It might be described as burnt hazelnuts, also reminds me of my toy steam engine that used to run on methylated spirits burning to heat the water.

What does methylated spirits taste like?

https://youtu.be/ep2I3Gf3Sec

Worth watching to the end!

Big Clive is pretty funny, watched quite a few of his teardowns of various things. Surprised he actually tasted it though, the alcohol composition of meths actually makes it a neurotoxin so even without the bitter flavour you wouldn't want to drink it - at best you'd go blind, worst you're dead. You probably wouldn't care much about the latter as it would be too late but the former would make life pretty difficult.

When i suggested burned hazelnuts that's the smell i usually associate with coolant being burned by the engine and with the extra vapour you mentioned suggests a weepy head gasket. Have you checked the coolant level recently?

Watched Big Clive quite a lot.

I also thought of head gasket, only checked level of coolant through plastic master cylinder tank. Will look properly tomorrow, also will look at oil. Engine runs fine above tickover.

Back when i was just a young pup and many of the cars i ran develped HGF, they almost always ran ok at higher revs in the first stages, there was just enough of a weep in the HG to allow coolant to pass into the combustion chamber and/or cause a slight loss of compression to give a misfore on idle.

If your coolant level has dropped a bit, i'd suggest looking at the plugs when the engine has been sat overnight to see if any of them are wet - coolant will leak into the pot where the HG is weeping and make the plug wet quite often. Also a hot compression test might be in order - all plugs out, disconnect the coil or ignition module if you have electronic ignition, wedge the throttle wide open to give it all the air it needs and test.

If it is the HG on its way out, the sooner you catch it the better. Might be worth doing a decoke and lap the valves in while you have it apart.

It's a wet-liner engine so don't turn the crankshaft with the head off, i know for some cars special service tools that are similar to head bolts with what amounts to a tube with a washer stuck on the end of the tube slid over the bolt can be used to hold the liners in place to facilitate turning the engine over while decapitated but even then it's not really advisable. If you break the seal between the bottom of the liner and the block, you'll find it hard to get it to reseal, on some engines this is near impossible and needs the whole block to be machined! :err:

Fairly sure the B14 isn't one of those but no sense in givng yourself extra work either way! :nah:

Party wall notice… now that brings back sleepless nights

Too hot for me today, just checked oil and coolant, both look OK, no coolant in oil, no oil in coolant.

If my guess is right and it's the very beginnings you may not see any cross-contamination yet, hence my suggestion of a compression test.

Were the levels both ok? :thinking:

Yes, both fine, oil quite clean too.

Too hot to go into the garage to search for the compression tester, perhaps ill do that early tomorrow. Garage has a flat reinforced concrete roof that has been absorbing the sun all day!

I can relate to that! My back garden is a sun trap and i need to weed my patio - despite being in the shade now the sun has moved round, the slabs are still throwing heat out! :err:

Hopefully the compression test won't show anything worrying and meanwhile the meths gets rid of the excess moisture. Out of curiosity, what petrol do you run on? A thought has just occurred to me about a few strange anomalies i've heard about, seemed to effect some cars more than others.