Stanky's Car Fixing Thread - What have I been up to?

[Tubbo]

Great news that you’re keeping the Daihatsu going. I do still miss that car to be fair and since my YRV turbo got sold last year I’m currently Daihatsu free 😥 Keep up the good work 👍

[RoverFolkUs]

18 hours ago, Stanky said:

It does burn a bit of oil, especially if you hoof it out to 5k+ rpm (which it loves, and is hard to resist) and does emit a puff of blue smoke if you go on the gas after coasting down a hill. I enquired about the appetite with the MOT garage for stripping the engine down and replacing the piston rings

I'm not sure if this makes it much better, but that's a classic sign of the valve stem oil seals rather than the piston rings. Inlet manifold vacuum during engine braking tends to pull oil past worn valve seals. 

Is it worth a dry, then wet, compression test to see how healthy the bottom end is? If it was my car, if the compression results were all within tolerance I'd probably just change the valve stem oil seals. It's still a fairly involved engine surgery, but it's a bit easier than a full rebuild. If the compression was a bit low, or uneven, then maybe the rings are knackered as well. 

Of course, the stem seals and piston rings could both be worn out, so you could go to all that effort to do the stem seals just to find it still burns a bit because the rings are tired. But the above is just my thought process on it

[Stanky]

On 26/07/2026 at 13:36, RoverFolkUs said:

I'm not sure if this makes it much better, but that's a classic sign of the valve stem oil seals rather than the piston rings. Inlet manifold vacuum during engine braking tends to pull oil past worn valve seals. 

Is it worth a dry, then wet, compression test to see how healthy the bottom end is? If it was my car, if the compression results were all within tolerance I'd probably just change the valve stem oil seals. It's still a fairly involved engine surgery, but it's a bit easier than a full rebuild. If the compression was a bit low, or uneven, then maybe the rings are knackered as well. 

Of course, the stem seals and piston rings could both be worn out, so you could go to all that effort to do the stem seals just to find it still burns a bit because the rings are tired. But the above is just my thought process on it

Thanks, some additional info which led me to believe it was a piston rings issue rather than a stem seals issue was that there is no blue puff of smoke on startup - which I was given to understand was a classic 'smoking gun' for steam seals. The car tends to only be driven about once or twice a week, so plenty of time for oil to leak past the stem seals while it rests in my garage. 

Happy to be corrected on this. TBH I think both options are going to be painful to resolve, though it does run fine and goes through MOTs too so I have mentally de-prioritised getting stuck into either issue. 

One of the learning's from my 'time off' has been that I have plenty of things which do need doing, and I need to be much more mindful of starting new jobs which don't actually need doing - I just need to enjoy what I have and deal with issues as they arise, instead of going looking for niggles to make everything 'perfect' - good is good enough, I need to just enjoy what I have.

[lisbon_road]

Agree with everything @RoverFolkUs has said - many (many) years ago I worked with a man who had a Volvo 360 which was using loads of oil.  We tried going downhill and he left it in gear and took his foot right off the accelerator.  You could hardly see out of the back window there was so much smoke.

I have a Laser tool for twin cam engines for changing stem seals without taking the head off.  Dunno whether it would work on yours but it might.  Worth doing if the compression test says that the rings and valves are ok.  I have a compression tester too.