Oil temp after change

[rtcage]

I took my car in for an oil change today. The oil was registering over 200 degrees by the time I got there. When I drove away I noticed that the oil was registering just under 200 degrees. Is there a good reason for this other than "the oil didn't get changed?"

[BigMatt]

r u sure it was the oil temp and not the coolant?

[Scott@Bjorn3D]

My oil is always around 200. Even when new oil put in. Oil temp is not going to change much, but as your oil gets older oil pressure will start to drop.

[rtcage]

Originally Posted by BigMatt

r u sure it was the oil temp and not the coolant?

Yes.

[rtcage]

Originally Posted by Scott@Bjorn3D

My oil is always around 200. Even when new oil put in. Oil temp is not going to change much, but as your oil gets older oil pressure will start to drop.

It's not so much the level it normally runs at, but the fact that it was at running temperature immediately after starting up with brand new oil that has me confused.

[canadian ss]

Your car was turned off when the oil was changed and parked till you got back in. Don't you think it could of maybe... COOLED OFF A BIT? The oil that came out was hot and was replaced with cooler oil as well, hence the cooler temp when you drove off. I'll put money down that 5 mns. later it probably went back to 200?

[rtcage]

Originally Posted by canadian ss

Your car was turned off when the oil was changed and parked till you got back in. Don't you think it could of maybe... COOLED OFF A BIT? The oil that came out was hot and was replaced with cooler oil as well, hence the cooler temp when you drove off. I'll put money down that 5 mns. later it probably went back to 200?

You're missing the point. I would have expected it to be much lower since it's essentially full of ambient temp oil. I'm just looking for the reason it wasn't closer to start-up temp. For example, "the engine was still hot so even though it was cold oil, it got to running temp faster," or "there's still old oil hitting the guage or in the system that doesn't completely drain out." Or, "it should be much lower and the dealer thought you were stupid for changing it at 700 miles and tried to pull a fast one on you."

[Banshee]

Possibly the block and heads were 210 when you pulled in...Then understand that once the cooling system shuts off, the temps will continue to rise in both oil and coolant. Try this. Run your car till the oil temp is at 210. Shut off car and after 20 minutes, turn car on, but do not start. Look at oil and coolant temps. They will be higher.

When you turn off a cooling system (oil cooler or radiator fan) the block temps will always raise and there is no effectual cooling and the heat sink from the block and coolant has no other option than to increase.

When you had your oil changed, likely the block and oil was 230 degrees...then the new oil was added and absorbed a lot of that heat from the block...engine is run for 5 minutes minimal and then you get into your car.

You may be confusing how long it takes a completely cold engine to get to temp. When the block, heads, coolant and exhaust manifolds are already at 220-230 degrees, it takes 5-10 minutes for all thet new oil to come to temp.

From the time they filled the oil, started it, drove off, you paid the bill and got in was sufficient time for the oil to reach 200 degrees.

Make sense?

[canadian ss]

Originally Posted by rtcage

You're missing the point. I would have expected it to be much lower since it's essentially full of ambient temp oil. I'm just looking for the reason it wasn't closer to start-up temp. For example, "the engine was still hot so even though it was cold oil, it got to running temp faster," or "there's still old oil hitting the guage or in the system that doesn't completely drain out." Or, "it should be much lower and the dealer thought you were stupid for changing it at 700 miles and tried to pull a fast one on you."

Im not missing the point. Its physics. Oil is a heat sink. It absorbes heat. How much depends on how hot the engine and how long was it turned off. Try putting cold water in a hot empty pot and see if the water stays cold. It will absorb the heat, to say, and the water will rise to a temp not as hot as the pot but it will rise even if you had a little hot water in it. The engine is basically on that same principle.
Does that make sense?

[rtcage]

Originally Posted by Banshee

Possibly the block and heads were 210 when you pulled in...Then understand that once the cooling system shuts off, the temps will continue to rise in both oil and coolant. Try this. Run your car till the oil temp is at 210. Shut off car and after 20 minutes, turn car on, but do not start. Look at oil and coolant temps. They will be higher.

When you turn off a cooling system (oil cooler or radiator fan) the block temps will always raise and there is no effectual cooling and the heat sink from the block and coolant has no other option than to increase.

When you had your oil changed, likely the block and oil was 230 degrees...then the new oil was added and absorbed a lot of that heat from the block...engine is run for 5 minutes minimal and then you get into your car.

You may be confusing how long it takes a completely cold engine to get to temp. When the block, heads, coolant and exhaust manifolds are already at 220-230 degrees, it takes 5-10 minutes for all thet new oil to come to temp.

From the time they filled the oil, started it, drove off, you paid the bill and got in was sufficient time for the oil to reach 200 degrees.

Make sense?

Thanks! Didn't know about temps increasing right after the engine is turned off. Makes perfect sense now.

[rtcage]

Originally Posted by canadian ss

Im not missing the point. Its physics. Oil is a heat sink. It absorbes heat. How much depends on how hot the engine and how long was it turned off. Try putting cold water in a hot empty pot and see if the water stays cold. It will absorb the heat, to say, and the water will rise to a temp not as hot as the pot but it will rise even if you had a little hot water in it. The engine is basically on that same principle.
Does that make sense?

Yes. My confusion was not so much that it wasn't ambient temp, but that it was within 90% of it's prior temp with brand new oil. I wouldn't expect room temp water in a pot that just had boiling water to be at 190 degrees the second the burner is turned back on (unless you're talking about a teaspoon of water in a super efficient pot). Thanks to the last poster, I now know that the temp rises before cooling and with the block, etc. still hot, 90% of the prior temp makes more sense.

[Banshee]

I 100% assure you this...

Run your car for at minimum 30 mins. Note the guge temps of oil and coolant when you turn off car. Wait 10 minutes. Turn key on and note temps again. They will be higher...then do your OWN oil change within 30 minutes.

I say 30 minutes because I would want you to drain the pan out completely. No 3-5 minute BS (oil change shops). When the oil is at temp, the final 5% of the oil contains 90% of the particles in the pan. You will note the temps of the oil will be higher than when you noted on the gauge, if gauge is accurate.

Replace plug, fill with new oil and start up for 5 minutes.....typical time from drive off until you get in car. You will see the oil temps 30-40 degrees cooler than your previous temps, and not the temps of the oil before you poured in or the outside temps (actual air temps).