Thread: Defender T seal 300tdi

Originally Posted by Shortshank

I am having a problem removing the actual No5 bearing cap to renew the seals.

The slight gap on the t-seal could be a cause, but if the sump was installed with sufficient goo then it should have filled the gap.

The crank seal supporting aluminium frame may have been sealed with self vulcanising rubber, which sticks to the 'back' of the bearing cap as part of the sealing process. Careful prying should break the seal. When you reinstall the cap you will need to scrape the old rubber and apply new. Sometimes a gasket is used instead of rubber when a new cranks seal is installed.

There are rubber and cork t-seals. Guiding the cap in without stretching the seals can be problematic. I try a more sideways installation rather that vertical.

There are a couple of alternatives to replacing old t-seals with new. I re-installed the cap (making sure I had re-sealed the crank seal); then I proceeded to push rubber soaked cordage into the 't', then the upright; let it set then trimmed it; don't know if it has been successful because I've got leaks elsewhere to resolve! Less likely to be accessible to us DIY is high pressure injection of silicon.

The manual says new cap bolts are required, but I could not find a supplier with the correct length. I don't think they are torqued to yield. Rang a well known independent workshop who said they always reuse the bolts, but on another occasion I got mixed results on whether to lube a new crank seal or not, so even a good shop might not have everything down pat; and if you do go there then don't lube a new crank seal.

A good source of engine oil leaking is the small o-ring under the cap that holds in a wax thermostat, located near the spin on oil filter (if your defender tdi300 is anything like the D1). This leak could be fooling you that you have a t-seal leak because you can't find the source of the leak anywhere else. The o-ring is very thin, and using anything else thicker will result in breaking the aluminium cap. The old seal will look triangular in cross section due to pressure of sitting in a tapered hole for years.