How long should a service test drive be?

[ThePrincipal]

Hi All,

Just had a car back from service at a dealer. How many miles would a dealer typically cover as part of a service?

[2 sMoKiN bArReLs]

5-10 depending on the car and what was being sorted

[ThePrincipal]

Just an oil and filter service

[2 sMoKiN bArReLs]

0-2



I'm guessing yours has done 100

...or if overnight the distance to the mechanic's house & back

[abzmike]

2 sMoKiN bArReLs said:

0-2



I'm guessing yours has done 100

...or if overnight the distance to the mechanic's house & back

Or a quiet evening minicabbing...

[The Surveyor]

ThePrincipal said:

Just an oil and filter service

Do you mean just 'an oil and filter' in which case I wouldn't expect them to drive outside the dealership at all.

If it's a minor service I would expect them to give it a road-test to check for faults but certainly nothing beyond 10 miles depending on how close the dealership is to open roads where they can get the car up to a decent (legal) speed.

[Ferruccio]

Always worth checking the max speed!

[caelite]

With my guy it depends what errands he had to run that day and what choice of cars he has lying about to run them in.

[Larry5.2]

Could have been used as a courtesy car for someone else's service...

[ThePrincipal]

The car was sent on a covered trailer to the main dealer and returned on one. While with the dealer the car has gained a few scratches and chips over the bodywork and wheels.

[Ferruccio]

You’ll need the before/after evidence.

[The Surveyor]

ThePrincipal said:

The car was sent on a covered trailer to the main dealer and returned on one. While with the dealer the car has gained a few scratches and chips over the bodywork and wheels.

OK, but how many miles did they actually do in the car ?

[cayman-black]

fk, that's just not funny.

[2 sMoKiN bArReLs]

The Surveyor said:

ThePrincipal said:

The car was sent on a covered trailer to the main dealer and returned on one. While with the dealer the car has gained a few scratches and chips over the bodywork and wheels.

OK, but how many miles did they actually do in the car ?

Yep, we are itching to know!

[belleair302]

Am hoping with a dash cam or Tracker you can find out exactly what was going on.

[voicey]

The Surveyor said:

Do you mean just 'an oil and filter' in which case I wouldn't expect them to drive outside the dealership at all.

With a dry sump it is absolutely necessary to drive the car to get the oil level correct.

For a regular annual service we'll typically drive the car 5 miles before and another 5 afterwards. For more involved work we'll drive more depending on the work. Setting a TCU up could involve quite a few miles.

[BarryP]

voicey said:

With a dry sump it is absolutely necessary to drive the car to get the oil level correct.
.

I would be very interested in your explanation for this statement.
As far as I'm aware, and that's due to working with dry sumped engines for about 40 years, the important factor is run the engine to ensure the oil is in the tank and get it up to the correct temp,as the oil will expand when hot. Most dry sumps will give an accurate level at about 80-90C. This can be achieved by running the engine static, can you explain why it is "an absolute necessity" to drive the car on the road to get an accurate oil level reading.

[voicey]

BarryP said:

I would be very interested in your explanation for this statement.
As far as I'm aware, and that's due to working with dry sumped engines for about 40 years, the important factor is run the engine to ensure the oil is in the tank and get it up to the correct temp,as the oil will expand when hot. Most dry sumps will give an accurate level at about 80-90C. This can be achieved by running the engine static, can you explain why it is "an absolute necessity" to drive the car on the road to get an accurate oil level reading.

As you rightly say, when setting the level on a dry sump engine you want the oil to be hot. In my opinion it needs to be as hot as possible which is best achieved after running the engine at higher speeds under load. If the level is set when running even slightly cooler temps then, when the oil does get hotter, the level can easily go over the max mark on the dipstick (because as you say it expands). The design of the oil separators on some cars allows oil to be sucked into the intake even with the slightest overfill. This can then easily contaminate the MAF sensor(s) causing all sorts of fuelling issues.

It is typical for a dry sumped supercar engine to hold up to 13 or 14 litres - when you factor in the fact that oil can expand 10-15% within the operating temperature window and that the min/max distance on the dipstick is usually just 1 litre, then the risk of an overfill is real.

For this reason I drive dry sumped cars to get the oil as hot as it will get under normal operating conditions and then set the level to midway between the min and max mark.

Edited for grammar

Edited by voicey on Thursday 1st November 07:44

[The Surveyor]

voicey said:

BarryP said:

I would be very interested in your explanation for this statement.
As far as I'm aware, and that's due to working with dry sumped engines for about 40 years, the important factor is run the engine to ensure the oil is in the tank and get it up to the correct temp,as the oil will expand when hot. Most dry sumps will give an accurate level at about 80-90C. This can be achieved by running the engine static, can you explain why it is "an absolute necessity" to drive the car on the road to get an accurate oil level reading.

As you rightly say, when setting the level on a dry sump engine you want the oil to be hot. In my opinion it needs to be as hot as possible which is best achieved after running the engine at higher speeds under load. If the level is set when running even slightly cooler temps then, when the oil does get hotter, the level can easily go over the max mark on the dipstick (because as you say it expands). The design of the oil separators on some cars allows oil to be sucked into the intake even with the slightest overfill. This can then easily contaminate the MAF sensor(s) causing all sorts of fuelling issues.

It is typical for a dry sumped supercar engine to hold up to 13 or 14 litres - when you factor in the fact that oil can expand 10-15% within the operating temperature window and that the min/max distance on the dipstick is usually just 1 litre, then the risk of an overfill is real.

For this reason I drive dry sumped cars to get the oil as hot as it will get under normal operating conditions and then set the level to midway between the min and max mark.

That's understood, but why do you have to drive the car? Yes, get the engine nice and hot but you don't have to do that 'under load'. I know owners who send their cars for a service with a note specifically instructing the dealer not to road test the car to ensure that no extra miles are put on it annually, the dealers are happy to service it on that basis.

As a side, checking the oil level in my 570s can only be done static, you can't perform the oil level check when the car is moving and there is no dipstick on the dry-sump tank. Car in neutral, foot on the brake, select oil level check on the menu, push the accelerator deep into the carpet and let the electronics do the rest.

[MDL111]

I am quite happy for them to drive it a significant distance and at high speeds to make sure everything works as it should