Depends. For the most part, I've always checked when cold. However, on my Pentastar -- with top mounted cartridge filter -- I have to check when warm/hot. Otherwise, it appears way overfull.
Check oil level cold or warm?
- Thread starter Gomer03
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Cold checkers: have you ever seen this technique listed in a owners manual?
I would think the typical statement to "check oil level when fueling" would require the dipstick to be calibrated for a hot oil situation.
It also gets them off the warranty hook when your car engine seizes from lack of oil.
I would think the typical statement to "check oil level when fueling" would require the dipstick to be calibrated for a hot oil situation.
It also gets them off the warranty hook when your car engine seizes from lack of oil.
I got curious so I checked what mine says. Here's the relevant highlights:
Originally Posted By: 1985 Pontiac manual
The best time to check the engine oil level is when the oil is warm, such as during a fuel stop. Make sure the vehicle is parked on level ground. After stopping the engine, wait a few minutes for the oil to drain back to the oil pan.
[...]
If you check the oil level when the oil is cold, do not run the engine first. The cold oil will not drain back to the pan fast enough to give a true oil level.
So while they do ask you to do it warm, they don't forbid checking it cold as long as it's done properly. They don't sound worried about thermal expansion, just that the oil isn't all up in the engine.
It's an old manual but the physics shouldn't have changed.
When I try to read mine warm, I can interpret it in a way that doesn't look much different from the cold reading. But it's enough of a mess that I'm never totally satisfied that I can read it, even after reinserting 5 times. The color is also harder to see.
Quote:
It also gets them off the warranty hook when your car engine seizes from lack of oil.
If they find the engine lacking oil, it's not going to matter how you say you checked it. When a teenager relative's Cavalier seized and we found scarcely 1.5 quarts of black gold in it, we knew it wasn't the engine's fault right there.
Originally Posted By: 1985 Pontiac manual
The best time to check the engine oil level is when the oil is warm, such as during a fuel stop. Make sure the vehicle is parked on level ground. After stopping the engine, wait a few minutes for the oil to drain back to the oil pan.
[...]
If you check the oil level when the oil is cold, do not run the engine first. The cold oil will not drain back to the pan fast enough to give a true oil level.
So while they do ask you to do it warm, they don't forbid checking it cold as long as it's done properly. They don't sound worried about thermal expansion, just that the oil isn't all up in the engine.
It's an old manual but the physics shouldn't have changed.
When I try to read mine warm, I can interpret it in a way that doesn't look much different from the cold reading. But it's enough of a mess that I'm never totally satisfied that I can read it, even after reinserting 5 times. The color is also harder to see.
Quote:
It also gets them off the warranty hook when your car engine seizes from lack of oil.
If they find the engine lacking oil, it's not going to matter how you say you checked it. When a teenager relative's Cavalier seized and we found scarcely 1.5 quarts of black gold in it, we knew it wasn't the engine's fault right there.
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1. Park vehicle on level ground.
2. Run vehicle until fans kick on.
3. Turn off engine and pull out dipstick.
3. Wait 5 minutes and then check oil level.
2. Run vehicle until fans kick on.
3. Turn off engine and pull out dipstick.
3. Wait 5 minutes and then check oil level.
Originally Posted By: Gomer03
The owner's manual to my new (to me) 2007 Corvette says to check oil after the car has been turned off - wait five minutes, but no more than 20 minutes - to get an accurate reading. I've been operating my whole adult life on the principle that only a cold reading is truly accurate.
When did the science of dipsticks change?
That was how I was taught, but with some of the engines having cartridge oil filters mounted on the top of the engine I guess the rules have changed. Follow the recommendation for checking the oil level from the owners manual, that would be the best advice to follow now.
The owner's manual to my new (to me) 2007 Corvette says to check oil after the car has been turned off - wait five minutes, but no more than 20 minutes - to get an accurate reading. I've been operating my whole adult life on the principle that only a cold reading is truly accurate.
When did the science of dipsticks change?
That was how I was taught, but with some of the engines having cartridge oil filters mounted on the top of the engine I guess the rules have changed. Follow the recommendation for checking the oil level from the owners manual, that would be the best advice to follow now.
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