Dipetane question, failed NCT smoke test

Mondeo Mk4 failed on smoke test last week, am running some Dipetane through the system at the moment to clean out carbon build up & getting full service with all new filters. Have heard plenty of reports of this stuff helping many to pass the test but one thing I cant seem to find out is if it's a good idea to use the Dipetane through the test itself or should it have cleared the system by the time of the test?

run_Forrest_run

Deleted User wrote: »

Mondeo Mk4 failed on smoke test last week, am running some Dipetane through the system at the moment to clean out carbon build up & getting full service with all new filters. Have heard plenty of reports of this stuff helping many to pass the test but one thing I cant seem to find out is if it's a good idea to use the Dipetane through the test itself or should it have cleared the system by the time of the test?

I believe it's perfectly fine for it to be in the system during the test.

biko

They won't bother with checking for Dipetane, I've used it myself (just as a precaution, not sure if it helped or not).
As long as car passes emissions it's all good

Ten Pin

Doesn't matter what's in tank as regards anti smoke additives, more important is to give it welly in low gears to blow out the exhaust system and have a hot engine going in to test. They will be doing high revs in the test anyway, better do it under load on the road than under no load in the centre. It will also mean they don't have to repeat high revs more than is necessary.

Thanks for the replies, I knew alright that it doesn't matter what's in the tank, was more concerned about the possibility of it being more smoky under high revs with the dipetane in the tank during the test as its more combustible than just diesel, its good for cleaning the system but wondering if it might give a higher reading than just plain diesel

MarkN

[Deleted User] wrote: »

Thanks for the replies, I knew alright that it doesn't matter what's in the tank, was more concerned about the possibility of it being more smoky under high revs with the dipetane in the tank during the test as its more combustible than just diesel, its good for cleaning the system but wondering if it might give a higher reading than just plain diesel

I used it in my car two weeks ago, put half a bottle in the tank an hour before the test and gave it some beans on the way to the centre in 2nd and 3rd. Don't know if it helped, again I just did out of caution but the car passed perfectly fine.

Ten Pin

[Deleted User] wrote: »

dipetane in the tank during the test as its more combustible than just diesel

Smoke is unburnt diesel so the more fuel that's burnt the lower the smoke reading, in theory at least, so dipetane will improve (lower) the smoke.

MarkN

MarkN wrote: »

I used it in my car two weeks ago, put half a bottle in the tank an hour before the test and gave it some beans on the way to the centre in 2nd and 3rd. Don't know if it helped, again I just did out of caution but the car passed perfectly fine.

I think that answers my question, wont be putting that much in but good to know..

run_Forrest_run

Deleted User wrote: »

I think that answers my question, wont be putting that much in but good to know..

well make sure you put the sufficient amount in relative to the amount of fuel in your tank, otherwise it may not be effective.

run_Forrest_run

run_Forrest_run wrote: »

well make sure you put the sufficient amount in relative to the amount of fuel in your tank, otherwise it may not be effective.

Thanks for the advice, the recommended mix is 1:200 & its a litre bottle with prices hovering around the euro/litre. So unless you're putting in 100 litres in the tank you wouldn't normally use half a bottle. I have a strong mix in at the moment to burn off excess soot but plan on putting in about 2 or 300ml with the next fill for the retest

Full service changing all filters & used about 250ml for retest and it passed with very low readout of 0.1 (threshold 3.0), plan on using it again few times a year to prevent build up.