does anyone know of a car that needs the engine running to check the oil?

[Zak33]

Just that really?

Is there such a car that needs the engine running to check the oil level?

[toolsong]

I've only heard of that in relation to checking the fluid level in some automatic transmissions.

[Zak33]

I'm dying to know which car, if any, needs this.

[TAKTAK]

But surely once you run the engine, it heats up and the viscosity of the oil would change? Giving an inaccurate reading (ish)

[chuckskull]

Some of the really big Caterpillar engines are checked while running. Never heard of a road car that does.

[TAKTAK]

Some of the really big Caterpillar engines are checked while running. Never heard of a road car that does.

I didn't know caterpillars had engines

[Shad]

Mine does

Caterham that is. I have an air/oil seperation device known as an Apollo tank, fitted to my K Series:

Alternatively known as an oil/air separator. Its job is to remove air bubbles that are generated in the engine as a natural "feature" of the way the engine is designed and installed in a 7. The Apollo is a tall, thin aluminium tank. The oil flow enters under pressure from the pump and swirls around the tank, exiting at the bottom. As the oil swirls, the air bubbles rise up the centre of the tank and exit through a restricted breather, venting to the cam cover. The return pipe feeds de-aerated oil to the filter and subsequently to the oil galleries in the engine. The tank adds approximately 2l to the oil system and as such can help marginally with lower oil pressure under cornering, but this is not its main purpose and results vary from one installation to the next, some people noticing no difference! What it does mean is that whatever oil reaches the engine is proper oil, and not a frothy mix of oil and water.

The end result is that the engine requires around 7.5 litres of oil to function because of the extra capacity in the tank and pipes. When the engine's not running the oil drains back into the sump and gives a very inaccurate reading!

Checking the Oil Level

Wet Sump
Run engine until oil is warm. Leave idling for 2 minutes on level ground.
While still running, dip using a sharp action to get a clean measurement. You can shutdown first as long as you dip immediately, but if you leave it for 30 seconds the oil drains from the head raising the oil level. If you cannot read the oil level on the dipstick because the oil is very clean, press the dipstick against a clean piece of paper towel and the oil will show up very clearly on the paper.

There have been two dipticks. The original Rover one was all yellow plastic and was modified by Caterham with a notch cut on it; the oil should be at the level of the notch. The new caterham specific dipstick has a yellow plastic hatched section on the end of a metal dipstick; the oil level should be at the top of the hatched section when measured in this way. Please note that the oil level is much higher than Rover ever intended for the engine and the oil level is very close to the opening of the dipstick tube in the sump. If you overfill the engine it may not show up as being any higher on the dipstick, so it is more important that you check frequently and add small mounts of oil; thinking you can get away with throwing in some extra oil to keep you going between less frequent checks is not good for your engine. The engine is non-standard on account of being fitted with a shallow sump.

Rationale (wet sump)
The original caterham instructions were to dip the engine at standstill. When the Apollo tank started coming into use, it was noticed that the oil in the sump was very low when the car was running - it is this oil level that is doing the important job of keeping the pickup immersed, so there was obviously more variation between running and resting oil levels with an Apollo tank equipped car than without. This was because the Apollo tank was draining back when the engine was not running giving a false high oil level reading.

It was also found that Rover fitted VVC engines with a different dipstick due to the amount of oil the VVC head retains. Caterham decided that, with all the different combinations, the simplest way was to check oil level with the engine running

Not an issue for most cars since the dip stick is designed with a cold engine in mind, i.e. to compensate for oil that has drained back from the head.


Apollo tank in situ


Slightly better view showing the connections with the rest of the engine

Hope that's useful

[Funkstar]

Is there such a car that needs the engine running to check the oil level?

Why do you ask?

What has prompted this curiosity?

[Butcher]

Mine specifies a warm engine - switch off for 30s then read the dipstick, rather then stone cold.

[Zak33]

Mine specifies a warm engine - switch off for 30s then read the dipstick, rather then stone cold.

yeah, many do.

but not running.....

[Knoxville]

Some of the big diesel perkins engines used in plant machinery need to be checked while running if my memory serves but I can't think of a road car that requires the same treatment.

[stevie lee]

and you lot call yourselves car enthusiasts, shame on you.

asked this question at work today and my mate geoff came up with the answer.

LANCIA BETA

had a dashboard oil meter that only worked when engine was turned on, also had dipstick.

heres a googled page - http://www.uniquecarsandparts.com.au...beta_coupe.htm

The Beta Coupe also came standard with some useful accessories, including an oil level gauge, oil pressure and temperature gauges; a rechargeable torch, underbonnet lighting, electric colling fan, Unus air-horns, four excellent Halogen headlights, adjustable steering cdlumn, two-speed and intermittent wipers. Unfortunately this was somewhat let down by the low-rent plastic facia, and the instruments were poorly caliibrated.

2nd paragraph from bottom.

[Zak33]

and you lot call yourselves car enthusiasts, shame on you.

asked this question at work today and my mate geoff came up with the answer.

LANCIA BETA

had a dashboard oil meter that only worked when engine was turned on, also had dipstick.

I had a Beta Monte Carlo and the oil meter on the dash was crap. DONT DIP IT with the engine running.. you'l regret it for as long as you have skin on your face.

[dkmech]

My problem with checking oil level is finding a flat enough piece of land to park on (dip stick on the side so tends to exaggerate on gradients)

[finlay666]

I had a Beta Monte Carlo and the oil meter on the dash was crap. DONT DIP IT with the engine running.. you'l regret it for as long as you have skin on your face.

Should have waited for the release candidate then