When is an engine more likely to leak oil? When it is warm or cold?

Question

Just curious, as I'm thinking of buying another car but want to know whether I should check for leaks when the car has been sitting for a while or after a test drive.

Answer 1

Both, but in a cold engine the seals and gaskets shrink slightly creating a bigger gap for oil to move through. When the engine warms up the seals swell slightly. Also, a running engine will have the tendency to blow the oil back across itself instead of drip straight down where you'd notice it on the ground. So it's always good to look under the car on the pavement to see if there are any wet puddles of fresh oil or antifreeze.

Answer 2

Oil can leak whether it's hot or cold so temperature really has nothing to do with it. It is more likley to show leaks after a good drive though b/c running the engine will get the oil circulating and if theres a leak anywhere you should be able to tell then. You should be able to tell just by looking under the car but it's always possible the seller has cleaned it to hide an oil leak.

Answer 3

When a car is cold the oil is thick but in the normal leak places, when its hot the oil is thinner but all over the engine. So the best time to check it is about 30 to 45 minutes after a good test drive and make sure the oil level is full before you test drive it.

Answer 4

Generally it will leak when warm because the oil is thinner. But normally the oil will sit on the engine parts or frame and drip while the car sits. So give the engine compartment a close look and have a flash light handy to look way down in where it is dark and if the engine is cold you can reach in and if your hand comes out oily you will know what you have got.

Answer 5

Check underneath the car first for leaks and then run it for a while to heat the car up.Look where you thought the car was leaking before and it should be tell tale.Use this bit of info for your answer:At 32 degrees it takes approximately three minutes for 10-40 motor oil to reach proper viscosity to free flow through the engine. Read it again I said FREE FLOWING, not three minutes to reach the top of the motor, there is a difference.Think about that and you have your answer.

Answer 6

Look around the engine for oil leaks and underneath the chassis. If you can see a visible oil leak... DON'T DRIVE THE CAR! Odds are it is going to leak oil when it is warm because the oil is thinned out.

Answer 7

Usually around the gasket of the head or the gasket to the oil pan. Sometimes the oil filter will leak if not put in properly. And it also can leak if the bolt to drain the oil was threaded wrong when put back in or not tight enough.

All above can be seen and happen hot or cold.

Answer 8

clean the section which you think of the oil is leaking from, then run the engine until it gets heat. (The oil thins because it gets heat). If the leak is from the distributor, replace the gasket with the appropriate one. If the single you put in became into too small, it could have chop up once you tightened the distributor. If the leak is coming from the manifold itself, the gasket could have slipped once you reinstalled the manifold. the only scientific care then is to take the manifold off and positioned a clean gasket in and use a stable extreme temp. silicone seal the place the manifold contacts the heads.

Answer 9

Mostly more when it's warm or hot, when the car is running the oil has a lot of pressure and the oil is thinner.

Answer 10

Check where the car is parked.Are has been setting in the same place for sometime.