DFI engine issues
02-16-2010, 07:20 PM
#61
Three Wheelin'
My car has a Dec 08 build date - sounds "early" to me. Good to know what symptoms to look out for. 
02-16-2010, 07:21 PM
#62
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Originally Posted by Onwer's Manual
If the vehicle is used for repeated short trips, and consumes a normal amount of oil, the engine oil measurement may not show any drop in the oil level at all, even after 600 miles (1,000 km) or more. This is because the oil is gradually becoming diluted with fuel or moisture, making it appear that the oil level has not changed. The diluting ingredients evaporate out when the vehicle is driven at high speeds, as on an expressway, making it then appear that oil is excessively consumed after driving at high speeds
If the vehicle is used for repeated short trips, and consumes a normal amount of oil, the engine oil measurement may not show any drop in the oil level at all, even after 600 miles (1,000 km) or more. This is because the oil is gradually becoming diluted with fuel or moisture, making it appear that the oil level has not changed. The diluting ingredients evaporate out when the vehicle is driven at high speeds, as on an expressway, making it then appear that oil is excessively consumed after driving at high speeds
Gary
02-16-2010, 07:56 PM
#63
Three Wheelin'
02-16-2010, 07:57 PM
#64
Remember, The Tubes act as a megaphone. While only Porsche and the pump manufacturer knows for sure, based upon the frequency of what does get posted, HPFP issues with 997.2 must be a very small fraction of overall 997.2's on the road.
Certainly not anything I plan to lose sleep over.
02-16-2010, 08:18 PM
#65
Savyboy,
I agree about not losing any sleep. It is not an inconveinance for me as I dont drive this car during the week. If we were still on a roadtrip it could have been an issue since Porsche of New Orleans closed down recently. I would have put it in Baton rouge and waited to get it replaced and drove it home. It doesnt appear to be major to me and only a handful of 997.2's appear to be having this issues so far.
I seriously doubt we will see it will be recalled unless it becomes a major issue. If that is all that happens then I am glad I got that over with and will be moving on to planning a trip to NAPA valley this summer.
I agree about not losing any sleep. It is not an inconveinance for me as I dont drive this car during the week. If we were still on a roadtrip it could have been an issue since Porsche of New Orleans closed down recently. I would have put it in Baton rouge and waited to get it replaced and drove it home. It doesnt appear to be major to me and only a handful of 997.2's appear to be having this issues so far.
I seriously doubt we will see it will be recalled unless it becomes a major issue. If that is all that happens then I am glad I got that over with and will be moving on to planning a trip to NAPA valley this summer.
02-16-2010, 08:38 PM
#66
Race Director
I have experienced the same thing - and in other cars as well. I always carry two qts in the frunk - old habit I got into with an e39 M5 that really used to use oil on the highway, probably for the same reason. And that car sometimes would go through 1-2 qts on a 500 mile trip. The 911 so far is more like 1/2 qt.
02-16-2010, 08:52 PM
#67
Nordschleife Master
02-16-2010, 08:57 PM
#68
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Well, to be honest, it sounds like one of those statements the engineering department of any business is sometimes asked to contribute to legal or marketing or such. I mean, the words are all there and it masquerades as a geeky sort of statement. It even sounds vaguely plausible but doesn't seem like it would stand up to arithmetic.
I'm open to learning something new here, but let me put my reaction into words. Briefly, because I have an obligation shortly.
We put oil in engines by quarts normally. We think of "burning oil" in terms of quarts, not milliliters for all love. Now suppose my car was being used in a city environment. Water would accumulate from day to day. No question. We know this happens, mostly from condensation, and if the engine never reaches a full operating temperature the water won't be evaporated and carried off. Fine. We also know that fuel gets into the oil. Again, inevitably.
But picture this accumulation of water amounting to a quart in any reasonable time. We are paranoid about this in small aircraft since the same process causes fuel build-up in the gas tank. If that water passes into the carburetor it causes icing in certain fairly common conditions. So we have drains at the lowest point of the fuel tanks and we drain them before each flight. I have found water in those checks. In moist climates, and after several days without flying, a noticeable, even worrisome amount of water. But that is in a fuel tank with a volume of twenty to thirty gallons!
The capacity of the 997 oil reservoir is what? Two gallons perhaps. I'm too rushed to go grab the manual. And a 'worrisome' amount of water in a draining an aircraft tank is anything more than a tablespoon. Twenty gallons, two tablespoons to push both values. Even if that two gallon volume in the 997 acquired an astounding two tablespoons, am I supposed to notice that and consider my car is burning oil when those two tablespoons evaporate? Gimme a break.
The same applies to fuel getting into the oil, but I haven't time for the parallel discussion. Basically, all I'm saying is that sounds reasonable until you realize it would have to be an amazing long time between fully warming up the engine before you significantly diluted the oil by either mechanism. Certainly more than mere weeks, because we leave aircraft standing with no engine use at all for much longer without accumulating such amazing percentages of water in the tanks.
Okay, someone with more time think about this. Am I missing something obvious? Gotta run,
Gary
I'm open to learning something new here, but let me put my reaction into words. Briefly, because I have an obligation shortly.
We put oil in engines by quarts normally. We think of "burning oil" in terms of quarts, not milliliters for all love. Now suppose my car was being used in a city environment. Water would accumulate from day to day. No question. We know this happens, mostly from condensation, and if the engine never reaches a full operating temperature the water won't be evaporated and carried off. Fine. We also know that fuel gets into the oil. Again, inevitably.
But picture this accumulation of water amounting to a quart in any reasonable time. We are paranoid about this in small aircraft since the same process causes fuel build-up in the gas tank. If that water passes into the carburetor it causes icing in certain fairly common conditions. So we have drains at the lowest point of the fuel tanks and we drain them before each flight. I have found water in those checks. In moist climates, and after several days without flying, a noticeable, even worrisome amount of water. But that is in a fuel tank with a volume of twenty to thirty gallons!
The capacity of the 997 oil reservoir is what? Two gallons perhaps. I'm too rushed to go grab the manual. And a 'worrisome' amount of water in a draining an aircraft tank is anything more than a tablespoon. Twenty gallons, two tablespoons to push both values. Even if that two gallon volume in the 997 acquired an astounding two tablespoons, am I supposed to notice that and consider my car is burning oil when those two tablespoons evaporate? Gimme a break.
The same applies to fuel getting into the oil, but I haven't time for the parallel discussion. Basically, all I'm saying is that sounds reasonable until you realize it would have to be an amazing long time between fully warming up the engine before you significantly diluted the oil by either mechanism. Certainly more than mere weeks, because we leave aircraft standing with no engine use at all for much longer without accumulating such amazing percentages of water in the tanks.
Okay, someone with more time think about this. Am I missing something obvious? Gotta run,
Gary
02-16-2010, 09:05 PM
#69
Nordschleife Master
Gary: This makes sense and I have seen it reported by owners. The post is always like this - 'my car did not use any oil but today I went on a trip and all of a sudden my oil level was down'.
02-16-2010, 09:31 PM
#70
Thats is what happened to me on this trip. My vehicle reported oil level lower than normal and I assumed that it was due to "burning oil". I usually drive around the city on shorts trips. It will be interesting to see what the level is when I get the car back. It has been sitting for a couple days now so will my level show overfilled or the full level?
I am somewhat perplexed by the statement in the manual but I understand what they are trying to convey. Nonetheless, it sounds like legal jargon due to fluctuating oil levels.
I am somewhat perplexed by the statement in the manual but I understand what they are trying to convey. Nonetheless, it sounds like legal jargon due to fluctuating oil levels.
02-16-2010, 09:35 PM
#71
Nordschleife Master
Thats is what happened to me on this trip. My vehicle reported oil level lower than normal and I assumed that it was due to "burning oil". I usually drive around the city on shorts trips. It will be interesting to see what the level is when I get the car back. It has been sitting for a couple days now so will my level show overfilled or the full level?
I am somewhat perplexed by the statement in the manual but I understand what they are trying to convey. Nonetheless, it sounds like legal jargon due to fluctuating oil levels.
I am somewhat perplexed by the statement in the manual but I understand what they are trying to convey. Nonetheless, it sounds like legal jargon due to fluctuating oil levels.
02-16-2010, 11:34 PM
#72
Race Director
Well, to be honest, it sounds like one of those statements the engineering department of any business is sometimes asked to contribute to legal or marketing or such. I mean, the words are all there and it masquerades as a geeky sort of statement. It even sounds vaguely plausible but doesn't seem like it would stand up to arithmetic.
I'm open to learning something new here, but let me put my reaction into words. Briefly, because I have an obligation shortly.
We put oil in engines by quarts normally. We think of "burning oil" in terms of quarts, not milliliters for all love. Now suppose my car was being used in a city environment. Water would accumulate from day to day. No question. We know this happens, mostly from condensation, and if the engine never reaches a full operating temperature the water won't be evaporated and carried off. Fine. We also know that fuel gets into the oil. Again, inevitably.
But picture this accumulation of water amounting to a quart in any reasonable time. We are paranoid about this in small aircraft since the same process causes fuel build-up in the gas tank. If that water passes into the carburetor it causes icing in certain fairly common conditions. So we have drains at the lowest point of the fuel tanks and we drain them before each flight. I have found water in those checks. In moist climates, and after several days without flying, a noticeable, even worrisome amount of water. But that is in a fuel tank with a volume of twenty to thirty gallons!
The capacity of the 997 oil reservoir is what? Two gallons perhaps. I'm too rushed to go grab the manual. And a 'worrisome' amount of water in a draining an aircraft tank is anything more than a tablespoon. Twenty gallons, two tablespoons to push both values. Even if that two gallon volume in the 997 acquired an astounding two tablespoons, am I supposed to notice that and consider my car is burning oil when those two tablespoons evaporate? Gimme a break.
The same applies to fuel getting into the oil, but I haven't time for the parallel discussion. Basically, all I'm saying is that sounds reasonable until you realize it would have to be an amazing long time between fully warming up the engine before you significantly diluted the oil by either mechanism. Certainly more than mere weeks, because we leave aircraft standing with no engine use at all for much longer without accumulating such amazing percentages of water in the tanks.
Okay, someone with more time think about this. Am I missing something obvious? Gotta run,
Gary
I'm open to learning something new here, but let me put my reaction into words. Briefly, because I have an obligation shortly.
We put oil in engines by quarts normally. We think of "burning oil" in terms of quarts, not milliliters for all love. Now suppose my car was being used in a city environment. Water would accumulate from day to day. No question. We know this happens, mostly from condensation, and if the engine never reaches a full operating temperature the water won't be evaporated and carried off. Fine. We also know that fuel gets into the oil. Again, inevitably.
But picture this accumulation of water amounting to a quart in any reasonable time. We are paranoid about this in small aircraft since the same process causes fuel build-up in the gas tank. If that water passes into the carburetor it causes icing in certain fairly common conditions. So we have drains at the lowest point of the fuel tanks and we drain them before each flight. I have found water in those checks. In moist climates, and after several days without flying, a noticeable, even worrisome amount of water. But that is in a fuel tank with a volume of twenty to thirty gallons!
The capacity of the 997 oil reservoir is what? Two gallons perhaps. I'm too rushed to go grab the manual. And a 'worrisome' amount of water in a draining an aircraft tank is anything more than a tablespoon. Twenty gallons, two tablespoons to push both values. Even if that two gallon volume in the 997 acquired an astounding two tablespoons, am I supposed to notice that and consider my car is burning oil when those two tablespoons evaporate? Gimme a break.
The same applies to fuel getting into the oil, but I haven't time for the parallel discussion. Basically, all I'm saying is that sounds reasonable until you realize it would have to be an amazing long time between fully warming up the engine before you significantly diluted the oil by either mechanism. Certainly more than mere weeks, because we leave aircraft standing with no engine use at all for much longer without accumulating such amazing percentages of water in the tanks.
Okay, someone with more time think about this. Am I missing something obvious? Gotta run,
Gary
But once this cool down is over there is not sufficient exchange of air to cause the drier air to be expelled from the crankcase and moister air to be allowed into the crankcase.
But moisture does accumulate in the oil when the engine's running. At cold start and for some time after considerable moisture is generated -- my info is for every pound of gasoline burned a pound of water is generated (though not all in the combustion chambers) -- and because the engine is cold some of this moisture in vapor form will condense right back into liquid. If it does this in the combustion chamber, and it does, just like we know fuel can make it into the oil past the rings this water is no exception.
Depending upon various factors there can be considerable moisture build up in the oil.
Now if the engine consumes oil - and they all do in varying amounts -- it consumes oil constantly -- though in small amounts -- as it runs.
But the accumulation of water in the oil - and unburned fuel -- acts to replace the burned oil thus the oil level stays relatively stable. In a worst case scenario I suppose it could even go up.
Now this car is taken on a long journey, or a long drive during which the oil gets above 212F or even a bit lower since in some cases the crankcase is at less than atmospheric pressure so the water (and fuel which boils at an even lower temperature) boils away.
"Suddenly" after one trip, the oil level has dropped drastically and because the oil level dropped in this one trip say 200 miles the owner estimates the oil consumption is 1/2 quart per 200 miles and thus works out the oil consumption per 1000 miles and all heck breaks loose.
1/2 quart unrealistic? Nope. I had my 02 Boxster's oil analyzed shortly after I bought it (several thousand miles after) and with several thousand miles on the oil and the analysis found around 7% water content in the oil. With approx. 9 quarts oil that works out to around 0.6 quarts of water.
This woke me up and I started paying more attention - both to the dash temp gage and more importantly to the actual coolant temp value via an OBD code reader/data viewer which made it cleared just how much driving a cold (below freezing) Boxster engine takes to get fully warmed up. It doesn't, is what I found, if the air temperature is cold and if I avoided stop/go driving. Even then if I had the autoclimate control on -- during the winter to keep the cabin warm and the windows fog free -- the electric radiator fans would run constantly and keep the coolant temperature way below 212F.
This nice on warm days when the engine could stand a bit of extra cooling but it is no so nice during the colder winter months when the engine could use a bit of heat enough heat to get the coolant temperature above 212F and thus the oil temperature as high as that (and probably higher) to boil away the water.
I vowed then and there to at least change the oil every 5K miles to if nothing else ensure water build up kept low.
Sincerely,
Macster.
02-17-2010, 01:35 AM
#73
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Gary, whose p-car doesn't use any oil either
but it isn't for lack of warm running
02-17-2010, 11:38 AM
#74
Three Wheelin'
