KNS

I clicked on this thread and it made me think about my 2013 BMW 128i. It does not have a traditional water pump but is electrically controlled to run at various speeds depending on demand.

Now, in BMW's infinite wisdom they eliminated the water temp gauge (even though they're pretty much glorified idiot lights these days...). So, I purchased a digital gauge that installs in a dash vent (made by P3 cars). It looks like it belongs there and matches the factory lighting - very slick. What it shows is your exact water temp at any given time. It also shows a bunch of other stuff if you scroll through: battery voltage, intake temp, etc.

It is interesting to see how these modern water pumps and T-stats operate. What I have noticed is that the temperature fluctuates depending on demand or engine load. Water temp may climb as high as 236 degrees F (though I haven't seen it that high yet and I live in AZ). For example - If I start climbing a long gradient or push the engine, the water temp will start to drop. I interpret this as the ECU telling the pump and T-stat that the engine is working harder and needs more cooling, at this point I imagine the T-stat opens wider and water circulates faster...

The water temp even while just tooling around town or on the highway is constantly fluctuating a surprising amount but this is actually completely normal.

It reminds me of old school water temp gauges as in the Camaro mentioned above. I remember on old Honda I had and seeing the gauge move around the scale in normal operation. Now days they just sit there and really don't give you much information.

Macster

The coolant temperature varies quite a bit in these Porsches too.

Here's a graph of the coolant temperature from my Turbo last July. I think this was a drive from the office to home.

lurchphil

The dealer drove my 997.2 17 miles trying to duplicate the strange coolant temperatures I have experienced several times lately. Of course, they wouldn't show up... No codes. They speculated that it sounds like a thermostat is stuck open. They need the fault codes to do warranty work. However, it is documented in case I get a code at some point in the future. My CPO warranty runs out 12/28/2015. However, I have an extended warranty with a $200 deductible so I am not overly concerned. Hopefully, (?) , my water pump will need replacing and the thermostat can be replaced at the same time under the extended warranty.

Bruce In Philly

Thanx Marc,

Our cars are accused of having fake temp readings..... did this temp graph match your dash gauge? Mine did. Any insights to the accusations of "fake" readings?

Interesting..... Your warm-up time is similar to mine and very linear (despite what I suspect was mixed loads).... mine was a bit longer but I suspect it was because ambient temps were 32 degrees F. Comments?

Peace
Bruce in Philly

More about this graph from my Durametric live data here:
https://rennlist.com/forums/997-foru...tric-data.html

mose121

Did anyone ever find a cooler temp t-stat? Was seeing pretty high temps last weekend at the track in a 2010 C4S. Granted it was hot as hell outside but none the less I'd like to go with a cooler t-stat if available. Couldn't find one in a quick google search so figured I'd check back here. Thanks!

dgjks6

does the 9a1 have the traditional water pump or electronic?

I concur with kns on the BMW. I replaced the thermostat and waterpump on my 535xi. Traditional thermostat - no electronics, but the water pump is electric and on demand controlled by a computer. When tooling around town or jsut driving ont he highway it keeps the temps high (for efficiency from what the techs told me) but when you get agressive the computer drops the engine temps.

lurchphil

Mose121,

Is this the answer to your thermostat question...?

http://www.pelicanparts.com/catalog/..._pg1.htm#item1

ADias

I do not understand the interest in a lower (than stock) temp thermostat. A lower temp thermostat does not add cooling capacity. For any reasonable length drive, once the thermostat opens, the engine temp is beyond its control. A lower temp thermostat will slow down engine warming. Why is that good?

After all oil temp should be around 200F and that relates to coolant temp.

Philster

Correct: A low-temp t-stat allows a more gradual increase in engine temps, but does not imply that an engine will run cooler.

Low temp t-stats are not going to make a difference in beating the heat.

For a manufacturer such as Porsche, go with their recommended t-stat temp, as the initial warming temps and warm-up routine affect fuel mixtures, detonation/pinging and emissions.

Or, ya know, ignore it, put effort/money into low temp t-stat, then don't get a cooler running engine, but get one that warms slowly, wears faster, is vulnerable to bad fuel/air mix, maybe some pinging, etc.

DFI engines might be less susceptible to fuel mix issues, associated emissions issues with that, and more suited to slow warm-ups, etc.

.

.

Hunt3R

Get a 3rd front radiator and/or upgrade your side radiators if you need more overall cooling capacity on the track. A low temp thermostat only opens up the coolant flow sooner at a lower temp as the car warms up. Some believe that's a good thing, Philster does not 😊

Philster

I do believe in the third radiator -- my current project.

gpjli2

As I read it the argument for low temp T was not that it reduced warm engine temps. It was that the stock .1 system was slow to respond to transient temperature spikes caused by sudden application of throttle from steady state condition. The 180 thermostat may not be fully open, the flow of coolant to the heads is sluggish, the #6 cylinder which has a flow/heat problem already due to poor design decisions experiences a temp spike and over time this repetitive issue causes bore problems The 160 T by definition opens sooner and the coolant system responds faster to the conditions above.

Problem I have with this concept is that if we wait for the engine to reach 200-220 degrees before we get on it we have already assured that both T's are out of the coolants way. We all do that right?In order to have a T that opens sooner we create the problems mentioned above related to reduced oil temps and resulting slow warm up with an increase in oil contamination. Not good for long term engine life.


I would prefer to see a 3rd radiator that is thermostat controlled. This would allow normal warm uptimes but allow increased coolant flow under high street/track conditions. Afaik that is not included in the installation. I wonder why.

gpjli2

Not to be Captain Obvious here but one of the desired effects of DFI is to cool the cylinder and lower temps. This allows higher compression w/o pre ignition or pinging.

Macster

For multi-viscosity oils like the ones approved for use in our Porsche engines, the upper viscosity is at a temperature of 212F.

That is given a 0w-40 oil the '0' viscosity is at 32F, the '40' viscosity is at 212F.

Thus with the oil temperature at around 200F or a bit higher is the "sweet" spot of temperature for the oil, the temperature at which it is designed/intended to work its best.

RichFL

i use a data logger at the track that reads engine coolant temp directly from the ECU and can confirm that the dash temp gauge is very much buffered and is not displaying the true temperature.