While performing my first oil change at 34,560 miles, I noticed a grey/tan film on the underside of my oil fill cap. Has anybody else experienced this? My Coolant doesn't seem low but I will be keeping and eye on it. The weather here in Iowa has been pretty wet and cold the last couple months; not sure if that would affect higher condensation in the motor?

My 2012 G37Xs was purchased back in October with 31,570 on the clock. The dealership performed an oil change with good ole dino 5W30 Valvoline and Nissan filter oil prior to purchasing the car. I changed that oil after only 3,000 miles of driving. The new oil I put in is 5W30 Pennzoil Ultra Platinum with Mobil 1 Filter and a new crush washer.

As of right now I'm just curious if anybody has seen this in their 3.7 motor?
Thanks

 

 

Sorry I'm a newbie at the forum stuff.
I know I know... Shame on me I didn't take any pics.

 

One cause could be due to cold and/or humid weather and short trips. This doesn't allow enough time for any contaminants (eg moisture) in the oil to burn off. Try a longer trip on highway and see if the cap material changes.

 

Ok, thanks for the advice. My daily commute is 50/50 highway/city and is 19 miles one way. It has been humid/cold here and I almost always warmup the car prior to driving.

What would be considered a short trip?

 

Short trip in this case would be 5-7 miles. Your trip is definitely long enough to FULLY warm up your car.

Next option is that the thermostat could be stuck open which makes the car run colder than the optimal temperature it was designed for. How many miles on your car? How long since last oil change?

I'm basing this on recent experience with another one of my cars where the oil cap would get what's called BMW mayo. Yellow looking crud under the cap. Short distances and/or thermostat not functioning correctly were most likely culprits.

 

Sorry. Reread your post and just answered my own questions.

 

Just changed the oil this weekend and noticed the cap while doing the oil change. Prior oil change to this weekend was done by the dealership where I purchased the car and that was around 31,570 miles. So I only went 3,000 miles on the dealer oil change.
The car is a 2012 with 34,600 miles currently.

What is the optimum temperature that car should be at? When looking at the temp gauge it never makes it halfway between the cold and hot readout. It usually reads steady at 1/3 or a little more up from the cold mark. Not sure what others are seeing for their temp read outs. I would be curious to know, if mine is reading where it should be for the temp.

 

So the coolant temp gauge won't tell you a thing except for when the engine is really cold and when it's approaching the danger point. Any temps in between could be in the range of 80 F to 250 F.

Normal operating temps should get to around 185-210 F. But you cannot tell this from the gauge. It must be from a digital readout like Torque or OBD Fusion which gives you exact temps via your phone and a wifi or Bluetooth dongle which connects to your OBD port.

I believe mine is reading about same as yours (1/3 to 1/2 way up range).

 

Is there an App that is better than others for the digital read information? I have an Iphone and was looking into getting one of the bluetooth OBII dongles off amazon.

As for now, I'll keep an eye on the oil cap and coolant to see if anything returns / happens.

 

I too have an iPhone. Bought OBD Fusion for $10. Then bought a compatible wifi dongle off amazon for $25. Works great. Simple to set up. No complaints with it

 

I'm going with OBD Fusion App as well. Is there a way to get Transmission temp as a read out? I don't see it in the standard PID's that are built in.

 

I believe it requires a separate sensor to be purchased and activated. I don't have one, wish I did have one for oil temp, pressure and transmission temp.

The reason I bought OBD Fusion in the first place was to understand the BMW mayo I had under my E46 oil cap, similar to you. Then I sold that car to get my G37 coupe. ;-)