Need help diagnoising Grinding Noise on startup.

[leonidasb22]

Hi Porsche Community, 

 

I need some help to diagnosis what this grinding noise is —— immediately after startup. The grinding noise lasts about 1-2 seconds and only happens on startup. It goes away after. It doesn't happen on every startup. It occurs about 1 out of 3 starts. Sometimes it happens on the first start. Sometimes it doesn't. I started the engine consecutively 3 times and it happened on the third start. I included a file called "good start audio" clip and a "grinding startup noise audio" so that you can focus on the grinding noise and only the difference in the sounds. It starts up right away, no problems or hesitation. No error codes. Taken well care of. 

 

2004 Porsche 911 Carrera 2 (996) - RWD

6 Speed manual 

78,000 miles

 

Thanks in advance. 

 

 

 

 

Good Start Audio.m4a Grinding Startup Noise Audio.m4a

Edited November 8, 2021 by leonidasb22

[JFP in PA]

Sounds like the Bendix drive on the starter is not retracting properly when you release the key.  This is a common problem and  can usually be fixed by cleaning the drive and relubricating it. 

[leonidasb22]

24 minutes ago, JFP in PA said:

Sounds like the Bendix drive on the starter is not retracting properly when you release the key.  This is a common problem and  can usually be fixed by cleaning the drive and relubricating it. 

 

JFP Thank you very much for your fast response!

 

Would you recommend "cleaning and relubricating the drive" or just replacing the starter with a rebuilt Porsche/ or OE new unit for about $275?

 

When this occurs does it signal that other parts in the starter are on their way out and will fail soon even if I was to "clean and relubricating the Bendix drive"? 

 

How hard is it to "clean the drive and relubricating it" vs just replacing it myself?

 

Thank you again. 

 

Edited November 8, 2021 by leonidasb22
quote

[JFP in PA]

We have cleaned and re-lubed a lot of them over the years and most went on to serve for many more years before the starter needed to be replaced.  This problem happens because the drive picks up debris from both the clutch and environment over time.

 

To clean the drive, use common brake cleaner, and once dry, spray the shaft with DuPont dry Teflon spray (Lowes and Amazon carry it) while moving the starter gear back and forth.  The advantage of using this type of lubricant is that it does not attract dirt and moisture like common greases do.  To facilitate this, the starter has to be removed from the engine, so the question as to fix it or replace it is purely a personal choice. As a shop owner, I don't like to replace parts unless it is absolutely necessary, maintenance is always preferable and cheaper in the long run.😉

[leonidasb22]

On 11/8/2021 at 6:54 PM, JFP in PA said:

We have cleaned and re-lubed a lot of them over the years and most went on to serve for many more years before the starter needed to be replaced.  This problem happens because the drive picks up debris from both the clutch and environment over time.

 

To clean the drive, use common brake cleaner, and once dry, spray the shaft with DuPont dry Teflon spray (Lowes and Amazon carry it) while moving the starter gear back and forth.  The advantage of using this type of lubricant is that it does not attract dirt and moisture like common greases do.  To facilitate this, the starter has to be removed from the engine, so the question as to fix it or replace it is purely a personal choice. As a shop owner, I don't like to replace parts unless it is absolutely necessary, maintenance is always preferable and cheaper in the long run.😉

 

JFP I have removed, disassembled, and cleaned the entire starter internally. Tomorrow I would like to grease and assemble it. The small internal gears appeared to have a thick grease on them. Is the DuPont Teflon Non-Stick Dry-Film Lubricant you recommended for all the internal gears? Or just the shaft of the starter gear which is more exposed to the clutch? Which lube do you recommend for the small internal gears and the Bendix drive gear? 

 

Also the DuPont dry Teflon spray is out of stock and I can't get my hands on it until next week.

 

These are alternatives that I have found in stock. Are you familiar and do you recommend any of these to the DuPont dry Teflon spray or any others?

 

Blaster Industrial Graphite DRY Lubricant (not teflon)

Blaster Advanced Dry Lube with Teflon

WD-40 SPECIALIST Dry Lube with PTFE (teflon)

 

Thanks again. You've been right all along so far. 

 

 

[JFP in PA]

The internal gears use a very heavy grease due to the temperature they see and are not good candidates for the Teflon spray lube, if anything I would use silicone-based brake grease is they need to be re-lubed as the brake grease is also for high temp applications. The Dupont product is only to be used on the shaft and internally on the gear of the Bendix shaft, I just checked Wal-Mart, and they are listing the Dupont product in stock with one day delivery locally, so you might want to look at other sources. As I am not familiar with the other products, I can't really recommend them.

 

      

[leonidasb22]

On 11/8/2021 at 6:54 PM, JFP in PA said:

We have cleaned and re-lubed a lot of them over the years and most went on to serve for many more years before the starter needed to be replaced.  This problem happens because the drive picks up debris from both the clutch and environment over time.

 

To clean the drive, use common brake cleaner, and once dry, spray the shaft with DuPont dry Teflon spray (Lowes and Amazon carry it) while moving the starter gear back and forth.  The advantage of using this type of lubricant is that it does not attract dirt and moisture like common greases do.  To facilitate this, the starter has to be removed from the engine, so the question as to fix it or replace it is purely a personal choice. As a shop owner, I don't like to replace parts unless it is absolutely necessary, maintenance is always preferable and cheaper in the long run.😉

 

JFP. I have decided that I will just swap out the starter with a brand new one. I just want a faster fix and I'm hoping a new one will outlast— rebuilding this one. I appreciate your help on this issue and help diagnosing the sound. Would you like me to send you my current starter for a spare? Its all clean, and worked perfect(except for the Bendix gear getting stuck sometimes— hence the reason for all this). Now that it is clean, you will have to grease it up. It seems that it was already replaced, as its BOSCH manufacture date is 2012. I also had to drill out the heads of the 3 torx M5 bolts so those would need to be sourced for a good rebuild.

 

Let me know, and I'll put it in the mail since you helped guide me along the way and I was able to learn about this. 

 

Thank you.

[JFP in PA]

Thanks, but we already have a shelf full of spare parts starters, but thanks for the offer! 😉

 

Perhaps a local tech school would accept it as an educational item, but you should also hang onto it just in case wherever you are getting the replacement from wants a core.

[leonidasb22]

Just now, JFP in PA said:

Thanks, but we already have a shelf full of spare parts starters, but thanks for the offer! 😉

 

Perhaps a local tech school would accept it as an educational item, but you should also hang onto it just in case wherever you are getting the replacement from wants a core.

Okay I will see. Thank you again!

[JFP in PA]

Anytime, that is what we are here for 😉

[Shrek]

Did changing the starter fix your problem?

[leonidasb22]

1 minute ago, Shrek said:

Did changing the starter fix your problem?

Yes! That was the issue. Sorry for the late reply. 

[Shrek]

Thanks.  I have the exact same symptoms.