Different oil after service

W0bble5

I have a 2006 Astra Sportshatch 1.4 that I'm going to service this weekend.

After the last service they put in 10w40 oil. I got the recommended 5w30 oil for the service.

A mechanic friend said that with my car 'used to running' the 10w40 oil I should keep using that from now on. Otherwise I could damage the engine.

Is there any truth to this? I would have thought that the car should have the better recommended oil regardless of what crap oil was in there previously.

Thoughts?.....

firefly08

I would have thought that the car should have the better recommended oil regardless of what crap oil was in there previously.

This. There is no reason not to switch back to the correct oil just because you've used the wrong oil before. Don't mix them of course; drain the old oil completely when you're switching back.

Not to say that the oil they used is necessarily 'crap', but if it's not what the manufacturer calls for, I'd replace it with the correct stuff, at least when the next oil change is due, if not sooner. The 30 and 40 in those numbers refer to the viscosity of the oil when it's at it's operating temperature - if the manual calls for 30 and you use 40, then your oil is always too thick for the engine. It might be OK for a while but I wouldn't use it for long. Some people like to second guess the manufacturer's recommendation, especially for extreme climates, but I wouldn't, and definitely not in Ireland where we don't have extreme hot/cold.

Nissan doctor

W0bble5 wrote: »

I have a 2006 Astra Sportshatch 1.4 that I'm going to service this weekend.

After the last service they put in 10w40 oil. I got the recommended 5w30 oil for the service.

A mechanic friend said that with my car 'used to running' the 10w40 oil I should keep using that from now on. Otherwise I could damage the engine.

Is there any truth to this? I would have thought that the car should have the better recommended oil regardless of what crap oil was in there previously.

Thoughts?.....

A trained and qualified mechanic told you this????

I hope he isn't servicing your car:rolleyes:

W0bble5

Nissan doctor wrote: »

A trained and qualified mechanic told you this????

I hope he isn't servicing your car:rolleyes:

He serviced it last time. And yes, he is trained & qualified with a main dealer. :P

I'm going to do it myself this time.....first time doing it but at least I'll know that the proper stuff will be going into it!

W0bble5

W0bble5 wrote: »

...........

A mechanic friend said that with my car 'used to running' the 10w40 oil..................

A complete f _ _ _ tard by the sounds of it.

You should run the car on the 5w30, the risk of engine damage (premature wear) has been increased a little (tiny but still) by having 10w40 in there.

W0bble5

RoverJames wrote: »

A complete f _ _ _ tard by the sounds of it.

Thought as much! I only got him to service the car last time as a kind of favour to him. Think I'll take the chance myself!

George Dalton

There is an element of truth in what he says. If 10w40 semi synthetic was used in the engine for an extended period of time then changing over to the recommended fully synthetic with its higher detergent content could in theory dislodge a load of crap inside the engine and cause problems.

However if the "wrong oil" was only used for one or two services then it should be safe to change back to the recommended oil.

W0bble5

George Dalton wrote: »

There is an element of truth in what he says. If 10w40 semi synthetic was used in the engine for an extended period of time then changing over to the recommended fully synthetic with its higher detergent content could in theory dislodge a load of crap inside the engine and cause problems.

However if the "wrong oil" was only used for one or two services then it should be safe to change back to the recommended oil.

I think the 10w40 was used the last year, maybe 2. If using 5w30 fully synthetic dislodges crap do you reckon another oil and filter change in a few thousand k's would help clean it out?

CiniO

W0bble5 wrote: »

I think the 10w40 was used the last year, maybe 2. If using 5w30 fully synthetic dislodges crap do you reckon another oil and filter change in a few thousand k's would help clean it out?

TBH if I were you, I would stick to 10w40 at this stage.
As mentioned above using 5w30 might cause trouble by dislodging.
It's not just urban legend, I've seen that happened in reality, where after switching from 10w40 to 5w40 engine started leaking oil.

Whateven manufacturer recommends he has to take an account for all possible climate conditions engine will be running at.
While you wouldn't want to start that engine at -40*C in Syberia with 10w40 from cold, there should be no problems with doing it in Dublin at +2*C

However that's just my own opinion.

CiniO

CiniO wrote: »

............ I've seen that happened in reality, where after switching from 10w40 to 5w40 engine started leaking oil...........

Coincidence imo.

kerten

RoverJames wrote: »

Coincidence imo.

I experienced a similar leak(rocker cover gasket) just after I switched from 10-40 semi to 5-30 full on primera 2.0. It may be coincidence or not. We all heard "use thicker oil to hide leaks" suggestion, so it could be thicker oil hiding a weak gasket situation in my case.

W0bble5

CiniO wrote: »

..... engine started leaking

What would make a perfectly sealed engined start leaking just by changing the oil?? Surely if all gaskets and seals are doing their job now then changing the grade of oil to the manufacturers recommended wouldn't make them suddenly perish?