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Rattle on cold startup


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I started my 03 C4S today after about 10 days. The first 2-3 minutes after startup, I was hearing a clearly audible rattle/tick tick/click click. I thought I saw some smoke from the exhaust, but then again, it was very dark and it is really cold here in Boston, so it could have just been typical exhaust smoke/mist. I backed up the car, moved it over and shut it off (whole reason I started it).

Upon searching here, it seems it could either be the IMS death rattle or chain tensioner related. My car has already had the IMS done with the LN Engineering kit, so I am hoping this is chain tensioner related. I am running Mobil 1 0-40, but pretty much always check the oil level every time before I start it (on the console) and it is always full. I change every 5k (last change was 4k ago). I have had the car for about 9k miles, it drives beautifully, doesn't burn any oil.

The threads suggest switching to a higher weight oil - maybe a 10-40? Or even a 15-50? I live in Boston and will be driving the car through the winter (not every day but often), so I am thinking 10-40 is a better bet.

Can Loren or JFP or anyone share any thoughts on this situation?

Edited by xxaarraa
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The tick-tick-tick sounds normal as the oil will drain out of the valve tappets in less than one week of not running. Should go away once warm.

If that is what you heard you are likely okay.

Thanks Loren. I have had the car sit for this long before (in fact, it sat for one month in August) but never had this happen. This time, it only sat for 8-9 days. Does the oil drain issue get exaggerated in colder temps?

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I would tend to agree with Loren on this, the M96 engine is prone to oil bleed down over time which leads to noise at start up. In addition, this problem is exacerbated by rather low film strengths in some very low viscosity oils (0W-just about anything), particularly when they have some miles on them. You might want to consider an oil with known better film strength characteristics such as 5W-40 Castrol Edge with Syntec Technology, or the new Joe Gibbs DT 40, which is also a 5W-40. The DT40 is particularly interesting as it shows a significant improvement in low temperature viscosity retention with accumulated mileage when compared to the Mobil 1 product, and DT40 has very high levels of ZDDP.

The chain tensioners are also somewhat problematic on these cars as well, and Porsche has updated the tensioners at least twice in an apparent attempt to address the problem of noise. If a better oil does not improve the situation, newer tensioners could be in your future.

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Thanks Loren and JFP. I'll keep an eye on the rattle. I just ordered Joe Gibbs DT40, will try that on the next oil change (very soon). Never ceases to amaze me that a $104k car rattles on cold start. Never had that happen in anything I have owned, but "its character" I guess (/sarcasm).

Drove the car about 100 miles in the snow today and it was mostly undramatic (I do have conti DWS on).

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My car scares the deers around on a cold (<30F) degrees startup in the morning. Lasts just 2 seconds, but doesn't sound good at all. I have M1 0W40 inside, next change will try DT or RP. Car is driven A LOT. Absolutely normal startup if temp is above 50. My wife's 996 with twice less miles with same oil has no such problem in any weather...

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  • 3 weeks later...

Wondering about any follow up on the change to the DT40? I have the same problem that Loren described in that when the car is cold(which in the last few days has been at least 5-8 minutes in the frigid weather.) Once warm the noise is gone. This happening with every cold start(so the end of a work day can do it)

Still not sure this is bleed-down, tensioners or a hydraulic lifter problem

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My 99 is fairly loud on cold start up (worse after a few days of not driving) but still faint after being fully warmed up/driven hard. When warm I can't hear it in the car but listening from the ground it's coming from the passenger side cylinder bank. I'm running Castro 10-60 (the BMW oil). Here in Norcal it doesn't get driven on any cold days. I'm just hoping it's just tappet noise as well.

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Wondering about any follow up on the change to the DT40? I have the same problem that Loren described in that when the car is cold(which in the last few days has been at least 5-8 minutes in the frigid weather.) Once warm the noise is gone. This happening with every cold start(so the end of a work day can do it)

Still not sure this is bleed-down, tensioners or a hydraulic lifter problem

I have only about 1000 miles on it since the switch to DT40, so this isn't an entirely informed point of view. Switching does seem to have helped. I haven't had the rattle appear again. And car sat for a week through the recent "Hercules" snow storm and subsequent polar vortex temperature dips. When I started it up this morning, it ran fine, no rattle.

Whether DT40 mitigates the cold start rattle or not (I am reading that it does), I am a believer in it now. The car runs and "feels" soo much smoother. I have actually never truly felt a significant difference by switching oil brands and forumlas in all the vehicles I have owned over the years. But I can feel the positive difference with DT40.

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Wondering about any follow up on the change to the DT40? I have the same problem that Loren described in that when the car is cold(which in the last few days has been at least 5-8 minutes in the frigid weather.) Once warm the noise is gone. This happening with every cold start(so the end of a work day can do it)

Still not sure this is bleed-down, tensioners or a hydraulic lifter problem

I have only about 1000 miles on it since the switch to DT40, so this isn't an entirely informed point of view. Switching does seem to have helped. I haven't had the rattle appear again. And car sat for a week through the recent "Hercules" snow storm and subsequent polar vortex temperature dips. When I started it up this morning, it ran fine, no rattle.

Whether DT40 mitigates the cold start rattle or not (I am reading that it does), I am a believer in it now. The car runs and "feels" soo much smoother. I have actually never truly felt a significant difference by switching oil brands and forumlas in all the vehicles I have owned over the years. But I can feel the positive difference with DT40.

Did you run the JG "breakin oil" thru it first like flat 6 recommends or just switch directly to the DT40? curious what folks think about that requirement?

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Wondering about any follow up on the change to the DT40? I have the same problem that Loren described in that when the car is cold(which in the last few days has been at least 5-8 minutes in the frigid weather.) Once warm the noise is gone. This happening with every cold start(so the end of a work day can do it)

Still not sure this is bleed-down, tensioners or a hydraulic lifter problem

I have only about 1000 miles on it since the switch to DT40, so this isn't an entirely informed point of view. Switching does seem to have helped. I haven't had the rattle appear again. And car sat for a week through the recent "Hercules" snow storm and subsequent polar vortex temperature dips. When I started it up this morning, it ran fine, no rattle.

Whether DT40 mitigates the cold start rattle or not (I am reading that it does), I am a believer in it now. The car runs and "feels" soo much smoother. I have actually never truly felt a significant difference by switching oil brands and forumlas in all the vehicles I have owned over the years. But I can feel the positive difference with DT40.

Did you run the JG "breakin oil" thru it first like flat 6 recommends or just switch directly to the DT40? curious what folks think about that requirement?

Running the break in oil first both cleans out any residual of the old oil, and exposes the engine to a lubricant with both very high ZDDP levels (well beyond even the DT40) and high detergency additives (also common in break-in oils), so the engine would be both cleaned out and well lubricated before going to the DT40. While this is an optimal sequence, it is both expensive and time consuming (the break-in oil is only run for a short period), and is typically reserved for engine's with signs of build up issues (ticking lifters, strong start up noise, etc.). Usually, just a full drain and refill with the DT40 can work wonders all by itself on an engine that is other wise fine.

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Had no idea about this break-in oil, I switched directly from Mobil 1 0-40 to DT-40. Since I did a direct swap without the break-in/flush, should I plan on changing the oil sooner than 5k miles?

I am mildly annoyed by how sensitive these Porsches seem to be to oil. No car I have ever owned in the last dozen seemed to care what oil I ran through it. My M3 was advertised to go 15k between changes, though I did it every 7.5k. Same interval on my AMGs too. This is crazy to be fretting about oil changes and oil consumption in this day and age, not to mention in a premium car. What do we live in, the 1960s? I do like the 911, it has grown on me, but boy is it an acquired taste. End rant.

Edited by xxaarraa
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Had no idea about this break-in oil, I switched directly from Mobil 1 0-40 to DT-40. Since I did a direct swap without the break-in/flush, should I plan on changing the oil sooner than 5k miles?

I am mildly annoyed by how sensitive these Porsches seem to be to oil. No car I have ever owned in the last dozen seemed to care what oil I ran through it. My M3 was advertised to go 15k between changes, though I did it every 7.5k. Same interval on my AMGs too. This is crazy to be fretting about oil changes and oil consumption in this day and age, not to mention in a premium car. What do we live in, the 1960s? I do like the 911, it has grown on me, but boy is it an acquired taste. End rant.

I would not be overly concerned about not running the break-in oil first, as I mentioned, that is more for severe cases where the noise may also be related to varnish or crud build up due to slack maintenance.

Don't be annoyed at how sensitive the car it to oils, be annoyed with the oil companies for making significant changes to oil formulations without telling anyone, and the oil and OEM marketing departments for creating long change interval fibs. And if you collected oil samples for analysis between oil changes from your prior cars, you would have found that the oils were beat long before 15K, and in many cases beat or approaching it at 6-7K miles. Just like "lifetime" coolants, 12-15K oil changes are marketing myth; all automotive fluids have a limited life expectancy, some more than others. You are going to get 5-6K out of your oil, 4-5 years out of your coolant, and 2 years out of your brake fluid. And don't even get me started on Tiptronic or power steering fluid change intervals............

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Had no idea about this break-in oil, I switched directly from Mobil 1 0-40 to DT-40. Since I did a direct swap without the break-in/flush, should I plan on changing the oil sooner than 5k miles?

I am mildly annoyed by how sensitive these Porsches seem to be to oil. No car I have ever owned in the last dozen seemed to care what oil I ran through it. My M3 was advertised to go 15k between changes, though I did it every 7.5k. Same interval on my AMGs too. This is crazy to be fretting about oil changes and oil consumption in this day and age, not to mention in a premium car. What do we live in, the 1960s? I do like the 911, it has grown on me, but boy is it an acquired taste. End rant.

I would not be overly concerned about not running the break-in oil first, as I mentioned, that is more for severe cases where the noise may also be related to varnish or crud build up due to slack maintenance.

Don't be annoyed at how sensitive the car it to oils, be annoyed with the oil companies for making significant changes to oil formulations without telling anyone, and marketing departments for creating long change interval fibs. And if you collected oil samples for analysis between oil changes from your prior cars, you would have found that the oils were beat long before 15K, and in many cases beat or approaching it at 6-7K miles. Just like "lifetime" coolants, 12-15K oil changes are marketing myth; all automotive fluids have a limited life expextancy, some more than others. You are going to get 5-6K out of your oil, 4-5 years out of your coolant, and 2 years out of your brake fluid. And don't even get me started on Tiptronic or power steering fluid change intervals............

JFP - would you point me in the direction of the Tiptronic discussion?

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Had no idea about this break-in oil, I switched directly from Mobil 1 0-40 to DT-40. Since I did a direct swap without the break-in/flush, should I plan on changing the oil sooner than 5k miles?

I am mildly annoyed by how sensitive these Porsches seem to be to oil. No car I have ever owned in the last dozen seemed to care what oil I ran through it. My M3 was advertised to go 15k between changes, though I did it every 7.5k. Same interval on my AMGs too. This is crazy to be fretting about oil changes and oil consumption in this day and age, not to mention in a premium car. What do we live in, the 1960s? I do like the 911, it has grown on me, but boy is it an acquired taste. End rant.

I would not be overly concerned about not running the break-in oil first, as I mentioned, that is more for severe cases where the noise may also be related to varnish or crud build up due to slack maintenance.

Don't be annoyed at how sensitive the car it to oils, be annoyed with the oil companies for making significant changes to oil formulations without telling anyone, and the oil and OEM marketing departments for creating long change interval fibs. And if you collected oil samples for analysis between oil changes from your prior cars, you would have found that the oils were beat long before 15K, and in many cases beat or approaching it at 6-7K miles. Just like "lifetime" coolants, 12-15K oil changes are marketing myth; all automotive fluids have a limited life expectancy, some more than others. You are going to get 5-6K out of your oil, 4-5 years out of your coolant, and 2 years out of your brake fluid. And don't even get me started on Tiptronic or power steering fluid change intervals............

OK, thanks for the info.

I don't mean to be a disgruntled grumbler on the sidelines but I am generally a little turned off by Porsche in many ways. I really do like the 996, it has a lot of personality and charisma, which is hard to quantify. I drive my cars all year, do not believe in tempermental garage queens at all, and expect premium cars to pull their weight. I know every car has its "quirks" and special needs, but the 996 has me irritated on many fronts. The blandness and borderline acceptability of its interior (the suede center tunnel covers are horribly cheap, the rubberized coating on the soft surfaces rubs off when you just look at it leaving nicks all over the interior, they charge you for a rear wiper, other Germans cars of the time were better equipped in the electronics department, etc.). A $100k car should act and feel like a $100k car. I know I am not buying a luxury car, but don't skimp on the basics and tell me its all worth it because of how well the car drives. M3s that cost half as much drive nearly as nicely (arguably better, with a more planted front end).

Having said all that (I got it out of my system, I am back to smiling now), I work in marketing and know that the value of something is purely what someone is willing to pay for it. The exclusivity and aesthetic simplicity of the 911 seem to be drivers of its price than the mechanical worth of the car itself. Kind of like buying a $10k handbag, I suppose. Only so many are made and there are enough people wanting to spend $10k on a handbag.

Sorry for shooting this thread off in a tangent! :thumbup:

Edited by xxaarraa
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Had no idea about this break-in oil, I switched directly from Mobil 1 0-40 to DT-40. Since I did a direct swap without the break-in/flush, should I plan on changing the oil sooner than 5k miles?

I am mildly annoyed by how sensitive these Porsches seem to be to oil. No car I have ever owned in the last dozen seemed to care what oil I ran through it. My M3 was advertised to go 15k between changes, though I did it every 7.5k. Same interval on my AMGs too. This is crazy to be fretting about oil changes and oil consumption in this day and age, not to mention in a premium car. What do we live in, the 1960s? I do like the 911, it has grown on me, but boy is it an acquired taste. End rant.

I would not be overly concerned about not running the break-in oil first, as I mentioned, that is more for severe cases where the noise may also be related to varnish or crud build up due to slack maintenance.

Don't be annoyed at how sensitive the car it to oils, be annoyed with the oil companies for making significant changes to oil formulations without telling anyone, and marketing departments for creating long change interval fibs. And if you collected oil samples for analysis between oil changes from your prior cars, you would have found that the oils were beat long before 15K, and in many cases beat or approaching it at 6-7K miles. Just like "lifetime" coolants, 12-15K oil changes are marketing myth; all automotive fluids have a limited life expextancy, some more than others. You are going to get 5-6K out of your oil, 4-5 years out of your coolant, and 2 years out of your brake fluid. And don't even get me started on Tiptronic or power steering fluid change intervals............

JFP - would you point me in the direction of the Tiptronic discussion?

Very simple: Because of the design of the Tip, it is impossible to either totally drain the unit without removing it from the car and disassembling it, or to power flush it with a machine. As the result, you can only drain about 4.8 qts of fluid out of it, or roughly half of its total capacity. That means if you follow Porsche's maintenance schedule for it, after 90K miles, you are still going to leave roughly one half of the dirty old fluid in it. Having opened up Tips for service long before 90K, we often found fluid that was already ink black and sometimes smelling pretty bad as well, along with clutch dust debris in the pan. While many have adhered to the factory recommendations and not had problems, continuing to run the trans with this crud in it strikes me as a bad idea, particularly when you realize the money involved in replacing a Tiptronic, so we started experimenting with shortening the fluid change cycles (fluid is cheap, Tip repairs or replacements are not).

For daily drivers that accumulate high annual mileage, we drain and replace the fluid and filter very 25-30K miles. On some severe use cases, we shorten the fluid change cycle to once every year. On occasional use cars that see very low annual mileage (we have a customer with a 2001 Boxster that only has 7,000 total miles on it), we do a fluid service every fourth year. Using this approach, you are regularly refreshing at least half the fluid in the trans, as well as draining off the accumulated crud the collects in the system. To help keep costs under control, we schedule the fluid changes when the cars are in for normal engine oil change service (the car is already up in the air, and it only takes a moment or two to pull the drain plug on the Tip while you are at it) so the additional time is reduced to a minimum level.

Has it made a difference? We think so. With the total numbers of Tiptronic cars rather low compared to the manual trans cars, the data looks compelling. We used to be changing out Tip valve bodies and solenoid plates more frequently than we do now, and we also noted that the fluid and filters for regularly serviced cars look one Hell of a lot better than they used to at 90K.

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JFP, excellent advice as always. I use the exact method you use on my Acura MDX (drains 1/3 of it each time every other oil change). You know how notorous Honda transmissions are.

I know they are on the fragile side.

Have you ever sent out an ATF sample for testing? UOA labs typically do it, and sometimes the results can be a little scary.............. :eek:

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JFP, excellent advice as always. I use the exact method you use on my Acura MDX (drains 1/3 of it each time every other oil change). You know how notorous Honda transmissions are.

I know they are on the fragile side.

Have you ever sent out an ATF sample for testing? UOA labs typically do it, and sometimes the results can be a little scary.............. :eek:

No UOA yet but the used fluid I drain still looks red and new. That's good enough for me.

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