PCV Focus MKII TDCi Diesel 1.8

[Aled H]

Hi, I'm enjoying the benefits of your collective wisdom in this forum. I have issues with my 2006 Diesel estate. Poor compression, down on horsepower, pinking in 5th gear, smoking when warm.  Suspect PCV has crapped out. I have taken a photo of the underside and nearside to the front of the engine block. Is the hose pictured the pcv? I cannot see the other end of what I presume is the short breather pipe in order to confirm. Many thanks.

[FatHead1979]

On 8/25/2020 at 11:04 AM, Aled H said:

Hi, I'm enjoying the benefits of your collective wisdom in this forum. I have issues with my 2006 Diesel estate. Poor compression, down on horsepower, pinking in 5th gear, smoking when warm.  Suspect PCV has crapped out. I have taken a photo of the underside and nearside to the front of the engine block. Is the hose pictured the pcv? I cannot see the other end of what I presume is the short breather pipe in order to confirm. Many thanks.

Not sure the engine has a PCV.

[Tdci-Peter]

On 8/25/2020 at 10:04 AM, Aled H said:

Poor compression, down on horsepower, pinking in 5th gear, smoking when warm.  Suspect PCV has crapped out. I

No PCV as such, there is some sort of valve thingy in the cam cover that the blow-by gas goes through, I have not been able to verify if it does anything on my car, it just seems always open. Since the outlet from it goes to the turbo intake, there will be very little suction there, only that due to the air filter and intake ducting. Blockages in the air filter or intake ducting could increase suction in the crankcase, increase blow-by, and increase the oil that goes into the engine intake. That would cause smoke with that nasty burnt oil smell.

The ventilation system on the 1.8TDCI is quite easy to get at and check or clean. There is a hose from the centre of the cam cover, that I think joins up with another vent hose from the crankcase, they then go into the oil separator near & under the fuel filter. A hose from the bottom of the oil separator returns most of the oil to the sump. The third hose from the top of the separator goes the the valve thingy in the cam cover, under the circular lid feature on it. This then goes down to the turbo intake, joining the main air intake there. The separator is held on by one bolt to the end of the engine. But problems with this system are rare.

I am not sure about the engine compression bit. If it is poor, then that sounds like bad news, damaged valves or rings. But compression on a diesel is much harder to measure properly than on a petrol. Access is hard, the glowplugs are much more awkward to get at than most spark plugs. The pressure is much higher, and peaks for a shorter time. It will also be very sensitive to added volume, replacing a glowplug with an adapter and gauge will add a lot of volume relative to the normal volume at TDC, giving a reduced pressure reading. Also adapter leaks will have a much greater effect due to the small volume and high pressure.

The alternative of applying pressure to measure leakage (leakdown test) requires practical knowledge of how much leakage to expect for a given engine and known pressure. It does not relate directly to compression ratio. It can identify differences between cylinders on one engine though.

One simple cause of smoke and reduced power would be bad leaks in the intercooler pipework. That is all the hoses from turbo compressor outlet, via intercooler, to the inlet manifold. There are 4 rubber hoses and 2 metal pipes in this system. Leaks here would usually be audible in the cabin as hissing under power, though.

 

[Aled H]

Hi, thanks for your replies and suggestions. There was a split in the lower turbo-intercooler hose. I replaced that for £11 and along with a terraclean from GB Motors in Walton (who advised of the split hose) all is sorted and engine running at full spec and no signs of smoke.