I have always been of the belief that it is better to let a cold engine idle for about 30 seconds before driving to allow time for the oil to be pumped througout the engine. Am I wasting gas?
Cold engine-Drive immediately or warm-up?
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I at least wait until the RPM's drop after the initial start, then take it easy until the car is warm.
I'd think in SC you can jump in and go within seconds, compared to starting a car in 0F a few dozen times a year its nothing.
Just take it easy until the engine is warm.
Until the idle drops, usually 30 sec to 2 min depending on outside temps. My cars always seem to run better if I wait for the ECU to be running off the O2 sensor (closed loop) before driving off slowly and under 2500 rpm for a couple minutes.
Originally Posted By: addyguy
For 30 seconds, no.
For 5 minutes, yes.
+1 At home, I start the engine and immediately pull out of the garage and stop. I then fasten my seat belt and close the garage door. That gives the engine plenty of time to get the oil circulating. I then drive off, but use conservative throttle settings and shift points.
Warming an engine up was much more important in the days of straight 30 weight oil and carbs. Of course, my old truck does still have a carb, but I never ran anything heavier than a 10W-30 and have retrofitted it to 5W-30 years ago.
For 30 seconds, no.
For 5 minutes, yes.
+1 At home, I start the engine and immediately pull out of the garage and stop. I then fasten my seat belt and close the garage door. That gives the engine plenty of time to get the oil circulating. I then drive off, but use conservative throttle settings and shift points.
Warming an engine up was much more important in the days of straight 30 weight oil and carbs. Of course, my old truck does still have a carb, but I never ran anything heavier than a 10W-30 and have retrofitted it to 5W-30 years ago.
It all depends on temp for me, but I've determined that for my car, it works out pretty well if I wait until the coolant temp gets 100* or so, as the timing coincides pretty well with the actual wait.
When it is 70* out, the oil just needs to circulate to the head and such. This doesn't long. Although, I still don't push it until well after the coolant has reached operating temp (no oil temp guage).
When it is 30* out, the coolant starts out at 40 or 50* so it takes some time for even the coolant to warm up. Running 0w-30, I don't think I need to sit for 5 minutes. If the oil flows at -30* I'm pretty sure that by the time my block gets a decent bit warmer than the outside temp I'm fine.
Maybe that is just me though.
When it is 70* out, the oil just needs to circulate to the head and such. This doesn't long. Although, I still don't push it until well after the coolant has reached operating temp (no oil temp guage).
When it is 30* out, the coolant starts out at 40 or 50* so it takes some time for even the coolant to warm up. Running 0w-30, I don't think I need to sit for 5 minutes. If the oil flows at -30* I'm pretty sure that by the time my block gets a decent bit warmer than the outside temp I'm fine.
Maybe that is just me though.
I dont doubt much, but I doubt that, Mega.
Originally Posted By: BeanCounter
... Running 0w-30, I don't think I need to sit for 5 minutes. If the oil flows at -30* I'm pretty sure that by the time my block gets a decent bit warmer than the outside temp I'm fine.
Maybe that is just me though.
That could be an incorrect assumption. The flow above at or above 10F has more to do with the test SAE Viscosity than the winter rating. A 0w40 will be much more viscous than a 5w30, and a 5w20 will be MUCH LESS viscous than a 0w30. In general though, a 0w should be somewht less viscous than a 5w, but not so if its a THICK 30w like Gc versus say PYB 5w30 which would be less viscous than the GC at 10F. I use 10F because its a more common cold start temp for many than -30F. Ive never started a car at any temp below -20F. Too cold to leave the house and VERY VERY hard on the car.
... Running 0w-30, I don't think I need to sit for 5 minutes. If the oil flows at -30* I'm pretty sure that by the time my block gets a decent bit warmer than the outside temp I'm fine.
Maybe that is just me though.
That could be an incorrect assumption. The flow above at or above 10F has more to do with the test SAE Viscosity than the winter rating. A 0w40 will be much more viscous than a 5w30, and a 5w20 will be MUCH LESS viscous than a 0w30. In general though, a 0w should be somewht less viscous than a 5w, but not so if its a THICK 30w like Gc versus say PYB 5w30 which would be less viscous than the GC at 10F. I use 10F because its a more common cold start temp for many than -30F. Ive never started a car at any temp below -20F. Too cold to leave the house and VERY VERY hard on the car.
I get in and go very gently for the first few minutes. The engine warms up best by being driven, not idling.
As long as you're easy on it, there's no reason to waste gas idling.
As long as you're easy on it, there's no reason to waste gas idling.
Originally Posted By: ARCOgraphite
Originally Posted By: BeanCounter
... Running 0w-30, I don't think I need to sit for 5 minutes. If the oil flows at -30* I'm pretty sure that by the time my block gets a decent bit warmer than the outside temp I'm fine.
Maybe that is just me though.
That could be an incorrect assumption. The flow above at or above 10F has more to do with the test SAE Viscosity than the winter rating. A 0w40 will be much more viscous than a 5w30, and a 5w20 will be MUCH LESS viscous than a 0w30. In general though, a 0w should be somewht less viscous than a 5w, but not so if its a THICK 30w like Gc versus say PYB 5w30 which would be less viscous than the GC at 10F. I use 10F because its a more common cold start temp for many than -30F. Ive never started a car at any temp below -20F. Too cold to leave the house and VERY VERY hard on the car.
I run Amsoil SSO so I'm not too terribly worried about it, to be honest. Anytime other than lower winter temps here, the idle doesn't even start higher and then drop after about the first second or two the car starts up.
Originally Posted By: BeanCounter
... Running 0w-30, I don't think I need to sit for 5 minutes. If the oil flows at -30* I'm pretty sure that by the time my block gets a decent bit warmer than the outside temp I'm fine.
Maybe that is just me though.
That could be an incorrect assumption. The flow above at or above 10F has more to do with the test SAE Viscosity than the winter rating. A 0w40 will be much more viscous than a 5w30, and a 5w20 will be MUCH LESS viscous than a 0w30. In general though, a 0w should be somewht less viscous than a 5w, but not so if its a THICK 30w like Gc versus say PYB 5w30 which would be less viscous than the GC at 10F. I use 10F because its a more common cold start temp for many than -30F. Ive never started a car at any temp below -20F. Too cold to leave the house and VERY VERY hard on the car.
I run Amsoil SSO so I'm not too terribly worried about it, to be honest. Anytime other than lower winter temps here, the idle doesn't even start higher and then drop after about the first second or two the car starts up.
gathermewool
Site Donor 2025
It's less about oil flow than it is about excessive heatup rates causing thermal stresses on engine components. The heat has to transfer from the combustion chamber to the cylinder walls/pistons/heads and then into the cooling system. Each of these is a different shape (and some times a different material) and will expand faster or slower than a contiguous component.
For my older car, I do exaclty what Arcographite does in waiting for closed loop fueling, which could take 0 seconds in the summmer to 1 minute in the winter, though I never warm up more than one minute unless my car is iced over and needs some help defrosting.
For the newer car, I wait the 15 seconds for the air pump to shut off before driving away.
For both I drive gently, and increase load slowly as the coolant temp rises. I don't really get on either car until after 5-10 minutes.
For my older car, I do exaclty what Arcographite does in waiting for closed loop fueling, which could take 0 seconds in the summmer to 1 minute in the winter, though I never warm up more than one minute unless my car is iced over and needs some help defrosting.
For the newer car, I wait the 15 seconds for the air pump to shut off before driving away.
For both I drive gently, and increase load slowly as the coolant temp rises. I don't really get on either car until after 5-10 minutes.
The aforementioned cold start testing is a routine part of most engine development. Start it, gun it, apply full load, repeat!
I actually witnessed a 5.7 Hemi test in 03 where they pumped FREEZING coolant into an overheated motor on the dyno!
I think if you want to baby your car a bit while cold it's fine.
I actually witnessed a 5.7 Hemi test in 03 where they pumped FREEZING coolant into an overheated motor on the dyno!
I think if you want to baby your car a bit while cold it's fine.
gathermewool
Site Donor 2025
I can't see a motor being frequently heavily loaded just after starting in below-freezing temps lasting 200kmi is all I'm saying. If you trade your vehicle in every 50kmi, then do what ever you want, and buyer beware of your used car. ; )
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Remeber that the EP adds dont work cold, the viscous oil doesnt get up the pistons too well. Cars Ive had ALWAYS ran poorly if tromped on cold.
Originally Posted By: labman
+1 At home, I start the engine and immediately pull out of the garage and stop. I then fasten my seat belt and close the garage door. That gives the engine plenty of time to get the oil circulating. I then drive off, but use conservative throttle settings and shift points.
That's the exact procedure I use. I go after the door is fully shut. I even disabled the chime in my dash so I don't have to listen to my car complain about my lack of seatbelt usage during the process!
+1 At home, I start the engine and immediately pull out of the garage and stop. I then fasten my seat belt and close the garage door. That gives the engine plenty of time to get the oil circulating. I then drive off, but use conservative throttle settings and shift points.
That's the exact procedure I use. I go after the door is fully shut. I even disabled the chime in my dash so I don't have to listen to my car complain about my lack of seatbelt usage during the process!
This topic seems to be popular. I let the engine tell me when to start driving. I start it up and wait for engine to get to about 1000 rpms. This can take from about 30 seconds to ~2 minutes. A racing engine doesn't do a clutch much good, and isn't good for an automatic transmission either. JMO
Originally Posted By: ARCOgraphite
I dont doubt much, but I doubt that, Mega.
Actually Mega is correct, only they run the test at -20 not -40.
Here is from bbobynski GM engineer (Post 130078)
"In the case of the Mobil 1 in the Corvette I would hazard a guess that the number of dyno engines run with Mobil 1 is in the hundreds....like somewhere between 200 and 300 all total. These are engines that run for 200, 300 , 400 or more hours at full throttle, max RPM, max power and are then torn down and analyzed in a variety of ways for wear and other lubrication performance. This is on top of the countless specific bench and dyno tests run on the specific lubrication system, cold start lube system performance, cold overpressurizaration (start at -20 and go immediately to 5000 RPM), cold start field testing and driveability, engine cooling testing, etc. Fleets or test cars are running with the production intent designs and lubes on accelerated durability, endurance, emissions, track testing, etc... The products are testing far in excess of what any customer can do.
"
I dont doubt much, but I doubt that, Mega.
Actually Mega is correct, only they run the test at -20 not -40.
Here is from bbobynski GM engineer (Post 130078)
"In the case of the Mobil 1 in the Corvette I would hazard a guess that the number of dyno engines run with Mobil 1 is in the hundreds....like somewhere between 200 and 300 all total. These are engines that run for 200, 300 , 400 or more hours at full throttle, max RPM, max power and are then torn down and analyzed in a variety of ways for wear and other lubrication performance. This is on top of the countless specific bench and dyno tests run on the specific lubrication system, cold start lube system performance, cold overpressurizaration (start at -20 and go immediately to 5000 RPM), cold start field testing and driveability, engine cooling testing, etc. Fleets or test cars are running with the production intent designs and lubes on accelerated durability, endurance, emissions, track testing, etc... The products are testing far in excess of what any customer can do.
"
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