srcn

I'm starting to wonder now if my C4S X51 got the lower temp thermostat installed. It's almost never above 200 degrees (only when I got stuck in Los Angeles traffic seemingly forever), and it takes forever to get there. Guess I'll have to dig through the maintenance records again.

mbatarga

If you think that changing out the tstat from 180F to 160F lowers the normal operating temp, then by that logic, don't even install one - or say you find a hypothetical tstat that opens at 100F or even 10F. Do you think your engine is going to run 60F or 150F cooler?

Ben Z

I have the 160 thermostat on mine, came with the new engine, part of RND's protocols. I don't know how much of a difference it makes in warmup here, as the outside temp rarely dips below 50F, and only a few days a year. I don't really see a difference in operating oil temp, but it's hard to tell because I never kept data on what the max temp was under specific driving conditions (trip length, revs, outside temperatures, etc.).

I would think though that if the goal was keeping a lid on the maximum operating temp, one would be looking at an add-on oil cooler, larger or additional radiator/fans, higher volume/flow water pump etc. right?

user 72902

I don't know what effect the LTT has on bore scoring but when I sent my car in for a preemptive rebuild they found 3 cylinder/pistons scored. As previously reported I ran the LTT for a long time and did everything by the book. As far as I'm concerned one of the best flat six engine builders put a LTT in my car and that is good enough for me.

user 72902

You make some very good points and I'd like to add to them if you don't mind.

I recently replaced my AC condensers because I saw that they were hammered closed when I put in new radiators. My goal was to improve the restricted air flow to the radiators. After the install my coolant temps dropped to the normal operating temp range of 180 to 183. I bet if I removed my Zunsport protective grills and allowed even more air to enter that those temps would drop further.

So is it possible that with a 180 thermostat that my car's thermostat might not fully open all the time during normal driving conditions?

Edgy01

When I replaced my waterpump a few months ago I routinely replaced the thermostat with the same one that was in it (factory installed). I had no issues with temps before so I figured there was no need to change anything. Only recently when I was in a very odd high temp situation in Las Vegas recently did I actually see oil temps at 250F and my water actually went to 200F indicated.

2011-sy-carreras

Have been following this tread and amazed how OCD a Porsche enthusiasts can get and spends time splitting hairs. I'll include myself and will save my own stories. I've been a member for little over 2 years on purchasing my 997.2 C2S and 10 years owned a BMW e46 M3 with Dinan S3 supercharger and suspension upgrades. Before getting married and raising 2 kids, had a hobby of working on late 70's 911's in the 80's. Started with a VW Beetle and graduated to a flat 6. Even tinkered with 914's.

I just drove my C2S cold from my garage as I normally do, 2 miles on a country road to the highway for another 8 miles on the highway. Drove it normally and in the habit to wait until water and oil temperatures are up to normal temps. Not pushing her at all, running it no higher tha 2,500 RPM. Oil pressure gauge moving between 2 to 3 bars, 70 MPH in 7th gear around 2000 rpm's. After ten miles car oil temp was low at 175. Between the 150 to 200 gauge. Water temp came up quickly 5 miles into the ride to a static 175. It's summer here in the NE, why would I worry, or care if the oil thermostat valve opens 20 degrees before stock 180 degrees. Isn't the piont of the tstat whether at the radiator or oil distribution to bring them up to temp quicker and would fully open on reach rated temps. If they don't, it's a part replacement for a malfunctioning tstat? Once fully open, tstats have done their job and have no effect on a fully warmed up engine. Whether it's During DD, or spirited driving.

My morning drive focused on this tread and working to keeping my OCD in check. Thanks

Petza914

Why is your oil pressure so low? Mine isn't even that low at idle with oil temps at 225 and above. Are you running a 0W/40 oil or something very thin like that?

Sporty

Noticed my oil temp was running high (225-235)on the way home from work last night on my 05 C2. Spirited highway driving 3-5k rpm , 80 degrees outside Motul 5-40 (which Jake R. says does run hotter) stock thermostat, oil level at middle bar, water 175, oil pressure good. Sending unit replaced few months ago. Is this normal or any ideas?. Oh , zunnsport grilles on and rads look fairly clean.

Wayne Smith

.2 cars have multi proportional controls to send different pressures to different parts of the motor depending upon operating conditions. The pressure never tops out. My question might be, given that there are multiple pressures ... What is the pressure gauge really showing?

2011-sy-carreras

Normal OEM Mobil 1 specs. Oil pressure does go over 3 and 4 when I open her up. Should I be worried? Car is running like a top, knock on wood.

Petza914, you're feeding my OCD. Thank you

Petza914

Missed that his was a .2. Knew those have variable oil pumps. Thanks Wayne.

Bruce In Philly

Now why would you ask such a sensible question? Same for temps......

Peace
Bruce in Philly

Iceter

If a thermostat is operating properly, when the water temperature drops below the Tstat's rated temp, it will begin to close, restricting water flow to the engine and allowing the temperature to climb back up into the optimal range. I would be surprised, however, if any changes you could make to the stock equipment could drop the normal operating temperature below the Tstat's range for any length of time. Usually, the Tstat is only a factor in the engine's temperature during warm-up. The normal operating temperature of the car is higher than the Tstat's rated temperature.

There are multiple places where the temperature of the coolant is hotter or colder than the reading on the temperature gauge. Engineers choose the location of the temperature sending unit based on several criteria. Most importantly, they put it on the engine side of the Tstat, in a place where temperature swings are minimized but not so far away from the hot spots (adjacent to cylinder bores and near combustion chambers) that a problem won't show itself quickly.

But none of that has anything to do with the fundamental operating principal behind the Tstat. Just think about how paranoid we would all be if the sending unit was adjacent to a cylinder! The temperature variations there would drive us to distraction, not to mention the gauge would become useless as it would constantly be moving.

On a side note, at least one person mentioned that when he tested his 180 degree Tstat, it was not opening correctly and that his 160 degree opened at exactly the right time. I assume he mentioned that as a rationale as to why going to the 160 made sense. To me, that only showed that his Tstat was malfunctioning and that a new 180 unit would have worked just fine. All Tstats can malfunction, no matter what their temperature rating. I always check my Tstats in a pot of water before I install them because on more than one occasion, I installed one (in old Fords, not Porsches) and it was bad out of the box. It just happens sometimes.

cvtbenhogan

iceter again with sound reasoning. baz might have meant the people taking precsutions with thicker oil/low t stats were seeing failures due to the crank weakness as just a unavoidable outcome. If the bore don't get you, the crank will. Hope he clarifies.