I have read many articles on this but just want to throw it by you guys.
Just completed a head job and had the head skimmed. All went well and used genuine gaskets from Mazda.
Engine started almost straight away and I let it run up to temp. Oil pressure and fan kicks in when ready.
However I have the moisture dripping from the tail pipe and a little vapour.
Is this OK and how long will it last?
obviously not oil as you will have checked that so as far as I know, water vapour & a bit of water dripping is normal but will not occur when engine is HOT although water is a by product of burning hydrocarbon.
someone more knowledgeable will surely be along soon with the definitive answer. good luck.
Water dripping from the exhaust is normal as water is a byproduct of the combustion process. Also, if you did the gasket because the old one had blown then you may have coolant in the exhaust which will take a while to boil off.
If it doesn’t stop after a while when the exhaust is really hot then you may have a problem.
Coolant has quite a distinctive acrid smell when it burns too.
You produce a litre of water for every litre of fuel you burn - when the engine is up to temperature most of that evaporates, but when the engine is cold it ends up in the exhaust as condensation - and in the oil as water vapour which creates that white gungy stuff round the filler cap. If the filler cap and inside the head is nice and clean ( when I say clean, I mean with brown oil, not white sludge ) then its not a big worry. Short journeys are the worst culprit … change the oil more often and do some longer runs to burn off the water, which when mixed with the combustion process gases creates some powerful acids. The oil contains additives to neutralise these acids, but the more acid you create the sooner these get used up
Cheers
The oxidation in the catalyst produces water.
Many thanks all and just to update.
Took her for a good run to see how she ran and must say very nice, needs a bit of tweaking.
Got back and let her cool to check water levels and all was fine plus the tail pipe was dry.
However over night and then starting gives me that dripping tail pipe with a hint of vapour.
Just wondering if any water got into the engine whilst I was cleaning before the head went back. The oil was changed but wonder if it could do with another change now she has run a bit?
When I bought her I can’t remember seeing this but it was running rough.
Relax. As everyone says, dripping water from the exhaust is completely normal when the exhaust pipe is cold. It’s just condensation from the water vapour produced by burning petrol.
When you burn hydrocarbons, all those hydrogen and carbon atoms have to go somewhere. The carbon forms carbon dioxide, the hydrogen forms water.
I guess you also have to consider moisture in the air, especially this summer.
Which, of course, is why mild steel exhaust systems rot from the inside out, as opposed to SS systems.
Bit like the cars themselves.
On tick over you have lovely hot gasses coming out of the head and hitting a stone cold manifold and system the result is condensation even worse the more free flowing the system as the gasses don’t slow down as much