Engine Hot AC off

**rglenn828** · 12-02-09 09:18 PM

I recently received the "Engine Hot AC off" message on my 2006 STS V while on a 30 mile trip. I watched the engine oil temperature on the digital display which never rose above 180 degrees so I was not to concerned. The message would go on immediately upon start which was puzzling to me as I knew the engine was cold.

As usual, the message went off after I scheduled an appointment at the dealer, the dealer ended up replacing the thermostat (got the car back yesterday).

My question is what are the normal ranges for the oil and transmission fluids?

Thanks in advance,

Bob

**LITTLEELVISDAN** · 12-02-09 10:40 PM

OOO welcome to the ghost in the cooling system. they replaced sensors, fan then fans, on mine. Others have had other things replaced to get rid of that pesky issue.

Seems to be an 06 issue

**jwall09** · 12-03-09 10:40 PM

Originally Posted by rglenn828

I recently received the "Engine Hot AC off" message on my 2006 STS V while on a 30 mile trip. I watched the engine oil temperature on the digital display which never rose above 180 degrees so I was not to concerned. The message would go on immediately upon start which was puzzling to me as I knew the engine was cold.

As usual, the message went off after I scheduled an appointment at the dealer, the dealer ended up replacing the thermostat (got the car back yesterday).

My question is what are the normal ranges for the oil and transmission fluids?

Thanks in advance,

Bob

I dont think I have ever ran my car under 180 oil temp. I even run Amsoil. What the heck?

**CIWS** · 12-04-09 07:26 AM

Depends upon outside temps and how hard the car is ran for a period of time.

**jwall09** · 12-06-09 12:18 AM

Originally Posted by CIWS

Depends upon outside temps and how hard the car is ran for a period of time.

I run 188-190 when its in the 30s outside.

**CIWS** · 12-06-09 08:25 PM

I took this today when I went for lunch. The car had been driven about 20 min before I stopped here and took the pic.

**jwall09** · 12-07-09 08:17 PM

Originally Posted by CIWS

I took this today when I went for lunch. The car had been driven about 20 min before I stopped here and took the pic.

any ideas as to why my motor temps run so much higher than yours? do you have a different therm?

**rglenn828** · 12-07-09 08:37 PM

Tonight on my way home from work 25 miles (the last 12 miles were interstate at 90 mph) the engine temp was 194 degrees and the transmission temp was 165 degrees with and outside temp of 68 degrees.

Regards,

**silverws6ta** · 12-07-09 09:02 PM

I should have monitored mine today more closely and took a pic as well and didn't think about it.. My outside temps would have been comparable to CIWS (here in South Carolina). Granted, we have less 'stop and go' traffic where i live --

I would guess we are all running PF26 AC Delco aka dumptruck filter (or comparable Amsoil) filters and Mobil Synthetic (or comparable Amsoil) motor oil and trans fluid here? Not after a pressure variant -- just the flow variant regarding the filter...

**CIWS** · 12-07-09 10:05 PM

Plain old Mobil 1 and PF26 here with the stock thermostat. I think later in the week we're supposed to go back up close to 70, when we do I'm betting it will be in the 190s and I'll shoot another pic. Oil is still pretty "new" BTW, I'm at 88% life.

Uhh well I say that, it's going to the dealership tomorrow morning to solve the control arms creaking in the cold. If they have to replace parts I may not have the car back for a bit.

**C66 Racing** · 12-09-09 08:22 PM

Originally Posted by rglenn828

My question is what are the normal ranges for the oil and transmission fluids?

Thanks in advance,

Bob

Bob,
I'm speaking a little out of my area of expertise here as I don't have an STS-V so I'm not exactly sure how the oil is cooled, so I'm going to assume the STS-V doesn't have an oil cooler (as neither my 02 Z06 or 06 CTS-V had one). Without an oil cooler, the oil temp is heavily dependent on two things. The first is coolant temp since that is really what is cooling the oil. Coolant temp is in turn primarly set on the low end by the thermostat opening point (typically around 194F for GM small blocks) and by the fan setpoints on the high end (typically around 212F to 230F). So in cool temps with good airflow (e.g. on the freeway), the coolant temp will likely ride around 194F and oil will follow. In high temps with low air flow, the coolant temp will likely be controlled by the fans coming on and off and you'll likely see higher oil temps. The second main effect is the engine load/rpm. One driver may run at lower rpm and thus see lower oil temps than another.

If your car does have an oil cooler (as my now not stock track day Z06 does), the oil temp is largely dependent on load, rpm, airflow and ambient temp. Very hard to make oil temp comparisons from one car with an oil cooler to another without equalizing those variables.

**CIWS** · 12-09-09 09:09 PM

Got the car back this evening. They replaced the left lower control arm and the creak is gone. They also gifted me with a 4" scratch on the driver's side rear door.

Took it back and showed it to the service advisor, they get to fix it.

My oil temps driving home were noticeably high despite the fact we are now in the 30s outside (205 when I got home). I'll recheck things in the morning so I can do an apples to apples comparison with the Tuesday morning drive in. I have a sneaking suspicion the tech drove the dog piss out of the car when it was taken out to test the alignment after the arm replacement. My avg fuel econ was at 16.2 per the DIC when I dropped it off, when I picked the car up it was at 12.1 and had been driven 16.7 miles and was down about 2.5 gallons of gas.

Also here's some fair warning. I had them go ahead and replace the fuel filter since I'm just over 31K miles. When I dropped it off they told me it would be 95.00. But when I picked the car up the actual cost was 149.63
Because my advisor wrote 95.00 on the initial ticket, they had to give it to me for that. So chalk that one up with the cost of our air filter.