Engine temperarture pass 180 F problem solved
 

This is for your information. I have 2002 Boxster base 2.7 L having a problem for 3 years on engine temperature passing 180 degrees. Last 3 years ago, I replaced my water pump, thermostat (160) and coolant. But after doing that, my engine temperature keep passing over the number zero "0". How can it be that after replacing the thermostat with low temp 160 thermostat, the temperature keeps doing it. Thinking that the new water pump may be broken, I replaced the new water pump with a new one for the second time. After driving the car, the temperature keeps passing the number zero (of 180). I followed Pedro's Garage instructions and even bought and used the pressurized method of charging coolant. I even have to pull up the coolant reservoir's pin to remove any air entrapment, no change at all and still the same. 3 years of thinking why after changing parts and spending a lot of money on cooling system, the engine temperature keeps passing the zero in 180 mark.

Last week, I decided to replace the "AIR TEMPERATURE SENSOR" that is located between the air intake in engine compartment. The sensor is very cheap why not change it. Behold..........after driving it for one week, the engine temperature never passed the the number "8" of 180 mark. I really don't know why, but I am very happy that I don't need to replace my water pump for the third times. I can drive all day long with the temperature needle never pass the vertical position.:dance:

Several sensors are connected to the cooling system diagnostics system. If you look up the various functions of a blinking coolant light, one is a defective engine compartment temp sensor.

Four functions of the coolant warning light:

1. Engine coolant level too low
— light flashes slowly (0.5 Hz)
2. Engine compartment temperature too high
— light flashes slowly (0.5 Hz) (engine compartment blower might be faulty)
3. Engine coolant temperature too high
— light is lit; pointer on the right
4. Temperature sensor at water outlet faulty
— light flashes rapidly (1 Hz); pointer on the right

Note
The temperature warning in point three is indicated if the conditions "engine coolant temperature too high" and "engine coolant level too low" are present simultaneously
(1Hz = 1 flash per second. 0.5Hz = 2 seconds per flash)

I understand why the engine compartment air temp sensor would be part of the cooling diagnostics, but the OP wasn't getting any temp warning lights; the engine temp gauge simply ran a little "high".

Any idea how the engine compartment temp sensor ties into the reading on the temp gauge on the dash?

If something was wrong with the temp sensor, and it was acting up electrically, it could affect other things in the same circuit, like the already questionable dash display accuracy.

Just another reason to not trust the dash gauge...........

I had this same problem on my '99 Tip and went through three water pumps, new coolant and new V belts until a coolant bypass valve, attached to the transmission and originally a 924 part, failed. Apparently it had been leaking for years but not enough to drip on the floor. After it was replaced my temp stays on the left side of the eight. Don't know if this part is for Tips only but suspect it has something to do with trans cooling.

I am having this same issue right now. Anyone have the part number for the sensor to be changed?

Antny, I sent you the wrong one in the text...
Figure 1 here I think.
Porsche Boxster Engine Sensor Replacement - 986 / 987 (1997-08) - Pelican Parts Technical Article

The engine intake AIR temp sensor is: 996-606-113-00
Oil temp and level sensor is: 996.606.150.00

Just another reason this board is imperative for Boxster owners...

Thx for sharing all the good info here!

Mike

Thanks Jon. I did get a bosch sensor to replace it. I ordered a relay and sensor and now I know I need to order a new fan. Dang those wasp mud nests. Now I need to find a how to replace that darn fan.

apologize for hijacking this thread but i really need your input!

2000 2.7L manual, 113k miles.

i had the same issue where the temp would go almost over the zero during spirited driving or sometimes just on hot days during slow city driving.

this is as high as it ever got (pushing it through artificial corners in miami):

20150414_225050_zpsp2h8mimj.jpg Photo by tita_cristian | Photobucket

as soon as i drive at highway speeds it cools down right away. even if i stand still and i accelerate a bit in neutral it stars to cool down. i understand thats because the fan is kicking in on second speed and i can see the needle go down.

i just replaced the engine bay sensor but nothing changed. engine bay fan is working i checked. i cleaned the radiators two weeks ago too.



my mechanic is telling me this is not that bad especially in Florida and thats how it works but then there's a lot of people who say the needle should be vertical right between the 8 and the 0. Manual says the same but that it could go higher if the engine is under load.

he suggests that if i want it to run cooler i should upgrade to a 996 (or maybe i got that wrong but anyway a slightly better pump..) water pump and i should get the bigger oil cooler. that should keep it nice and cool.


what do you guys think? should i live with it or go for the upgrade?
theres not a day that i dont do some spirited driving and plan on taking this thing to the mountains soon and putting it through its paces. i dont want to have to worry about overheating..

coolant was serviced a year ago and water pump replaced as well (not thermostat) so its not really time to do that kind of maintenance.

the larger oil cooler is an excellent suggestion, one of the best moves for the money. I would also switch to a 160F stat.

good point! i see they go for about 200 new but no reason why i couldnt get it used right? i would get new o-rings of course.

should i get the one for the S model? i think that is the typical upgrade as its bigger.

Yes, get the "S" model, they are about twice the size:

http://i1140.photobucket.com/albums/...comparison.jpg

Just want to make sure I understand correctly...

My car sometimes behaves like this too - it creeps a little beyond the "0" mark during hot days and only during slow city driving, no warning lights, no other indications come on. As soon as I start driving, it returns to the right point sitting on the "8" I believe. Is this a sign of over heating or thermostat malfunction, what are we saying here? Could this behavior above result in damage to my engine or other components?

What does the 160 thermostat do? I presume it enables the fan to cut in earlier to keep the engine cooler?

Please advise. Thanks.

Could it mean the engine compartment fan is just not coming on when it should due the faulty sensor? The result being a higher steady state temp.

That is possible. I finally swapped mine out today and it now kicks on. I think I will not worry about it as long s I doesn't climb past the 0. Seems like a lot of other people have this same problem.

People seem confused when they put in a 160 thermostat and the car doesn't run cooler. I guess the visual is that the radiator system had infinite cooling capacity and that lowering the thermostat opening temp would lower the running temperature.

Not the case at all. Do a search and you'll see that the back sides of the radiators get clogged with road debris. If they are plugged up then it wouldn't matter if you ran with no thermostat at all.

I just replaced my oil cooler and it is the larger style like in the picture in this thread. I would suggest that you NEVER buy a used oil cooler. Most of the time a used oil cooler came from a failed engine. One look up inside and you'll see lots of places for metal debris to hide, waiting to score up the inside of your engine - the very reason i chose to replace mine.

No Thermostat
 

It will actually run hotter...the water needs to be slowed down by the thermostat to have time to cool down in the radiators

Did the bigger oil cooler make any difference temperature wise?

Too many variables to tell for sure since I just went through a complete tear down, but yesterday I spent two hours in complete crap traffic in what amounts to a heat wave in the PNW. Since the engine is unproven I was paranoid and fixated in any indications that things weren't going as well add I hoped.

My fears were unfounded. Temp went back and forth between the 8 and 0 depending on how much I was sitting idle.

i'm gonna go ahead and get a NEW bigger S oil cooler as a start (thanks flaps10 for the tip!)

found one on pelican made by BEHR for $168.50 and the Porsche OEM one for $342.50.

part number 996-107-025-59.

a few questions before i go ahead and buy it:
this will fit my 2000 2.7 right?
any reason why i should spend more on the Porsche one? price difference is considerable.
what else should i be buying with it? i see two different sets of O rings (4 in total). is that right?
anything else?

thanks!

We have never used anything but the factory part (996-107-025-59), so I cannot speak for the other unit. The factory unit usually retails for about $260.

It will fit your 2.7.

There are four O-rings in two different sizes, and they should never be reused.

ScanGauge ?
 

Possible cooling problem & suspect calibration of the dashboard instruments.
Has anyone had success using a Scangauge or Ultragauge as a way of verifying the accuracy of the dash instruments? Yes, I know theses aftermarket gauges just read the same sensors that the OEM dash gauges read but perhaps they are more accurate.
I ask because some Forum members have spent much $$ and time chasing non-existent coolant temperature issues.

what about connecting the OBD2 tool which will read the exact engine data to rule out any gauge fault?

I use the app Dash Command pretty often to see what's going on with water temps and a few other things. For both my 986 and 996, the line at 180 is 180 degrees; straight up is around 200, and the right edge of the "0" is 220. I'll get the right edge/220 on a hot day in traffic, and as soon as I'm moving 35+ for a bit, the temp drops back down to 190-200.
Both cars have the 160 T-stat, new water pumps, and the larger water/oil cooler. 986 has a center radiator, 996 does not.

thanks a lot for these details they really help paint the picture and put my mind at ease as i'm getting the same temperatures (and sounds like your setup is even better than mine for the 986, i'm all stock with no center radiator) so its not out of the ordinary. i was about to drop quite a bit of money into it to try and sort it but i think i'll let it be until the next coolant change when i will upgrade to a better water pump.

still thinking about upgrading to a bigger oil cooler as that is a cheap easy improvement.

I don't think you understand the function of the thermostat. It opens at its set point to allow the flow of coolant, but it has no control over what temperature beyond that the coolant might eventually reach.

Fwiw
 

Mine runs at just past 180, all the time I though this was normal.......it never runs hot in the very hot Alabama sun here.

Which OBD BT are you using for the Boxster?

ELM 327. I got it on Amazon under $30. Wifi, not BT.

I noticed that Pelican & L&N sell an instal tool for the low temp thermostat. Do I really need that? Previous (non porsche) cars, I've just dropped the new thermostat in. Thanks in advance

You have a couple of options. You can buy a thermostat already in a housing. This is a bolt-on and doesn't require the tool. Or, you can just buy a thermostat and re-use the existing housing. The tool makes it easier to install the new thermo in the old housing, but isn't absolutely necessary - you can do it without the tool.

I use this one ELM327 OBD II Wifi CAR Wireless Scanner Tool Diagnostic FOR Iphone Ipad Android | eBay

I use it with an iPad App 'DashCommand' It works well, and my temp readings are pretty much the same as others' here. Just had the WaterPump changed and the cooling system flushed amongst other things.
Driving around winding and hilly country the other day in some heavy traffic I guess the temp reached maybe 220F around 100C. Going up hills behind slow cars is murder as couldn't really get it out of 3rd in a TIP.

These 986s seem to have this heating issue, but reading through this I may just change Air Temperature Sensor for Intake Manifold. Pretty sure the fans kick in, but still I'll change the sensor just to see if it makes any difference. At the moment no CEL lights come on, so I don't know if any real issue exists.

thanks for the info! i got the same OBD II device now and using it with DashCommand its pretty cool and useful! :)

i went ahead and changed the engine bay temp sensor but didnt do anything. did quite a bit of research and it sounds like the only thing that will really help is an upgraded water pump from the 987 and a bigger oil cooler.