External oil cooler thremostat

code7rpd · 04-25-2005, 03:27 PM

Does anyone know at what temperature the factory external oil cooler thermostat opens? I've heard 180 degrees as well as 210 degrees. Any ideas?
Thanks.

afterburn 549 · 04-26-2005, 09:21 AM

I think you will find a couple of diff ranges.....

juanbenae · juanbenae's Garage

i would say 180, 210 seems high considering 250 is considered "too dam hot" for these motors.

Miguel Antonett · 04-26-2005, 11:12 AM

Mine opens around 180.

afterburn 549 · 04-26-2005, 11:12 AM

I am no expert but have read and read and read.......210 seems voted perfect for most.....h2o stays away,oil flows good and ect. ect.and 250 would be too HOT!

code7rpd · 04-26-2005, 01:47 PM

The reason I ask is that my original appeared to open at about 180 and with the 3.6 conversion, I never ran past 190 to 200 degrees even when driving hard during the summer months. My car started running at about 250 degrees so I replaced the external thermostat as it appeared to not be opening (front lines and coolers were cold to the touch- nose mounted and carrera) and now it runs at about 220 to 230. An IR temp reader shows the thermo to be hitting about 210 when the lines to the front coolers get hot. I ordered another insert for the external thermostat and was told that they are all the same temp although no one could tell me what temp the thermostat opens at. If it is opening at 210 I think that is too high as by the time the oil gets to the coolers it is probably running at about 220.

jaydubya · 04-26-2005, 01:53 PM

Mine opens at 180 (checked with thermocouple).

Formerly Steve Wilkinson · 04-26-2005, 02:56 PM

They all open at 180, as far as I know.

Stephan

Chuck Moreland · 04-26-2005, 02:56 PM

Did you retrofit the 3.6 with your old sending unit, or at least a sending unit correctly matched to the dash guage?

My money says you have a mismatch.

fintstone · fintstone's Garage

It should open when the oil is 180F at the thermostat. The oil temp gauge will probably read about 210F by then due to its location. The thermostat on the fan (fender cooler) turns on at@ 240F (factory Porsche), or 210F (BMW) depending on which you use. The gauge would read significantly higher.

Formerly Steve Wilkinson · 04-26-2005, 04:28 PM

When my thermostat opens, the gauge (numerical, not just slashmarks) reads 180. I know that because I spent an hour today trying to get the oil up to thermostat-opening temp to check for leaks in a new front-mounted B&B cooler--65 degrees ambient, public roads--and it was a battle. It finally opened, at an indicated 180. (I got out and checked every five or ten minutes, so I'm not guessing. I was running on a heavily patrolled New York Interstate (87) with no front bumper, air dam or--most important--license plate. Took several hard rusn to 110 to get the job done.

I can't imagine there would be a 30-degree temperature difference in oil rapidly coursing through an engine and its oil lines, measured in different places.

Stephan

code7rpd · 04-26-2005, 04:43 PM

The gauge and the sender are new and are the numerical type so the sender and the gauge are compatible. My carrera fan has a BMW sensor which is supposed to come on at 210 but my gauge reads about 230 when it comes on. That amounts to a 20 degree difference between the gauge sensor and the temp sensor on the fan. This is puzzling because the car used to run at 190 and after changing the externel thermostat the car runs cooler but still hotter than it used to. I am thinking about trying another t-stat because I can't think of anything else. No dents in the oil lines and everything is new (coolers).

Formerly Steve Wilkinson · 04-26-2005, 04:51 PM

I'm trying to get my head around the fact that the car runs cooler but hotter than it used to...

And must we assume the "BMW sensor" is accurate? After all, they are responsible for iDrive...

Stephan

Jack Olsen · 04-26-2005, 05:30 PM

When did you change the sender/gauge? It's common with 3.6 swaps to have the newer sender (from the 3.6) sending falsely cool readings to the earlier car's gauge.

If you think the problem is elsewhere, test the thermostat in boiling water.

code7rpd · 04-26-2005, 08:49 PM

The temp gauge and sender are matched with an earlier numerical gauge and matching sender. I will test the t-stat - I can't think of anything else being wrong.

fintstone · fintstone's Garage

Quote:

Originally posted by code7rpd
The gauge and the sender are new and are the numerical type so the sender and the gauge are compatible. My carrera fan has a BMW sensor which is supposed to come on at 210 but my gauge reads about 230 when it comes on. That amounts to a 20 degree difference between the gauge sensor and the temp sensor on the fan. This is puzzling because the car used to run at 190 and after changing the externel thermostat the car runs cooler but still hotter than it used to. I am thinking about trying another t-stat because I can't think of anything else. No dents in the oil lines and everything is new (coolers).

I would certainly hope that the oil would be at least 20 degrees cooler after going the length of the oil lines and through the oil cooler..or else the setup would be of little value.
The biggest differentials between the engne and the external points, would be when the external thermostat initially opens, before the lines, oil in the lines and cooler temps are fully up to the temperature of the oil. This would be the point the fan first turns on.
I have the same setup with the BMW fan thermostat. My car runs at about 210F during cool weather and about 225-230F when it is warm and I am in traffic. My fan never comes on unless I switch it on manually....which I do at 210F.

code7rpd · 04-26-2005, 10:54 PM

My fan is supposed to come on at 210 but the gauge reads about 230. I replaced the sending unit and gauge and there is no change. I would be surprised if the BMW sender and my thermostat both went bad at the same time especially since the t-stat is about one month old and the entire cooling system is less than 2000 miles old. I am going to test the t-stat this weekend because if it isn't opening at 210, the oil is so hot by the time it gets to the coolers it will never drop below 210.

fintstone · fintstone's Garage

I guess I don't understand. It sounds to me like your system is operating perfectly. 210F is normal. Your external thermostat should open at 180F, but there is no way that the oil will remain that cool very long after it opens. The purpose of the external thermostat is not to keep the oil at 180F or even 210F, but to prevent thick, cold oil under pressure from going to the cooler before it has sufficiently warmed. It does not regulate cooling. The thermostat (sender) to turn on the fan most likely never reaches 210F to turn on the fan until the oil temp at the engine is close to 230F. If you want to turn it on sooner, you need to use a switch.
Once the external thermostat opens, don't expect the oil temp to ever go down where it is measured at the engine as oil temp is still rising at that point..it only keeps the overall maximum lower.

code7rpd · 04-27-2005, 01:43 AM

That makes sense but I don't understand why its running hotter than before. It used to never get past 190 - no matter how hard I drove it or how hot it was outside - even though it is not running extremely hot I don't know what has caused the running temp to change.

Miguel Antonett · 04-27-2005, 04:37 AM

It appears that your system is doing what it supposed to do. Have you considered the possibility that your initial configuration - original 190 degree readings under ALL conditions - was off ? May be your original setting was stuck at 190...