high water temp?

[jhandy]

Hi, I have been watching my water temp with the "scangauge" now for a while and I have noticed that on warm days, the temp goes up to 198-205 and stays there. The fans are on of course, but it stays at least 198.
Is there a way to lower it?
Should it be lower?
Are the radiators not working well?
62,000 miles and the system has not been flushed, never had to add any coolant.
The dealer swears that the system is sealed and life time coolant does not need to be changed.
Thanks

[Lil bastard]

Not lifetime coolant. Should be no more than 5yr./150k mi. whichever comes 1st.

Also, when was the last time you cleaned the radiators? They clog up fairly easily after a few years.

Also, are both fans working? Turn on AC and go to the front to check. It's not uncommon for the ballast resistor on one or both of the fans to go. Replacement is available and you need to splice it into the original harness, not a big deal, but you need to pull the bumper, a good thing is to plan a radiator cleaning at the same time.

[jmatta]

This is not unusual, which is why LN Engineering designed the lower temp T-stat, which is a simple bolt on replacement.

Please take a moment and read the article by Charles Navarro as to why this could be a valuable upgrade. I will install one in my '02 S as soon as I have time and can figure out what to do with spent coolant. LB is correct, lifetime coolant doesn't forever, but there are other steps you can take to protect your engine.

http://www.lnengineering.com/lowtemperaturethermostat.html

[jhandy]

I read the article and I have a question. Maybe Mr. Raby can chime in (hint hint).

How would this be better? Opening sooner would just make the motor take longer to warm up. Factory thermostat is open at 186 and the motor still goes to 205. The way I look at it, Open is open. sooner or later, the engine will get as hot as the radiators allow it to.

I was thinking..... is there a bigger better fans to install? Better ducting? Clean the radiators ( thanks Lil bastard).

I would think that cooler is better to a point, but how cool is too much?, IE: "dont drive hard until the car is at normal operating temps"

The dealer would not even set up a time to flush the system. They where emphatic that the system does not need it and even suggested that it would do more harm than good. dont ask me why....I dont understand. They said that they only do it if the system needs to be repaired.

Also is there a hack to make the engine bay fan turn on sooner? Or I guess I could hot wire it to be always on.

[Cloudsurfer]

I am with you on the lower temp T-stat- once it is open, it is open and the system will regulate itself based on the cooling capacity of the radiators. Now, opening sooner will give the system more time until it reaches this point of equilibrium, but still, assuming the car is to be driven for more than 20 min it becomes a moot point.

If you want to wind up with cooler operating temps you would need to add cooing capacity- either with larger radiators and thus more coolant volume, or by taking the oil cooling out of the liquid cooling loop (by eliminating the laminar flow oil cooler and installing a conventional air/oil cooler) or some combination of both.

The coolant Porsche fills is absolutely not lifetime fill, and you certainly cannot do any harm by changing it- provided that you do it correctly (when bleeding mainly).

[Jaxonalden]

I think there's one other thing your not addressing, the thermostat itself. Is it opening all the way? Flush water through the radiators for a quick cleaning and start the car and allow to run up to temp. Do not run the A/C.

1. Do the fans kick on? Yes, does the temp cool down and the fans stop? Yes, no problem.

2. Do the fans kick on? Yes, does the temp cool down and the fans stop? No, Possible coolant flow problem.
a. Bad pump (impeller blades coming apart and not moving fluid).
b. Thermostat not opening all the way (replace).

3. Do the fans kick on? No, troubleshoot electrical problem. Not enough airflow to cool the coolant.

Our radiators are well away from the engine, unlike most cars where the coolant is in and out of the radiator in just a couple of feet. Ours travels the length of the car and cools on the way to the nose and cools on the way back. There is no way you should have a temp of 200-205 degrees. Living in TX you're going to want to fix this before it gets really hot.

Good luck

[Lil bastard]

I've read both Jake's and Charles explanations and remain somewhat skeptical, no offense guys.

I get it that the t'stat opens sooner. I get that the gauge is both inaccurate and not indicative of temps in the engine's hot spots.

What I'm unconvinced about (though am ready to be) is whether or not the OEM t'stat actually cycles, that is, opens/closes within the normal temp swings of the engine and within the difference between it and the low-temp t'stat. I'd like to see someone test one in a pan of hot-to-boiling water and accurately record the temps at which it opens and closes. Even if it does cycle, udner most operating conditions, it will nonetheless stabilize at some point.

While they report cooler operating temps, or at least temps lower than 186° (OEM t'stat) with the low temp unit, they have not reported the operating temps with the oem unit vs the lower temp one.

Nor has any info been posted as to how 'bad' this actual operating temp difference is to the engine and it's components. I mean we're talking about materials like steel and alloy, but temps of only between 160° and boiling (250° under pressure), well under any critical temps for these materials. Even the oil is resistant to such relatively low temps.

To me, it sounds like a belief in the concept that anything lowering temps is better. While theoretically this sounds good, it may have no practical effect, especially if the higher temp is not in itself destructive, or more destructive.

All t'stats pose some degree of flow restriction due to their outlet diameter and their size. Could it be that the low-temp t'stat has a larger outlet, or is a smaller unit allowing more flow?

I would think that switching to a waterless coolant, such as Evans NPG because of it's much higher boiling point, would provide much more protection and, because of reduced hot spots would also give a lower overall operating temp. Plus, it's rated to 500k mi., instead of the 5yr./150k mi. of the Porsche coolant argueably making it more economical.

Whatever, these are just some further questions I'd like to see answered. I do hope the debate continues and that more accurate info is passed along.

[jhandy]

OK, I know this sounds silly, so dont cut me down all at once.

You know the oil cooler heatsink on the drivers side of the motor behind the intake manifold? What if I rigged something like a super duper fan onto the oil cooler kind of like a hopped up CPU freon self contained system. It would not be hard to do, but is it practicle ? It would be fun.....

[Lil bastard]

Originally Posted by jhandy

OK, I know this sounds silly, so dont cut me down all at once.

You know the oil cooler heatsink on the drivers side of the motor behind the intake manifold? What if I rigged something like a super duper fan onto the oil cooler kind of like a hopped up CPU freon self contained system. It would not be hard to do, but is it practicle ? It would be fun.....

I think it would be doable, but would there be any benefit? You'd need a pretty hefty, all-weather, fan to do it.

I think it'd be more effective to have some kind of ducting to redirect air to it.

Either from under the car (I believe the underpanels already do some of this) , or as a 'take off' from either the air intake or the engine bay side vent.

Even then, I wonder if the heat exchanger isn't 'maxed out' already and getting all the airflow it can handle.

Interesting concept though.

[Cloudsurfer]

I've thought of running Evans in street cars before, and have used it on race bikes over the years with good results. Problem seems to be that it has less specific heat capacity than water does, though it does boil at a far higher point. Either way, it would be a decent size project to get ALL the water out of the system prior to filling with Evans. It's a pain on a bike so I imagine it'd be a big pain on a car (esp a mid engine car with rads up front).

As to the oil cooler, I think the solution is not to direct more air to the laminar cooler, but rather get rid of the cooler and just run the oil to a "normal" air/oil unit so that the coolant now only has to cool the engine, with the oil being cooled by its own cooler.

[Sputter]

Both you and I posed similar questions.
If I understood it correctly, since the t-stat opens sooner (lower temp) and the system is cooling earlier then the temp shouldn't reach as high as a later (higher temp) opening t-stat.
But,,
where the wheels fall off for me is once both t-stats are fully open then everything is equal. It seems to me it has to be in the cycling to make a meaningfull difference.

As for any real benefits in the reduction of 15 degrees I don't think anyone has said.

Originally Posted by Lil bastard

I've read both Jake's and Charles explanations and remain somewhat skeptical, no offense guys.

I get it that the t'stat opens sooner. I get that the gauge is both inaccurate and not indicative of temps in the engine's hot spots.

What I'm unconvinced about (though am ready to be) is whether or not the OEM t'stat actually cycles, that is, opens/closes within the normal temp swings of the engine and within the difference between it and the low-temp t'stat. I'd like to see someone test one in a pan of hot-to-boiling water and accurately record the temps at which it opens and closes. Even if it does cycle, udner most operating conditions, it will nonetheless stabilize at some point.

While they report cooler operating temps, or at least temps lower than 186° (OEM t'stat) with the low temp unit, they have not reported the operating temps with the oem unit vs the lower temp one.

Nor has any info been posted as to how 'bad' this actual operating temp difference is to the engine and it's components. I mean we're talking about materials like steel and alloy, but temps of only between 160° and boiling (250° under pressure), well under any critical temps for these materials. Even the oil is resistant to such relatively low temps.

To me, it sounds like a belief in the concept that anything lowering temps is better. While theoretically this sounds good, it may have no practical effect, especially if the higher temp is not in itself destructive, or more destructive.

All t'stats pose some degree of flow restriction due to their outlet diameter and their size. Could it be that the low-temp t'stat has a larger outlet, or is a smaller unit allowing more flow?

I would think that switching to a waterless coolant, such as Evans NPG because of it's much higher boiling point, would provide much more protection and, because of reduced hot spots would also give a lower overall operating temp. Plus, it's rated to 500k mi., instead of the 5yr./150k mi. of the Porsche coolant argueably making it more economical.

Whatever, these are just some further questions I'd like to see answered. I do hope the debate continues and that more accurate info is passed along.

[jmatta]

If I'm not mistaken, the factory t-stat starts to open at 186* and is not fully open until 205*...the low temp stat opens at 160* and is fully open at the same temp the factory unit begins to open.

Between 186* and 205*, the factory unit restricts flow, artificially keeping temps higher. Only data logging can provide evidence the lower temps help the engine, but I'm always open to ideas (especially inexpensive ones) to promote longevity in my engine.

[cnavarro]

Yes, the thermostats are designed to cycle. The low temp thermostat doesn't start to open until 160F (hence why it's called a 160F thermostat) whereas the factory ones doesn't open until 186F. There is no meaningful difference in warm up nor in heat to the cabin (ran one most of winter here in Chicago even on sub zero days and no engine codes either, which other users have also confirmed with me on their cars with the 160F thermostat. The low temp T-stat has full flow by around 175F (give or take a few degrees) where the factory one doesn't until around 200F. I tested a handful of factory thermostats and some didn't fully open until 205 or even 210F, which was very scary.

The thermostat will cycle closed if there is too much cooling capacity, but you really don't see this unless outside ambient temps are under 50F (which I've observed with data logging with a momentary drop of coolant temps to 166F, then it rises about 10F before settling back at 172F).

It's a given, in traffic, without sufficient air flow, the low temperature thermostat cannot take advantage of cooling capacity of the radiators. In motion or on the track, that's completely different scenario, where the low temp thermostat, especially at higher rpms with lots of coolant flow, keeps the engine well below the temperature that an engine with a stock t-stat runs.

Lots of people also don't equate coolant temp to oil temp, as these engines use laminar flow oil to water heat exchangers. A 15-20F drop in temp is a big deal to oil temperatures, which in my own testing, are usually about 10F above the coolant temp in normal driving and in hard driving, upwards of 20+F over coolant temp. This is huge!

[JFP in PA]

Originally Posted by Sputter

Both you and I posed similar questions.
If I understood it correctly, since the t-stat opens sooner (lower temp) and the system is cooling earlier then the temp shouldn't reach as high as a later (higher temp) opening t-stat.
But,,
where the wheels fall off for me is once both t-stats are fully open then everything is equal. It seems to me it has to be in the cycling to make a meaningfull difference.

As for any real benefits in the reduction of 15 degrees I don't think anyone has said.

OK, as I have been one of the posters that has actually used and tested the LN 160 degree stat, let me sum up what we have seen:

1. Lowering the temperature of the coolant appears to have no negative effects (check engine lights, lack of heat, etc.).

2. The M96 is running a lot hotter than you think it is with the OEM stat, mostly due the inaccuracy of the factory gauge.

3. Oil life and performance are closely correlated to heat exposure, the hotter it gets, the faster its performance (and life expectancy) falls off. That, plus the fact that the number one function of oil is heat transfer, not lubricity, allowing the engine oil to get too hot is a recipe for problems. This is why one of the first “performance mods” we suggest for non S cars is to swap out the oil cooler for the S unit which is nearly twice the size.

4. The factory OEM 186 degree stat starts to open (in a pot of water) at 185-189 degrees; it does not fully open until well over 200 degrees.

5. The LN 160 degree stat (in the same test) starts to open at 161-162 and is fully open at about 168 - 170 degrees.

6. Around town and open road tests of a 160 stat equipped 2.7 base car on a 72-75 F day consistently showed lower coolant temps between the high 160’s and low 170’s. Before the swap, the same car showed running temps in the 193 – 210 range under similar conditions. All “real time” test data was captured via the OBD II port.

7. Visually, the OEM and the LN stats appear identical, other than the temp rating markings.

8. I see no reason to believe that “cycling” of the thermostat comes into play at anything other than cold ambient temps. Once the engine, its oil and coolant, are up to temp (regardless of what temp that is), it takes a lot of heat transfer to pull it back down; that is why it takes a bit of driving after being stuck in traffic before the car cools to its normal steady state. So, unless the ambient air is below say 40 degrees F, cycling of the stat does not occur to any great level.

9. Does it increase performance? The correct answer would be “Damned if I know.” We have heard of slight gas milage increases after doing this, but currently have not data to confirm or deny that. Should it increase oil and engine life expectancy? My response would be “Definitely.” Cooling the engine, and in particular the oil, is “a good thing”…………

Feel free to continue to debate its value, but I think from what we have seen there are real benefits from a relatively simple “once and done” parts swap.

[jmatta]

All the convincing I need...just placed my order.

[jhandy]

Well I figured someone though of it before me.

http://www.elephantracing.com/oilhandling/fans.htm

That site has aftermarket oil cooler fans to addon to your spec 911.

Anyway, would some like this be a benift? I bet it would.




How do you take the oil out of the loop and install a seperate oil cooler?

Thanks

[cas951]

Everyone covered most of the items you need to check. If the Engine temp is constantly high and you've already checked that the airflow to the radiator is not clogged these are your other possibilities.

1. Thermostat can operate normally but they can be sticky and open partially. This will cause your engine temps to be higher than normal since the flow of coolant is limited.

2. I have not replaced a water pump on a Boxster but if the water pump material is similar to BMW's and Vw's this could be at fault. BMW and VW waterpump uses a hard rubber compound impellers. These wear out overtime and can no longer push the required volume of coolant to cool the engine and cause your temp to be higher than normal. VW had a recall on their waterpump due to this and BMW's require to change at 50k.

Inspecting either of these route will require you to get into the engine compartment and also drain the coolant. Probably a good time to replace both.

I have seen both BMW and VW pumps when they failed. The impeller was completely rounded

[JFP in PA]

Originally Posted by jhandy

Well I figured someone though of it before me.

http://www.elephantracing.com/oilhandling/fans.htm

That site has aftermarket oil cooler fans to addon to your spec 911.

Anyway, would some like this be a benift? I bet it would.




How do you take the oil out of the loop and install a seperate oil cooler?

Thanks

These will not work for a Boxster. The oil cooler on the M96 is an oil/water design mounted under the rear driver's side of the intake manifold. It does not depend upon air flow for cooling. To convert it to air/oil cooling, you would need the LN oil filter adpaptor, then run lines to the front of the car and add the heat exchanger. You will also need a thermostatic flow control valve to prevent the air/oil unit from over cooling the oil (yes, that is an acutal problem).

In reality, the OEM M96 oil cooler design on the S model is pretty good and also acts as an oil warmer in colder weather to get the oil up to proper temps quickly. Much simpler and more compact than going air/oil............

[jhandy]

JPF.
that is true. look on the top drivers side of the motor, There is a oil heat sink. looks like a square compact radiator.

part number 996-107-025-57-OEM

if a fan was placed on this part, it would push more air through the fins and cool the oil more.??.
I am going to check the front, and the t-stat, but as an addon this is simple, and if it would cause lower oil temps, that would save the life of the motor, at least from my understanding.
just drove to lunch, and the car went to 198 and stayed there, so i guess something is not right.
I am checking real time temps via the port under the dash.

Did we ever establish what the "normal" temp should be?

[JFP in PA]

Originally Posted by jhandy

JPF.
that is true. look on the top drivers side of the motor, There is a oil heat sink. looks like a square compact radiator.

part number 996-107-025-57-OEM

if a fan was placed on this part, it would push more air through the fins and cool the oil more.??.
I am going to check the front, and the t-stat, but as an addon this is simple, and if it would cause lower oil temps, that would save the life of the motor, at least from my understanding.
just drove to lunch, and the car went to 198 and stayed there, so i guess something is not right.
I am checking real time temps via the port under the dash.

Did we ever establish what the "normal" temp should be?

When you actually see one of these up close, you will understand a bit more. The exchanger is a "laminar" design, kind of like a loaf of bread on end, where the odd numbered slices have coolant flowing thru them in one direction, and the even slices have oil in them going the other way. There are no air passage ways like a radiator has; it is a solid object, so putting a fan on it will gain you nothing as the heat exchange takes place at the "slice-to-slice" interfaces.............

Have you verified that your front radiators are clear? And I don't mean just looking at them thru the grills; I mean pulling the front cover off and looking between the A/C exchangers and the radiators? You might be surprised at the junk that collects in there and causes cooling issues......we have found everything from a ton of foliage to dead birds inside these systems.



Here's a good "backyard DIY link: http://www.realtime.net/~rentner/Porsche/Radiator/Radiator.html