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Discussion Starter · #1 ·
Hi all

Engine oil level is slightly above minimum on a ST-3 (64 plate) and needs to be topped up. Can you please tell me what engine oil i should use as i have got seveal separate answers from various sources including:

Castrol Magnatec 5W-30 fully synth (A5)

Castrol Magnatec 5W-30 fully synth (A1)

Castrol Magnatec 5W-20

Hope you can advise

out of interest any idea what the A+number means?


2,602 Posts

You will never get a consensus of opinion on what oil to use on this, or any other, forum. The topic has been discussed many, many times and the threads always go the same way.

Some people (including some who work for Ford) say that the Mk7 ST has 5w30 put in it at the factory...

5w30 is what these engines have from factory and what ford dealers use, i work for ford and thats what we use
If it should have 5w20 in it,why does it come from the factory with 5w30 in it.
1L EcoBoost comes with 5w20 oil in it.
1.6 EcoBoost comes with 5w30 oil in it.
Others who work at a Ford Factory state that it comes with 5w20...

The 5w20 is much more expensive. I work with the castrol blokes every day & trust me they want to make more money, I mean ensure better running, higher performance & economy every day. I'm not here to make up things. The engine plant uses 5w20 & a tiny percentage of UV reactive dye to check for leaks. Up to you guys, but that's fact & ive worked there for 19 years in case you doubt my credentials.
People who have checked ETIS say it can use either...

I checked this on ETIS at work during the week, using the VIN of my car. It can use both. The spec sheet lists 5w-20 (WSS-M2C948-B) as recommended, 5w-30 (WSS-M2C913-C) as an alternative. My owners manual also states the same.
This appears to be backed up by Mountune (via a Ford Service Bulletin they have), although they use 5w20 when they service them...

Mountune said:
We use 5w20 on all Fiesta ST Mk7 services, 5w20 and 5w30 are a directly compatible oil and therefore you can use either - there is a Ford Service Bulletin to confirm this.
Some people say their manual (mine included) states that 5w20 is the first choice oil with 5w30 listed as an alternative. This is confirmed here, although it is more specific by naming Castrol or Ford oil as the suggested brands...


Some people are even more specific and state it should be Castrol Magnatec Professional.

Others have said their manual only states 5w20 is to be used...

...I'm still skeptical as to why there is this change to 5w-30. The manual states 5w20.
Some dealers use 5w30 (including mine who are Jacksons Ford of Henley), whilst other dealers use 5w20.

Some say that 5w30 is being used instead of 5w20 because it makes the engine quieter, others state it is used purely to save money.

Others use different brands that have the correct specification such as Millers or Shell Helix.

Basically, you need to decide which oil you are happy using. It has to be assumed that either 5w20 or 5w30 is acceptable, otherwise dealers all over the country would be at risk of invalidating warranties and leaving themselves open to litigation. Whether one oil is better than the other for the engine is open to debate and personal opinion and, like the tuning debate, there will never be a consensus of opinion.

I have 5w30 in mine, I trust Jacksons Ford of Henley and if it's good enough for them, it's good enough for me.

As for the "A" numbers, they've never been mentioned on here as far as I'm aware, but look at section 4 here for an explanation...

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