Help!

GENERAL

Redex

Q In CM June 2020 issue the feature about top-end cleaning was very informative. However, it was the readers’ responses to the July 2020 issue on Redex that caught my attention. Unfortunately, Redex is not available here in India. There are other brands like Abro, Würth, Liqui Moly, 3M, Gum Out, STP.

I have the following questions:

1. Are there products equivalent? For your information, I am adding the safety sheet of Abro, Liqui Moly and Würth which I have purchased post your June 2020 issue. Can you tell me the difference between them please? For example, Abro’s base is kerosene. Is this safe for my car? Do these three products (Abro, Würth and Liqui Moly) have the same ingredients? Then why are their quantities different? I humbly request you to refer my attachments.

2. What is the difference between a Fuel Injection Cleaner and a Fuel System Cleaner? The Redex website shows both, and equivalent products from competitors are available here? Which should I use? My car has run only around 26,000 miles.

3. There are forums where it is mentioned that PIBA can be damaging to the engine, especially increasing metal-to-metal contact and causing wear over the long-term, especially if used frequently. However, the stickers on the products say that it reduces friction. Can you resolve this paradox?

Kishore (India)

A It is difficult to compare the products because in the same way that Coke guard the recipe to their cola, Redex also closely guard the formula to their products.

It would take a chemist to fully analyse the difference between the products and then research would need to be done to closely access the benefits of each product. There are over 4000 fuel additives listed and each will have a slightly different formula.

I would also note that modern Redex fuel system and injector cleaners are very different from the earlier Redex oil product used to shift carbon from the top of the piston.

Additives can generally be put into four categories of cleaning. The petrol treatments, fuel injector cleaners, fuel system cleaners, and multi-system additives. Each one a step-up from the previous level, and of course slightly more expensive.

Petrol system treatments are typically the lowest priced fuel additive, fuel Injector cleaners offer a more concentrated cleaning power and a variety of other benefits. Fuel System Cleaners take this one step further and contain more powerful cleaning agents, whilst multi system additives are designed to endure through the combustion process to also clean valves and pistons.

Petrol will leave deposits on the vital fuel system parts which if left to build-up will result in combustion problems. The additive is designed to restore or improve combustion by cleaning the parts. All fuel additives contain detergents that can clean the components in the system and help prevent new deposits from forming. These of course will vary according to the manufacturer.

One of the common cleaning agents used is Polyisobutylene amine or PIBA. This is nitrogen based and acts as a detergent. Without the nitrogen base an additives cleaning ability is negligible.

PIBA isn’t durable enough to survive in the combustion chamber and polyetheramine (PEA) would be preferred as it is stable enough to be able to remove carbon deposits in the high heat, making it a good choice for cleaning cylinder-heads or direct injectors.

I can find no chemists report which would suggest that either of these additives or the lower rated polyisobutene (PIB) would cause any harm to the engine from contact and the friction reduction quality would presumably be due to the cleaner surface left after the cleaning process. I would also add that these chemicals do only form one part of the additive and most fuel does contain additives to help keep the system clean.

Unfortunately, forums are open to all and whilst there is a vast amount of knowledge which can be gleaned from forums, there are also many reports which are posted up with no basis.

AUSTIN MINI

Jumping gears

Q I have been restoring a 1989 Mini 998cc with a DAM 5626 gearbox and what appears to be a genuine 40,000 miles. The car had been standing for approximately 10 years before I bought it, so I changed the oil before using it again.

I am having problems with it jumping out of 2nd gear on acceleration. This is often worse when the engine is warmed-up. Occasionally, it crunches a little when engaging 2nd gear, but usually it feels OK to select. I have changed the steady bar bushes and the engine now feels secure, but this hasn’t made a difference to the gears - the bracket on the bulkhead had rusted away, so the engine wasn’t secure previously. Other than stripping down or replacing the gearbox, is there anything else I can look at? I’m considering adjusting the selector, but how would I do this?

Simon Beer

A The majority of the mechanism is inside the Mini gearbox and there is little that can be done without removing the engine and gearbox, splitting the two units.

There are a few reasons why the vehicle may be jumping out of gear. The most likely is that the synchro hub is worn, but the source of the problem could also be a worn selector fork and/or possibly a weakened or broken detent spring in the selector mechanism. All of these possibilities do require the gearbox to be stripped down in order to make a repair.

It may also be worth checking the bush where the gearchange rod enters the gearbox, but this would normally result in an oil leak as opposed to affecting the gearchange. If the problem was due to any external gear selector adjustment problem, then it would be as prevalent in 4th gear as in 2nd.

FORD FOCUS CC

Management light

Q The EML keeps coming on in my 2009 Ford Focus CC 2.0 TDCi when stopping, but goes off after a mile or so. The car runs fine and does not go into ‘limp-home’ mode when the light is on, but no one can find a problem using diagnostics.

David Tranter

A As the car continues driving and the triggering of the management light does not appear to be leaving a fault code, the problem may be related to a poor earth somewhere in the vehicle; the most likely position of this is the battery earth connection located beneath the battery. Another possibility is that the injector codes have become corrupted. This may have little noticeable effect, but would leave a code in the system, although retrieving this would depend on what diagnostic equipment is being used.

I know from experience that some diagnostic scanners are more successful than others at interrogating the Ford system. From your comments, you seem to have already tried more than one garage in an attempt to pinpoint the problem but, if this is not the case, I would be inclined to find another independent