Quote:
Originally Posted by bl52krz
Checked when hot, normal running temperature, will give a false reading of being higher than it should be from thermal expansion. Law of physics.
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Hi David,
MG Rover issued a technical bulletin to dealers on the subject of checking the oil level of the KV6 engine. You are quite right that it is permissible to check the level when the engine is cool
provided that sufficient time has been allowed for the oil to drain down from the upper parts of the engine. If sufficient time has not elapsed a low dipstick reading will result. This must have been a regular occurrance for MG Rover to go to the trouble of issuing a bulletin. This document specifically recommends taking the measurement on a hot engine after waiting five minutes as you can see here:
"A significant amount of engine oil is retained in the upper levels of the engine. Should a level check be carried out on an engine that has recently been switched off, a low oil level reading may result. This may mislead dealers and customers into concluding that the engine has consumed a quantity of oil.
A revised oil level checking procedure has been developed and will be introduced into future editions of the owners handbook. The procedure is as follows:
1. Ensure that the engine is at full working temperature. Turn off the engine.
2. Remove the dipstick and allow the oil to drain down for 5 minutes.
3. Clean the dipstick and insert it gently into the tube until the 'O' ring on the handle moulding is about to enter the tube.
4. Slowly push dipstick fully home.
5. Wait for 5 seconds, withdraw the dipstick and take the level reading.
Should a second reading be required it will be necessary to repeat operations 2 to 5 to allow the dipstick tube to drain down. Similarly, should it be necessary to add oil to the engine, operations 2 to 5 must be repeated."
This is the official advice which I have passed on to members several times, including in this thread.
I suspect that the recommendation to ensure that the engine is at normal working temperature is because the oil will flow out of the upper parts of the engine much more readily than when it is cold.
I expect that MG Rover considered any increase in oil level due to thermal expansion to be so small that it can be disregarded.
Simon