Oil Temp On 2.8Q - 130 degrees From Idling??

**Siena** · 04-08-2008 03:56 AM

Hi guys, yes, I know this car I'm referring to isn't an S4, but the principles would be the same, with regards to oil / coolant temperatures, so please, bear with me.

Just trying to clarify a point I'm not too sure of.

We know the normal coolant temperature range on a B5 is about 90 degrees, regardless of driving style, providing the thermostat is working as it should, and it's the correct one fitted.

Oil temperature however, is different. From experience, coolant temperature MAY rise if the engine's labouring on a very hot day - slow forward motion, in higher gears, uphill, towing etc. Again, if the thermostat is operating correctly, it shouldn't rise by more than a couple of degrees, so probably about 93 degrees.

With the low rpm though, oil temp is likely to be lower than if high rpm's are used.

Conversely, at high rpm / road speed, coolant temperature MAY drop slightly, again, with a correctly operating thermostat, not more than a couple of degrees, so maybe about 87 degrees. Oil temp however, will go the other way - higher. I've only ever experienced both coolant and oil temperatures rise together, if the coolant temperature rises excessively, due to too low coolant level, or a faulty thermostat, i.e jammed shut. Then, if the engine boils, the heat WILL transfer to the oil, and it'll go way too high. Oil pressure MAY drop over 150+ degrees, depending on oil grade used.

My concern here is, a guy has a 2.8, and he says his coolant will reach 90 degrees from idling, which you'd expect, with no forward motion. But his oil temperature reaches 110 / 120 at idle too! Now, the oil temperature in my 2.6 will ONLY reach that level, from sustained high rpm, on a very hot day, or the motor's boiling, either due to coolant loss, or a jammed thermostat. I also used to run an RS2-engined type 85 Coupe quattro, last power output from a 2.5 stroker was 426 hp. On track days, I HAVE seen temperatures reach 130 degrees, but it took a hell of a hammering, and a long time to get there. Regular driving on the open road produced oil temps of around 90 - 100 degrees.

I know there's an optimum oil operating temperature, after which the motor can be hammered, but I'd have said that'd most likely be between 75 - 80 degrees. I wouldn't have thought 110 / 120 oil temperatures are the optimum, as most cars under normal driving conditions seldom get that high.

Any opinions?

**Siena** · 04-08-2008 01:16 PM

Anyone??

**Siena** · 04-10-2008 05:56 AM

Not even any personal experiences with an S4?!?

Come on, guys!

**looseboost** · 04-10-2008 08:39 AM

Now you got me worried about oil temp what is the Oil temp gauge suppose to be around on our s4s when being driven ?? Mine when idling stays down to 150 F

**VR4-S4** · 04-10-2008 10:31 AM

just depends on how long i let it idle for...but usually oil temp wont go over 150F at idle

**looseboost** · 04-10-2008 11:37 AM

what temp is normal for when driving?

**RolledMySTi** · 04-10-2008 08:57 PM

are we talking F or C for those degrees?

**Siena** · 04-11-2008 03:46 AM

Either C or F. Whatever your gauges are calliberated in.

**looseboost** · 04-11-2008 07:55 AM

F ....

**JackalS4** · 04-21-2008 07:35 PM

Siena, yeah you're on the right track, the oil temps should not be that high.

Let's talk Celcius AND Fahrenheit lol.

The oil temperature gauge on my Canadian S4 goes from 60 degrees (140F) right up to 180C (356F). A warmed up car will run from approx. 80-100C (176-212F-ish), depending on the climate and driving style etc. When pushed of course it might go a bit higher, but idling or perhaps soft highway driving should cool it down again.

The owner's manual cautions that if your car goes into your gauge's "higher range", which I would guess means at least 120C (248F), that you let it run gently to cool it down again. It says if the temps are persistently in the high range to have it checked. In addition, it also adds to use no full throttle (full load) while the gauge is in the 60C (140F) area.