oil temperature when changing oil

[robertmark]

How hot should your oil be prior to changing. I have heard to just warm it up briefly. I have also heard to drive the car 20 minutes and change it when it's hot. I just wonder if you do that, aren't you risking damage from the heat with no oil to disipate the heat? 88 911

[pete3799]

Just warm it up.
It'll drain better.

[Noah930]

OP, you're overthinking this. Just drive around 'til everything's at least warm. Personally, I'll take at least a 15-20 minute drive. Then drain.

When you're changing your engine oil, even if the engine's hot nothing bad will happen. The motor's shut off, after all. What difference is it if the oil's sitting in a plastic oil pan on the ground or in the sump tank behind the rear wheel? Either way it's not circulating through the motor.

[RWebb]

Mike/Lubemaster said he did tests on this & no difference. There is a prev. thread if you search.

He works for a specialty oil manf. so ...

[jlex]

What I do on all my cars is to drain the oil and remove the dipstick and filter just after the engine is fully warmed up. I then let the oil drain all night & fill it the next morning. Easy weekend job.

[Gunter]

In the summer, I use 2 containers, open the sump and oil tank and let it drain out overnight.

For colder temps, or if you're in a hurry, I'd recommend warming the engine first.

No need to be anal about it; most people change the oil well before the recommended Mileage or time-period.

No matter if it's done hot or cold, 2-3 Liters of old oil are left in the external lines and cooler anyway.

[AlfonsoR]

The theory behind getting the oil hot (to normal engine temp) is two fold:
1. is get the oil to drain better
2. is to circulate any sedimentary debris in hopes that it will stay suspended in the oil instead of laying in some corner or crevis.

According to RWebb post and the test done by Lubemaster, there is no difference, but this is a time honored practice. I wonder if Lubemaster or RWebb warm their engines before oil change? I know I always do and always will.

On your question of damaging the engine, once you turn the engine off, first, there is not very much oil in the engine case (dry sump system). Second, the oil that stays in the case might do a little cooling when you first turn the engine off, but fairly quickly it will absorb the heat from the engine and equalize in temperature. This happens pretty quickly. You are correct that the function of the oil is to cool the engine, but it has to be circulating. No circulation, no cooling.

Also, there was a recent thread on Rennlist.com on tips for your first engine oil change. Do a search, there as well as here.

Main tips:
1. use an open top oil container, otherwise you will get oil all over your floor
2. poke a hole in the filter before you remove it and blow it down with compressed air. This pushes all the oil into the oil tank, and makes filter removal a fairly clean process. Otherwise, if you don't remove the oil from the filter, you will have an oily mess in the engine compartment.
3. Use gloves that provide thermal protection and be quick with a towel to not let oil run down your arm. The oil can be fairly hot, so take precautions to keep it off your skin.
4. For recommended oils, search this forum for the "ultimate oil thread". The first page is a summary of the recommended oils. A lot of good discussion, but many, many pages long. Get a beer and some popcorn.

[RWebb]

even after Mike's post, I warm the engine before an oil change - it's no biggie to do that.