Oil, Man

Well, I knew my smugness at finding a low mileage LT with an engine which didnae leak oil would not go unpunished for long and so it has turned out.

As you will have read, being the attentive viewer that you are, I put Herman through his MOT last week and got an advisory on an ‘oil leak’ which was a bit of a bummer, as he’d not been dripping at all when I first got him.

Anyway, the MOT was a bit of a last-minuter, because I only got him through on Friday morning and was off to Ireland on Saturday [3rd] night, so it left me no time to do much investigating –especially with trying to get his innards sorted at the same time. Anyway, we left on Saturday night and drove up to Scotland without incident. I did notice though that, when we arrived at the ferry port in Cairnryan, he sounded a bit rougher on idle than usual.

Home Sweet Home, but my first mission was an oil and sealant hunting one
Home Sweet Home, but my first mission was an oil and sealant hunting one

Across we went on the car ferry and, when we got to Belfast and went to rejoin our vehicles, I had the habitual cursory glance underneath to see how many spots of oil he’d dropped during the crossing and was shocked to see what looked like about a pint, sitting in a puddle underneath. I should probably have checked the oil level then but, being knackered after driving through the night and being only a twenty minute or so drive from the mammy’s, we just set of and drove off. Again, he seemed to drive fine but, when I pulled up at the oul’ homestead I noticed the rough sounding idle was back. Anyway, I parked up and went off to do the prodigal son bit.

Later that afternoon, I went out and looked underneath and found another massive puddle of oil. I pulled out the dipstick and it was completely dry –not even a lonely drop clinging to the bottom. Cue a tortured evening and night as I tossed and turned in my farting platform, imagining all the horrific damage that Herman’s engine must have undergone having apparently done the last couple of miles of his journey lubricated by oil fumes alone.

Next morning I lifted the engine cover and found a nice trickle of oil running down the engine block around the two oil pressure sensing valves. That was a bit of a relief, as a good hoke round with the torch showed there was no oil leaking from other more worrying “usual suspect” areas such as crank seals or sump, etc. I had read up a bit overnight and found that consensus seemed to believe that these older engines don’t like their oil too thin [I had stuck 10W/40 in, as it was all I could find] and that some semi-synthetics can shrink the oil seals on older engines, causing leakage.

So I trotted off and got several litres of 15W/40 mineral oil and a tube of high temp silicone sealant. Took out both the oil pressure sensing valves, gave them and the engine block a good clean, dolloped them with sealant and put them back in. Topped the boy up with his new gloopier oil and gave him a tentative turn -over. To my relief, he’d not seized during the night and sprung merrily to life. I switched off then, to leave the silicone sealant time to cure overnight.

The offending orifices, where the pressures sensors live
The offending orifices, where the pressures sensors live
Both sensors removed, ready for cleaning up and silicone lathering
Both sensors removed, ready for cleaning up and silicone lathering
Glooping on the sealant
Glooping on the sealant

Which brings us onto today [5th]. I fired Herman up and was disturbed to hear he was still idling rough. I hoped it was just a bit of oil starvation which would go away once the new oil circulated. So I went for a gentle drive and, sure enough, after about ten mins, he was purring like a kitten again. I pulled up in a shop carpark and had a look underneath and we were a drip free zone –Hurray!

Joy was a bit short-lived though for, after a couple more mini missions, I came out of one shop and saw that, once again, there were spots of oil underneath. Nowhere near the puddles there’d been before, but still a good few drips. I came back home and had a quick shine of the torch down the oil filler hatch on the engine cover and I can see that there is oil on the high pressure sensor again. So it looks like either I didnae lather enough of the sealant round it, or the actual sensor itself is leaking. I’d have thought the latter was unlikely, as it must be pretty much a sealed unit, but who knows?

Unfortunately this has happened right at the start of my holiday, so I think I’m going to have to give it another bash with the sealant, make sure I have plenty of spare oil on board and just keep checking my levels regularly –unless I can find a friendly VW parts dealer in Belfast and try sticking another sensor in.

It is really amazing though, just how much oil I managed to lose from such a small looking leak. When I’ve had leaky engines before, I’ve been used to sticking a top-up pint in every month or so, but this seems to have practically emptied the sump during the space of a 200 odd mile journey.