987 OIL LOSS AND OVERHEATING

Bit of a strange problem. 2007 987S 45,000miles While driving the other day the front cylinder head oil plug popped out on the drivers side causing a 2.5q oil loss over the course of a 30 min drive. When I pulled into my driveway (lucky timing) the oil warning came on and I immediately turned the engine off. Upon inspection, I noticed oil coving the bottom of the car. The oil was topped off to determine the amount lost, then completely drained and inspected: No unusual debris in the oil or filter. The oil was clean, it was changed 1000 miles prior to the incident. Took the car on two-10 min test drives, with similar results: -car ran 100% -came up to and held operating temp for the first 8ish minutes. -after serval minutes at operating temp, temp needle rapidly climbed to 250F-engine was shut down. -while on acc power, needle returned to operating temp in 5min. -temperature continued to climb while returning home. -while on acc power, needle returned to operating temp in less than 5min. My questions are: -How can the temperature fluctuate so rapidly? -Is there a was to verify engine temperature besides the gauge? -Is it possible overfilling the oil by 1/2q caused enough excess pressure to pop the oil plug out? -What kind of damage can running 2.5q low cause? Thanks

My initial guess would be a head gasket. Pressuring the crankcase which blew out the plug which leaked the oil. Temp fluctuations from a bubble in the coolant jacket. Check the coolant level to see if it is down, and to see if there is oil in the water. No proof. Just a SWAG. Sent from my iPad using Tapatalk

Sounds like you blew a crankcase plug . They are only pushed into place so this can happen when the crankcase pressure is too high. It happened to me while on the track and the oil loss ended up on my rear tires causing me to spin out. There are a few causes of this happening although I was never able to solve the cause on mine. I this has been covered before so perhaps do a search on this topic to pull up how other solved it Here is a start https://www.planet-9.com/threads/cam-plug-pops-out-oil-evacuates-panic-ensues.233015/ .

Thanks for the info. I topped off the coolant with distilled water (1/2 a gallon low) and bled the system. I did not see any coolant in the oil or oil in the coolant. Still having the same overheating issue. I’m hoping there is just an air bubble trapped somewhere. Thoughts?

The cooling system is a sealed system. It really should never require "topping up" - as far as the air bubble - how did it get there? It really sounds as if you have a leak somewhere. As far as how the temperature can vary so quickly - the gauge on the dash is no better than an idiot light. All the german cars went to this sort of design around 1990 to keep people from running to their dealer every time the gauge wasn't straight up at "normal" (or 180F) - it's buffered. When the engine is cold it will report the engine is warmer than it actually is. When the engine is hot it will indicate the engine is cooler than it is. If you want proof - get a Porsche capable diagnostics tool and set it up to record the engine temperature while you go for a ride. You'll find the temperature varies widely. The ECU changes the engine temperature to maximize efficiency and hence - gas mileage. If you had a gauge that actually showed the actual operating temperature, you'd be at the dealer weekly asking why it moves all over the place. So - do NOT trust the gauge that the engine isn't overheating or very close to it. When it indicates overheating, you've been approaching that temperature for some time and possibly been doing damage to your engine. I have no idea of your situation - or skills - but I'd suggest you consider taking it to a Porsche specialist. That will be more expensive short term than trying to solve the issue with internet guesses made by well-intentioned people. But long term seeing a specialist will likely be a good choice if the professional can keep you from destroying the engine trying out tests that don't gain you any knowledge of what's going on. Good luck. Whatever way you go I suspect this will be an expensive adventure.

to get a more accurate reading for temperatures, you need to get something like an OBD gauge. https://www.planet-9.com/threads/additional-digital-gauges-for-987.114539/#post-1001129 have you checked your water pump and coolant expansion tank for leaks? has the water pump been changed before?

This was over about 25 minutes? Did you ever hear the radiator fans come on? Unless the system was open to air - the coolant won't boil at 212F - the pressurization raises the boiling temperature, I'm not sure how much, but probably over 230F. What should have happened is somewhere around 210-220 the fans should have come on (anyone know the trigger temperature for the fans?) BTW - claimed on the web - the maximum opening of the thermostat is at 210F - which might explain the leveling off. From the AllDataDIY version of the service manual: THERMOSTAT MONITORING General description After engine start and under the conditions: no hot engine ambient temperature within range normal driving average vehicle speed > 25km/h sufficient mass air flow an increase of the coolant system temperature will be expected. Monitor structure If the engine coolant temperature does not reach a certain value under normal driving conditions, the coolant system is defective. And it has a graphic: The problem is - there are no real temperature models.. and the graph above shows 55F - which doesn't make any sense. And the one below - well - it shows the temperature peaking at 90C - which is 194F.. but it's saying that's the "model" temperature - which to me means the temperature the ECU has decided the engine should run at.. and the green line is ? the temperature it is running at ? Nowhere in the factory manual are any coolant temperatures given. From some searches using Google, I turned up this on another forum: "The OEM thermostat in the M96 starts to open at 186F, and typically is not fully open until nearly 210F. The dash gauge is typically way off, indicating around 180 or so when the actual coolant temp (read by a Porsche specific scan tool or an after market temp gauge) is commonly around 205-215F at steady state. Along with the dash gauge being nearly useless, the data you get from the AC panel is a often close second in inaccuracy." There are also reports that the thermostats in the Boxster and Cayman have different opening temperatures, and temperatures up to 230F have been seen and not considered "abnormal".. So - did your fans start to run when the temp approached 230F? If not - why not? Have you looked at the fuse for them? Are the radiators plugged with debris?

Those graphs would be more useful if they had actual temp vs time data. The fans came on “full” around 214F The radiators look clean from the outside, although I suppose there could be debris in between the ac condenser and radiator. I initially had the same thought regarding the thermostat fully opening at 210F. Honestly not sure why I changed my mind, the system is sealed and was pressure tested prior to refilling with coolant....Although the coolant was audibly bubbling @230F when I shut it down. Any ideas on how my mechanic might think this was caused by a clogged catalytic converter ?

And the temperature continued rising after the fans came on? A clogged catalytic converter in my experience reduces power. I imagine some engine cooling is done simply by the air thats pumped through the engine during the combustion cycle - so backpressure could reduce that flow - perhaps causing overheating. I think you really want to ask your mechanic why he thinks it's caused by a clogged converter. To me the symptoms indicate one of two things: 1. the engine is making more heat than the cooling system was designed to handle or 2. the cooling system isn't working correctly (bad waterpump, thermostat, clogged radiators, ??) It would be very interesting to hear from your mechanic. It may be that he's seen this before..

Seems strange that there wouldn't be any codes for cat problem. They usually throw codes on any of this stuff. But cat problem would make sense. Did you ask them how they determine the cat were bad and why wouldn't be any codes. They maybe just guessing