Oil consumption and finding oil leaks

[Alex]

Few questions here

My car uses next to no oil on the road, and doesn't seem to be incontinent either. The floor of the garage in Kettering was clean when we moved out.

However, I seem to have used quite a bit yesterday - which I understand is normal. Topped it up, checked this morning and it was about a quarter of the way between min and max. Close to the bottom basically.

This evening after a 230 mile drive it appears to be under the minimum again.

That's concerning me because it stinks of evaporating oil, and I'm getting smoke from evaporating oil. The bay looks oily though the charger and boost return are fine. It also dropped a bit of oil at the services, looked like it was dripping off a few bits.

So, next question, I spilled some oil while topping up yesterday. Is it possible that some of this hasn't evaporated after a 230 mile drive?

Or have I broken something? If so what's likely to have let go and what should I look out for?

Can I clean my engine bay with brake cleaner, to see where the leak is coming from?

Is it possible yesterday's hoonery has warmed up old oil deposits which are now dripping off the engine?

It's running fine otherwise, despite a boost leak.

[scotsjohn]

Wouldn't be a blocked breather Alex? Sounds like crankcase fumes which have that distinctive smell. What's the underside of the bonnet like?

[hayesey]

you sure the charger seals arent on their way out?  Might explain the lack of boost too

[Alex]

Yeah the boost leak is almost definitely just a leak - you can hear air escaping at full throttle. I tightened things up at the hotel yesterday morning, got a few seconds of normal boost and then it hissed and dropped back down to 0.5 bar. It's only a few months since the charger was rebuilt, so I doubt it's that.

The breather pipe was replaced last week, but I tucked it behind the lead on the coil pack so that might've restricted it. There looks to be oil on the front of the gearbox casing, but none below the dizzy - there's a seal which can leak there iirc?

I assume it's happened since I parked up but there's a film of oil dripped on the downpipe. Couldn't see any around the oil cooler or the charger oil lines though. My mate following me back from Blyton to the hotel said it wasn't smoking while I was driving, but if I stopped at traffic lights it was smoky as I drove away. There was a mist of evaporating oil when I got home and was sat on the drive yesterday, because the fan was blowing it out from under the car. It's possible he was seeing that.

It had a new cambelt last week, which would've meant slackening the charger and possibly removing the charger-intercooler pipe as it's not a ribbed one it's just an angled piece of silicone hose. I'll refit that tonight, tighten up the hose coming out of the top of the intercooler and see what happens.

It's one of those, where it doesn't feel like I've got a serious problem, but I'm concerned enough to keep the miles down until I know what's wrong with it. The car idles fine, drives normally until you're at full throttle and doesn't seem to be using more fuel. My hope is I've just got evaporating oil spillage to worry about.

[hayesey]

oil on the gearbox casing but not the dizzy could be the small pipe between the aux air valve and the plastic boost pipe

[Alex]

I'll have a look later. That'd imply it's split, I assume? Could also explain the boost leak, but with the anomaly that I got full boost after tightening other bits yesterday. Makes sense!

[ereeiz]

Checked the rocker/cam cover?
mine spits it out the dipstick neck  (assume a blocked breather or similar causing excessive pressure) could be worth checking this too.

[Alex]

It doesn't seem to be coming out of the dipstick tube, bonnet looks ok on the underside but I was looking with a torch. It's definitely got more oil under the bonnet than it had before, but some of that is what I spilled. The rocker cover for example is quite oily still.

Rocker cover gasket is weeping too, but it'd need to be weeping a lot

[ereeiz]

Forgot to say, cleaning with brake cleaner is fine just make sure it's cold as you may have a wee flamethrower on the go otherwise
Alloy wheel cleaner is fine too, I used to use Autoglym wheel acid (neat) when I was a valeter.

Plastics, rubbers, etc can all be tarted back up quickly with any plastic restorer, again I used to use autoglym "wheel milk" (it's tyre shine but looks like milk), spray it over everything then wipe it off 20mins later

[Alex]

I'll grab some brake cleaner on the way home then, clean it up a bit. I'm not bothered about it from a show and shine point of view, but it's obviously much easier to find oil leaks when everything is clean.

[Yoof]

Oil smokes for ages, mine was smoking almost all the way to BVF after emptying about 1 litre over my wrapped downpipe and manifold...

Common places for leaks on G40s:

- Rocker cover gasket (use a genuine one, much better)
- Head gasket (worse with metal ones, use a dab of sealant on the front left above the alternator)
- Crank seals- both ends, solution is new ones
- Oil breather - make sure it's of sufficient diameter (1"+) and not kinked
-Sump gasket, knackered/damaged sump replace with nw gasket & sealant
- Oil pressure take off, use a small amount of PTFE tape and don't over tighten, use fresh copper washers.
- Dizzy oil seal, usually destroys hall sender first...

Track driving will always highlight oil leaks, you're generally getting the oil much hotter, thinner, and running much higher pressure for a sustained period than you can on the road, so will always leak more. You'll generally get more blow-by too (combustion pressure escaping past the rings into the crankcase) so the car will breathe more heavily.

Check the plugs too, it will be fairly evident if you're burning a substantial amount of oil, and make sure the breather isn't blocked, that the dipstick o-ring isn't hard, and that the seal in your filler cap is good.

[Alex]

This ^^ is why I love Club G40.

So it's possible the oil use is a red herring, I guess, and that it's my oil spillage that's made most of the mess.

I'll get the rocker cover gasket changed next week as a matter of course, there's definitely a small amount leaking through that and it's a GSF part. I intend to spend the next few years irradicating non-genuine bits from this car, as it appears to eat through them!

Dipstick was new with the conversion so again should be fine, and one of the oil pressure sensors was renewed when I fitted the gauges.

New crankcase breather pipe went on last week, as the old one wasn't sealing properly. So that should be clear and not leaking, though it's venting into the chassis leg still. It's possible some of the oil at the back of the bay is left over from the before this was changed though, at a guess?

The rest I'll have to check as best I can on the drive, but I've booked it into the garage next week to get checked over (the CV joint needs to be changed anyway). It's probably nothing serious - I hope not anyway - it might just have highlighted areas where things weren't sealing properly. This is the first time I've been out on track in it for three years.

As I say, it seems fine to drive. If it wasn't for the boost leak I'd say it feels no different to how it did on the way up, except the brakes are obviously bedded in now.

I'm doing YouDrive@Porsche on the 18th, and hopefully I'll be taking the Polo, so I'm praying it's an easy fix.

[Alex]

Just had a poke about under the bonnet, and it appears my oil leak is a combination of rocker cover gasket (which is weeping almost the whole way round) and the T piece for the oil pressure gauge. It's loose enough to wobble and undo by hand, and there's oil around it, so it's not helping even if it's not THE problem.

Dipstick tube is bone dry, and so is the cambelt cover underneath. Breather hose under the plastic boost pipe isn't oily and nothing around it is oily either. There's a coating of oil on the engine side of the gearbox, which I've washed off with brake cleaner. I dunno, maybe the gearbox doesn't get hot enough to burn it off quickly?

Boost leak, I think I've found that too. Top intercooler bolt was loose, so the intercooler had dropped about 10mm and the jubilee clip was squiffy. Tightened the bolt, pulled the intercooler into place, slipped the pipe back onto it properly, fitted the jubilee and it all seems tight. I'll get the bottom intercooler bolts changed next week, I assume they're not doing their job, or they've dropped off at some point.

The car starts and runs smoothly, with no smoke. I was shining an iPhone flash on the tailpipe and it wasn't even puffing condensation.

Not been for a test drive yet though. Too tired, can't be bothered. The rest I can't see while grovelling on the inlaws' lawn using my iPhone as a light. It went dark not long after I went outside.

[PeteG40]

if the t-piece or oil pressure senders are loose -the haemorrhage  oil!! so i'd bet thats your problem.

the gaskets - vag ones are g40 specific as they have a metal strip in them...  but i still use blue gasket on it too!! 

beware they are like £25 at vag or something silly

http://www.ebay.co.uk/itm/VW-PY-Polo-Derby-1984-1982-1994-Cover-Gasket-030103483C-/270608018249?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3f017eab49#ht_3330wt_977

[Alex]

Yep, that's first port of call tomorrow, tightening the T piece a little. I'll get some PTFE tape on it next week while it's in the garage - I don't have any. I'm in St Albans on Wednesday/Thursday and away Monday-Wednesday next week so it can stay where it is until Saturday when I drop it off.

Rocker cover gasket is non-VAG and has always weeped a little. £25 is steep but worth it.