Riddle Me This -- Mystery Oil Check Thread - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Camarotobeornottobe · 06-14-2015, 07:12 AM

So, my car is a weekend toy, so it doesn't get driven often. I changed the oil last September (with 875 miles) and put in Amsoil. I don't remember if I filled to the top of the 'crosshairs' section, but I know if was in the middle somewhere.

Fast forward to last week, the car as 2500 miles, I check the level, and I find it slightly below the very middle of the crosshairs. Keep in mind, the engine is cold and on a level spot . . .the car's spot in the garage. All in all, good to go, since I know it is in the sweet spot and possibly where I originally filled it last September.

Yesterday, I check again on a hunch, cold engine, hadn't been run for hours, and in the same spot, and it is at the bottom of the crosshairs. I'm a little concerned that it went down so much after only about 100 miles, so I check it three times. Finally, I conclude that I ran the pi$$ out of it the last week or so and decide I probably just got some higher amounts of blow-by. The catch can had about 2 oz in it. I topped off with almost a full quart of Mobil 1 and decided to monitor it.

I let that oil sit for a hour, and then I check it again three times. It now shows at the top of the crosshairs. All makes sense, right?

I then take a 25 mile cruise around town. I come home and park the car in the same spot in my garage. I let the car sit for two hours. I then check the oil and . . . . it is overfilled (passed the crosshairs) by almost 1/2 quart. WTF.

I check it five times over the next hour cause I can't figure out what changed. Yep, it is overfilled. So, I gently unscrew the drainage bolt and let a little over 1/2 quart out. I then check again, at least 5 times, and I'm nicely just below the top crosshairs mark. Perfect.

Checked again this morning after sitting overnight, and it is still right below the top of the crosshairs and perfect.

WTF? When it showed at the bottom of the crosshairs yesterday, I must have checked it 5 times. It was level (same spot as the other times in my garage). The car was cold. I even started the car after, let it sit two hours, and checked again with the same result -- bottom of the crosshairs.

I'm happy that I am apparently not losing any oil like I feared, but what explains the strange reading from yesterday? I can program my VCR, if you know what I mean, so checking oil is not outside my abilities

christianchevell · 06-14-2015, 09:17 AM

the upper valve train will hold enough oil to make it interesting..... it sits in the back corners of the heads, and of course you have hydraulic lifters full of oil and rockers that get coated in oil..... So really you need to go with what you know.... If you had a oil change and you know its got 8 qts and the engines not over 100k then rely on it to be full the gaskets are tight the oil pressure up, its not like my old SBC/BBC cars the gaskets are not felt and seeping and getting brittle.....the rear main is not tossing oil either, and some times a little extra oil would not hurt anything either, but you do not want so mush its going to get thrown around by the crank over the windage tray.

Camarotobeornottobe · 06-14-2015, 02:10 PM

Alright, new theory.

I get up this morning and check the oil -- as before, it is at the top of the crosshairs.

I run the engine for two minutes, and then shut it down without moving it. I wait two hours and check, and the oil shows almost 1/2 quart lower than it did!

I take the car out for a 30 mile run, then park it back in the same spot. I check it 20 minutes later, and it is at the top again!

My theory is that when the engine is shut down with the engine oil still cold, a small amount (maybe 1/2 qt) sticks up in various parts of the motor even after a significant time period. But, when run until hot, the oil thins out and all of it falls back to the oil pan when shut down. Kind of like what ChristianChevelle was saying, only I would take it a step further and note it is temperature (of the oil) dependent.

shibbs · 06-14-2015, 02:27 PM

I know my Subaru needed to sit for around 15 minutes before checking the oil level after being run. And yes, always check it hot.

I guess that just "broke" me and I still let it sit before checking it to this day.

Banshee · 06-14-2015, 02:37 PM

I always check it hot.

Try this...check it hot...wait a specified time of 30 minutes exact. Don't matter where you are...I assure you the reading will be the same if you check it however many times while hot.

Camarotobeornottobe · 06-14-2015, 03:43 PM

Yeah, I always allow it to sit for at least 15 minutes after running before checking. The difference seems to be whether the oil was hot or cold when I shut it down before that 15 minute period.

Am I off base in thinking that the 1/3-1/2 qt difference is because the oil stays caught up in the engine when thick and cold versus hot and thin? Again, assuming you always wait to check at least 15 mins after shutdown?

06-14-2015, 07:12 AM	#1
Camarotobeornottobe Drives: 1LE Join Date: Feb 2013 Location: East Coast Man Posts: 550	Riddle Me This -- Mystery Oil Check Thread So, my car is a weekend toy, so it doesn't get driven often. I changed the oil last September (with 875 miles) and put in Amsoil. I don't remember if I filled to the top of the 'crosshairs' section, but I know if was in the middle somewhere. Fast forward to last week, the car as 2500 miles, I check the level, and I find it slightly below the very middle of the crosshairs. Keep in mind, the engine is cold and on a level spot . . .the car's spot in the garage. All in all, good to go, since I know it is in the sweet spot and possibly where I originally filled it last September. Yesterday, I check again on a hunch, cold engine, hadn't been run for hours, and in the same spot, and it is at the bottom of the crosshairs. I'm a little concerned that it went down so much after only about 100 miles, so I check it three times. Finally, I conclude that I ran the pi$$ out of it the last week or so and decide I probably just got some higher amounts of blow-by. The catch can had about 2 oz in it. I topped off with almost a full quart of Mobil 1 and decided to monitor it. I let that oil sit for a hour, and then I check it again three times. It now shows at the top of the crosshairs. All makes sense, right? I then take a 25 mile cruise around town. I come home and park the car in the same spot in my garage. I let the car sit for two hours. I then check the oil and . . . . it is overfilled (passed the crosshairs) by almost 1/2 quart. WTF. I check it five times over the next hour cause I can't figure out what changed. Yep, it is overfilled. So, I gently unscrew the drainage bolt and let a little over 1/2 quart out. I then check again, at least 5 times, and I'm nicely just below the top crosshairs mark. Perfect. Checked again this morning after sitting overnight, and it is still right below the top of the crosshairs and perfect. WTF? When it showed at the bottom of the crosshairs yesterday, I must have checked it 5 times. It was level (same spot as the other times in my garage). The car was cold. I even started the car after, let it sit two hours, and checked again with the same result -- bottom of the crosshairs. I'm happy that I am apparently not losing any oil like I feared, but what explains the strange reading from yesterday? I can program my VCR, if you know what I mean, so checking oil is not outside my abilities

06-14-2015, 09:17 AM	#2
christianchevell old school chevy rodder Drives: 2021 zl1 a-10 WildCherry Join Date: Jul 2012 Location: Oregon Posts: 5,622 View My Garage	the upper valve train will hold enough oil to make it interesting..... it sits in the back corners of the heads, and of course you have hydraulic lifters full of oil and rockers that get coated in oil..... So really you need to go with what you know.... If you had a oil change and you know its got 8 qts and the engines not over 100k then rely on it to be full the gaskets are tight the oil pressure up, its not like my old SBC/BBC cars the gaskets are not felt and seeping and getting brittle.....the rear main is not tossing oil either, and some times a little extra oil would not hurt anything either, but you do not want so mush its going to get thrown around by the crank over the windage tray. __________________ 2021 Wild Cherry ZL1 A10, Sunroof, Data,Red Carbon Interior, Nav, RotoFab Big Gulp , Elite x2ultra, Borla ATAK, Driveshaft shop, BMR susp, Speed covers, intercoolers, ATI , 2650 MAG, DSX lid, 103 NW, TSP Longtubes & cats, LPE, 1le mods, ,LME cover, Katech pump and chain, Trunnions, BTR stage 2, LPE boostapump, Gforce, Speed eng , Granetteli, etc etc

06-14-2015, 02:37 PM	#5
Banshee Institutionally Insane Drives: 2013 IOM 2SS/RS 1LE Join Date: Feb 2009 Location: Detroit MI Posts: 2,115 View My Garage	I always check it hot. Try this...check it hot...wait a specified time of 30 minutes exact. Don't matter where you are...I assure you the reading will be the same if you check it however many times while hot. __________________ It's got a cop motor, a 440 cubic inch plant, it's got cop tires, cop suspension, cop shocks. It's a model made before catalytic converters so it'll run good on regular gas. What do you say, is it the new Bluesmobile or what?

06-14-2015, 02:10 PM	#3
Camarotobeornottobe Drives: 1LE Join Date: Feb 2013 Location: East Coast Man Posts: 550	Alright, new theory. I get up this morning and check the oil -- as before, it is at the top of the crosshairs. I run the engine for two minutes, and then shut it down without moving it. I wait two hours and check, and the oil shows almost 1/2 quart lower than it did! I take the car out for a 30 mile run, then park it back in the same spot. I check it 20 minutes later, and it is at the top again! My theory is that when the engine is shut down with the engine oil still cold, a small amount (maybe 1/2 qt) sticks up in various parts of the motor even after a significant time period. But, when run until hot, the oil thins out and all of it falls back to the oil pan when shut down. Kind of like what ChristianChevelle was saying, only I would take it a step further and note it is temperature (of the oil) dependent.

06-14-2015, 03:43 PM	#6
Camarotobeornottobe Drives: 1LE Join Date: Feb 2013 Location: East Coast Man Posts: 550	Yeah, I always allow it to sit for at least 15 minutes after running before checking. The difference seems to be whether the oil was hot or cold when I shut it down before that 15 minute period. Am I off base in thinking that the 1/3-1/2 qt difference is because the oil stays caught up in the engine when thick and cold versus hot and thin? Again, assuming you always wait to check at least 15 mins after shutdown?