99 C2 Tiptronic Heat and Oil Pressure

With the warmer weather has also come construction season, which has increased my already heavy stop and go 25 minute commute to bumper to bumper and more than 35 minutes. I've noticed the coolant is now creeping past half way through the 0 in 180. I'm measuring the coolant temp through the obd2 port and am seeing it in the low 200, and sometimes hitting 212, where the low speed fans turn on. From reading it seems this isn't a surprise or abnormal. What is concerning me is my 99 has always read around 0.8 to 0.9 on the oil pressure gauge at idle, even when warmed up in the winter. Now with the coolant rising to 212f in the middle of my commute and being in full bumper to bumper traffic i'm seeing that value drop to 0.5 bar. I'm not getting any oil warning lights or anything, but it is making me nervous. At cold start I'm getting 4.5 to 5 bar. When the pressure is at 0.5 bar at idle , I am getting about 3.7 bar on the gauge at 5k rpm which is above the minimum the manuals states 3.5 at 5k rpm, but obviously not alot higher. I've read lots of threads about the oil pressure sensor going bad, but I don't seem to have any of those symptoms, No erratic readings, no full 5 bar or 0 bar events, when the key is on but the engine is off it reads exactly 0 bar. I just changed the oil within the last 700km with 0-40w Mobil 1. So my question is should I: 1. Drive more worry less, trust the oil pressure gauge idiot light to warn me if the pressure truly is low 2. Switch to 5-50w Mobil 1 3. Switch to Motul 5-40w, I've heard this seems to provide better idle pressure 4. Replace the sensor anyway just to be sure 5. Other?

Have you changed your water pump and Tstat yet?

Also - Clean between the coolant radiators and the a/c condensers. Move the engine putrge fan sensor closer to the heat source. In desperation Water Wetter and LTT.Yes a lower temp Tstat. And check for Pending codes.Some of these are mere palliatives but may prevent overheating pending a discovery of the real issues(s)

Anybody has experience to reprogram the fans to kick in faster at a lower temp? Would be a good solution with those slow speed traffic. In these stop/go situations the torque converter could slip a bit more and creates some extra heat transferred to the coolant. The temperature reading in the dash is not the exact water temp. The actual water temperature is higher. The dash temperature comes from a sensor in the block which adds to some inertia in the way it reacts to the real conditions of the coolant. What is your oil temperature on the OBD? 0.5 and 0.8 are very low oil pressures. If the reading in the dash is correct. Faulty pressure sensor? Mine stays around lets say 1.5 with a 0w40(M1) 5w40 (Motul) and a little bit higher with the 10w50 (Millers) I am running now. Mobil Peak Life 5w50 is also a good oil. These engines run hot so why not use a good w50 oil i.e. during summer. Maybe time to check/renew the oil pressure relief spring and plunger. This could provide for a higher idle pressure. There are some threads here in the 996 forum with the correct part numbers. Easy to do with next oil change.

The car likes to go fast. When I'm in stop and go traffic I see higher temps too. Regarding the oil pressure at idle, do a search on oil pressure and spring. It may be the case that there is an easy and inexpensive fix to that issue.

I haven't done the water pump or tstat yet. I have no records from the previous owners, but I can tell its been changed at least once. Might need to move these up the list of things to do. I pulled off the bumper and cleaned the rads. There was certainly some debris but nothing massive. I'll wash it with the garden hose tomorrow and reassemble. I have changed the oil pressure spring, it did not make a difference plus I think the previous owner changed it as well; the piston had the beveled edge which was a revision well after my 99 was manufactured. Does anyone know at what pressure the oil warning light comes on? Also I found this youtube video that shows some of the variation in the gauge cluster. Is there any way to test this without having another car? You Tube

tried running the AC? it turns the fans on by default. or try mob 1 15w50?

I have the impression reading the various post about oil pressure that the early 996's run pretty hot. As a reference for my previous post above the ambient conditions for the values I mentioned are 78-88F. Further I do not see any difference between temperatures between the tiptronic and manual version after the recent conversion to manual gearbox of the car everything seems to run at same temperatures. Especially in low speed and stationary conditions the engine runs hot because the lower pump rpm. One modification on this side would be to run a slightly smaller pulley on the waterpump, together with a shorter belt.

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Really don't see anything to be concerned about. Hot idle oil pressure is like gas mileage or oil consumption. Somebody's car is going to get better gas mileage or use less oil then your car or have more hot idle oil pressure than your car's engine. The engine's oiling needs at idle is very low. Also, if you are relying upon the dash oil pressure gage the pressure it displays may not reflect real pressure. Furthermore the 996 engine's oil pressure reading is taken from one of the camshaft covers which means the oil pressure at the mains/rods is probably higher than what the reading is. A "thicker" oil may not help. For my both my 2002 Boxster and my 2003 996 Turbo I have switched from 0w-40 to Mobil 5w-50 (not a typo for 15w-50!) because while it doesn't get very cold where I live and drive it does get pretty darn hot, up in the triple digits hot. But I might mention for years I ran 0w-40 oil in both of my car engines and the cars saw plenty of high ambient temperature usage without any issues at all so it is not like 0w-40 can't handle the heat. Have to add regarding running 5w-50 oil vs. 0w-40 oil and that is I can't tell by the oil pressure gage which oil is in the engine. The hot idle oil pressure behavior is as best I can tell the same. Regardless of which oil is in the engine on a mild day the hot idle oil pressure is 2.0 bar. On a real hot day it drops to around 1.5 bar. Even if you are tempted to run a "thicker" oil be aware that Porsche calls for using 0w-40 oil if the car is used in cold weather and Porsche considers -25C cold weather.

Schnell Gelb you mention moving the purge fan sensor closer to the heat source. I searched the forum and have seen it mentioned, but never any specifics. Is there a thread or specific location that it is moved to? Thanks everyone for the feedback. Seems that I need to focus my attention on the cooling system. I'll probably do the manual fan switch mod, and maybe in the mean time jumper the fans so that high speed comes on when the AC is turned on instead of low speed, then start gathering parts for a water pump and t-stat change.

I'm guessing the purge fan sensor is the metal one clipped into the bottom of the radiator mounting bracket? It's just a spring clip so we can just pull it out from in front of the rad where it's cold and place around the back where the air will be warmer after passing through the rad??