Should I put Redex In My cor Or Not

croyland87

Hi I have a 1997 P reg vauxhall corsa and bought some Redex it says on the bottle (fuel system cleaner petrol injector) can I put this in my car? or will it damage the engine I am not good with stuff with cars.

Sam_Fallow

Redex is a tried and trusted product. If you have a petrol engine with fuel injection and the instructions you'll be fine.

forgotmyname

You can put it in if you like, Dont expect it to actually do anything though.

Is there any reason why your thinking of putting that in?

arcon5

Some people have had success with it some haven't. But it shouldn't do any harm.

A lot of people swear by it before they go for an MOT to help with the emissions.

AdrianC

forgotmyname wrote: »

You can put it in if you like, Dont expect it to actually do anything though.

Is there any reason why your thinking of putting that in?

This, with bells on.

If your car actually has a problem, it won't fix it.
If your car doesn't have a problem, it isn't needed.

agrinnall

arcon5 wrote: »

A lot of people swear by it before they go for an MOT to help with the emissions.

Have any of those people actually had their emissions tested before and after using Redex though?

Joe_Horner

Never been convinced by Redex in fuel but the stuff does work for carbon build-up and sticky rings if you put it straight into the plug holes. I've confirmed that in the distant, carb-fuelled, past with compression readings before and after. IIRC the instructions used to suggest using it that way initially, then adding to fuel as a "top up" treatment.

Given that it takes several years / 10s of k miles for any significant carbon to accumulate (especially nowadays with far more efficient combustion than carbs ever gave) that's always seemed like little more that a way to get repeat sales - it works well on the initial treatment so must work well on the top-ups (or not!), right?

forgotmyname

Its usually the thrashing they give it before testing the emissions again. Sister old focus diesel used to smoke because her commute was a steady crawl in traffic.

It rarely got a good thrashing to clear the soot out. I would drive it arounf for about an hour flooring it then slowing the flooring it. After an hour its totally smoke free.

Modern petrol is very clean burning, Ive changed the oil on cars that have done 10 - 12,000 miles and the oil looked almost as clean as the stuff i was putting in.

arcon5

agrinnall wrote: »

Have any of those people actually had their emissions tested before and after using Redex though?

Probably not. Probably scraped a pass then put all the credit on the new additive they will be using every year from now on!

AdrianC

Joe_Horner wrote: »

Never been convinced by Redex in fuel but the stuff does work for carbon build-up and sticky rings if you put it straight into the plug holes. I've confirmed that in the distant, carb-fuelled, past with compression readings before and after. IIRC the instructions used to suggest using it that way initially, then adding to fuel as a "top up" treatment.

But doing that to a car with a cat will almost guarantee killing the cat. Which is why the homeopathic approach is now recommended.

Each fill of the cylinders with air-fuel mixture is roughly 14.7:1 air to fuel. Follow the instructions on the bottle, and add 125ml to 60 litres of petrol, and that fuel is 480:1 petrol:redex. So the contents of that cylinder are just over 1/7,000th redex. It might be in there for about 1/3,000th of a second before being burnt.

I don't think that's going to do very much to the hard carbon deposits baked and burnt onto combustion chamber surfaces...

Joe_Horner

Exactly. Only it's worse than we thought!

Don't forget that a/f ratio is by weight[/] rather than volume. With petrol being around 755 kg. m^-3 and air at sea level being about 1.23kg.m^-3, that means that by volume the bottle of redex in a 60l tank will make up about 1/4300000th of the volume. If you have a 2 litre 4 cyl with perfect breathing (which you won't have) then each cylinder charge is 500ml total, with 1/10000th of a millilitre being Redex. Not sure how much anyone expects to dissolve in 1/50000th of a teaspoonful!

In the old days of carbs and 2 star it might have kept deposits down once they'd been cleared (although I have doubts) but actually removing existing ones at that sort of concentration is doubtful to say the least.