Hi,

I am new to this group and this my first post...

My car broke down on the way to our holiday and I am interested to learn if anyone has any words of wisdom as to what it may be and maybe has experience or knowledge of this happening before with a similar engine, please.

It was owned by "one careful OAP gentleman" who never serviced it or even changed the oil and only traveled about 5 miles at a time to the shops and back, mostly.

Mileage was only about 64,000 when I acquired the vehicle in Dec 2020 and since then I have done about 18,000 miles in just under two years of longer mileage journeys with no problems except the AC didn't work. This eventually led to a break down as the AC Compressor clutch started smoking. I did a workaround fix for this by removing the compressor clutch (effectively disabling the entire AC system but it wasn't working anyway) however this was only a temporary fix as the compressor totally seized a month later meaning that I could no longer drive the car without it smoking! lol. I replaced the ac compressor, the drive belt and the ac condenser (radiator) just before I left for our holiday and had the system professional flushed, leak-tested and re-gassed to manufacture's specs.

I also took the opportunity to perform a full-service (but never got time to change the pollen filter or the spark plugs before the holiday). [When I first acquired the vehicle, I performed an oil and filter change - the system takes 4.3 litres but when I drained it all out there was only about 2.5 Litres (the oil light had only just started to flicker on...) and the filter looked like the original white FoMoCo one as it was so rusty that oil was seeping out of it (no drips on the drive though)!]

And this time, I did another oil and filter change and was very surprised to find only about 1.7 litres of oil!!! (Again, the oil light and only just started to flicker on and off)? I had resigned myself to the realisation that I was going to need to check the oil more frequently and top up quite frequently as well too - I didn't want to consider piston rings etc. and am only planning on keeping the car another year or two for my business and then either upgrading or leasing a van, so was ok with adding a litre of oil every couple of months...

During the service though, when I changed the air filter the little oil sponge on the crankcase breather hose inlet disintegrated (the car is 14 years old) so I replaced it with a fine/medium blue aquarium filter sponge. I was worried that it would block the air flow so I tested it by blowing into the inlet and air came out easily so I was no longer worried. (I didn't want oil contaminating my new, clean air filter!)

Also, as part of my service routine for every car I have ever owned, I sprayed some bursts of Carb / fuel injector cleaner (Wynnes) into the air intake (with the filter removed) to clean out any deposits etc. Doing this makes the engine stall so you have to rev it a little to keep the revs up (2 - 3 thousand) while spraying so it doesn't stall. However, I had my partner operate the pedal while I sprayed and she got a bit carried away and over-revved it for a second or two, and I might have sprayed one too many bursts....? I also had the battery disconnected, and had not performed the powertrain re-learn sequence before doing this procedure...? I should have as maybe the ecu was injecting too much fuel or not enough?

My neighbour (A Harley owner) says that cleaning old motorbike engines sometimes causes problems that weren't there before as the sludge was probably holding everything together and sealing any leaks and so cleaning it presents these problems. I think that this is what damaged the engine though as it is obviously burning oil somewhere (no leaks) and with the extra explosive cleaning power of the injector cleaner damaged things further (I suspect the valve oil seals?) This spraying and over-revving produced a clicking sound which I attributed to the rev limiter, and upon restarting the car it seemed ok. (Although this is the same noise that now happens with the engine running?)

The car seemed fine and drove perfectly smoothly (with lovely AC) however half way there I could hear a feint tapping sound, (Much like the sound of the valve tappets/lifters (?) on a Ka and a Nova when it is low on oil.) I had only poured the 4 litres of oil in so we stopped at the services and I poured the remaining 0.3 litres in (as the dipstick was only just above the MIN) hoping this was the cause. However, literally 15 miles from the holiday destination, whilst going up a steep hill and working the engine harder, the very loud rattling sound appeared! (I wish I had filmed it.)

I pulled over into a layby almost immediately but the traffic was busy and there was a local garage only 300 yards up the road so I drove there hoping they could fix it and because it would safer as off the road. The mechanic talked of hydraulic valve lifters (but this engine has springs) and said it sounded like a bolt had worked loose and was being thrown around inside the crankcase cover. But they were just closing so I called the RAC.

Upon tuning the engine back on for the RAC man to diagnose, he said, "Turn it off now! I really wouldn't recommend turning it back on until it is fixed or you risk fatally damaging it..."

They towed the car home for us and arrange onward travel.

After our holiday, I took the crankcase cover off hoping to find something easy to fix but it all looks solid...

I have seen a video on YouTube about a diesel Mondeo (Peugeot engine) that had a broken valve spring so I suspect maybe a broken valve spring, fallen-out Collets or a deteriorated rubber-like-material Valve Seat/Oil Seal leaving the valve free to rattling around? I suspect this because of the slow but steady oil burn which may be from the crankcase valve oil seals rather than the piston rings as the engine drives smoothly and powerfully, so no loss of power / compression.

My friend has suggested that we carry out a compression test on the engine first to rule out the piston rings and head gasket. After measuring the valve clearances, we will be removing the Cams and the valve spring "tappet buckets" to see if we can see anything although I don't really fancy having to remove the cylinder head in order to depress the springs to change anything, I also don't want to lose the valves into the cylinders! We will also use a micrometer to measure the tappet buckets thickness as I also suspect that maybe they, and/or the cams, are worn? Could this also be the Cam bearings/shims? The cams etc (mainly on the input side/front) were surrounded by sludgy oil which I have cleaned off and the metal work is a little bronzed - is this normal or does it show signs of low oil / high heat?

I have probably answered my own questions writing this post, hopefully it is just worn tappet buckets that can be relatively easily replaced and maybe cams and/or their bearing shims?

Thank you for your help and for reading all the way to the bottom.

Adam.