Fuel Additives

[jdmini]

hey all,
this is my first 4 star car, and i'm a bit worried i'm not using the fuel additive properly...i've done 60 miles in the car so far with a splash of additive.

but i was wondering how important is that i use it?

i don't want to do any damage, so any advice would be really helpful.

Thanks

[E_T_V]

What engine and what age car? Some are unleaded compatible and some aren't.

[jdmini]

it's a C reg 1.6L

[threelitre]

So I assume it's an unleaded car - like my 1.3. I do run my 1.3 since about 45k miles now without additives, but have to closely monitor valve clearances now. Using an additive should add a good safety margin here, but the car will not be harmed immediatly if the additive is forgotten once, or the dose is too small.

Don't worry and try to think about adding it regularly and you should be fine...

Alexander

[E_T_V]

Ahh well it needs an additive then, or an unleaded compatible head (hardened valve seats).

[C191JOE]

I'm sure its somewhere written on the forums here that leaded cars will run on unleaded for many thousands of miles so long as the engine isn't thrashed.
And as its a C reg the bodywork may conceivably give up the struggle before the engine does. Can someone confirm this view?

[E_T_V]

Well our old S series topped itself running on LRP when it was available. (burnt out the valve seats)

[threelitre]

As said, I do run mine since a long time on unleaded (or LPG - even worse), and since about 25,000 miles I need to check and often adjust exhaust valve clearances (say every 5000 miles). The beauty of the A-series is that this is a fairly simple process. On the S-series you'd surely not want to do this, so I'd stick to an approved additive. But I'd still say that the engine will not suffer noticeable if the additive is left out for the odd couple of tank fills. If a valve burns extremely quick after changing to unleaded it can be assumed that not all was right to start with...

Alexander

[BikerGran]

I use the Castrol additive in my S Series, as I understand that it's far more effective than the more widely available Redex and petrol companies' own brands. It's also somewhat more expensive but my feeling is that if I'm going to be paying for an additive I may as well pay a little more for one that works!

Read the instructions, they all tell you how much to use and have either marks on the bottle or a clever device on top to measure it. No point using it at all if you don't get the dosage right!

[jdmini]

can i put too much in?

[Austin-Rover]

No

[BikerGran]

Yes, according to what I read - but I can't remeber why! Anyway it's expensive so putting too much in is a waste of dosh!

[Austin-Rover]

In terms of not getting the doseage spot on, then no. You can't cause any damage. Using a full bottle on a fivers-worth of petrol...may be a different story.

I've done about 30,000 miles in my Montego 1.6. Sometimes I go for 3-4 tankfulls after using the last of my additive before I get a new bottle. Infact I am sans bottle now and haven't been driving my car any differently.

[threelitre]

If grossly overdosed it can have bad effects, i.e. on the spark plugs and leave deposits. But with most bottles measuring the right amount is dead easy, as a measuring device is built into them that has markings showin the amount of petrol you filled in to get the correct mixture.

Alexander

[jdmini]

thanks for the advice guys...much appreciated.

[e692wtt]

Just out of interest, what additive are you using now?