The M96 stat already has a hole in it………..

Typically, we use the middle of the “8” as our reference point, and when the needle is there, the coolant is 210-215F; go past that and it gets even hotter, often reaching 225F by the time it is over the “0”. Because of the non linearity of the gauge, the relationship of position to actual temp is very misleading……

JPA_PA

Yup you do, Your a "CARB state", California has special status, its sets it's own standards, other states can choose between weak Fed standards and tough CA standards. PA and others follow CA. Lucky us lucky you. Unfortunately with the motor totally re-tuned for the blower, I barrrrrely squeaked by ...at idle no less!?!

A water to oil cooler makes them (the fluids) the same temp and that is 220-210, O.K. Why does my oil appear to be 188f. If you read my methodology & you get the logic, I think it's pretty sound. If you got a better method, let me know. Punch holes in mine. I don't care as long as the the numbers add up.

Funny thing though, I suppose if I already had a 160 thermostat (or 140 (?)), oil at 188f might be just about right and we could all go home. (Gotta get a good read on the coolant temp I guess.)


Regards, PK

BTWx2. Porsche has "a' hole in the thermostat, quaint. We just kept drilling till it worked right. 3 or 4 holes I think was the magic number. Did take longer to warm up though.

The problem is your methodology; you are not measuring the actual temperature of the flowing oil, you are measuring the outside metal of the sump using and indirect (non contact) method…………..there is no way your oil is circulating at 188F if you are running the OEM stat……………The M96’s coolant is pulling heat out of the oil once the engine is up to operating temperature, the oil typically is running 20-30F higher than the coolant…………………….

temp display
 

I will have to drive my 2000 "S" this evening and look at how the HVAC control panel diagnostic mode display for coolant temp compares with the needle position on the gauge. I should look at oil temp, too. Right now, ambient temp is in the neighborhood of 100 degrees in the inland areas of Southern California.

Here's the procedure for putting the HVAC panel in diagnostic mode:

Blue_s.

Let me know what you find. I think I have that setup too but quite frankly, I never saw much of interest. Looks like you have though. Be nice to see some alternative numbers.

Only a hundred in Corona eh? It was 97 the day I did my test, about as hot as it's been, I live about 40 mi. south west of you. Figured at least 110 further inland.

Regards, PK

JFP in PA,

Working on a rebuttal. Have dyslexia but good. Takes forever to write something legible.

You make some good points but I think I have you on a few. To one point, you might look-up "digital laser pyrometer" on Wikipedia or wiki-answers (for simple answer).

Regards, PK

Actually, as I already own two of them, a look up is not required, I know how they work, and their level of accuracy..................

Ya I guess not, ... perfect. You just saved me about an hour and a half trying to explain and key in what it's all about.

So, with this one, Ive measured quite a few different materials (including my head, including aluminum) and from different distances in different ambient environments etc. pretty accurately (used a standard scientific thermometer to verify a few). At the Lab I've seen them take pretty precise measurements at at least 1400 degrees. The only thing I can't measure is flame.

Since all it it sees is infared (IR), not the material or you or me, and the IR is all the same no matter where it comes from, and all it does is measure the intensity iradience) of the IR. Why do you think it can't accurately read the temp of this particular aluminum alloy of the sump?

Listen, I really appreciate you humoring me and sticking around. I think I just have one more thing that doesn't quite compute for me, and then I'll leave you alone.

It's sounding like this may be a genuine good thing.

Regards, PK

After recently installing a new water pump, 160F thermostat and new coolant in my 2000 2.7 I've been monitoring my coolant temperatures. With ambient temperatures in the mid-eighties and speeds in the 70 MPH range I'm running between 80-85C (176-185F). When I slow down or stop in traffic the temperature quickly rises to 95-99C (203-210F). I haven't cleaned my radiators in 5 years so I assume they aren't ideal. I haven't yet looked at oil temperatures but will on the next outing.

Curious to see what you are running with your S.

ddb

That's typical. The only way to keep the coolant at the cruise temp is to make the fans come on earlier. There's a thread on the 996 forums at Renntech on how to do the mod:

http://www.renntech.org/forums/index.php?showtopic=28093&st=0&p=148785&#entry1487 85

I plan on doing this mod to our Boxster myself as I see the very high trigger point for the fans as the real limiting factor.

I will have my car back from Raby soon with, amoung other stuff, a 160 Stat, however lets take this thinking to the extreme.

If lower is better, what would happen if the Tstat was removed and water was allowed to flow unhindered?

Not to hijack, just to understand better.

I think the water (and maybe oil) temperatures could be too low for too long. Maybe not a big issue in your climate, but in colder areas you wouldn't have any (or enough) heat. Engine oil and coolant temps. too low probably isn't good for the engine just like too hot isn't ideal.

Removing the T stat makes the engine run HOTTER.. The coolant goes through the radiators too quickly to cool.

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No problem

I like that attitude. I can see your ratcheting it up bit by bit.

I did take the thermostat out of my old 6cyl bmw cs coupe a long time ago. The problem was it never really warmed up. In fact it was down right cold, in the blue at speed somtimes.

With alot of trial and error, I think 3, 1/8th" holes through the thermostat gave me the temp I wanted (140??...maybe?). To be honest though, I didn't really notice a diff. Only that as db said, it took a little longer to warm up. I guess we're talking 5 hp here? I built the whole engine and tweaked quite a bit. 5 hp just might not have registered.

But, I think I agree with db, It's used to be, and I pretty sure it's still true to a degree, only when the engine was warmed up and running within a certain temp window that all the moving parts have expanded and fit together correctly as designed (we hope). So in a way I think driving around a cold engine is just as hard on it as driving it to hot.

Anyway, pop in any time. I'm the hijacker here. Till I arrived this thread was about changing a water pump. PK

DB, your fans aren't turning on very early. Mine come on within a minuet or 2 of hitting traffic. Once It''s warmed up, for what it's worth, the needle doesn't move much.

Don't know what your using for coolant, pretty sure it's not your prob but, your ready for a change. Might consider something like a quality version of GM.s Dex cool. Most of us traitors use Xerex dex-cool (compatible), about 1/5th the price of Porches exclusive juice and chemically identical where it counts (no silica or phosphates).

You probably knew all that already. If not, don't trust me, do some research. That's how I figured it out. It may still be controversial, so is the current issue at hand though.

Regards, PK

I had some time this evening to drive a bit and collect some data from the HVAC control panel's diagnostic mode as explained above. The car was a 2000 Boxster S 6-speed, with a new Porsche water pump and a 1-year-old standard replacement thermostat (presumed to be 80 deg C). The A/C compressor was off throughout the testing.

* During warmup, with the temp gauge needle exactly on the "tic" mark above the "8" in the "180" label, the HVAC panel (in 6c display) read 79 degrees C coolant temp. That converts to 174 degrees F.

* After allowing coolant temp to stabilize by driving approximately 10 miles with cruise set at 71 mph indicated in the digital speedometer display, I saw the following in the HVAC panel diagnostic mode:

Outside Temp Average (5c display) = 30 deg C (converts to 86 deg F)

Coolant Temp (6c display) = 91 deg C (converts to 196 deg F)

Vehicle Speed (20c display) = 111 km/h (converts to 69 mph)

RPM (21c display) = 2700

The coolant temp gauge needle in the instrument cluster was pointing straight up between the "8" and the "0" of the "180" label.

Oil temp was unavailable in the HVAC control panel diagnostic mode, because (I think) the 986 Boxster does not have an oil temp sensor in stock form.

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When I returned home, I idled the engine for a while and gathered some more data:

* at 100 deg C (6c display on the HVAC) the gauge needle was approximately in the middle of the "0" in the "180" label.

* at 102 deg C (6c display on the HVAC) the right side radiator fan came on. This correlates with the specification in the Bentley manual for HIGH speed (stage 2) fan. The coolant temp crept up to 104 deg C (219 deg F) and stayed there for at least 5 more minutes with the right side radiator fan running. The gauge needle was at the right edge of the "0" of the "180" label when the HVAC was displaying 104 deg C coolant temp.

It is apparent that I have a radiator fan problem on my car. According to the wiring diagrams, both left and right side fans should be controlled at the same speed (stage 1 or stage 2) at the same time. It should be pretty simple to begin testing at the relay locations under the dash, since the relays seem to follow the standard ISO terminal definitions. I'll start with my Fluke 88 meter and a fused jumper wire...

So, what's going on here? These coolant temperatures do not match what JFP in PA, cnavarro and Jake Raby have posted on multiple occasions. Is the DME lying to the cluster and/or the HVAC control panel? Is the cluster lying to the HVAC control panel? Is the HVAC control panel lying to me? Or is the HVAC panel diagnostic mode accurately reporting the coolant temp as the DME reads it from the ECT sensor? None of the scan tools I have access to will read DME data, so this might be the push I need to buy the Durametric package...

Blue s,

Great work. So what has been said appears to be true. Have to ponder a bit...Think I'll see if I can get the same in my car... maybe I can even get the oil temp.

Let ya know whhat I come up with.

Regards, PK

I have never used the climate control panel, so I cannot vouch for its level of accuracy, or how it compares to those seen on a scanner. You also need to recognize that these cars do vary somewhat in the temperatures they run at, even with the LN stat, due to differences in the cooling system (debris in the radiators, condition of the pump, non linearity of the dash unit, etc). I do know that the water temperature senders, at least those I have had the chance to evaluate, are pretty accurate. When using an OBD II scanner to monitor coolant temps, you are seeing the actual sensor data being relayed to the DME, so the numbers are also pretty reliable, and have correlated well with aftermarket gauge setups in the same cars.

On the Boxster, you cannot see the M96’s oil temperatures with out adding an oil temperature sensor to the engine, and while it can be done a couple of ways for testing, it is not a practical setup for day to day driving; so we only have used it for test purposes.