How long do you wait after shutting off eng. to check oil ?

[Scali62]

Nah that's OK, keep it .. LOL

I just didnt pick it up, I think that when my mind sees c or celsius {s} as in you post..
It doesnt register because Id have to take out a calculator to convert it

Or maybe it's because it's the day after Thanksgiving here in America & I have a little turkey hangover..

But anyways it was posted that hot oil does expand to a a degree but I'd would love to see more posts explaining or concurring this fact...

[ November 28, 2003, 05:34 PM: Message edited by: Scali62 ]

 

[unDummy]

You can first check the owners manual. Some cars are pretty specific with time.

I prefer no more than a couple of minutes after shutdown on a hot engine(since engine is only cold for a few minutes after start). This way, my oil is topoffed and running level is nice and high. Waiting overnight(unless spec'd by owners manual) allows too much oil to drip into the pan. This might reduce the running level too much. You'll also have oil from the filter if the ADBV has failed.
This could cause the level to be too low.

 

[geeeman]

Correct me if I'm wrong, but don't some cars (Porsche ?) specify to check the oil when the car is RUNNING?

I think a friend told me this once; I didn't believe him.

 

[White 03]

I think some of the Porsche's had dry sump oil systems awhile back. That might have been why to check with the engine running.

 

[Ferb]

Maybe also thinking of transmission fluid? Mine says 'in park, level surface, with the engine running'.

ferb!

 

[Scali62]

I guess this may seem a stupid question but I allways check mine @ least 5 minutes of so after shutting off the engine, is this right ?
I was watching " A car is born " a British show on the dish where the Chap is restoring an XKE type Jaguar & he read from the dipstick where it's engraved " check hot, wait 30 seconds after shutting off eng." I thought to myself that wasnt long enough for an accurate reading.
I mean, you can check the oil 4 different times a day & get 4 different readings all about a 1/2 qt. different I bet, so how much time should you wait after shutting her off { assuming we all agree to check the oil when hot or warm }

 

[Pablo]

Some cars drain back quite slowly and even 5 minutes may be a minimum. Consistancy is the key.

I always wonder about these slow drain back cars -
and I have to trust the design engineers. There are some engines out there that had/have problems due to trapped oil topside. I suppose if you had a car that normally drained down fast and suddenly it slowed down, then there would be concern....

 

[Alex D]

Most car manulas ask for 5 to 10 minute wait. The C5 Corvette says a MINIMUM of 15 minuts and so does the manula for cars with the GM 3.4 V6

 

[Forkman]

Here's one reference to the "check when hot" recalibration of dipsticks although I recall reading it several other places as well.

quote:

---

Dear Tom and Ray:
When are you supposed to check your oil, when the engine is warm or when the engine is cold?--Paul

Tom: That's an excellent question, Paul. We've always told people to check the oil level first thing in the morning when the engine is cold.

Ray: But a few years ago, Ford Motor Company started recommending that people check their oil on Fords, Lincolns and Mercuries when the engine was warm.

Tom: "Warm!" we said. "How can this be?" So we called Ford and they told us that they determined that very few idiots like us were going out first thing in the morning in their bare tootsies and checking the oil. Most people, they said, tended to check their oil when they stopped for gas, when the engine was warm. So they simply recalibrated their dipsticks to read correctly in a warm engine, when the oil has heated up and expanded.

Ray: "But what about all the oil that's still at the top of the engine?" we asked. "The stuff that hasn't dripped down to the oil pan yet? Won't that result in an inaccurate and greatly varied reading, depending on how long you wait after turning off the engine? How can this possibly work?" we wondered.

Tom: So we called our secret industry oil source, who we'll refer to here only as Deep Dipstick. Deep Dipstick is a widely respected auto-industry authority, which explains why he begged us not to use his name in OUR column. Suffice it to say he is intimately familiar with all issues relating to lubrication. And what did he say?

Ray: He said the amount of oil at the top of the engine wouldn't be enough to make any significant difference. "Unless the oil passages are all plugged up, you're probably talking about an eighth of a quart or less," he said. Not enough to induce you to add a quart when you don't really need one.

Tom: So our advice is to follow the instructions in your owner's manual when you're in the mood for a really accurate reading. If it says to check the oil cold, the dipstick has been calibrated for cold, unexpanded oil. If it says to check it warm, we and Deep Dipstick hereby give you our heartfelt blessings.

---

quote:

---

Tom: But in cases where there is a difference between hot and cold readings, we'd have to suggest that you follow the instructions in the owner's manual. First of all, the manufacturer presumably knows exactly what situation the dipstick was calibrated for. And more importantly, if the company does screw up in the manual, it'll be paying the warranty costs.

Ray: And in most cases these days, the manual will tell you to check the oil at the gas station, after the car has been shut off for a few minutes. And that seems reasonable to us.

---

I've noticed a large difference between hot and cold readings on many GM vehicles, up to 1/2 a quart difference.

My father always went buy the add 1/2 qt less than what the car calls for and then check it when the engine is cold a couple of hours later to top it up. By following this methodology he almost never needed to add more oil because the stick red right in the middle of the operating range.

With the newer vehicles my family owns this means that he was always driving around at or just below the "MIN" mark on the dipstick as I demonstrated to him buy showing him the 1/2 qt varience on all of the families GM vehicles when comparing a cold reading, which always showed almost exactly in the middle of the of the operating range vs. a hot reading (as per the owners manual) which always showed just at or below the "MIN" mark on the dipstick.

In short, the dipsticks on most newer vehicles are calibrated to take into account the oil that may still be residing in the upper portions of the engine that has not completely drained back down into the sump on a hot engine a few minutes after shutdown.

By using a "cold" reading it will actually appear that there is the correct amount of oil in the engine when in reality the amount is actually below what it should be because the dipstick is not being read for the conditions it is calibrated for.

I finally convinced him to simply fill with the engine with the amount of oil called for in the owners manual and then check when hot. Accurate reading (about 1/4qt down from the MAX mark) every time.

 

[Scali62]

Forkman, great post. Informative.
Those whacky Car Talk guys also have some good information to offer from time to time.
I bet many people didnt know that thier dipsticks may be calibrated to be checked when the oil's warm..
Learn something new every day

 

[javacontour]

quote:

---

Originally posted by Scali62:

I bet many people didnt know that thier dipsticks may be calibrated to be checked when the oil's warm..
Learn something new every day

---

I'll bet many people don't even know where their dipsticks are, people on this board excluded, not double entendre intended.

Put me down for checking after EACH fillup.

TB

 

[Holden McRoin]

quote:

---

Originally posted by javacontour:

quote:

---

Originally posted by Scali62:

I bet many people didnt know that thier dipsticks may be calibrated to be checked when the oil's warm..
Learn something new every day

---

I'll bet many people don't even know where their dipsticks are, people on this board excluded, not double entendre intended.

TB

---

In order to locate ones dipstick a man must get up from sitting on his shoulders.

 

[jsharp]

On the original topic - I wait at least an hour after I shut the engine off, and prefer to wait all night and check in the morning...

 

[Cutehumor]

food for thought...

I checked my oil this morning stone cold..it was 1/3 down from the full mark. I add 400 ml of oil..I drive 40 miles..to be sure..I wait 10 minutes after shut off and I'm still 1/3 down from the full mark. I add another 400 ml. what do you make of that?

 

[VaderSS]

With my LT1, it takes less than a minute to drain down.

When I did the oil change bit over the summer one year, I found that some engines, small block Dodges being one, IIRC, took up to 10 minutes to drain down. Most of the vehicles we handled were late model, lower mileage, so it was not indicative of a problem, unless it took substantially longer.

I recall having a one small block Chevy that took over 10 minutes to drain down. I had noticed that it had been 25000 miles since the last oil change from the window sticker. The date on the filter matched up with the sticker. The oil listed was Mobil 1, but that's a long stretch even for Mobil 1, and with no filter change... When the plug had been pulled, I noticed chunks coming out.

I immedietly let my boss know, and he informed the customer that his engine was badly sludged and probably needed dissasembly to clean. The customer requested a flush, understanding that it would probably plug something up. Sure enough, the oil pressure dropped to zero. We took the pan, valve covers, and intake off, and I swear, it looked like black jello except for little valleys where the oil had flowed. We cleaned it up, changed the oil pump, and he was on his way.

 

[JD Green]

Sounds like alot of owners manuals are pretty specific about when to check the oil. Here's one that's very vague. Here's 2 sentences from an owners manual for a Dodge Neon (2001). Check the oil level at regular intervals, such as every fuel stop. The best time to check the engine oil level is about 5 minutes after a fully warmed engine is shut off, or before starting the engine after it has sat overnight.
According to the above, I would think that the oil that's left in the top end of an engine (shortly after it is shut off) is minimal. This also tells me that you could theoretically check it whenever you wanted to.
BTW I have always checked my oil prior to starting a cold engine.

 

[Doug Hillary]

Hi,
this issue is a very real "problem" in some cases

In my 500hp Detroit Diesel engines we have found that the best time to check is prior to a cold start and on a known flat surface
Newly employed Drivers ( and some mechanics ) - even after detailed training - revert to familiar old practices and check the level when hot or at fueling
The result is wasted expensive synthetic topup oil!
And, it results in a reprimand to the individual concerned
Likewise, we know after millions of kms experience, that running the oil at midpoint ( between full and add marks ) on the dipstick and only adding enough to return to midpoint has a good effect on oil use. This is common with many engines

Most people cannot forget old/past practice

Regards

 

[97tbird]

Tom: "Warm!" we said. "How can this be?" So we called Ford and they told us that they determined that very few idiots like us were going out first thing in the morning in their bare tootsies and checking the oil. Most people, they said, tended to check their oil when they stopped for gas, when the engine was warm. So they simply recalibrated their dipsticks to read correctly in a warm engine, when the oil has heated up and expanded.
[/QB][/QUOTE]
========================
hmmmm....I have a 97 Ford T-bird.. i checked my oil when "stone-cold" after sitting overnight and it reads right at the "full" mark...this means when hot and expanded, the level will be _over_ the "full" mark....should I worry?

 

[TheTanSedan]

I'm not about to argue with Doug Hillary with this statement, I offer it as a rule-of-thumb for all vehicles: The Detroit Diesel engineering rep I spoke with at GATS several years ago said that on the 60-series (about 12 GALLONS capacity) that fifteen minutes after hot shutdown was adequate for a quick fuel-stop check, (800-900 miles or daily for a semi in OTR).

This is offered as a rule-of-thumb as, when I have finished slow-pumping gasoline in my personal vehicle, made other vehicle checks, paid, bought a Coke, what-have-you . . . more than 15" has gone by since shutdown. This r-o-t is for when I am under heavy load/towing.

Otherwise -- and our company shop guys told me the same thing with the Detroits -- check for level after six hours or more past shutdown in order to keep accurate consumption levels recorded.

Tires and all fluids ought to be checked cold and hot in order to keep a weather eye on what is happening. The owners manual spells out LIST #1 and common sense LIST #2, so to speak.

(Doug, I very much enjoy your many posts on maintenance, schedules, and experience in these forums. You've an avid reader here even though I no longer drive Class 8, I find that the attitude, the approach is pretty well the same for the best service and longest life from our personal or business light-duty vehicles.)

 

[RichR]

Rich, let's keep it clean. -Joe

[ December 07, 2003, 10:02 AM: Message edited by: joee12 ]