K series pink spark plug - THE OUTCOME

[StevehS3]

I’ve just checked the plugs and the rear most (scuttle end) is a slight pink colour compared to the others as per the photo. The coolant has dropped from Max to Min level over approx 4,000 miles and I can’t see any external leaks. It’s a 2012 standard 1600K, 120hp.

Is this likely to be a leaking inlet manifold gasket? If so, is it difficult job to change (it looks awkward!)?

Many thanks, Steve

[revilla]

Yes it could well be the manifold gasket, and no it's not a bad job to change it. Drain the coolant, remove the nuts and bolts holding the manifold to the head (a long wobble bar extension helps), extract the gasket, clean the faces on both head and manifold thoroughly and reassemble with a new gasket. It does make it easier to clean up properly if you can remove the manifold entirely from the car which means disconnecting the throttle cable, two fuel pipes an unplugging things like the throttle, temperature and pressure sensors. There is a specified torque setting and sequence in the Overhaul Manual, I can dig them out for you if you need. And some people use a bit of silicone around the bits of the gasket that seal the two waterways although you don't have to. If in doubt, get a local member with some experience to do it with you? Where exactly are you?

[StevehS3]

Many thanks Andrew. It doesn’t sound too bad a job. There doesn’t look much space to access the bolts etc but I am happy to do it myself as I am trying to do more myself these days. I live in Eyam in the Peak District (great roads for blatting when it’s not busy!). There are quite a few local 7ers around if I get stuck. Once again, thank you for the info. 

Steve

[oilyhands]

I would use an application of silicone sealant at each end as a back up.

Oily

[StevehS3]

Thank you Oily. I will use a bead of silicone at the ends too.

I have the tightening sequence but not the torque. It’s the plastic manifold type. Does anyone have that please.

Steve

[revilla]

I've got the following on the list I've collected, not sure where it came from though as I can't see it in the Overhaul Manual:

17 Nm

13 ft.lb

[revilla]

From here:

It is 17Nm. 

The figure given in the list of torque settings at the start of the 'Fuel and Exhaust Systems - Petrol Engines' chapter of the 200 Haynes is incorrect (25Nm): Rover later revised this to a lower figure of 17Nm for all models fitted with the plastic manifold, and this figure is given in the Rover 25/MG ZR Haynes. 

All the torque settings can be found here: https://forums.mg-rover.org/showthread.php?t=394089 

The sequence for tightening is basically start at the middle and work out to the ends, doing one bolt one side of the centre, and then one the other side.

[StevehS3]

Thank you Andrew. I just googled and the MG forum says 17Nm too so that will be correct. My Haynes manual gives the sequence but just says tighten to the specified torque!

[oilyhands]

Tightening torque depends on whether your manifold uses bolts or studs and nuts. 17nm for the bolts, I always use 20-25nm with the studs and nuts.

Oily

[StevehS3]

I swapped the IMG today. Strangely the gasket looked perfect (see pic) and no obvious signs of a leak. Thanks for the help. Time will tell if it’s fixed. 

[revilla]

No it doesn't look obviously shot does it? I changed somebody else's recently and it was rather more clearly suffering.

[StevehS3]

I’ve swapped the sparks plugs around and will check to see if that one goes pink again. It runs perfect. Time will tell. 

[StevehS3]

10,000 miles later and I've just had the plugs out. All good with no signs of pink coolant. It must have been a slight leak around the inlet manifold gasket, even though it looked fine when I removed it. Thank you to Revilla and Oilyhands for the help and advise.

[revilla]

Glad to hear it's sorted.