Flooring It Cold Is DESTROYING Your Engine

Added: 2026-05-06

[00:00:00]If you understand this, you'll understand cold start wear. Oil keeps your engine from grinding itself to death by lubricating rotating parts, but way different from what you're imagining. It isn't normal lubrication.

[00:00:10]The journals of the crankshaft sort of grabs the oil and pulls it around itself like a blanket as it spins and creates a wedge between the spinning journal and the bore. This is just called a hydrodynamic wedge and it gets better.

[00:00:22]Metal on metal wear drastically decreases once this wedge forms, but when the parts stop moving, this wedge obviously isn't being created anymore.

[00:00:30]Oil leaks out of the clearance and after sitting overnight, it could take seconds in the worst case scenario for that wedge to form once the engine turns over. It depends on the design, but let's assume the worst case and say it actually takes a second or more. A disproportionate amount of true metal on metal wear occurs here. It isn't instant death because of boundary lubrication, which is literally just remaining oil and additives clinging to the metal surfaces. Then as it starts up, it's mixed between boundary and hydrodynamic and then finally it forms a full hydrodynamic wedge. This brief period you'd never even think about repeated over thousands of cycles accounts for a large portion of total engine wear.

[00:01:07]Engine wear you can avoid if you subscribe. But then 15 seconds after startup, you leave your driveway and floor it to clean your engine. Sure, the hydrodynamic wedge has formed, but then you remember the oil and metal are both cold and you're at 6,000 RPM. So, how screwed are you? Probably dead if it's a race engine. Not very screwed if it's a normal modern engine since there's still a wedge. Unfortunately, there are weak wedges, partial wedges, and unstable wedges. Flooring it cold can create any of the three or all at once. That's where the excess wear comes from [music] because cold oil doesn't flow at an optimal speed for higher RPM and load since it's five to 10 times thicker than when at operating temp. You could see this with a gauge because pressure is higher when cold. Pressure builds because of resistance to flow. Load can actually stabilize the hydrodynamic wedge at operating temp. It just can't work well outside of ideal conditions without fast oil flow constantly distributing and replenishing. If you lessen the load and just have RPM, you'd think you'd get the same wear if only it were that simple. RPM itself without heavy load when cold is still bad, but not nearly as bad because now you aren't hammering the rotating assembly downwards to break the weak hydrodynamic wedge you have at that RPM. You're just spinning. Like spinning a drill on a plank of wood and letting it spin instead of spinning it and pushing it down on that plank. The part everyone screws up is that cold oil clearances aren't always tighter than ideal. They can actually be looser. It all depends on metal expansion differences. Both are equally non-optimal flooring conditions.

[00:02:37]Just wait till your oil is up to temp to avoid this excess metal on metal wear and don't forget to subscribe.