Oil usage

[Nick Jones]

Thanks. Interesting observation about varying oil levels. I've noticed something similar (except it never seems to go up!). I also notice that small inclines (front to back or side to side) make a big difference. My drive is pretty flat, but not flat enough apparently. I have to park in the same spot for meaningful results.

Shortish runs seem to use more. My normal commute is 15 miles of mixed driving each way and a couple of weeks of that has it wanting a litre or so. However, I've done a couple of 300+ mile trips where it barely seems to have moved. Would have expected the opposite! Perhaps it is an indicator of valve guide seals past their best (on 2 & 4 especially). Certainly the only time I've ever seen smoke is on hot re-start.

Totally agree on the 5-30 Vs 10-40. My A6 TDI has survived nearly 300k on the Quantum Synta 10-40 (though the 5 pot diesel is known to be a survivor).

Will try changing it to 10-40 and see what happens.

Cheers

Nick

[Nick Jones]

So finally got around to crawling under this properly today for the first time in a while. The main mission was an oil change (to 10/40 as previously discussed), but it was also rather obvious that it has a fairly big oil leak.

I have been aware that it had oil leaks pretty much since it came to live with me, but as it doesn't drip hugely on the drive (I'm also a Triumph owner so my calibration is quite coarse!), I assumed the leak wasn't that big.

Possibly it's got bigger, as they do, but anyhow, as you can see from the pics there's enough coming out to blow back under the car and cover the subframe and further back.

It's coming from somewhere on the right hand side and, I think, near the front. Seems to be an engine-running-only leak but I'm struggling to spot where from. Pretty sure it's lower than the cam cover gasket.

No oil in water or water in oil so I'm hoping it's not the oil cooler. Could possibly be cam seal and running down - though belt seems dry?

Any favourite sources in that area?

Thanks

Nick

[27litres]

Have a good look at the lower sump.
When full, the oil level is above the join between the upper and lower sumps
The early 32V engines use a gasket, while the later 40V engines use a silicone type sealant.

The sealant ones do start leaking with old age.
I can't speak for the gasket, but it's certainly worth a look as the lower sump is just pressed steel and subject to some stress when the sump plug is removed and reinstalled.

[Ameiseuk]

Go for the simple repairs first and see if it eliminates the problem. When i first got under my car mid rebuild I had a similar mess front right of the engine.
I found all the sump bolts slightly slack, most took a 1/4 turn on the ratchet. Other item to check is the oil level sensor- this turned out to be the main culprit. Took it out, cleaned sump and o-ring, reinstated with a smear of instant gasket. Problem solved

If you are going to replace rocker cover gaskets, follow the original workshop instructions and put the necessary blobs of sealant in the sharp corners of the head. If its been off and these havent been done it could be enough to leak from there.

[27litres]

There's a product you can probably pick up off eBay called AT205.
It's a plasticiser and rejuvenates seals rather than swells them. This could be useful for your valve stem seals and other internal engine seals.

5W30 is almost certainly too thin at operating temperature for this engine too. Correct spec is 5W40.
If you still have consumption (not leaks) with 5W40, you can try a 5W50 or 10W50. Just check it meets VW504 spec.

[Dezzy]

Jizer and plenty of it, clean it all up and keep an eye out and take it from there.
My 8 uses oil not as much as that but depending of how the engine is being used. Pushing hard will burn a bit, noticed at 150 I leave a blue smoke trail.

[Architex_mA8tey]

Originally Posted by Dezzy

noticed at 150 I leave a blue smoke trail.

That will be your brains reaction to the speeeeeeed!

[Nick Jones]

Thanks. I'll keep an eye out for the AT205 - doesn't appear to be very readily available in the UK though. I note that it seems to have some kind of ester as it's active ingredient which sounds rather like brake fluid....... So I did some googling around that and it seems that I'm not the first to have thought of this and it is a long standing dodge in the trade. Opinions vary on the effects, long and short term!

More common UK solutions seem to involve different chemistry and once again opinions vary as to the short and long term effects. Must say I'm somewhat horrified at the cost of a cam cover gasket. I saw a price which I thought was steep for a pair and then realised it was for 1 side only!

I'll see how the 10/40 does initially. Car is running well at present so it'll probably get work duties next week which'll be 500 miles or so.

Haven't tried for 150 mph.....

Thanks

Nick

[27litres]

Depends what you think is dear, but FCP do genuine 32V valve cover gasket sets for US$53.99ea plus US$22 freight - so about £90 delivered.

They have Victor Reinz brand ones on clearance at US$16.99 too, which are a reasonable brand (just be wary of their cam end caps - ones I bought are a bit loose).


Easy Square sell genuine VAG for €29.92ea as well.

[Nick Jones]

Call me tight (many do!) but I think any more than £30 a side is taking the mickey. All the UK one I've found have been £ 50 ish per side. I'm used to old Triumphs with a cork gasket costing a few quid.

Don't recall the one on my C4 A6 (I5 TDI) being stupid money and that's a fairly complex rubber moulding. It's also only needed changing once in 300k/20 years.....

The very similar 1.8 20v ones seem to start at £ 15 though admittedly a much more common engine.

The 10/40 seems to be helping, but early days yet.

Nick