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Loren

Reliability of 996 Engines

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Actually thats a little off for PM. At a minumum you should:

Use the best oil and change it 6 months/5000 miles.

The Porsche maint schedule is laughable.

I know the usual things, IMSB, etc, I was referring more to internal upgrades to make the engine more reliable. Better rods, rod bolts, liners, pistons, head studs, etc. I think Jake is finally going to reveal his exact method to bullet proof the M96.

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New oil every six months(!!) will do nothign to prevent your sylinders from going oval ;)

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New oil every six months(!!) will do nothign to prevent your sylinders from going oval ;)

Not necessarily true; use of low ZDDP oils and fuel intrusion combine with longer maintenance cycles to accelerate cylinder wall scoring and wear. More frequent oil changes lessen it.

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JFP, you are exactly right. When I posted "use the best oil" I was indeed referring to JG DT40 and Jakes 6 month/5000 mile schedule. Common sense dictates that this alone may prevent many problems for the M96. Dont know why that seems to bother so many Porsche owners.

Edited by krazyk

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The sylinders on the M96 engines go more and more oval over time, until they eventually crack. Hartech and others reinforce the engine block to prevent further "ovaling", which is said to be a permanent fix. How will new oil stop that process?

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The sylinders on the M96 engines go more and more oval over time, until they eventually crack. Hartech and others reinforce the engine block to prevent further "ovaling", which is said to be a permanent fix. How will new oil stop that process?

The so called "ovaling" results from multiple sources; starting with overly hot engine coolant temperatures, thin cylinder walls, alloy selection for the cylinders, high piston thrust angles from the basic Boxster engine design, excessive heat build up on the piston skirts, and pure wear (scoring) that thins the walls further. A superior oil (one with high heat and shear resistance, better film strength's, as well as gobs of ZDDP) will help to address the skirt heat and ultimate wall scoring that tends to occur; significantly slowing the process. Here, to put a more permanent end to the problem, we bore out the cases and put in superior cylinder liners on engine's up for rebuild, but for more pedestrian daily drivers the more economic approach is to go with better oil (changed more frequently), lower the engine temperatures, and improve oil cooling where possible; all of which contribute to significantly lessening the process.

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Hot oil and coolant are the primary culprits here

Mitigate by:

1. Adding 3rd radiator

2. Doing the "fan mod"

3. Keeping an eye on temps via monitoring oil pressure at 3000 rpm. If less than 3.2 Bar @3000 rpm then take few cool down laps

4. 50 weight oil with zddp

5. Reduce run session time on very hot days

And by all Means make sure you have full oil level!!

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I've added the third radiator. What is the "fan mod" referred to? I just jumped in on this page, so if it's discussed on a previous page, I'll just apologize for my laziness now and get it out of the way. 120,500 miles and counting. (It's my daily driver.)

Edited by 99911

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Hot oil and coolant are the primary culprits here

Mitigate by:

1. Adding 3rd radiator

2. Doing the "fan mod"

3. Keeping an eye on temps via monitoring oil pressure at 3000 rpm. If less than 3.2 Bar @3000 rpm then take few cool down laps

4. 50 weight oil with zddp

5. Reduce run session time on very hot days

And by all Means make sure you have full oil level!!

I would also add a 160F thermostat to that equation as well.

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JFP also suggested a larger oil cooler!

Not sure if it would apply to a non-Boxster?

IMG_3795.jpg

Edited by kbrandsma

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JFP also suggested a larger oil cooler!

Not sure if it would apply to a non-Boxster?

IMG_3795.jpg

Most of the 911 variants carry the larger oil cooler from the factory, it is the Boxsters that got short changed on this one.

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It would seem to me that just adding the 160 degree thermostat would do the trick. My 06 C4S has no trouble keeping itself cool on the street up here in New England. I have never run it on the track down south with higher ambient temps. I do push the car hard though. I'm afraid my right foot has only two positions, on and off.

My oil use to run right at 210. It would get up to 220 on hot days. When I switched to Miller's CFS 5W-40 the car runs on average 5 degrees cooler. CSF does have more ZDDP and it is substantially heavier than Mobil 1 0W-40. As JFP mentioned fuel intrusion and the resultant drop in viscosity are a real problem with these engines. I get about 1.5% fuel intrusion per 3000 miles. By 6000 miles my oil is 3% fuel and has dropped a full grade in viscosity. So, I change the oil every 6000 miles. If I went the full 10,000 my oil would be no better than a 0W 30!! This will vary from one engine to another and will also vary by the way the car is driven. Frequent short trips in cold climates is the worst situation for this compared to long trips in warm environments. I believe the combination of fuel intrusion and long oil cycles is the real culprit behind these middle cylinders cracking and scoring. Keeping the engine cooler might help with the cracking but I do not think that will prevent scoring once the oil is diluted. Fortunately, these problems are rarer than they seem on the internet which has a tendency to misrepresent stuff. Using a heavier oil with more ZDDP will obviously help. You just have to be careful not to go too far in cold climates. Up here the best thing to do is test your oil and change it more frequently.

I am an unabashed Miller oil fan. I also use their EE 75W 90 gear oil. I have run the car through two Winters with temps down to -14 F. The car runs like a top, the transmision is noticably quieter and with the CFS engine oil combined I have a milage improvement of just under 1 mpg average. DO NOT use their racing gear oil in a street car. It has specs similar to Delvac and the car will shift like s--t when it is cold.

Have a look, performanceracingoils.com. I will change my new Turbo S over to Millers at 10,000 miles when it is broken in. The PDK of course must use OEM fluid.

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I've added the third radiator.  What is the "fan mod" referred to?  I just jumped in on this page, so if it's discussed on a previous page, I'll just apologize for my laziness now and get it out of the way.  120,500 miles and counting. (It's my daily driver.)

Sorry about resurrecting this query, but I would still be interested in finding out what that "fan mod" is all about. TIA!

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I've added the third radiator.  What is the "fan mod" referred to?  I just jumped in on this page, so if it's discussed on a previous page, I'll just apologize for my laziness now and get it out of the way.  120,500 miles and counting. (It's my daily driver.)

Sorry about resurrecting this query, but I would still be interested in finding out what that "fan mod" is all about. TIA!

Radiator Fan and Engine Compartment Fan Switch Mod

The 3.4 996 runs extremely hot when driving around town in temperatures higher than 75 degrees. This mod is a way to reduce coolant temps back to a safer level, helping to reduce oil temps and improving performance.

The mod consists of installing a switch that will allow you to turn on the high speed radiator fans at any time, while maintaining the automatic operation of the fans. We do the same for the engine compartment fan.

Radiator Fans

Connect a wire to the ground of the 2 high speed fan relays located on the relay carrier located in the driver’s side foot well. The relays are #20 and #22. Feed this wire to where your switch will be located. Connect the wire to one side of the switch. Connect another wire from the other contact on the switch and then connect the other end of this wire to a chassis ground point.

With key on, this switch will now immediately turn on both radiator fans providing maximum cooling. When you turn the key off, the fans will continue to run for about 5 seconds until the relay shuts down. Your fan operation remains normal when the switch is off.

Engine Compartment Fan

Connect a wire to the ground of the relay located in the relay carrier behind the passenger seat, driver’s side. Relay #8. . Feed this wire to where your switch will be located. I simply fed the wire along the driver’s side of the car and under the door sill. Connect the wire to one side of the switch. Connect another wire from the other contact on the switch and connect the other end of this wire to a chassis ground point.

With key on, this switch will now immediately turn on the fan drawing air into the engine compartment. When you turn the key off, the fan will continue to run for about 5 seconds until the relay shuts down. Your fan operation remains normal when the switch is off. This mod helps keep the engine compartment much cooler when driving around town and is particularly beneficial to any engine that draws its intake air from inside the engine compartment, such as the EVO SC.

If you are adventurous, you can automate the operation of these switches so they will switch off at a specific speed, or operate when vacuum is present only, etc. You can choose any style switch you want and even use Porsche switches. I simply used 2 toggle switches that I installed in the batwing.

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Mfarrell;

A belated thank you! Sorry that I had lost track of this previous request.

Edited by Y2K911

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Dear Internet, I post today with a heavy concerned heart for my little lady. Someone who I love who has shown me the utmost respect and dedication for the last few years since we've been together. I'm talking of course about my one and only 2004 996 carrera coupé. Not 12 hours ago my wife and I drove over to the park to walk around and enjoy a beautiful day and I parked the car. Unusually the engine died right as I pulled into a spot. Not thinking anything of it (operator error) we took a stroll around. Returning to the car I turn over the ignition to nothing. Uh oh battery? Replaced last summer so not likely. Kept turning it over and all of a sudden we're lit up with what sounds like rocks or small bearing fragments invading the engine?? Immediately I shut off with my mind racing and a feeling of indescribable despair in my soul. I turned over once more to get a quick video to ask a professional. YouTube linked right here....

So I'm hoping no engine damage and like this guy I'll be able to remove the engine pan clean out what seems to be a blown apart intermediate shaft bearing and as described here a few flushes with oil

http://www.pelicanparts.com/techarticles/Boxster_Tech/14-ENGINE-Intermediate_Shaft_Bearing/14-ENGINE-Intermediate_Shaft_Bearing.htm

I live in Stamford Connecticut which borders on Greenwich (expensive) and I'm wondering if anyone has a suggestion on where to go... I would also love some assurance that the engine and car will be fine since I wasn't driving at the time only had the engine on for 5-10 seconds max and the bearing fragments are probably stuck in a quagmire of oil before they get to the engine... Can't sleep

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Dear Internet, I post today with a heavy concerned heart for my little lady. Someone who I love who has shown me the utmost respect and dedication for the last few years since we've been together. I'm talking of course about my one and only 2004 996 carrera coupé. Not 12 hours ago my wife and I drove over to the park to walk around and enjoy a beautiful day and I parked the car. Unusually the engine died right as I pulled into a spot. Not thinking anything of it (operator error) we took a stroll around. Returning to the car I turn over the ignition to nothing. Uh oh battery? Replaced last summer so not likely. Kept turning it over and all of a sudden we're lit up with what sounds like rocks or small bearing fragments invading the engine?? Immediately I shut off with my mind racing and a feeling of indescribable despair in my soul. I turned over once more to get a quick video to ask a professional. YouTube linked right here....

So I'm hoping no engine damage and like this guy I'll be able to remove the engine pan clean out what seems to be a blown apart intermediate shaft bearing and as described here a few flushes with oil

http://www.pelicanparts.com/techarticles/Boxster_Tech/14-ENGINE-Intermediate_Shaft_Bearing/14-ENGINE-Intermediate_Shaft_Bearing.htm

I live in Stamford Connecticut which borders on Greenwich (expensive) and I'm wondering if anyone has a suggestion on where to go... I would also love some assurance that the engine and car will be fine since I wasn't driving at the time only had the engine on for 5-10 seconds max and the bearing fragments are probably stuck in a quagmire of oil before they get to the engine... Can't sleep

 

First, welcome to RennTech :welcome:

Something you need to understand from the outset is that if you have had an IMS failure, it didn't just start, but has been shredding metal and dumping it into the oil for some time, so the debris is everywhere inside the engine, not just in the sump.  As such, any shop worth its salt would look at the sump and oil filter contents and tell you that it is already too late to consider a retrofit.  In addition, a common side effect of losing the IMS is piston to valve contact, which results in bent valves at a minimum, or worse:

 

Catastrophic_failure_001.jpg

 

From experience in my shop, I am sorry to tell you that if you have suffered an IMS failure, at a minimum your engine will have to come out and apart, if for no other reason than to check all the components and have everything properly cleaned of the fine metal that is most likely everywhere in the engine. 

 

From time to time, someone posts about having an IMS failure and then replacing it and doing some oil flushes to cleanout the engine.  Again, from direct experience, the number of times that process is actually successful can be counted on one hand with several fingers left over.  Usually, 50-75 mile down the road, the engine simply grenades from that one spec of ferrous grit that ultimately found a rod or crank bearing and tore it to shreds. And all the money spent is wasted as well.

 

To have someone pull your car apart, replace the IMS and do some oil flushes is going to cost a considerable amount of money, and has little (if any) chance of succeeding.  You would be better off pulling the engine, taking it apart and seeing if it can actually be saved, or needs to be replaced.

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Agree with everything John said and sorry to hear your story.

Note there were quite a few owners on Rennlist who had gone through similar scenario so you may want to post there too. There have been a few new replacement/rebuild engine options lately discussed there also.

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Thanks ahsai and John.... I'm still hopeful that perhaps there's something else going on or that the engine is not completely obliterated.... What am I looking at for an engine pull and rebuild in terms of $$ for an independent Porsche person or dealership.

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I would check the oil, the oil filter and the oil pan for debris and go from there. Sorry to say but your video sounds gut wrenching.

Ballpark numbers...$10-15k for a used or rebuilt engine + $2k labor to remove and replace. All out option will be $25k+ all-in for a Jake Raby Flat 6 engine (kinda like Ruf, M, and AMG) with increased dispalcement. Forget about the dealers, a new engine from Porsche is $40k+(not a typo).

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I just went through a similiar experience though I didn't have the same engine noises. Cost was $17,000 at the local Porsche dealer to replace the IMS and have them to disassemble the engine to check for wear and tear ($13,000 labor cost). They replaced the compression rings and I was at the end 'lucky'. That failure sucks big time. I should have spend the money the first time on a turbo model. Lesson learned too late... They quoted me $27,000 total cost for a new engine.

Edited by Varianti

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Back in May I found oil in the coolant in my 1999 C4. 123,xxx miles, water pump changed @ 96,xxx miles. I sent an oil sample to Blackstone and it showed no water, but traces of sodium and potassium, indicating minor coolant contamination. I flushed the system with distilled water and ran the car a bit to flush... Now I've got milky oil. $hit. I dropped the engine and pulls the heads. There are no obvious cracks, but it looks to me like the head gasket on driver's side was allowing the mix. Thoughts on the pics??? For those who had intermix and fixed heads, what did you do about rod/main bearings??

 

 

image.jpeg

image.jpeg

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