300Tdi rear main - Again!

[Taz]

Just wondering if others have had similar experiences...

Replaced rear main seal & T-seals 20,000km ago and has been leak free up until recently. A slight leak started a few weeks ago and now it's dropping 6-7mm on the dip-stick per 100km. It's leaking from the hole in the bell housing (r380).

Does not leak when parked overnight, nor when idling cold (stationary), and only a few drops when idling warm (stationary). 20,000km ago I used a high temp silicon sealant instead of a gasket on the seal housing and a lite smear of grease on the crank; contrary to RAVE but I did not want to burn the seal and it certainly worked well up until now.

Anyone had a re main seal fail after only 20,000km?

[Discomark]

Just a thought but have you checked your crankcase breather is not blocked, its usually the biggest seal that lets go if pressure builds up in the crankcase. Check for blowback when the oil filler cap is removed when motor running.

BTW, I've had my T-seal replaced twice in 145k.

Cheers

Mark

[steane]

Seal face should not be touched or have oil/grease come in contact with it, they have a film/coating applied during manufacture that helps them bed in and seal. That will most likely be why it is leaking. Also heard that some of the non-genuine seals are rubbish.

[Vanderz]

apparently you need one of these? so i have been told on here. the boys there have made it better than OEM

Turner Engineering LUF100430 Rear Oil Seal (http://www.turnerengineering.co.uk/acatalog/info-832.html)

[redrovertdi]

apparently you need one of these? so i have been told on here. the boys there have made it better than OEM

Turner Engineering LUF100430 Rear Oil Seal (http://www.turnerengineering.co.uk/acatalog/info-832.html)


This is the way to go since the Dowty[OE] are no longer available, i use ultra blue and nothing on the seal face, if you ar buying a vrs kit with this from turners DO NOT USE the backing plate included behind this seal, Turners used to use/supply the dowty rear main seal but they are no longer available and now supply the 2.8 seal above

[Reads90]

Had the problem a few years ago and was crank case pressure from worn rings.

Make sure you check this. I did not have any other signs other than three rear main seals nackered. There was no normal smoke from the rear of the car.

Quick little check. Start the car and take out the oil dipstick and give it a little rev. If oil sprays out of the dip stick tube you have too much crank case pressure.

[Vanderz]

This is the way to go since the Dowty[OE] are no longer available, i use ultra blue and nothing on the seal face, if you ar buying a vrs kit with this from turners DO NOT USE the backing plate included behind this seal, Turners used to use/supply the dowty rear main seal but they are no longer available and now supply the 2.8 seal above


do you have to buy another backing plate? or use the current one that is on there with the new seal?

[redrovertdi]

do you have to buy another backing plate? or use the current one that is on there with the new seal?


Just to clarify the backing plate i refer to is a tin gasket that goes behind the rear main seal[i shouldnt have reffered to it as a backing plate], i was told not to use it in the past by MR automotive and didnt, at a much later date a friend doing a rebuild with all turners supplied parts had the new rear main leak immediately and after contacting turners they said he shouldnt have used the tin gasket with the new tgv2.8 rear main that was supplied in the kit, it was also supplied in my kit from them[why include it if its not needed?]

[Vanderz]

so does nothing go in the place of that said tin gasket or do you need to find a rubber land rover equivalant ?

[redrovertdi]

dont use the tin gasket, i use a thin smear of permatex ultra blue, make sure you dont get any on the lip of the seal or the crankshaft

[Taz]

Update...

No significant blow-by and the exhaust gas recirculation was not blocked. So the donk came out. I fitted a new rear main and T seals and now it is all back together and leak free once more. Although the underlying cause was not immediately obvious...

A few observations:

The seal itself was bone dry. I used a magnifying glass and torch up under the bottom of the rubber lip and it was completely dry. The crank was dry all the way around. BTW - this seal was installed with a very light smear of grease, so I will be doing that again.

Whilst one of the T seals appeared wet, there was no apparent leak path to get past the seal housing.

A small amount of oil dripped down the bottom of the housing as I removed it. Some of this oil must have been sitting just behind the crank, yet it's plausible that I had a sealant failure (or I didn't apply enough sealant) at the bottom of the housing as well.

There was oil on the outer face of the crank (flywheel mating surface). Again, at least some of this oil could have dripped on the face as I removed the crank bolts, or it might suggest that oil was leaking through these threads. The outer surface of the flywheel (clutch mating surface) was dry.

Any thoughts as to the cause? Considering the amount of oil leaving the engine, I doubt leaking past the flywheel bolts was the main cause or a contributing factor at all. So I suspect it was the sealant. I had used Permatex ultra grey. But it's weird that it held for 20,000km before letting go.


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