Not a Landrover, I'm afraid. The daughter's Mazda 2. It has a pressed steel sump which has rusted through and was leaking. I bought a new sump and fitted it last night, using Loctite SI5980, which says it's suitable for sumps and indeed, I've used it before on similar applications.

To my dismay, after leaving it to cure overnight, I stuck the oil in this morning, went for a drive, and was dismayed to see it leaking from the joint when I got back!

The silicone that had squeezed out of the joint on the outside, seemed to be the usual rubbery substance. When I got the sump off, the stuff that had oozed out on the inside, was also starting to set, but less so. However, the stuff actually in the joint, hadn't set at all! I was able to just wipe it off with some kitchen roll.

I'm not really sure what I've done wrong. The sump was new and I put the bead round the sump. The engine was still slightly warm and there were a few drips of oil running down the inside of the block. I wiped the mating surface with acetone, having cleaned the old sealant off, then immediately offered up the sump and put the bolts in finger-tight. I then waited about half an hour or so, and did the bolts up properly, then left it from about midnight to 08.00 and put the new oil in. The only other thing worth mentioning, is that it was a tube of sealant that had been opened around Christmas for another job. However, it was still sticky and soft enough to squeeze into a bead.

What am I doing wrong?

Might sound silly, but ring Mazda and see what they use?

"Directions for use:
1. For best performance bond surfaces should be clean and free from grease.
2. Moisture curing begins immediately after the product is exposed to the atmosphere, therefore parts to be assembled should be mated within a few minutes after the product is dispensed.
3. The bond should be allowed to cure (e.g. seven days), before subjecting to heavy service loads.
4. Excess material can be easily wiped away with non-polar solvents"
http://tds.henkel.com/tds5/Studio/S...at=MTR&subformat=REAC&language=EN&plant=WERCS

Ratae said:

"Directions for use:
1. For best performance bond surfaces should be clean and free from grease.
2. Moisture curing begins immediately after the product is exposed to the atmosphere, therefore parts to be assembled should be mated within a few minutes after the product is dispensed.
3. The bond should be allowed to cure (e.g. seven days), before subjecting to heavy service loads.
4. Excess material can be easily wiped away with non-polar solvents"
http://tds.henkel.com/tds5/Studio/ShowPDF/243 NEW-EN?pid=5980&format=MTR&subformat=REAC&language=EN&plant=WERCS

Click to expand...

7 days!

Thanks guys. I think pretty much all Loctite data sheets say 7 days for full strength before any high loads, but of course, this is only a sump! However, I have made some progress with the sump though. It seems, looking at the data sheet, that Loctite 5980 is a pretty slow-curing one. Whilst it has worked well for me in the past, I've never been in this much of a rush before, and I am on this occasion because my daughter needs to be in Inverness tomorow afternoon! . A 1mm thick bead takes 24h to fully cure at 22 degrees C and 55% humidity. OK, I'm dealing with a bead thickness FAR less than that, but as the daughter needs to be back tomorrow afternoon, I was running out of options. Halfords had some Loctite 5990 which is supposed to cure a 1mm bead under the same conditions in 40 minutes. I also had the idea of leaving it with the filler cap off and the sump plug out over the afternoon, in the hope that some moisture might get inside the crankcase and start curing it a bit from the inside too.

Long story short, I stuck the sump back on with Loctite 5990 at 17.00 today and I've just put the oil in and sent her out in it to try it. It does seem to be dry under there, so hopefully, that it sorted this time!