So, I entered a side road from the main road today - main road heads down, side road slightly up. Entered the side road at a sedate 38 kph/24 mph (according to my dashcam GPS), and graunched the front spoiler on the dip - it's a sharper angle than I had expected, or is sensible, frankly. Might have bottomed out the suspension as well. So I got home, which wasn't far, and checked out the spoiler. Some scuff marks on the bottom, but it's still there, and seems pretty firmly attached still.

Anyway, while examining it, I noticed what seems to be seeping oil from one of the nut-holes holding up the underbody fairing thingy. Now, British cars leak oil, I know this from my father's old Triumphs. This doesn't appear to have been caused by the knock, as the outer parts of the stain have dried, but I'm not sure if it was there before or not. The oil at the thickest part, right by the bolt, was warm (this was just after getting home). I have never detected any oil on the ground, or at least not noticed any. And this leak is really more like seepage, and doesn't seem likely to drip.

My question, which is probably a bit paranoid really, is "is this a symptom of something major, or pretty much SOP for an old British engine?" Just the usual oil leakage being trapped by the fairing and leaking out the bolt-hole, or has something maybe ruptured?


This is the oil stain. The hole is where it's coming from.
Incidentally, I've ordered new tyres, and they should arrive in a day or two. The steering alignment that caused that wear has been fixed.


General view of underside showing location of oil seepage.

Apologies if this is the Jaguar equivalent of "I just stubbed my toe. Do you think it needs amputation before gangrene rots my foot off?" It's sometimes ridiculous how nervous I get around my car - the biggest purchase I've yet made, plus the culmination of a thirty-year dream. Each time it starts up I breathe a sigh of relief, even though it has never, ever had problems starting up.
I am sometimes glad I don't have children, as I worry enough about my car when something isn't 100% perfect - hate to think how I would cope with a child getting sick....

 

Some Day, Some Day,

It's not right for the car to be leaking any fluid. If I were you, I would undo the front undertray and establish the source of the leak. Because it's so far forward, if it's engine oil, it could be that it's the oil cooler or (more likely) the attachment of the pipe to the oil cooler.

Good luck

Paul

 

Paul's advice sound as always, but before removing the undertray which is a pain, it could also be the pipe join into the tranny cooler in the rad RHS. Run your finger round the joints and see if they are oily. If you fitted a new rad recently (I seem to remember?) they may not be quite tight enough. Also you can see the engine oil cooler pipes from outside the front lower grille, looking in. So worth have a dekko before removing anything to look more closely.
Greg

 

Jaguars don't leak oil- they mark their territory
If it stops leaking oil- add more oil, your probably low

 

You're right, Greg - she has a new radiator, a nice shiny aluminium one from Wizard. I'll check the RHS of the rad where the oil coolant is, and see what I can see through the lower grille. Your suggestion makes sense.

I actually checked oil levels a few days ago - bang on midway between the dipstick markings. Probably wouldn't hurt to add some more, however. Actually, I wonder if a full change might be worth the money - considering it's the first time she's been driven regularly in, judging by records, several years (the last four years she only had 4,000 km added: I've already put that on and more in 50 days). Although it's been only about 6 months and 1,200 km or so, I'm going by the assumption that the first oil change after less use is going to collect more gunk than normal due to regular renewed use (though the oil itself, while darkish, appears free of any grit I could feel).

 

Today I got the front tyres replaced, getting the front wheels rotated to the back as well. This meant that all four wheel were off, the car was on a hoist, and I could get under with a torch ("flashlight" to Americans) and have a good look. Greg's hypothesis seems to be right - the bottom pipe going into the rad at the right bottom, as seen looking forwards, is covered in a thin sheen of oil. There's also oil coating the RH chunk of metal below leading backwards, there appears to be some minor seepage from the... crank case? on the same side, and the transmission round bit (torque converter housing, I think) is also a bit oily, with probable seepage from the thin metal plate next to it covering whatever that thin metal plate is covering. (Before, I took a careful reading of the dipstick: 3-4 mm below the midway line, where the crosshatches start. No sign of any grittiness at all.)

So as it's apparently connected with, at least, the radiator work, and possibly the tranny work too, I'll have a chat with the garage. It's a pretty minor amount all told, in that it's not enough to drip onto the ground it seems, but the oil coats a moderate amount of the underside. No doubt doing wonders keeping rust at bay, mind....

 

Those two pipes to the RHS tank of the rad, one above the other are the transmission cooler lines (the cooler is a coil within the rad RHS tank). Ask the garage to tighten them a touch (very CAREFULLY if they are the screw on type) as ally will not take much abuse. They should renew the O ring seal, or whatever it is, in the screwing-on bit too, which might be the real cause. If the cooler pipes are held on by jubilee clips (about 1986/7 or so they changed to the screw on type connector) then best to change out the entire flexible, if tightening the clip does not quite seal it.


The weep below the cover at the rear is almost certainly one of the oil gauge sender unit, the oil warning light unit, or the half moon seals on the cam covers, or all three of them, allowing oil to run down the back of the engine from the top. The senders can be changed easily-ish (but get your garage to support the ally casting they fit into against the undoing torque or they will break it off). The half moon seals and cam cover gaskets can be renewed when you feel rich enough to do it. This is an inlet manifold off job, so you can get the injectors seals done at the same time, clean up the V etc etc. But there is nothing dangerous in small leaks like this. However, he sensors can lose a surprisingly large amount of oil on a long fast run, and it can be very hard to spot it actually coming out of a faulty sensor. I had a very bad one that lost nearly half the oil on a long run, the bottom of the car was dripping with oil! But it was still hard to pinpoint the cause at tickover with clean oil being very hard to spot deep in the V. run your finger round the bottom of the sensors and see if you can find oil. If so, get them changed. The pic shows them, the two things with wires going to them just behind the throttle capstan stand (ie nearest to the foreground of the photo).
Greg

 

Thanks very much for that wonderfully detailed explanation. I'll translate the relevant bits into Japanese and provide them to the garage when I take the car in. I'm planning a long run (300 km) at the end of the month, though it won't be that fast (speed limits of 100 kph, might push it to 120, but the idea isn't to speed), so if the garage can't get her ready before then, I'll add some oil, take some along, and check once she's cooled from the run.

If I read your directions right, the oil sensors are the grey nut-looking things at the back of each bank, attached with black wires to something behind the capstan, right? I'll check them out in the morning.

Thanks again. I'm reasonably sure, based on the puddles my father's British cars left, that some seepage is basically expected, but was especially worried that hitting that different slope with a graunch (at less than 40 kph!) might have ruptured something important. I didn't see anything underneath during my inspection today that looked obviously ruptured, at least....

 

If I read your directions right, the oil sensors are the grey nut-looking things at the back of each bank, attached with black wires to something behind the capstan, right? I'll check them out in the morning.

NO, they are the oil feeds to the camshafts, leave them well alone!!

The sensors are IN THE MIDDLE of the V, just towards the photo foreground aft of the throttle capstan stand. One is round and drum-shaped and sits flat side up with one brown wire coming out of it, the other is at about 45 degrees to its right, and has a black plastic top to it above the metal bit. they have taper threads, so when going back in, when they are reasonably tight that is tight enough!! warn the garage.
Graunching the undertray/spoiler make a scary noise, but cannot do any damage apart to the plastic itself, do not worry!
Greg

 

Oops. I was trying to find two identical things, which is where I went wrong. I've circles where I think you mean now - is that correct?

 

100% right! And the casting they are fitted to must be supported when undoing AND doing up the new sensors. I carries oil feed under pressure and if the garage cracks it, replacing it is not that easy. I know I am being repetitive, but one clown with a spanner is all it takes!
Greg

 

Cool! I'll take a look tomorrow for any oil around there.
Thanks again!

 

Hi Greg. I had a look at the sensors - they're a bit differently shaped on my facelift, but the upright and angled parts were the same, and they're shiny and clean. So that doesn't appear to be an issue, at least. I'll be able to take the car in for a check on Tuesday, however, with your comments in hand.

 

That is something I am trying to stop my Jag doing... My driveway is nearly new... Don't want territory markings here

 

.

hope you have better luck than i have.

especially after a few thousand miles on it, i have replaced many engines with rope seals, most no probs. but something about that long crank wobbling around with a heavy auto converter tied on the end seems to open up the rope!

time will tell,altho i'm used to it and dont bother me anymore, i'm careful where i park it so as to not upset anyone(overnight park has a spot around couple inch in diameter).

good luck

 

Try putting down a sturdy doormat where the leak will drip. That might absorb most of it.