1999Porsche911

The air diverter valva eon the 996 is for the secondary air pump and should not cause a problem because there is a check valve inline. Get out a vacuum gauge and hook it up to one of the vacuum lines and see what your reading is on a warm engine at idle. Might aid in determining an air leak.

What year car is it?

Concur

Dell:

The "High Shear" viscosity number is the one that actually correlates with oil film thickness on your bearings at operating temperature. The 0W-40 only has a shear rating of HSHT value of 2.9 cP at 150ºC . 15W - 50 has a HSHT value of 3.7 cP or 27% more viscous oil at 150ºC .

As a matter of fact, Mercedes-Benz recommends use of ONLY Synthetic Motor Oil that is at least SAE 5W-40! This is a recent increase in recommended viscosity from SAE 5W-30. Apparently customer research indicated that engine longevity is more important to typical MB customer than fuel economy.

Any of the quality oils with weights of 0w -40 will give you the protection you need in the short run and probably an unmeasurable increase in fuel economy. However, for long term protection of the bearings, a 10W or 15W - 40 or 50 should prove better. In your case, since you do not have any bitter weather like hear in Chicago, I see not downside up moving up to a higher viscosity.

I really believe that the 0W oil is a fad and, like Mercedes, it will be found that a higher shear viscosity and the longevity it provides the engine will outweight the fuel economy.

212?  I assume that is F?  Do you have any documentation that you could point me towards.  Thanks everybody! 

Thanks for helping me learn about this stuff so I am not just doing what I am told by a piece of paper but rather making informed decisions.

BTW, I would be curious to know what the cup cars in the GT class are running (just the Porsche's) during those grueling long days at high RPM's???

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There are numerous sites to get info from. many display tests performed by a specific manufacturer. Here are a few:

http://www.performanceoiltechnology.com/ap...roiltesting.htm

http://www.answers.com/topic/motor-oil-2

http://motorcycleinfo.calsci.com/Oils1.html

Jim

Don't forget about the shear factor that reduces the maximum viscosity. On many oils, a viscosity is reduced to as low as 30 because of the shearing of the oil in the engine. This is very evident at high temps and rpms. The stated maximum viscosity is measured at 212 degrees and many of our engines are running hotter than that.

Let the car sit for at least 20 minutes before testing the oil level. I think your find it hasn't changed.

Well, the 5W does make more sense than 0W out here but I am not sure about the 40 v. 50 weight issue for the higher temps.  It sounds like they (my local dealer) should be using and rec'd the 5W-50 for this region.  Low about 20 F in the winter and high about 120-125 F in the summer.

Thoughts on that logic?

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I don't put much credence in what a dealer says. Here is an example. I wanted to find the required tranny lube for my 99 so I called the 6 dealers in the area. EACH one gave me different info. Ranging from only use fossil gear lube to use any $3/liter brand you can find at the local auto store. Just yesterday, I went to pickup the RIGHT lube from a dealer that I had ordered after I provided them with the part number. While I was there, I asked about the PCV valve in the 99. Parts could not find it on the diagram and 2 of the mechanics, who I had look at my car had no idea where is was located on the car or if it even had one.Finally, 1 mechanic was interested in looking at the sensor reading on my SC'd engine so I let them hook up the tester. They noted that bank 1 LTFT was more negative than was bank2. This I knew and I knew the reason why. However, he called over 2 other "so called" technicians to look at it and each and every one of them insisted that my MAF was bad without any doubt. I asked them why they thought that and they said because the fuel trim on bank 1 was removing more fuel that it should be. I told them that the MAF could only effect BOTH banks equally and they argued that the MAF effected each bank separately.

It was close to closing time, so I bet them each $100 that they were wrong and that I could prove it is they installed a brand new MAF right from the part's department. One of them disappeared and shortly returned with a MAF still in the box. We recorded the readings of my MAF, Fuel trims, etc and then installed the new one. We then looked at the readings and, guess what? They were the same as before. One tech went and got the service manual and a memo that clearly stated that he was right in that the MAF was the cause of the difference in fuel trim between banks.

So you see, for most techs, their extend of knowledge comes from what a piece of paper says and they have little to no experience or even understanding of the cars they work on. Unfortuantely most of them hae never worked on a non-computerized engine and have no basic understanding of how an engine works.

Finally resolution of our bet was me getting the $96 worth of gear lube free of cost.

With temperatures as high as 135 out by you, I would recommend going to the 50 weight oil. It will give you the same protection as the 5W-40 or 15W-40 but will give you better protection on the hot days.

Outlet air should be around 50F or colder.

Have you poured 15-50? It's thicker than 0-40 or 5-30 for sure.

I have heard 10-40 dino juice has too much additive and is not recommended. Not sure about synthetic or if this is actually true.

0-40 is the only weigh approved by Porsche. Modern engines are moving to thinner oil to improve engine efficiency as modern oil provide good protection at high temperature.

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First of all, at normal ambient temperatures of 80F, both oils pour equally. Secondly, 0W - 40 IS NOT the only weight oil recommended by Porsche. It is only the factory fill. Recommended oil for -13F and above it 0W-40, 5W-40 and 5W-50 for the 2005 engines. On some ofthe older engine, including the 3.4, 15W-50 was also recommended. There is no way I would run 0W-40 where the average temp is above 80F, especially in a hot running engine like the 3.4. Porsche only insists on 0W-40 when temperature is generally below -13F. When was the last time the temp in the southwest was below -13F.

At minimum, I would run 5W-50, but presfer the 15W-50. It would not surprise me to see Porsche change the 0W oil to the upside in the near future. But, life is full of choices, just make sure the choice you make has sound basis.

LVDell: You should be running either 10W - 40 or 15W - 50 there in Vegas. There is absolutely no benefit going to the low 0W with temps like you have. Even in the summer here in Chicagoland, I run 15W - 50 Mobil. Statements that the Variocam need the 0W is bull**** and a 15W has the same flow rate as does 0W in moderate climantes anyway and you gain additional protection when it really gets hot.

The car is designed to run with a coolant temp of 190F. When your gauge is betwen the "8" and the "0" in 180, you are right about there. When it is covering the line on the right side of the "0", you are at about 215F. You need to improve air movement past the radiators. Hardwire a switch so you can turn on the radiator fans. Running the fans at hgh speed wil keep your engine as cool as it is when you are speeding down the highway.

Ahhh...it's so nice having a car that will let you slip and slide when you want and not have some computer telling you where the limit is or to simply malfunction.

Since you have already switched tires once and the problem remains, you would have to assume that the problem is not with the tires. I would take the suggestion above and reset the computer by disconnecting the battery for a few minutes. If that does not work, you may have a sensor problem.

In the 99, there is an electric sensor that installs into a cavity on the bottom of the tank. It reads the coolant level.

The are numerous possible causes for an engine to run rich, including fuel pressure, plugs, cats, MAF, O2 sensors, coils and wires, intake, and on and on and on. If you do not have a scanner, that should be your first investment. You can get a good one for $100 -$250. This will allow you to look at readings of all the major sensors of your car's engine. Knowing the sensor's readings will greatly help in determining what may be wrong. Most likely a lazy O2 sesor if the car is otherwise running properly.

It's on the fuel rail.

I would suggest taking the car up to redline often. It doesn't have to be in every gear, but when getting ion the highway, there is no reason you cannot redline it in 1st and 2nd gear. The pressure in the cylinders at these high RPM's is needed to help maintain clean cylinder walls. As the pressure increases, it forces the rings to expand (open) to their maximum ability and scrape the cylinder walls firmly. You may find that after doing this regularly, your oil consumption will decrease.

Jarrod:

Is the car (for the most part) driven easily? You may try driving it hard (redline) regularly and see if forcing the piston rings against the cylinder walls will help seal them better. (if that is contributing to the oil burning)

1 quart per 1200 miles???? No wonder the previous owner sold it. Check the PCV system and make sure it is not blocked. Otherwise, if you are not leaking oil, that is alot of oil to be pumping through the combustion chamber. That's like adding 1 1/2 cups of oil to the gas tank everytime you fill up. So, if you are in fact burning that much oil, you will occasionally see it being blown out of the tailpipes when accelerated hard.

Total of one hour including coffee break.  Use two short socket extenders and a standard 5/8" 3 inch socket.  Loosen using all three plus ratchet and then remove 1 extension to remove plug.   Allen screws for the 2 back plugs are easiest to get to by reaching under and through the exhaust rather than trying to reach back to them from accros the head.  Screws should be loosened with allen wrench and then can be removed with fingers.  I am 6-5 with large hands and have no problems.

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Thanks for the tips and words of encouragement. Getting the plugs out and in is duck soup with a 3" wobble extension + 1.5" extender. It's the %$^ socket cap screws that are giving me fits. I'm not looking forward to disconnecting and reconnecting the coil pack "one handed" either.

Gonna give it another try tonight with the ball-end allen key. Stay tuned...

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The worse cap screws to get out are the back one (closest to the bumper). I found I can get to these better by accessing them from directly below them, kind of manuevering my hand around the exhaust. (Works much better when the engine is cold). Once the screws are broken loose, you should be able to use you fingures to unscrew them the rest of the way.

Total of one hour including coffee break. Use two short socket extenders and a standard 5/8" 3 inch socket. Loosen using all three plus ratchet and then remove 1 extension to remove plug. Allen screws for the 2 back plugs are easiest to get to by reaching under and through the exhaust rather than trying to reach back to them from accros the head. Screws should be loosened with allen wrench and then can be removed with fingers. I am 6-5 with large hands and have no problems.

... I use a 3/16 inch allen wrench.

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All German cars use fittings and fasteners that are metric. Use the correct metric size or you risk rounding out. For drain plugs like this, I use a hex key that fits my rachet so you can get good pressure on the plug and turn it cleanly.

Serious bleeding question: would you be able to park nose down on the steepest hill you can find and idle for a few minutes operating the bleeding valve?

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I realize the bolts are metric but this plug is only lightly torqued and a 3/16 works fine. The correct metric wrench would also work.

If you look at my first picture, the drain plug is centered on the car from left to right and 12 inches in from the lip of the back bumper and exactly 4 inches to the right of the end of the water hose. I use a 3/16 inch allen wrench.

My coolant is 6 years old next month. It is neither dirty or broken down. I test it at least once a year and it has not lost any of it's cooling properties. Unless you have a leak or somehow dilute the mixture too much with water I see no reason to change it.

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Loren: There is no such thing as LIFETIME ANTIFREEZE, only extended life. Not only do the protectants wear out, but if you catch your coolant when you drain it, you will see quite a bit of crap in the liquid from metals and rubber that have eroded off over the years. Much of this debris over time will clog the small veins n the radiator, reducing it's cooling capacity. As time goes on, you can accumulate so much material in the veins that the only way to clear them is to reverse flush the radiator.

The protection from freezing and boiling will last considerably longer that the anti corrosion chemicals do and a tester will not identify this. As these dilute, the fluid will allow buildup in the system (especially radiator) and will reduce the efficiency of the cooling system. The fluid will eventually become caustic and actually create pitting in the metals of the system.

Antifreeze also developes and electric charge over time (as it's additive deplete) as it passes over the metal in the system. As this charge increases, it begins removing metal from the surfaces of the engine. You can measure this votage by putting one end of your multi meter in the coolant in the tank and the other end to ground. If you have ever done work on old cars that have had old coolant in them, you may have found a bolt or 2 that was actually welded to the metal componant it was securing because of sweating or a small coolant leak.

Periodic changing of the coolant will help eliminate buildup and caustic conditions and keep the system running as efficiently as possible.

MY996. here are the pics. You can see the allen wrench inserted in the plug. And YES, the coolant SHOULD be changed every 2 - 3 years regardless of what Porsche says. It breaks down and gets dirty just like your oil. It will also help prevent hard mineral buildup and blockage that would require more costly repairs in the future. It is a great investment of 1 hour time and $20.