OV9

duncs500 wrote: Mon Jul 16, 2018 6:33 am Had a look at the coolant situation yestersay.

So coolant reservoir actually had a bit in it (when I left it before it was dry), which I thought was odd. Anyway topped it up to near the max line. I also noticed there was some oil on the floor, it appears to be dripping from the driver's side at the bottom where the gearbox and engine join. No evidence of anywhere else in the engine bay.

So anyway, I topped the oil up, ran the engine for a while (which seemed normal), checked the oil and the level seemed fine. Took it out for a drive, expecting the misfire to be there, but at least wanting to get to the bottom of the coolant issue. Weirdly initially there was no sign of the misfire when I drove it round the block so I decided to take it a bit further. Sure enough it started appearing again so I decided to head for home.

When at home, before turning it off I took the bonnet and nose cone off to look for signs of the coolant leak. The fan was on at this point. The coolant reservoir was now full up well over the max level. No sign of leakage. So I shut the engine off, and then all the coolant got sucked out of the reservoir and I could hear the cap squealing as it was continuing to suck. Put a little more water in which soon got swallowed up... wouldn't be surprised if it was full again later as there was nothing visible externally so I can't see that it's going anywhere.

Does any of this make sense? I do start to get the feeling misfire is related to heat levels given that initially it was ok, in which case I presume it is a doomsday HGF situation? I always thought HGF was quick and unexpected though?

Sundayjumper wrote: Mon Jul 16, 2018 9:08 am I’ll be honest - I don’t like the sound of that. Any sign of oil in water or vice-versa ? I think you’ll need to get it booked in for some investigation.

speedingfine wrote: Mon Jul 16, 2018 9:14 am
The cap sounds faulty if it's air or coolant escaping. I would definitely order another given how cheap they are and how often they break.

Also K Series' in Caterhams are renowned for difficulties in bleeding them, you have to jack the front end in the air or believe it or not blow into the tank to sort it out so that may also be worth a try.

Oil you can see may well just be excess coming out of a breather depending on how much is there.

duncs500 wrote: Mon Jul 16, 2018 11:15 amWould they have bled the system when they changed the hoses?

integrale_evo wrote: Mon Jul 16, 2018 3:08 pm They are headgasket like symptoms, but airlocks can do that too. Usually a head gasket, cracked liner or cracked or porus head will pressurise the cooling system to the point it fountains out of the cap or bursts a hose if you give it a bit of stick.

The misfire would link in to moisture in the cylinder, but if the lead is as bad as was thought previously then it could be giving false symptoms, and you'd expect enough water in a cylinder to cause a misfire to be pissing out of the exhaust and leave obvious signs on the piston crown / spark plugs, or at a minimum leave a nice steam trail behind you.

Try and find a garage that can do a sniffer test to see if you're getting exhaust gasses in the coolant.

IanF wrote: Mon Jul 16, 2018 9:47 pm Duncs, I’d go with your own suggestion and take it somewhere reputable so they can diagnose it. Even if you find the solution by trial, error and vague internet ideas, would you feel comfortable fixing it and then driving it spiritedly? And that’s ignoring the fact you could be making it worse by your own fiddling.

I get the wanting to fix it yourself mindset, but if it was serious enough to stop you from driving it on a track day, I’d say this isn’t the best place to start developing your own skills. Get it fixed, have a great few drives before summer ends, and then think about upgrading thing/tinkering afterwards.