Fiesta Endura Engine - smoking

[SWJ]

Can anyone help !!
My daughters 1996 Fiesta Endura is doing my head in.

We bought it last year at 68,000 miles, 'quite rattly' but otherwise seemed OK.

I changed oil / filter / plugs, but soon afterwards, the engine started smoking badly - when cold & started using oil. Once it's run for a minute or so, the smoke clears without any further problems.

My initial reaction was the valve stem oil seals, but the plugs are clean and no oil is thrown out when turned over cold with plugs removed.

I intend doing a wet v dry compression test in the next few days to check the oil rings.

Are there any further checks I can do that could identify for sure what the problem is?

Also, could this oil burning have damaged the CAT?

Thanks,
Steve

[SWJ]

Hi Mark,
Thanks for your reply. The way I saw it, if oil has seeped down the valves overnight, then:-
a) one or more of the compression chambers would be quite wet, which I hoped would lead to oil particles being forced out through the plug holes, onto my kitchen roll.

b) the plug in the offending cylinder would look quite oiled / black. However, this was not the case.

Before buying the car several months ago, I tried coasting down a long steep hill & decking it at the bottom but no oil smoke was seen. However, I suppose the stem seals might have gone in the meantime. I'll try it again.

Thanks again,
Steve

[SWJ]

Thanks everyone for their advice.
I may be a little too quick in writing this, but crossed fingers, I think that the problem (as 360 Stradale advised) was a blocked oil filler cap.

Having washed it out, the blue smoke has now disappeared.

Another question:-
Whilst I understand that the filler cap also acts as the crankcase breather & directs any unburnt fumes through the combustion chamber, how does the poor crankcase breathing cause so much smoke and where does it come from ?

Thanks again everyone,
Steve