Norfolk Garage
The differences between the 200Tdi and 300Tdi oil seal
Crank seal problems, diff issues and a savaged sump – every day brings new challenges for Richard Hall
Ihave been fitting Tdi engines to old Land Rovers for some years now, and up until recently one component which never gave me much trouble was the oil seal at the back of the crankshaft. The 200Tdi engine uses a design carried over from the older pre-tdi engines, with a large seal pressed into a close-fitting recess in the back of the flywheel housing. The seal itself has a ridged plastic inner part, crimped into a thin aluminium outer shell. They can be damaged by clumsy fitting, with any distortion of the outer shell tending to result in oil seeping past the joint where the shell is crimped over the inner seal. But provided they are pressed in nice and square, using a flat metal ring to exert even pressure on the outer face of the metal shell, they generally have a long service life.
These seals replaced an earlier type made from an orange rubbery material, which tended to cut into the surface of the crankshaft and wear a groove in it, just as so happens with front crankshaft pullies, transfer box output flanges, differential pinion flanges, etc. The plastic material on the later seals may seem harder than rubber, but it causes far less wear: I have had engines to bits with upwards of 250,000 miles on them and barely any detectable wear ridge on the crankshaft. So, even though the earlier orange seals are still available, and far more tolerant of brutal fitting techniques than the later metal-cased ones, I would still tend to recommend the latter.
I used to always use genuine Dowty seals with the maker’s name stamped on them, but a few years ago these became unavailable, being replaced by OEM (Original Equipment Manufacture) seals of unknown origin. These seemed to be of equivalent quality to the Dowty seals, and I carried on using them until a few months ago, when I had a seal fail after only a few hundred miles. On inspection it turned out that the lip of the seal had not been cut cleanly (possibly due to worn tooling) and had high spots on it, preventing it from sealing properly.
A couple of other seals I had on the shelf from the same supplier had the same fault so I switched to an alternative supplier whose product seems adequately well made, at least for now.
The lesson here is that before fitting a five-bearing rear crank seal (part number ERR2532) it pays to carry out a careful visual inspection, and also to run your finger round the lip of the seal. If you can feel any roughness or pimples, or if the seal is visibly not cut square, with the ridges parallel to the seal edge all the way round, reject it. Of the two seals in the photo, the upper one is fine: the lower (from the faulty batch) has some fairly obvious issues.
In evolving from the 200Tdi to the 300Tdi, Land Rover somehow managed to end up with an engine of identical size, weight and power output, while changing almost every single component. The rear crankshaft seal was among the items redesigned, with the seal now being encased in a detachable cast aluminium carrier. The seal no longer has to be pressed into the flywheel housing, but is simply bolted on (complete with carrier). And there the fun begins. Earlier engines had a rubber and steel sandwich gasket between the seal carrier and the engine block. The carrier was held on with five widely-spaced bolts, and there were no bolts along the lower edge where the casting was very thin and not overly strong. The result was that if the retaining bolts were done up much more than finger tight, the seal carrier tended to bend outwards at the bottom, leading to oil leaks.
At some point Land Rover did away with the gasket, instead recommending that a bead of RTV silicone sealant should be used to seal the carrier to the block. Care still had to be taken to do the five bolts up slowly and progressively to avoid distorting the carrier. At the same time the part number was changed from RTC6818 to LUF100430, although I have been unable to ascertain what change if
any was made to the seal assembly itself. The Brazilian-made 2.8 litre development of the 300Tdi had the seal redesigned to incorporate two small bolts along the lower edge, which is what Land Rover should have done in the first place. These seals are quite readily available, made by Corteco, which means the quality should be good. and it would in theory be possible to drill and tap the holes for the two extra bolts. Although they should not be needed if care is taken fitting the seal in the first place.
Given that I am very aware of the issues with these seals and always take great care in fitting them, I was more than a little disappointed when I took a Defender 110 with a newly-fitted 300Tdi conversion for a test drive and it came back dripping oil from the bottom of the flywheel housing. I had fitted this one with a supposedly OEM seal with the earlier part number and had used the corresponding gasket. I assumed that the seal itself must have failed (this happens occasionally) but on removing the flywheel there was no oil present in the recess between the seal and the crank. There was however plenty of oil along the bottom edge of the seal carrier. I removed the carrier and placed a straight edge along the bottom, and found that it was bent like a banana. Since I did not check the seal before fitting, I have no idea whether it came out of the box like that, or whether it was just an unusually weak casting which distorted when the bolts were tightened. It went in the bin anyway, and a Genuine Parts replacement, with the later part number, was fitted using RTV sealant and no gasket. This time the underside of the engine stayed gratifyingly dry.
Lesson number two: on the 300Tdi engine, don’t just check the seal itself (as for the 200Tdi seal above), put a straight edge along the bottom of the seal carrier as well. If you can see daylight, take it back and ask for another one. The 300Tdi also seems more prone than earlier engines to leaking oil from the T-shaped seals either side of the rear main bearing cap. If you have the engine out to change the crank seal, it is worth dropping the sump, removing the bearing cap and fitting new seals. The sump itself has no gasket, just a bead of RTV sealant. Land Rover recommends that new bolts are used when refitting the bearing cap.