Go Back   986 Forum - The Community for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster General Discussions

Post Reply
 
LinkBack Thread Tools Display Modes
Old 05-30-2013, 02:08 PM   #1
Mobile Porsche Surgeon
 
kashmir's Avatar
 
Join Date: Mar 2012
Location: Plano Texas
Posts: 239
Installed water pump and 160 thermostat today

Just in time for the dallas summer.





__________________
Mike's Specialty Porsche Service
Mobile Mechanic Specializing in Porsche and Select Automobiles

http://www.mikesspecialtyautomotiveservice.com/index.html
Early 1996 / 97 Boxster, 130 k, De snorkeled, IMS, Top Speed Headers.
kashmir is offline   Reply With Quote
Old 05-30-2013, 05:30 PM   #2
Registered User
 
Join Date: Jun 2012
Location: Frederick MD
Posts: 658
Good deal. Can you explain why you installed a 160df thermostat? No one (including those that sell them) has been able to give me a reasonable and scientific based answer as to why they are beneficial. Is there some advantage to having a longer warm up period?
shadrach74 is offline   Reply With Quote
Old 05-30-2013, 08:43 PM   #3
Registered User
 
rp17's Avatar
 
Join Date: Apr 2011
Location: DFW
Posts: 713
What did you use to purge the system of the air bubbles?
rp17 is offline   Reply With Quote
Old 05-31-2013, 05:33 AM   #4
Registered User
 
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 6,261
Quote:
Originally Posted by shadrach74 View Post
Good deal. Can you explain why you installed a 160df thermostat? No one (including those that sell them) has been able to give me a reasonable and scientific based answer as to why they are beneficial. Is there some advantage to having a longer warm up period?
OK, here goes: The thermostat sets the baseline minimum operating temp for the engine; it is the temperature the engine returns to when running at a steady state (road speed air flow across the radiators). Because of the convoluted design of the M96/97 cooling system, particularly the engine passages themselves, these engine's typically run a bit hotter than the temperature at which the thermostat opens. As the result, with the OEM stat opening at 186F, it is not unusual for the engine to run 210-215F at steady state on a fully instrumented 986 (forget what the dash gauge say, they are well known for being both woefully inaccurate and non linear). Because of the cooling system layout, at that temp the engine is actually much hotter in some internal areas, and as the oil is always hotter than the coolant (even though the engine uses a oil to water heat exchanger).

Changing to a 160F stat tends to lower the steady state coolant temp to around 175F, and more critically lowers the oil temps by over 25F, which the oil likes much better (UOA's before and after have shown the oil actually shows better parameters for longer distances between changes with the 160F stat). And on a base car, adding both the 160F stat and the "S" oil cooler (nearly twice the capacity of the base unit) improves the oil life even more. In essence, lowering the coolant and oil temps translates into improved life for both the oil and the engine.

And once and for all, cars with 160F stats do not warm up more slowly; in fact, the tend to warm up more quickly as the warmed coolant starts to flow sooner, not later.
__________________
Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
JFP in PA is offline   Reply With Quote
Old 05-31-2013, 07:22 AM   #5
Homeboy981
 
Homeboy981's Avatar
 
Join Date: Jan 2012
Location: Sherman, TX
Posts: 663
Garage
Quote:
Originally Posted by JFP in PA View Post
OK, here goes: The thermostat sets the baseline minimum operating temp for the engine; it is the temperature the engine returns to when running at a steady state (road speed air flow across the radiators). Because of the convoluted design of the M96/97 cooling system, particularly the engine passages themselves, these engine's typically run a bit hotter than the temperature at which the thermostat opens. As the result, with the OEM stat opening at 186F, it is not unusual for the engine to run 210-215F at steady state on a fully instrumented 986 (forget what the dash gauge say, they are well known for being both woefully inaccurate and non linear). Because of the cooling system layout, at that temp the engine is actually much hotter in some internal areas, and as the oil is always hotter than the coolant (even though the engine uses a oil to water heat exchanger).

Changing to a 160F stat tends to lower the steady state coolant temp to around 175F, and more critically lowers the oil temps by over 25F, which the oil likes much better (UOA's before and after have shown the oil actually shows better parameters for longer distances between changes with the 160F stat). And on a base car, adding both the 160F stat and the "S" oil cooler (nearly twice the capacity of the base unit) improves the oil life even more. In essence, lowering the coolant and oil temps translates into improved life for both the oil and the engine.

And once and for all, cars with 160F stats do not warm up more slowly; in fact, the tend to warm up more quickly as the warmed coolant starts to flow sooner, not later.
What he said, And….IF you are added an UD Pulley, the water pump will be spinning at a slower rate, so you need all the help you can get REDUCING ENGINE TEMPS. A cooler engine produces more power. All I know is, I put a low-temp thermostat in and it seems to run better, warm up quicker, and WHEN IT DOES GET REALLY HOT OUTSIDE the temp of my vehicle may go up a bit higher than normal BUT it stays UNDER the hottest temp that the higher thermostat allowed. In other words, the engine temps don't seem to get AS HOT…cooler = faster.

Sorry but that explanation was anything but fast.

Kashmir…what the heck is that swimming on your seats?
__________________
2002 Porsche Boxtser S - Silver & Chrome - Died from IMS failure AFTER IMS was replaced!
Homeboy981 is offline   Reply With Quote
Old 05-31-2013, 08:24 AM   #6
Registered User
 
Join Date: Jul 2009
Location: Arlington Heights, IL
Posts: 1,561
Does a 986 have a different thermostat than a 987? When I asked L&N about swapping out to the 160 thermostat I was told it was not necessary in the 987.
Flavor 987S is offline   Reply With Quote
Old 05-31-2013, 09:28 AM   #7
Registered User
 
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 6,261
Quote:
Originally Posted by Flavor 987S View Post
Does a 986 have a different thermostat than a 987? When I asked L&N about swapping out to the 160 thermostat I was told it was not necessary in the 987.
Fits up to model year 2008, does not fit 09+.
__________________
Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
JFP in PA is offline   Reply With Quote
Old 05-31-2013, 09:43 AM   #8
Registered User
 
Join Date: Jul 2012
Posts: 21
986 Bentley service manual

Quote:
Originally Posted by rp17 View Post
What did you use to purge the system of the air bubbles?
the Bentley service manual provides the full coolant replacement procedures, I used these procedures when I did my water pump and low temp thermostat.

its a little long but very effective. My neighbors were probably wondering why i was revving the engine for 5 minutes.

The procedures are also on the Pelican website
troop1 is offline   Reply With Quote
Old 05-31-2013, 09:46 AM   #9
Registered User
 
Join Date: Jul 2012
Posts: 21
installed water pump and 160 thermostat today

Quote:
Originally Posted by rp17 View Post
What did you use to purge the system of the air bubbles?
the Bentley service manual provides the full coolant replacement procedures, I used these procedures when I did my water pump and low temp thermostat.

its a little long but very effective. My neighbors were probably wondering why i was revving the engine for 5 minutes.

The procedures are also on the Pelican website
troop1 is offline   Reply With Quote
Old 05-31-2013, 01:29 PM   #10
Registered User
 
AKnowles's Avatar
 
Join Date: Nov 2012
Location: Southern, CA
Posts: 460
FWIW, I used the Bently method while I was flushing with distilled water. Then ordered a vacuum system for the final fill. Was much easier and had no worries about air bubbles. For the $100 I seriously recommend one. Particularly if you plan to add a third radiator as I do (just need the front hoses and one more frame bracket) or a flush and fill every couple of years.
__________________
1999 Boxster Zenith Blue Metallic/Savanna Beige
AKnowles is offline   Reply With Quote
Old 06-01-2013, 02:12 AM   #11
Registered User
 
Join Date: Jun 2012
Location: Frederick MD
Posts: 658
Quote:
Originally Posted by JFP in PA View Post
OK, here goes: The thermostat sets the baseline minimum operating temp for the engine; it is the temperature the engine returns to when running at a steady state (road speed air flow across the radiators). Because of the convoluted design of the M96/97 cooling system, particularly the engine passages themselves, these engine's typically run a bit hotter than the temperature at which the thermostat opens. As the result, with the OEM stat opening at 186F, it is not unusual for the engine to run 210-215F at steady state on a fully instrumented 986 (forget what the dash gauge say, they are well known for being both woefully inaccurate and non linear). Because of the cooling system layout, at that temp the engine is actually much hotter in some internal areas, and as the oil is always hotter than the coolant (even though the engine uses a oil to water heat exchanger).

Changing to a 160F stat tends to lower the steady state coolant temp to around 175F, and more critically lowers the oil temps by over 25F, which the oil likes much better (UOA's before and after have shown the oil actually shows better parameters for longer distances between changes with the 160F stat). And on a base car, adding both the 160F stat and the "S" oil cooler (nearly twice the capacity of the base unit) improves the oil life even more. In essence, lowering the coolant and oil temps translates into improved life for both the oil and the engine.

And once and for all, cars with 160F stats do not warm up more slowly; in fact, the tend to warm up more quickly as the warmed coolant starts to flow sooner, not later.
JFP,

Thank you for the explanation.
Have you instrumented the "steady state" temps you're speaking of?
Your explanation contradicts my understanding of the principles of thermo dynamics. If the car runs steady state of 210-215f with with a 186df thermostat it should run the same with 160df thermostat. Both thermostats will be wide open flowing fully. The engine produces the same amount of heat and the cooling system has the same capacity. "Turning the cooling system on sooner" should have no effect on the steady state operating temp.

As to the "once and for all" comment. I'm not talking about water temp,in the radiators, I'm talking about the block. As far as heat in the cabin, I was not aware that the thermostat controlled the flow to the heater core, that is uncommon in most cars. What i am concerned about what is important to engine longevity for cars operating in a 4 season environment, the oil temp. Adding 30df radiator coolant to an engine that has just gotten its recirculating engine coolant 160df is a recipe to slow the warm up to steady state temps... Like adding ice cubes to a pot of water that your trying to boil.

My contention all along has been that the only thing a low temp thermostat does is slow the time it takes for the engine to get to "steady state" and you've not changed my mind.

Those of you running low temp thermos: What changes are you seeing on your temperature readouts? Notoriously inaccurate or not, the gauge ought to at least be consistent in its inaccuracy (I mean there not made by Smiths or Lucas) and show a lower steady state operating temp if what JFP says is the case...even if the number is wrong.

Last edited by shadrach74; 06-01-2013 at 09:55 AM.
shadrach74 is offline   Reply With Quote
Old 06-01-2013, 02:17 AM   #12
Registered User
 
Join Date: Jun 2012
Location: Frederick MD
Posts: 658
Quote:
Originally Posted by AKnowles View Post
FWIW, I used the Bently method while I was flushing with distilled water. Then ordered a vacuum system for the final fill. Was much easier and had no worries about air bubbles. For the $100 I seriously recommend one. Particularly if you plan to add a third radiator as I do (just need the front hoses and one more frame bracket) or a flush and fill every couple of years.
This...^^^

I have one and it makes a huge difference, but you will still need to pull the coolant bleed valve and drive it for a bit.
shadrach74 is offline   Reply With Quote
Old 06-01-2013, 06:40 AM   #13
Registered User
 
Join Date: Apr 2008
Location: Southern New jersey
Posts: 1,054
I think the part you are missing is that a thermostat does not just run fully open, it's the device that actually controls your coolant flow and engine temperature. Otherwise, in winter our engines would never get up to operating temperature. If they operated as you state, with the heat input and cooling capacity in equilibrium, the temps. would be all over the place with varying engine load (heat input), and ambient temperature (cooling capacity). If a car wasn't designed with excess cooling capacity, it would overheat any time conditions aren't ideal.
stephen wilson is offline   Reply With Quote
Old 06-01-2013, 07:38 AM   #14
Registered User
 
Join Date: Aug 2012
Location: Los Angeles
Posts: 124
This is absolutely right. The thermostat controls the lower temperature of the engine when the radiator cooling capacity is sufficient to keep it there. What I didn't quite appreciate is that the steady state temperature is about 15degs higher than the marked stat temp, which means it is already starting to close at 15-20 deg above marked, and regulating the flow. What no one is pointing out here is that the high temperature of the engine is regulated by the cycling of the cooling fans when the air flow is not sufficient.

For me, I am often not driving at a steady fast clip, LA traffic, city streets etc, so I would only really see the benefit of a lowT stat when cruising on the highway. I assume this situation to be true for many folks.

Out of curiosity, when pushing one of these cars on a track, > 100mph, (never done it) do you see elevated temperatures, or is there enough airflow to keep it pegged at the stat determined temperature?
teleski is offline   Reply With Quote
Old 06-01-2013, 09:25 AM   #15
Registered User
 
Join Date: Jun 2012
Location: Frederick MD
Posts: 658
Quote:
Originally Posted by teleski View Post
This is absolutely right. The thermostat controls the lower temperature of the engine when the radiator cooling capacity is sufficient to keep it there. What I didn't quite appreciate is that the steady state temperature is about 15degs higher than the marked stat temp, which means it is already starting to close at 15-20 deg above marked, and regulating the flow. What no one is pointing out here is that the high temperature of the engine is regulated by the cycling of the cooling fans when the air flow is not sufficient.

For me, I am often not driving at a steady fast clip, LA traffic, city streets etc, so I would only really see the benefit of a lowT stat when cruising on the highway. I assume this situation to be true for many folks.

Out of curiosity, when pushing one of these cars on a track, > 100mph, (never done it) do you see elevated temperatures, or is there enough airflow to keep it pegged at the stat determined temperature?
You make my point with the comment "The thermostat controls the lower temperature of the engine." That is its exact function. Most cars normal operating temp is slight above that of the factory installed thermostat. Meaning that it is open under normal driving conditions additional cooling beyond is provided by air over the radiators whether it be from forward motion, or the fans.

If anyone here is suggesting that my stock thermostat does not run wide open during the spring and summer then please tell my fans to stop coming on to cool all the hot water running through the radiator.

High temp thermos are common snake oil sold to the ricer crowd as well. The whole point of the thermo is to minimize warm up time. Lowering the temp that the thermostat opens is counter to that objective. And Homeboy while I truly admire your enthusiasm, you are deluding yourself if you believe it gives you even an inkling of additional power. It will do jack $hit to cool incoming air and have no effect on the combustion event. Do not believe everything that people market to you.

I'll submit it again if anyone can provide instrumented data showing that a stock porsche thermo remains closed while the there is water in the system that is well above 186df, then by all means produce it.

If in fact the steady state temps are in the 215 to 220 range for this vehicle then the issue is with the capacity of the system and no thermostat is going to change that.

A fool and his money...

Last edited by shadrach74; 06-01-2013 at 09:30 AM.
shadrach74 is offline   Reply With Quote
Old 06-01-2013, 09:37 AM   #16
Registered User
 
rp17's Avatar
 
Join Date: Apr 2011
Location: DFW
Posts: 713
Thanks Troop.

Quote:
Originally Posted by troop1 View Post
the Bentley service manual provides the full coolant replacement procedures, I used these procedures when I did my water pump and low temp thermostat.

its a little long but very effective. My neighbors were probably wondering why i was revving the engine for 5 minutes.

The procedures are also on the Pelican website
rp17 is offline   Reply With Quote
Old 06-01-2013, 11:29 AM   #17
Registered User
 
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 6,261
Quote:
Originally Posted by shadrach74 View Post

I'll submit it again if anyone can provide instrumented data showing that a stock porsche thermo remains closed while the there is water in the system that is well above 186df, then by all means produce it.

If in fact the steady state temps are in the 215 to 220 range for this vehicle then the issue is with the capacity of the system and no thermostat is going to change that.
The OEM stat is rated to start to open at 186F; you can prove it for your self, just take an OEM stat and suspend it in a beaker of water with a thermometer in it, apply heat, and watch what temp it starts to opens at (186F), and what temp it is fully open at, which is much higher.............

The 215F+ running temps are real, try hooking a scanner with PID capability up to the car and take it for a ride, you just might be surprised at how hot it gets....... Then repeat the same test on a car with the 160F stat and see what you get; the "proof is in the pudding"..........
__________________
Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
JFP in PA is offline   Reply With Quote
Old 06-01-2013, 12:32 PM   #18
Registered User
 
Join Date: Aug 2012
Location: Los Angeles
Posts: 124
I believe we are all in complete agreement. When running the car on a hot day in traffic with the fans cycling, both stats have got to be wide open making no difference. I would like to see how much lower mine would be in that intermediate range when the temps are not bottoming out like on the highway, but not high enough for the fans to be needed. It sounds like the low T stat in that case would be providing more coolant flow.

What I would really like to see is a curve of flow rate vs temperature for the two stats. That would settle it for me!
teleski is offline   Reply With Quote
Old 06-01-2013, 12:35 PM   #19
Registered User
 
Join Date: Aug 2012
Location: Los Angeles
Posts: 124
Here they claim that engine wear is worse at low temperature, hence a low T stat could be detrimental for cool low load highway runs.

Low Temp Thermostats: What’s the Advantage? | Tuner University

I have no basis for an opinion on this matter. JFP, it sounds like you do. Whats the tradeoff here?
teleski is offline   Reply With Quote
Old 06-01-2013, 01:51 PM   #20
Registered User
 
Join Date: Jun 2012
Location: Frederick MD
Posts: 658
Started a new thread with a poll to continue the discussion in tech. Sorry for the hijack Kashmir!

shadrach74 is offline   Reply With Quote
Post Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 12:33 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page