Will 15W/40W Full Synthetic Oil Be Any Good?

[lovesmyvoyager]

I have some oil left over that i used on my last car and wondering if its suitable for the voyager.

 

Its tescos own make full synthetic 15w/40w  and have about 6 litres left. Bought it when it was on offer at half price. 

 

I think the recommended is something like 5w/30w or 10w/30w but as i have enough left to do an oil change is it advisable?

 

its a 2003 2.5 crd. 

[Dazandtrace]

Hi stick to what should be used. 5/30 full synthetic. I use shell helix ultra. Very reasonable price euro car parts for 6ltrs about £30

[crispinchurch]

use 5w30 5w is telling you its very thin 15w is too think you could us it for a top up when it only needs half a pint 

asda sell 5/30 under £20 most of the time or europarts have 4l for £14

[Dazandtrace]

 

What's written on your oil bottle, and what does it mean?

 

This post may seem like going back to basics but I'm constantly surprised by the number of people who do not know, or understand, what is written on a bottle of oil, and therefore have no idea what they are buying/using.

To be blunt about the subject, if a bottle of oil does not contain the following basic information then DO NOT buy it! Look for something that does!

1) The purpose for which it is intended (i.e. Motor oil, Gear oil etc)

2) The viscosity (i.e. 10w40, 5w30 etc for Motor oils and 80w90, 75w90, etc for Gear oils)

3) The specifications that it meets (should contain both API and ACEA ratings)

4) The OEM Approvals that it carries and the codes (i.e. MB229.3, VW503.00, BMW LL01 etc)

Ignore the marketing blurb on the label - in many cases it's meaningless and I'll explain later what statements you should treat with some scepticism.

So, what does the above information mean and why is it important?

 

THE BASICS

 

All oils are intended for an application and in general are not interchangeable. You would not for example put an Automatic Transmission Oil or a Gear Oil in your engine! It's important to know what the oil's intended purpose is.

VISCOSITY

 

Most oils on the shelves today are "Multigrades", which simply means that the oil falls into 2 viscosity grades (i.e. 10w-40 etc)

Multigrades were first developed some 50 years ago to avoid the old routine of using a thinner oil in winter and a thicker oil in summer.

In a 10w-40 for example the 10w bit (W = winter, not weight or watt or anything else for that matter) simply means that the oil must have a certain maximum viscosity/flow at low temperature. The lower the "W" number the better the oil's cold temperature/cold start performance.

The 40 in a 10w-40 simply means that the oil must fall within certain viscosity limits at 100°C. This is a fixed limit and all oils that end in 40 must achieve these limits. Once again the lower the number, the thinner the oil: a 30 oil is thinner than a 40 oil at 100°C etc. Your handbook will specify whether a 30, 40 or 50 etc is required.

SPECIFICATIONS

 

Specifications are important as these indicate the performance of the oil and whether they have met or passed the latest tests, or whether the formulation is effectively obsolete or out of date. There are two specifications that you should look for on any oil bottle and these are API (American Petroleum Institute) and ACEA (Association des Constructeurs Europeens d'Automobiles) all good oils should contain both of these, and an understanding of what they mean is important.

API

 

This is the more basic as it is split (for passenger cars) into two catagories. S = Petrol and C = Diesel, most oils carry both petrol (S) and diesel © specifications.

Edited February 6, 2016 by Dazandtrace

[Dazandtrace]

Remember what you put in is what you get back. Buy cheap reduce engine performance and life span.

[QinteQ]

We in the UK only get 3 cold months and 1 zero°C month occasionally. I look at it the other way the 5 'W' is ok at°C but still copes fine with viscosity in our our temperate 3 month [Met office] sub 30°C summer and our 'cold running' engine. The UK current averages are around 15°C and the hottest UK place of 38°C has not been seen since the early 2000's some 16 years ago. So everyone has an opinion, mine is common sense - we have a voltage hungry car and a compression engine with the worlds worst CCA recommended battery. My radiator cooling fan has activated once in its life on a 2 hour motorway stop-start hold-up after a quick 3 hour run. I agree with Dazandtrace the cost difference between the semi and full is worth it for risk avoidance.

[tomada3]

hi i got v6 petrol had t reg v6 used cheap oil in that it was a mistake 

now have 53 reg v6 only use castrol magnatec fully synthetic 5w 30

had car nearly 3 yrs now when bought car i done oil and filter change and put in castrol magnatec 

car runs beautifly you can hardly hear it on tick over

[bignev]

If you have the original handbook (of any car) there is an interesting chart which shows the crossover ambient air temps of the oil grades.

As Qinteq says we don't exactly have real extremes of cold (2 years around 2008 ish excepting I believe).

But as 5w 30 is thinner it helps get round quicker on cold starts, and less drag on running.

One of the several reasons almost all stuff uses it now - fuel economy.

And people used to warm up engines before driving, a long time ago hey!

But as an old school engineer I used t worry how it could do its job when it was like pee when pouring it in, but it does.

I did try 10w 40 for a week in my 3.3 petrol as a flush through, didn't sound or feel or start any different.

Back to Magnatec after that.

 

On another point, lots don't recommend it, but I've used actual "Flushing Oil" on a few occasions in my 2.5 diesel van. It takes 8 litres!

Followed by a sacrificial oil change before putting the proper oil in. It looked like new through the filler for ages, and ran and sounded better too.

 

Just an interesting point, the motor factors tried to sell me 5w 30 full synthetic for it, after 6 years of 10w 40, their data base had changed. So I carried on with the 10w 40 semi it was built with. Had it just short of 10 years, and about 20 oil changes - because it can do lots of short trops some weeks which means repeated cold starts and the usual sooty diesel oil.

[bignev]

Managed to scan part of my book, shows that in theory 10w 40 is totally suitable for our climate.

 

But as mine is petrol, I have just read onwards, see this about the diesel oil - sorry to put the cat amongst the pigeons as it were, but Chrysler recommend 10W-40 for diesels, see the second page below.

Oil Grades.pdf

Edited February 7, 2016 by bignev

[bignev]

This is the next page refering to the oil for diesel engines.

Sorry, just proof read it!!!

Will rescan it later just on was out, it say " "Engine Oil requirements - Diesel Engines" the bit it missed.

Diesel engine oil.pdf

Edited February 7, 2016 by bignev

[QinteQ]

Managed to scan part of my book, shows that in theory 10w 40 is totally suitable for our climate.

 

But as mine is petrol, I have just read onwards, see this about the diesel oil - sorry to put the cat amongst the pigeons as it were, but Chrysler recommend 10W-40 for diesels, see the second page below.

Chrysler recommend 2.8's engine codes use semi 10-40 till 08 then fully synth 5-40 from 08. Semi 10-40 for the 2.5 engine codes - but for which country ?

[lovesmyvoyager]

thanks all for taking the time to reply. 

 

will use the 5w/30w full synthetic - just a shame i have the other oil left over and cant use. 

[bignev]

lovesmyvoyager - use that 15 / 40 to give your engine a good flush out of all that black cack.

And put some flush additive in the old crap oil before you drop it out - plenty hot - and you will see / feel a genuine difference.

Yes it will take you a bit longer on the drive, but worth it.

 

My time consuming technique for my vehicles (not every time guys no)

1 - drive the car get it hot, come home put the additive in, idle on the drive for recommended time until fans come in / go off (if they do on your diesels)

2 - drop old crap out. If you can bring yourself to do it swap an extra filter too.

3 - fill engine with your 15 / 40 (or in my case when I'm feeling OCD the flushing oil)

4 - run till hot again, or say 20 mins, with occasional fast idle

5 - drop that cack out and be surprised how black it still is

6 - change filter

7 - put in your lovely new 5W-30 and be surprsed how clean it is, for a bit anyway!

 

So to sum up, in Britain, for diesels, without any silly extreme cold winter days, either 5W-30 or 10W-40 is fine.

And basically for petrol the same ultimately, but with preference to 5W-30, semi synthetic.

And don't stretch oil change intervals, especially if you do towing, lots of idling, short journeys, my book says 10,000km (6250 miles) in that instance, or twice that if considered "normal" driving routine.

Petrols are down to 3000 miles for town work etc!!!!! Or 7500 miles for normal use.

Or you choose obviously, it's your engine.

Edited February 7, 2016 by bignev

[tomada3]

hi change mine every 3 months dont do lot miles hence the frequent oil changes lucky if do 3000 miles in 3 months mines v6 53 reg with 91000 miles on clock

[bignev]

Yep good idea, keep it looked after, they are ancient technology engines after all.

Not remotely like the "modern" stuff that will go ages between changes.