Engine oil question

xcessive · 1 May 2006 at 17:00

Hi

My friend bought his car round today (Ford Fiesta X reg) and i pointed out that his engine oil level was low.
The only engine oil i had in my garage is Castrol GTX Magnatec 10W-40. In the Fiesta handbook it states that it is recommended to use 5W-30 engine oil.
My friend topped up engine oil with the 10W-40 Castrol stuff and said it should be fine. It even says on the bottle 'recommended for modern engines' and his car is fairly modern.

Will his car be ok?

I have always been under the impression that you can't use different grade engine oil in the same engine. I assumed his car had already had 5W-30 in it so surely topping it up with 10W-40 is a bad idea, isnt it?

Thanks

Acolyte · 1 May 2006 at 17:03

The oils dont mix and it isnt a very good idea in the long run, its not a good thing to do. However it wont break the engine.

But i would do a complete oil change on the car anyway.

agw_01 · 1 May 2006 at 17:04

From what I can remember...

A viscosity rating of 10 will be thicker than 5 when the engine is cold. This means that the oil won't protect as well when the engine is first started.

With the viscosity of the Castrol oil being 40 rather than the 30 that is recommended, the oil will actually be thinner when hot than Ford recommend.

I once ran 15W40 in my car and had no problems.

xcessive · 1 May 2006 at 17:06

So, i take it it shouldnt be a problem in the short term but i will tell my friend that he would be better off getting a oil and filter change soon though ?

agw_01 · 1 May 2006 at 17:08

Yep. Also, best to check out where the oil is going. It's either leaking from somewhere (oil filter or sump probably) or is being burnt off.

xcessive · 1 May 2006 at 17:14

He hasnt got an oil leak.
He just doesnt ever check his fluid levels!

agw_01 · 1 May 2006 at 17:24

Well that oil is going somewhere

When was the last time he checked/had it checked/oil changed?

xcessive · 1 May 2006 at 17:30

agw_01 said:
Well that oil is going somewhere

When was the last time he checked/had it checked/oil changed?

He bought the Fiesta about 5 months ago and since then it hasnt been serviced.
The oil was only 2 notches above the minimum mark so i suggested it would be good to top up the oil so it doesnt fall below the minimum level.

He has never mentioned an oil leak so i assume there isnt one.

Simon · 1 May 2006 at 17:34

No point topping it up if it was above the minimum to be honest

thebrasso · 1 May 2006 at 18:31

A lot of cars will burn a bit of engine oil, but it shouldn't be a massive amount so I'd definitely get it checked for leaks.

[TW]Fox · 1 May 2006 at 18:36

His car has a Zetec engine. Ford recommend 5/30 for a reason - it is the correct oil for the engine and the wrong oil can cause serious problems.

He should get a complete oil and filter chang asap.

Fulcrum · 1 May 2006 at 18:44

Simon said:
No point topping it up if it was above the minimum to be honest

Unless he drives it around corners like an Elise he would have been fine. Only mix oils like that in emergency or if its a banger, my car I chuck anything in there but then the leak it has makes it like it gets an oil change reguarly anyway

agw_01 · 1 May 2006 at 18:54

xcessive said:
He has never mentioned an oil leak so i assume there isnt one.

You don't have to see oil on the floor to have a leak.

My oil level goes from max to empty in 5 weeks.

There's no oil deposits on the driveway (thank god, my Mum would kill me) but if you look at the sump, it's covered in it.

MrCake · 1 May 2006 at 18:56

As Fox said, get it changed asap! I seem to remember seeing something that using the wrong oil in the zetec lumps can cause major problems.

HonestJohn states for the fiesta engine that

Zetec S 1.25, 1.4 and 1.6 engines may have been filled with wrong oil (MUST be 5W-30). Wrong oil leads to sticking valves, blocked arteries and oil starvation problems.

Simon · 1 May 2006 at 19:05

A top up shouldn't be a problem. Contrary to common belief, oil's mix together without problem.

The 0w30 has now changed to a 2w32 oil with 1 litre of of 10w40.

iCraig · 1 May 2006 at 20:01

My friend had a 1.4 Zetec engine and used 10w-40.

About a week later the car was running like a dog and it was in the garage for a complete oil and filter change, and his valves cleaning.

The mechanic told him off for not reading his manual properly or seeking advice instead of just guessing the oil rating he would need.

My advice to you is to change the oil immediately, it will only cause more problems and money when the engine starts playing up if you've left it.

iCraig · 1 May 2006 at 20:04

Simon said:
A top up shouldn't be a problem. Contrary to common belief, oil's mix together without problem.

The 0w30 has now changed to a 2w32 oil with 1 litre of of 10w40.

It all depends on how much of the wrong oil was used. The issue isn't that the oils won't mix properly, its that the Yamaha Zetec engine is specifically designed to run on 5W-30. They have put the wrong oil in, and should drain it and put the proper oil in.

I'm sure the price of an oil change is pale in comparison to the engine valves and other parts needing to be cleaned.