It's showing its character. The *****

[Goodwin]

Hi,

looking for a little guidance. I have a pre serp 400 Chimaera. It has started to show a little personality. When I first picked it up and drove home (Norfolk to Hampshire) it ran absolutely fine. Now about 6 weeks on it has a couple of quirks; possible related.

Firstly its temperature behaviour seems a little odd. Up until about a week ago all was fine. Then coming home noticed it got hotter quicker in traffic/town and took a while to cool - even with otter switch bypass. when cool I checked the coolant level and water was at the bottom of the swirl tank (I have no header) so I topped it up. the following day (Last friday so quite hot) it still was hot and got to an indicated 92C even with fans on, and took an age to cool down. Monday morning (quite cool) it took forever to warm up - stayed at 70ish for about 10 miles (15mins) before creeping to 80C and upto 90C in town, but once on open roads it would drop back to low-mid 70C. Home in the evening everything OK except for quirk 2 below. This morning again the same cold behaviour. Is my thermostat on the way out? Any ideas appreciated.

Quirk 2. Sometimes runs absolutely fine other times it feels rich - lots of pops and bangs (good) but feels flat at about 3k rpm but open throttle wide and goes like a freight train. Last night was quite bad (almost sounded/felt like a misfiring cylinder) for quite a while but once upto temp it was much smoother (but still not quicte right). This morning much better.

All help, clues, pointers gratefully received. I suspect something is worn (car is 17 years old) but I don't want to replace everything as I won't know the root cause for the future.

Thanks All

[Mark_S_24]

I'm sure an expert will be along soon, but have you checked the coolant levels?
Is it still topped up?
It might be that there is an airlock in the system now which may be confusing a sensor into feeding bad info to the ECU?

HTH
Mark

[M@H]

Quirk 2: If it feels like a misfire then it probably is - check the plugs, extenders, ht leads and distributor cap.

Quirk 1: System may not be bled properly, when you filled up your swirl pot did you undo the bleed valve on the radiator too (actually on pre-serp is it on the rad still?)

I would thoroughly reccomend a copy of the Bible by Steve Heath.

Cheers,
Matt.

[LordGrover]

Has the radiator/cooling system been flushed lately? I know mine was well silted up which meant flow could be 'sporadic'.

[Tyre Tread]

You'll probably find most of the rad fins missing and its weeping coolant from the rad pipes.

Take a look at the rad from the front looking upward through the grill holes.

I'll bet the temperature variances are to do with air locks.