Oily heating plugs

My 1998 306 TD LX was never a good starter. It has always taken 3 or 4
s on a good day to get it going, even after fitting new heating
plugs. I last changed them about 40,000 miles ago - it's now got
120,000 on the clock. So when the car almost refused to start one very
cold morning last week (it caught just before the battery totally died)
I figured it might be the heating plugs again. The next day it started
fine but the next cold morning it went the same way, ing and
making a wheezing / whistling sound. Bought some new heating plugs but
when I took out the first 2 old plugs they were black and oily and
covered in grit. Then I noticed that the main air flow into the
intercooler also had a sizeable amount of black oil in it. My best
guess is that I've got a damaged piston ring possibly, causing oil to
leak into the compression chamber. Is my amateur guess right? What
would it cost to repair?

 

The first thing to check is that the heater plugs really are getting power
to them. Your non starting symptoms sound as if the control relay is not
working. You would need a voltmeter, or a 12 volt test lamp which you can
connect between the engine block and the terminal on the end of any heater
plug. Then, when you turn them on you should see probably between 10 and 12
volts, or the light should illuminate quite brightly.
As far as the oil in the intercooler is concerned, this is from the engine
breather, which feeds into the aircleaner box, or near to it, part of the
emission control system. It means that there is some blow-by past the piston
rings, pressurising the crankcase. Don't worry too much about it.
Brian.

 

Thanks, Brian. I'll check the control relay and take it from there.
Would my heating light on the dashboard still light up even if the
control relay is not working? Also are the gritty oily plugs nothing to
worry about? The last ones I removed were oil free but had blackened /
sooty tips. I guess my constant attempts at starting could leave them
coated in unburned diesel. I'm very much an amateur at this stuff - if
it has more than 2 spanners next to a job in the Haynes manual I take
it to a garage. Is replacing the control relay a big job?

 

No to replace the control relay will only take you about 10 mins to
fit.and i found a good place to get one was french spares,they are very
helpful.web site is www.frenchspares.com tele.01777817070. give them
a call or look on there web site.good luck from chris addlestone