Thread: oil not heating up

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I have an oil temp gauge in my truck and the scale starts at 140. I took my truck out today for about 20 miles (it was about 40 out today) and the oil didn't even get up to the 140 mark.

I read in hot rod one time that optimum oil temp was over 200.
what gives?
I have 10W-30 in the thing, maybe I should put lighter oil in considering how cold the oil stays.

Originally posted by tcodi
I have an oil temp gauge in my truck and the scale starts at 140. I took my truck out today for about 20 miles (it was about 40 out today) and the oil didn't even get up to the 140 mark.

I read in hot rod one time that optimum oil temp was over 200.
what gives?
I have 10W-30 in the thing, maybe I should put lighter oil in considering how cold the oil stays.

what was your water temp.? get the water temp. right and the oil timp. should follow.

I have a 180 thermostat in it but it was running a lot cooler than 180, more like 160 or so.

Originally posted by tcodi
I have a 180 thermostat in it but it was running a lot cooler than 180, more like 160 or so.

Probably your oil runs 20 degrees cooler than your water, so that would make your oil about 140 degrees. You need to get some temp in your motor, to cold is almost as bad as to hot. you cant increase your oil temp. without increasing your water temp.

check your thermostat for when it actully opens, using some boiling water, a thermometer and drop it in, watch for it to open and at what temp.

I know the thermostat is operating right because when it was warm out and I'd run the engine I could watch the water temp hit 180 and then drop slightly right after it opened. Then it would go back to 180 and hold.
Today I think the water in the radiator was cooling off so much that when it opened it dropped the temp way down and then it would have to heat up again.
It was kind of back and forth between 180 and 160.

Originally posted by tcodi
I know the thermostat is operating right because when it was warm out and I'd run the engine I could watch the water temp hit 180 and then drop slightly right after it opened. Then it would go back to 180 and hold.
Today I think the water in the radiator was cooling off so much that when it opened it dropped the temp way down and then it would have to heat up again.
It was kind of back and forth between 180 and 160.

put a 195 thermostat in and it will be ok. what you are seeing is the thermostat doing what its suppose to. if you want to get your oil hotter you need a hotter thermostat.

Where is your guage sender located? Many times people screw it into the drain plug hole, or a bung in the side of the pan. The oil doesn't circulate on a cold day, a layer stays cold for a long time.

On top of the above mentioned ideas, check to see if you have a remote oil cooler assembly, if you do, take a piece of cardboard and place it in the front of the cooler on extremely cold days to partially block the flow of cold air through the fins. Do this, but watch your oil temp gauge at the same time, as you do not want to completely block the flow of air through it, just partially.

Bill S.

the sender is the drain plug, that's what the gauge company offered.
I do not have an oil cooler.

The oil definitely does take a long time to heat up, much longer than the water, but even after about an hour drive it was below 140. It used to run hotter when I was just test running in my garage. It also seemed to cool down as I drove at speed for a while with lots of air flow.
Perhaps it is reading slightly lower than it really is, but I think it may be better for my engine to run 5W-20 or so just for the winter.
Do you guys agree?

Originally posted by tcodi
the sender is the drain plug, that's what the gauge company offered.
I do not have an oil cooler.

The oil definitely does take a long time to heat up, much longer than the water, but even after about an hour drive it was below 140. It used to run hotter when I was just test running in my garage. It also seemed to cool down as I drove at speed for a while with lots of air flow.
Perhaps it is reading slightly lower than it really is, but I think it may be better for my engine to run 5W-20 or so just for the winter.
Do you guys agree?

No, I don't agree, assuming that your gauges are mounted and working properly and your water is running 160 to 180 degrees then it sounds to me your oil temp is probably what it should be. I've never heard of anybody trying to increase the oil temp without increasing the water temp. I left home this morning it was 10 degrees and in a few miles the water temp. was 200 and if I have had a gauge in the oil it would have been around 180. I use 10w40 motor oil, and I had 50 lbs. of oil pressure. you don't need a 5w20 in 40 degree weather. I always used an oil gauge to make sure the oil didn't get to hot, I wouldn't think to cold would be a problem in 40 degree temp. its a wonder you have heat as cold as you're running the motor. heat the water and the oil will take care of itself.

Stop driving so fast... Stick your head out the window when you are going 60 mph at 40 degrees. The effect on you and on your engine is a wind chill factor of 25 degrees...

Not much you can do about it but move to California or Florida.

http://www.nws.noaa.gov/om/windchill/index.shtml

ok, I'll stick with the 10w-30.

As for the thermo, I thought 180 was a pretty ideal temp for water, maybe I should have gone a little hotter.
Although I should probably wait until I find out if I have bad knocking to switch up to 195.
I just put 89 octane in it since it was the first time I really had it out and I'm still taking it easy. I did do one little test at about 1400 rpm's in 4th gear to see how the torque was. I pressed it down to the floor and about 3/4 of the way down the engine started shaking like a gypsy dancer.
My compression is about 9.5:1 so it was no surprise, hopefully when I put in 93 it will be ok.
otherwise I'll be stopping at the tractor store to pick up some lead additive.

My experience with an engine oil temp gauge is that it takes a while for the oil to come up to temp.

You can see the temp rise - or lack thereof - if you have a mechanical oil pressure gauge.
Takes a while for it to settle in at running pressure.

180 degrees F is an excellent engine temp winter or summer.

Don't sweat the oil temp.
You probably won't see it come off the bottom during the colder months of winter unless you're making a long trip.

I have a trans temp gauge and it takes quite a while for it to come off the bottom in winter.

What can help bring the oil temp in engine or trans up is to run a bunch of short errands.
The engines water temp comes up to 180, you park the car, the engine oil and trans case/oil does the heat soak bit with heat from the engine and it's not long until oil temps are up to where they will probably be during a long trip.

Stick with the 10-30 engine oil.
I talked to a nationally known magazine tech writer who really knows his stuff a while back, the subject was multi-viscosity oils for my new F-150 SuperCrew.
He didn't come right out and say it, but if you read between the lines the allusion was easy to see . . . use 10-30 instead of 5-20 or 5-30.

What a lot of folks don't know about 5 wt and lighter engine oils - there is a 0 weight out there - is that they were designed to improve the CAFE auto manufacturers go by.
(CAFE being Corporate Average Fuel Economy.)

Buick burned up a bunch of engines when they were ran on 5 wt a few years back.

C9x is right about multivis. oils. The more difference between the two numbers, the more "friction modifier" there is in it, and the less actual oil. Friction modifiers are stringy latex-like crap that sometimes precipitate out and goo up cold internal surfaces, like valve covers. Also known as "White Paint".