Oil temp
 

After having an oil temp gauge for a while now I have some data for WHEN my car is fully up to temp, ie- when it STARTS getting good mileage.

As we all know the coolant temp comes up quick, less than 2 miles even on a cold day, but the oil temp lags way behind. On a 70f day it usually takes around 15 miles to get the oil up to 180f or so and that temp is when my car starts getting good mileage.

This morning I did a 49 mile trip with a starting temp of 39f and ending temp of 43f. The oil took 35 miles to get to 180f! I struggled to get over 35 mpg during oil warmup, but brought it up to 39 mpg by the time I finished the trip.

Had seen this trend developing the past few tanks as cooler weather arrived.
This morning after the trip I took the belly pan off and insulted the oil filter and oil pan. Both are in the air flow at the bottom of the radiator shroud so that does explain why it takes so long to get up to temp.

Will know Monday morning how well it works but am looking for another solution just in case the temps get too hot, or 212f+.

By the way, on 80f days the oil temp only runs 185-193f, or about 5f over coolant temp.

Thanks for the data!

But sorry Harvey, I just can't pass this one up! :p You insulted your oil filter and pan? They might get hot under the collar now!

What kind of oil are you using? Dino or synthetic? What viscosity grade? Is the one recommended fer yer vehicle? ;)

Snap some piccies of what you did to insulate yer oil filter and oil pan. :D

Frank, :D.

So then an oil pan warmer might produce better fe than a block warmer. I wonder if this is in part caused by oil viscosity? The 212 oil temp is that the spec for your car? I know this is a general rule for block temp.

Yes I think it is actually entirely caused by oil viscosity. I've been reading bobistheoilguy and apparently the difference in oil pressure at startup is as much as 20 psi between different 0W-20 rated oils, with Toyota's 0W-20 having the highest viscosity index. Maybe I read it wrong, but someone definitely posted saying that their oil pressure dropped 20psi when switching to Toyota 0W-20, and I don't think they were going from a 40 or 50 weight oil either. In fact Toyota's 0W-20 is so good that some people there apparently recommend adding some as "viscosity index improver". Seems like a thinner oil is the easiest way to get better gas mileage on shorter trips.

100C is a typical temperature for listing the oil viscosity at, I think it's considered the "correct" temperature.

Perhaps a good fuel economy addition could be an oil to water oil cooler. "Coolers" are usually used to reduce oil temp on the track, but obviously if the water is hotter than the oil, then the water will heat the oil up :D

Good catch Frank!

Oil spec is 5w20 or 10w30, dino or syn. Running Pennzoil Ultra 5w20 and have no idea what the spec is for oil temp, but the sender is also the drain plug so it's reading average sump temps. Oil viscosity is based on 212f, so I'd rather run a shade cooler (thicker) than too hot (thin).

Basically, I wrapped the filter with header wrap and aluminum INSULATION tape, and then used a small soldering blanket which is like header wrap for the pan.

BITOG is a great site.

If your car is designed around a 8.5cst (xW 20) oil at an oil temp of 212f, then at 104f the oil is 30-48 cst, or WAY thicker than even a xW60 at 212f.
Too thick and it kills mpg...

My diesel has an "oil cooler" in the radiator that flows oil all the time. It brings the oil up to temperature with the coolant.
Sounds like you need something like that.

Or you might want something like this:
Epic oil pan heater w/pics - Diesel Place : Chevrolet and GMC Diesel Truck Forums
Has pics

Oil pan heaters. The magnetic ones are fairly cheap and work well... providing you have a steel oil pan.

Been running Toyota 0w20 for the last 100000kms, year round. Mind you, my engine's spec'd for it.

BTW, it was -16C this morning... so enjoy your warm southern temps!

Thanks for this, guys.

I'm watching with distress as my mileage keeps dropping as the temps drop and I'm doing less highway testing. Because of these short trips, I'm thinking I should get some sort of engine pre-heater. I'm thinking about one of those KAT's silicone "pad" heaters for the bottom of the oil pan (150 watt), AND one of the coolant type heaters that is installed by cutting the lower radiator hose and fitting it in there.

Any advice? Would this be enough? - too much? - potential problems?

Oh, and I had my ScanGauge set to display water temp & noticed when I first started my car this morning, both the outside air temp and coolant temp were in the low 40's. I hit my stopwatch when the engine started & took off. In a few blocks of city driving (EOC at stoplights), it took 3.5 minutes for the water to reach 100 deg. F. and after about 5 minutes (when I reached my destination), it was only at around 125 deg. F. or so. Does this sound "normal"? This afternoon, in some longer duration operation, it seemed to stabilize at around 172 deg. Wondering if I should be concerned about my thermostat or anything???

Thanx in advance...