do you know if you have "limited slip" or "non limited slip?" :huh:

Phillipj

Hey Phillipj you found the trans post. I put some GL5 oil 80w-90 I found at Wal-Mart. I think its made by Shell. Going to run it for a few weeks and change with Redline. Wanted to get the Mobil 1 out.

My car does not have PCM or traction control. I think I read somewhere that only those cars have limited slip. It was an option.

[phillipj]

Thanks !

[deanslist.us]

Get ready for the oil guys to beat up on you now.... According to Porsche you have sinned...They are very sensitive about lubricants.. :lol:

Non-Synthetic?!?

Non-Mobil 1?!?!

SINNER!

Repent and change back to Mobil 1 15-50!!

Edited May 20, 2009 by deanslist.us

[dr7966]

I have owned the car for 4 years now with 98000 miles. Finally fixed the P0455 CEL by replacing the gas cap with a 30 dollar german cap.

New California law would not allow me to clear the CEL and take it for a smog check so i had to fix it. Car is running good, still using petroleum.