When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
unless you're measuring coolant temp with an OBD2 type reader, you don't know your actual coolant temp. The gauge built into the dash for coolant temp is heavily buffered and not a real gauge - it's an idiot light disguised as a gauge.
You need oil temps to be around 220 degrees as this is the temp at which water boils and what you need to evaporate start-up condensation out of the oil. Short trips will just keep adding condensation, not only falsifying your true oil level readings, but also never evaporating away, causing your oil to foam or become milky and less protective.
Hasn't anyone compared the OBD2 reading from the readings on the Audi-based HVAC control (6c) readings? I would assume that if someone did this, that it would be consistent across the models (996.1 or 996.2, since I'm not sure of the engine differences across these models).
Will Durametric also be able to get this data? If not, what ODB2 do you all use?
Hasn't anyone compared the OBD2 reading from the readings on the Audi-based HVAC control (6c) readings? I would assume that if someone did this, that it would be consistent across the models (996.1 or 996.2, since I'm not sure of the engine differences across these models).
Will Durametric also be able to get this data? If not, what ODB2 do you all use?
Not to split hairs, but water boils at 212F/100C
Regarding boiling.... the system is under pressure so the the boil point is raised as well as the effect of the added glycol.
I pulled water temp (denoted as "Engine Temp") from OBD2 and from this exercise, and others I did..... it appears to me that the dash needle is correct...... at least it matches what is on the OBD2. I am not sure what this means or proves.... but I understand the OBD2 and the dash all get their data from the same place... the CAN bus. The bigger question is where is this sensor? If the sensor is at the pump, it may be measuring "diluted" fluid and therefore showing a true average temperature. If it is measuring the water directly after a cylinder, it will be measuring at it hottest state and you may then see way more fluctuation. But I don't know what I am talking about.... to get a definitive answer, you would need to find all temperature sensors in the engine, and then map them to the Durametric table, and then run my test again. This was a few years ago and I remembering trying to do this but gave up.... I just don't remember the details but I do know it was a difficult exercise.
I did this for a few reasons..... 1) I am neurotic and need to know this stuff which then fuels more neurosis.... 2) I was parking outside in the Northern NJ and was starting the car very cold and heading out.. so I wanted to get a feel for actual warmup times. In doing this exercise there were a few mysteries.... i am going from memory here so I may have forgotten some details..... the Durametric sees a ton of CAN values and the labels are very very obtuse.... some saying the same thing but returning goofy values. There was no, at the time, data dictionary for me to use to understand these values.
Anyway, check out my link for a longer, in depth discussion.
Regarding boiling.... the system is under pressure so the the boil point is raised.
I pulled water temp from OBD2 and from this exercise, and others I did..... it appears to me that the dash needle is correct...... at least it matches what is on the OBD2. I am not sure what this means or proves.... but I understand the OBD2 and the dash all get their data from the same place... the CAN bus. The bigger question is where is this sensor?
Right, but presumably, the oil tank and system are not under pressure, so water should boil fairly easily from the oil to allow the moisture to escape over time.
Wow, awesome charts. I'd bet that some folks will have evidence that temps are going to range and fluctuate depending on which tool is used to measure and from where. But if we're talking about only a few degrees difference among them, that's good enough for me. Those that have a gauge that reads 175 and never changes, even if the car is running at 215 or 225 - must have something wrong with their gauge. My 996.1 gauge moves all over the place and is pretty much in line with what the HVAC shows, but not always. There's a 3-5 difference at times. But again, for me, that's fine, as the engine is allowed to have some freedom itself due to lots of reasons, including how much air is moving through the radiators, the outside temp, RPM, etc.
Bruce, would you be willing to record the same events when the outside ambiet is much hotter? Say, 84F like it is today (in Chicago anway), LOL?
The fact that you had 89-90C in the "winter" at 32F is similar to my car. Which is why folks always used to say to be careful about short trips, 'especially' in the winter months, since even a mostly-closed t-stat still results in oil/water temps below 100C. This was true with air-cooled Porsches, and apparently true for water-cooled 996s as well.
Bruce, would you be willing to record the same events when the outside ambiet is much hotter? Say, 84F like it is today (in Chicago anway), LOL?
The fact that you had 89-90C in the "winter" at 32F is similar to my car. Which is why folks always used to say to be careful about short trips, 'especially' in the winter months, since even a mostly-closed t-stat still results in oil/water temps below 100C. This was true with air-cooled Porsches, and apparently true for water-cooled 996s as well.
I've been planning on doing just that.... for two summers now.... while not difficult, it is a royal pain to do this..... I saved the profile in Durametric so I can pull it up again but....... the real issue is the sensors and the data dictionary for Durametric.
I really need an inventory of oil, air, and water temp sensors in the engine. Then of course, I would love to see oil pressure sensors too. After the inventory, I would then need to have them mapped to actual Durametric data buckets. This will take time and perseverance...... it is far easier for my neurotic brain to focus on a resonance flap than all of this complex stuff.
Maybe we can crowd source this effort of sensor inventory? Start with the parts Katalog.... examine the crap out of it, cross ref the parts on line to see if the parts description is a sensor (sender)....... anyone take the bait? I have a PDF of the Katalog for the 997.2 published in 2010 so it has parts revisions up to that point...... just PM and I will forward it to you. Another line is the Turbo guys... they are always using Durametric... I always wanted to start PMng them.
What I always wanted to do, was dump all values in Durametric that appeared to track, say, water temp.... IIRC, there were many like five or so... I did tap a few and would get back noise. When I got something that looked correct, I stopped and used that value.
Then there is consolidating the data in excel, downsampling, etc etc etc....
Dude, that took some time to do that chart. Maybe if some of you threaten me enough, I will take a stab at it. What I really would like to do is track the temps when I get those infamous oil temp spikes..... and the ambient temps have to be above 70-75 to get them.
Installed the LN low temp thermostat while I had the water pump replaced....Oil temp takes twice as long to reach 105 C (40 minutes drive instead of 20) .... so it is doing what it is supposed to do...
unless you're measuring coolant temp with an OBD2 type reader, you don't know your actual coolant temp. The gauge built into the dash for coolant temp is heavily buffered and not a real gauge - it's an idiot light disguised as a gauge.
You need oil temps to be around 220 degrees as this is the temp at which water boils and what you need to evaporate start-up condensation out of the oil. Short trips will just keep adding condensation, not only falsifying your true oil level readings, but also never evaporating away, causing your oil to foam or become milky and less protective.
That's why I don't go to a 160 stat. The oil temperature of my car never gets to 220 unless I'm beating the hell out of the car. I live in hot South Florida and the temperature of my car remains around 200.
That's why I don't go to a 160 stat. The oil temperature of my car never gets to 220 unless I'm beating the hell out of the car. I live in hot South Florida and the temperature of my car remains around 200.
The low temp thermostat has nothing to do with the eventual running temperature of the motor, because whether you have the low temp 160 thermostat or the regular 180 thermostat, at 200 degrees both of them are fully open and coolant is fully flowing through them. The running temperature of the motor then is determined by cooling capacity, load, airflow, humidity percentage, and ambient temperature.
The low temp thermostat just starts opening sooner (20 degrees sooner to be exact) and because of this helps modulate the warm up of the motor more gradually. In cold weather climates, this may actually help prevent bore scoring and in hot weather climates helps the 10 quarts of oil to all come up to an even temperature more gradually and more evenly.
In cold weather climates, this may actually help prevent bore scoring and in hot weather climates helps the 10 quarts of oil to all come up to an even temperature more gradually and more evenly.
We sell a bunch of the low temp t stat's. We put one in our spec Boxster and noticed cooler temps on warm up (according to the needle). Our holdback on the early Boxster's is smaller coolant pipes, on our new car we're currently building we are putting in the upgraded coolant pipes from the Boxster S (wider diameter). We need as much cooling as we can get so by using the low temp t-stat we at least start "getting the juices flowing" earlier
You catalytic converters need to heat up to a certain temperature to work, if they do not get up to temp, you risk damaging the cats, not to mention that your car may start throwing error codes now.
You need to also tell the cars ECU that it has the different thermostat on other brands of cars (like BMW), not sure for Porsche, but the cat problem is a def issue.
Getting a third radiator would be a better option IMO
The low temp thermostat has nothing to do with the eventual running temperature of the motor, because whether you have the low temp 160 thermostat or the regular 180 thermostat, at 200 degrees both of them are fully open and coolant is fully flowing through them. The running temperature of the motor then is determined by cooling capacity, load, airflow, humidity percentage, and ambient temperature.
The low temp thermostat just starts opening sooner (20 degrees sooner to be exact) and because of this helps modulate the warm up of the motor more gradually. In cold weather climates, this may actually help prevent bore scoring and in hot weather climates helps the 10 quarts of oil to all come up to an even temperature more gradually and more evenly.
By this logic it seems like the best bet would be to cut the core out of any thermostat, letting the warm up be as gradual as possible while still remaining some restriction to flow. Then live with whatever temperature results based on motor load and ambient conditions.
I still say that the thermostat would ideally regulate temperature. It can't do that and be open all the time. IMHO, more cooling capacity is a better answer to maintain a constant operating temperature while the thermostat cycles on and off. I know, the thermostat is linear rather than digital, but hopefully you get my point.
If 20F difference in the water temperature makes that much of a difference protecting the motor during warm up, what does a 50F to 75F variation in oil temperature going up a pass and then coming down the other side do to the motor?
I've had a 160 thermostat for about 6 years without an issue. My cats are fine and my oil analysis reports show no water or fuel in my samples. Seems like those who warn against using them don't have experience with them.
I've had a 160 thermostat for about 6 years without an issue. My cats are fine and my oil analysis reports show no water or fuel in my samples. Seems like those who warn against using them don't have experience with them.
05-17-2017, 12:55 PM
