I just replaced a 20 year old waterpump...

[Rob175]

Please DON'T RELY on seeing or feeling a "wet carpet" in the truck in order to determine IF the coolant tank is leaking! In my case the carpet was bone dry and the tank was still leaking (actually weeping from it's bottom when up to temp and pressurized).

The trunk in my 1998 has a masonite type of raised flooring that sits 1 inch above and between the metal trunk floor and the carpet....that allowed the coolant to collect below the masonite raised floor and just slosh around until it eventually found a way to drip a few drops on my garage floor.

I suggest you removed ALL the fabric lining in the rear trunk (bottom & sides)....(easy to do but time consuming). Then lift up the raised floor boards and drive the car for a day or two and just keep opening the truck to look for coolant collecting. I took rolled up paper towel and placed it all around the tanks sides and bottom, drove the car for a bit, and saw the paper towel began getting wet.

[blue62]

Originally Posted by pilut2

Ok- so you don't want to do the research.... I'm not an expert, but those who are explain that the stock thermostat starts opening at about 186 F and is fully open by 210 F- whereas the low temp version starts opening at 160 F and is fully open by about 185 F. This results in lower operating temperatures- oil and coolant- for more most driving conditions.

I have done research, lots of it over the years.
It is why I am surprised that so many people are going to a thermostat that is outside the manufactures system operating parameters.
When you run cooler then the system is set up for it takes longer to go into closed loop.
You run on cold startup fuel map longer.
harder on the Cats. hard on o2 sensors
Running at lower temp takes longer for the oil to reach its operating temp. (which is typically very close to 195)
Resulting in oil being bypassed at the bypass valve for a longer period of time.
Takes longer for the oil to reach a temp where it burns off water.
For every pound of fuel burned (that's about half a quart) a pound of water is produced. Not all of it goes out the tail pipe.
Some of it ends up in the oil.
Just a few things that result from running cooler then spec.
Now if it is a race car or a car you track I get it.
If it is a street car?????

So that is why I was curious as to why it seems that lots of people are going to the cooler thermostat.

[Ciao]

Originally Posted by blue62

I have done research, lots of it over the years.
It is why I am surprised that so many people are going to a thermostat that is outside the manufactures system operating parameters.
When you run cooler then the system is set up for it takes longer to go into closed loop.
You run on cold startup fuel map longer.
harder on the Cats. hard on o2 sensors
Running at lower temp takes longer for the oil to reach its operating temp. (which is typically very close to 195)
Resulting in oil being bypassed at the bypass valve for a longer period of time.
Takes longer for the oil to reach a temp where it burns off water.
For every pound of fuel burned (that's about half a quart) a pound of water is produced. Not all of it goes out the tail pipe.
Some of it ends up in the oil.
Just a few things that result from running cooler then spec.
Now if it is a race car or a car you track I get it.
If it is a street car?????

So that is why I was curious as to why it seems that lots of people are going to the cooler thermostat.

Makes sense; factory specd water pump has and continues to be my choice.

[bcrdukes]

I recently had my cooling system overhauled, and originally wanted to get the lower temperature thermostat, but was persuaded by several shops not to for the same reasons blue62 mentioned.

My car is 99% daily driver, and there is a 1% chance I'm going to the track regularly (once a year at most, and if even.) If my Boxster were a dedicated track/race car, I would have opted for the lower temperature thermostat. It gets quite cold in Toronto over the fall and winter months, so the last thing I need is for the car to warm up to operating temperatures longer than usual. I'm also not attempting to break world records on my 35KM commute to and from the office every day. Most of the time, I'm stuck in stop and go traffic.

[pilut2]

Originally Posted by Starter986

I'm no expert, either.


So "This results in lower operating temperatures" is incorrect.

I installed the low temp thermo and my operating temps have remained unchanged.

My experience has been different than yours. I drove for a hour or so yesterday with a combination of city and highway driving. In stop and go traffic my temps (according to the gauge) were slightly lower than with the stock thermostat but my highway temps showed a significant reduction with the needle settling just under the 180 mark, where it would've previously been a few needle widths higher, resting in the middle of the 8. It is my understanding that the actual coolant temperature is a fair bit higher than the indicated temperature- so there is no concern about the temperature being too low to burn off any moisture in the oil.

[Starter986]

Pilut2... interesting.

There seems to be two camps on the efficacy of the low temp thermo.

I'll wait for Jeff in PA to chime in. I'll follow his recommendation. If that means he recommends the stock thermo... I'll soon be swapping my low temp out.

Cheers!

[pilut2]

Originally Posted by Starter986

Pilut2... interesting.

There seems to be two camps on the efficacy of the low temp thermo.

I'll wait for Jeff in PA to chime in. I'll follow his recommendation. If that means he recommends the stock thermo... I'll soon be swapping my low temp out.

Cheers!

Some great back and forth in this thread.

Why I installed a low temp thermostat.

[JFP in PA]

Originally Posted by blue62

I have done research, lots of it over the years.
It is why I am surprised that so many people are going to a thermostat that is outside the manufactures system operating parameters.
When you run cooler then the system is set up for it takes longer to go into closed loop.
You run on cold startup fuel map longer.
harder on the Cats. hard on o2 sensors
Running at lower temp takes longer for the oil to reach its operating temp. (which is typically very close to 195)
Resulting in oil being bypassed at the bypass valve for a longer period of time.
Takes longer for the oil to reach a temp where it burns off water.
For every pound of fuel burned (that's about half a quart) a pound of water is produced. Not all of it goes out the tail pipe.
Some of it ends up in the oil.
Just a few things that result from running cooler then spec.
Now if it is a race car or a car you track I get it.
If it is a street car?????

So that is why I was curious as to why it seems that lots of people are going to the cooler thermostat.

Simple: It is better for the oil, and for the engine. In spite of your research, the only reason the factory run these cars so hot was emissions, period. Back when LN first introduced a 160F thermostat, we collected data on UOA's in cars before and after installing the thermostat. Net result was that nearly all of the oil values (film strength, TBN, viscosity, water content, fuel content) were excellent for longer run times on the car running the cooler thermostat. We saw absolutely NO increase in either fuel of water contamination in oil samples, and oil quality was much better for many more miles. We have also seen no change in O2 sensor life or performance, or in cat life expectancy. And contrary to your data, oil temps in these engines are typically much hotter than 195F when running the OEM stat; 225-235 is more like it.

As for fluid warm up, your data is also suspect. How fast an M96 heats up is a function of the engine's specific heat out put rate at any given ambient temperature; the thermostat functions just like the one in your home: Regardless of where it is set, how fast the temperature rises is constant, only the point at where the thermostat takes control and throttles the system changes. Fully instrumented M96's warm up both the oil and coolant at the same rates, regardless of which thermostat is in play. Only their final "steady state" temperature changes.

You might also be interested in the fact that every turbo, GT2, and GT3 car left the factory with a 160F stat in them...…….

[blue62]

Originally Posted by JFP in PA

Simple: It is better for the oil, and for the engine. In spite of your research, the only reason the factory run these cars so hot was emissions, period. Back when LN first introduced a 160F thermostat, we collected data on UOA's in cars before and after installing the thermostat. Net result was that nearly all of the oil values (film strength, TBN, viscosity, water content, fuel content) were excellent for longer run times on the car running the cooler thermostat. We saw absolutely NO increase in either fuel of water contamination in oil samples, and oil quality was much better for many more miles. We have also seen no change in O2 sensor life or performance, or in cat life expectancy. And contrary to your data, oil temps in these engines are typically much hotter than 195F when running the OEM stat; 225-235 is more like it.

As for fluid warm up, your data is also suspect. How fast an M96 heats up is a function of the engine's specific heat out put rate at any given ambient temperature; the thermostat functions just like the one in your home: Regardless of where it is set, how fast the temperature rises is constant, only the point at where the thermostat takes control and throttles the system changes. Fully instrumented M96's warm up both the oil and coolant at the same rates, regardless of which thermostat is in play. Only their final "steady state" temperature changes.

You might also be interested in the fact that every turbo, GT2, and GT3 car left the factory with a 160F stat in them...…….

JFP
Glad to see you jumped in on this.
Yes it seems all car manufactures number one concern is emissions everything else being secondary.
The primary reason modern day cars run hotter then pre smog days.

Interesting data you collected.
Good information to be considered.
Always trying to broaden my knowledge base.
I wonder if your findings are relatable to most modern day cars???
That would be interesting information

[Starter986]

Thank you, Jeff.

You saved me some quid, and peace of mind. Coffee on me next time you're in SoCal.

Or a cocktail. You can choose your poison.

[kk2002s]

Originally Posted by pilut2

My experience has been different than yours. I drove for a hour or so yesterday with a combination of city and highway driving. In stop and go traffic my temps (according to the gauge) were slightly lower than with the stock thermostat but my highway temps showed a significant reduction with the needle settling just under the 180 mark, where it would've previously been a few needle widths higher, resting in the middle of the 8. It is my understanding that the actual coolant temperature is a fair bit higher than the indicated temperature- so there is no concern about the temperature being too low to burn off any moisture in the oil.

This is the same behavior I'm experiencing with the low temp thermo. You see a more detailed temp readout looking through the ECU.

[bcrdukes]

I now feel stupid and regret getting the factory thermostat after reading JPF in PA's reply. lol

[pilut2]

Originally Posted by bcrdukes

I now feel stupid and regret getting the factory thermostat after reading JPF in PA's reply. lol

Don’t feel stupid. You sought advice, but just got it from the wrong folks.

[pilot4fn]

Thank you Rob175 and NewArt for this very good info. I'm back from travels and will open up the carpets on the wekend to come. I've had the car only 2 months and can see now that the water in the reservoir is at the lower mark now when the car warm... can't remember how it was at the time of purchase

Originally Posted by NewArt

Check under the carpet/liner in the trunk near the tank for wetness.
Replacing the tank with an original Porsche part is recommended. Aftermarket tanks have often proved to be unreliable; you don't want to do the job twice!
DIY tips and videos abound. You might want to tackle this job, it's not as daunting as many make you believe!

Originally Posted by Rob175

Please DON'T RELY on seeing or feeling a "wet carpet" in the truck in order to determine IF the coolant tank is leaking! In my case the carpet was bone dry and the tank was still leaking (actually weeping from it's bottom when up to temp and pressurized).

The trunk in my 1998 has a masonite type of raised flooring that sits 1 inch above and between the metal trunk floor and the carpet....that allowed the coolant to collect below the masonite raised floor and just slosh around until it eventually found a way to drip a few drops on my garage floor.

I suggest you removed ALL the fabric lining in the rear trunk (bottom & sides)....(easy to do but time consuming). Then lift up the raised floor boards and drive the car for a day or two and just keep opening the truck to look for coolant collecting. I took rolled up paper towel and placed it all around the tanks sides and bottom, drove the car for a bit, and saw the paper towel began getting wet.

[Rob175]

From what I've seen, the DIY job of replacing the tank is VERY difficult unless you can raise the car and work underneath in addition to from the top. Remember there is also the connections for the oil dip stick and oil filler in addition to coolant connection. For me, I didn't want to tackle the job because failure or any difficulties encountered in the process would render the car un-drivable......and the cost to have it towed in would exceed the price of my "indy" doing the job AND guaranteeing the work. But, having said that, there are some that do tackle it, just not me.

Good luck and keep us posted.

[Ciao]

Originally Posted by Rob175

From what I've seen, the DIY job of replacing the tank is VERY difficult unless you can raise the car and work underneath in addition to from the top. Remember there is also the connections for the oil dip stick and oil filler in addition to coolant connection. For me, I didn't want to tackle the job because failure or any difficulties encountered in the process would render the car un-drivable......and the cost to have it towed in would exceed the price of my "indy" doing the job AND guaranteeing the work. But, having said that, there are some that do tackle it, just not me.

Good luck and keep us posted.

That's one DIY I would probably have the Indy do; there are many others that will save me $ equalizing the cost of having the tank done by the Indy.