Question for car mechanics

[LoveCurryPies]

Just took my car in for the annual service and MOT. Thought I would give Halfords a go.

On arriving I was asked “Would you like additives in your oil and petrol to make the engine run smoother? Normally £20 each but our offer is £30 for both”.

In 40 years of owning cars I have never been offered this, so declined the offer. My car is a 14 year old Mercedes and only doing 4,500 a year.

My question is (a) what additives are they talking about, and (b) is it worth doing?

[ClaretEngineer]

No. Simply not required.

Mercedes engineers know far better than any Halfords salesperson.

If you use Mercedes specification oils and lubricants there’s no need to add anything extra. I service and maintain my own 13 year old Mercedes diesel.

[lesxdp]

Fairly sure that most manufacturers say not to use additives

[Tricky Trevor]

Back in the day I was advised to pour Redex into my carburettor and rev the guts out of the car for a couple of mins. When I drove away the full length of the bottom half of my exhaust was lying in the road. Never again. If it needed additives it would be in your handbook.

[Bosscat]

Just took my car in for the annual service and MOT. Thought I would give Halfords a go.

On arriving I was asked “Would you like additives in your oil and petrol to make the engine run smoother? Normally £20 each but our offer is £30 for both”.

In 40 years of owning cars I have never been offered this, so declined the offer. My car is a 14 year old Mercedes and only doing 4,500 a year.

My question is (a) what additives are they talking about, and (b) is it worth doing?

NO

[LoveCurryPies]

Thanks for the replies. Really appreciated! MOT passed.

[Lowbankclaret]

The only additive I have seen have any benefit was slick 50. But then you see reports saying things against it.

The two cars I used it on certainly did a few more mpg afterwards.

[GodIsADeeJay81]

As mentioned, with the right oil used additives aren't needed.

Mind you it is halfords so I doubt the oil they use is up to standard anyway.

[Rick_Muller]

Whilst we have the attention of mechanics... how come a 75k mike service for a 3 year old Honda Civic is £600 when there’s only a couple of additional items above the normal fluid changes (I think pollen filter change and gearbox fluid change)...?

And where can I find out exactly what should be done for each service...?

[beddie]

Not a Mechanic but I've found if I change the oil and filter every 10,000 and use good petrol/diesel (Esso-Shell-BP) the car runs like a dream. Currently getting 62 mpg and I don't hang about.

[GodIsADeeJay81]

Whilst we have the attention of mechanics... how come a 75k mike service for a 3 year old Honda Civic is £600 when there’s only a couple of additional items above the normal fluid changes (I think pollen filter change and gearbox fluid change)...?

And where can I find out exactly what should be done for each service...?

Manual or automatic?
Manual is easy to change and it's only a couple of litres.

Automatic is time consuming, can be 7plus litres plus a filter and gaskets.

As for finding out what required, what does your service books state?

[Rick_Muller]

Manual or automatic?
Manual is easy to change and it's only a couple of litres.

Automatic is time consuming, can be 7plus litres plus a filter and gaskets.

As for finding out what required, what does your service books state?

Manual mate, I’ll check the service book. I was just surprised that a normal service is about £200 then this one service is £600

[GodIsADeeJay81]

Manual mate, I’ll check the service book. I was just surprised that a normal service is about £200 then this one service is £600

Hmm did they do brake fluid and anti freeze?

[Tricky Trevor]

Manual mate, I’ll check the service book. I was just surprised that a normal service is about £200 then this one service is £600

Do you have expensive plugs? I had a Renault Scenic and the coil was built into each one making them £40 apiece.

[Rick_Muller]

Hmm did they do brake fluid and anti freeze?

Don’t know tbh - not done it yet, it’s the next one... I have extended warranty so not sure if I can go else where. I wanted to set up a service plan, but the cost of that one surprised me

[GodIsADeeJay81]

Don’t know tbh - not done it yet, it’s the next one... I have extended warranty so not sure if I can go else where. I wanted to set up a service plan, but the cost of that one surprised me

Due to the Block exemption act within reason you can go anywhere, just check small print.

So long as garage is vat registered and using proper oil and quality filters it's usually fine.

[GodIsADeeJay81]

Do you have expensive plugs? I had a Renault Scenic and the coil was built into each one making them £40 apiece.

You mean you had individual coil packs on each cylinder instead of one pack with 4 leads.

Yeah they're common for failing because water leaks onto the top of them from the bonnet

[Tricky Trevor]

You mean you had individual coil packs on each cylinder instead of one pack with 4 leads.

Yeah they're common for failing because water leaks onto the top of them from the bonnet

They were a crap idea that Renault soon ditched. Renault recommended that if one went you change all four. Sod that.
I take it you’re meaning condense from the bonnet? It does sound feasible.

[GodIsADeeJay81]

They were a crap idea that Renault soon ditched. Renault recommended that if one went you change all four. Sod that.
I take it you’re meaning condense from the bonnet? It does sound feasible.

They recommend it because it's usually more than one that fails, I'd be the same at my workshop tbh.

In regards to the bonnet, water drips down when it rains and lands pretty much on top of the coil packs.
Results in them corroding around the plugs and the bolts that hold them in place also have a tendency to snap.

[dsr]

Just took my car in for the annual service and MOT. Thought I would give Halfords a go.

On arriving I was asked “Would you like additives in your oil and petrol to make the engine run smoother? Normally £20 each but our offer is £30 for both”.

In 40 years of owning cars I have never been offered this, so declined the offer. My car is a 14 year old Mercedes and only doing 4,500 a year.

My question is (a) what additives are they talking about, and (b) is it worth doing?

Without even being a mechanic, I would say that oil manufacturers have been making motor oil for well over a century and if there was a way of making it better, they would have done it.

And I would also say that whatever you put in petrol, it will swill round the engine and then disappear. £20 for one tank plus some residual gunk staying in the engine? Not value for money.

And finally, I would suggest that Halfords sound like a bunch of chancers who care nothing whatsoever about providing value for money, and will rip you off with any old rubbish if they get cash in hand now. If they don't care about long-term customer service, then find a garage that does.

[Walton]

And finally, I would suggest that Halfords sound like a bunch of chancers who care nothing whatsoever about providing value for money, and will rip you off with any old rubbish if they get cash in hand now.

Their owner is a massive donor to the Conservatives, so sounds about right

[GodIsADeeJay81]

One of the co-founders of the equity firm who owns halfords is a donor to the Tories?

Not really sure how that's relevant, as all the large companies like Halfords, Kwik Fit, Formula One etc tend to be ripoff merchants/chancers and you'll find most of us in the industry will have the same opinion.