Yd25 D22 no compression

Hi, I've got a D22 with the YD25 engine and it started running rough and rattling with grey/blue smoke, a couple of days ago.
Got it home and had a look over it.
Cleaned the intercooler, pipes and egr. Blanked off the egr as it seems better to take it out of the equation but it's no different.
Compression tested it and I've got bugger all compression on cylinder 4.
I'm assuming rings and maybe bore damage, but there's no nasty nasty noises from the bottom end.
My questions are;
How difficult is it to strip down, assess and repair, considering this'll be a driveway job?
Also, is there anyway to tell if its had the bottom end upgrade?
Cheers

I think that you're in the UK? If so, we didn't get that YD25Di engine here in Australia. We have the YD25 common rail engine. No bottom end upgrade required on ours.

Removing the motor to strip down isn't to hard, as long as you have the correct tools available.
As for checking the bottom end,... If it's already apart for the inspection it's a no brainer to replace what is required. Always used new bolts on the big end as well as the head studs.
Good luck

During the compression test, did you pour a little oil into the cylinder and try again?

If you're pulling the pistons out ... two ways to do it.

1) Engine out. Easiest access to everything, can go as far as you need to just in case.

2) Engine in, sump and bonnet removed. Fiddly, you're doing some of the work overhead, changing big end bearings is possible but not mains. Care needs to be taken around the radiator (water pump needs to come off, timing chains too, so take extra care to put alignment marks on it all including the crank pulley).

Here's a thought - if it's just stuck rings, have you tried one of the additives to unsieze them?

Thanks for the advice everyone. @Old Tony we didn't try the oil in the bore. What would that tell me? The needle just twitched up and down cranking it over.
Considering my situation and the costs, that I've seen online, even a DIY might be uneconomical and impractical for me.
I'll give an additive a go to see if that makes any difference as the egr and pipes were pretty fouled up.

Qonqr said:

@Old Tony we didn't try the oil in the bore. What would that tell me?

Click to expand...

Thanks for the video. I'm looking at zero compression on number 4. The needle on the unit twitched up an down and retained no pressure at all.
Would it still be worth trying an addictive, do you think?

If the wet test improves things, sure. It might free the rings. Otherwise, if there's no improvement, you might be looking at a valve or piston failure - there's no point using an additive with a hole in the piston.