Xantia-threaded hole behind timing belt idler roller

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NewcastleFalcon
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Xantia-threaded hole behind timing belt idler roller

Post by NewcastleFalcon »

Its still Crankshaft pulley bolt 1 Newcastle Falcon 0 refering to my previous thread. With a bit of precise surgery with my penknife involving one cut at the very bottom of the lower timing belt cover I have managed to prise the cover off in one piece, and can now get on with replacing the timing belt.


Prior to my recent timing belt failure, I had been ignoring an oil leak for about 20,000 miles emerging from behing the lower timing belt cover towards the bottom of the block at the front of the car.

When I took the idler roller off I did discover a threaded hole in the block, with oil emerging from it which was behind the metal plate on which the idler roller is mounted.

There is a brassy looking round stud of 5p type dimensions which the idler roller locates on and the threaded hole is just to the left (ie towards the rear of the car) of this stud.

It is covered completely by the idler roller metal plate, and I can't see what purpose it serves other than to generate an oil leak.

Anyone come across this before?

Thanks Neil
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Post by CitroJim »

This will be a threaded core plug sealing off an oil gallery drilling. They do occasionally weep and the best course of action is to remove it, clean it very thoroughly and replace it with a smear of Hylomar or Wellseal. This'll keep the oil where it belongs!

Don't use too much sealant. You don't want lumps of it floating around in the oil galleries.. Take acre doing it as there is a fair old pressure behind this plug...
Jim

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Post by NewcastleFalcon »

Thanks Jim

There is literally nothing in the threaded hole, nothing to remove just a threaded hole. I think its a M8 type of size. The 'brassy round thing" adjacent does look like some "plug" which could be removed and reinstated as you suggest. This is what pokes through the existing drilling in the idler pulley mounting plate.

I probably need to block the open threaded hole off with something. At the moment I have just coated the back of the idler pulley metal plate with hylomar and bunged more hylomar in the hole.

Any more permanent arrangement would require a plug completely flush with the block face or I would have to drill a hole through the idler pulley and fit an appropriate bolt assuming the position of the bolt didn't foul the timing belt.

thanks Neil
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Post by CitroJim »

Sorry Neil, mis-read that a little :oops:

Can you post up some pictures of it? It'll be a great help.
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Post by NewcastleFalcon »

Hopefully I will get a picture later in the week. I think I'll give my heath robinson solution a chance, maybe the metal plate bolted down against the block face with the hylomar will seal the hole sufficiently to cure the leak.

If not then I will have to come up with something along the lines of my previous post.

I did think for a minute-have I put the Idler roller plate back on correctly, but as far as I can work out you can just put it on one way with the upper bolt also serving as an engine mounting bolt, and the two lower bolts just fitting in the appropriate holes the block.

Thanks Neil
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Post by the_weaver »

M8 sounds like the same size as the mounting bolts for the idler. The idlers are normally held on in three places. Are you missing a mounting bolt? One of the bolts goes through the engine mounting. One of the bolts may be a spindle type.

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Post by NewcastleFalcon »

Thanks Paul, the idler mounting plate has three bolts all in and mounted correctly with the top bolt also serving to act as an engine mounting bolt. This threaded hole is behind the idler mounting plate, just to the side/left of the "brassy round thing" which conveniently pokes through the large hole already there on the mounting plate.

I am sure the anatomy of my block must be slightly odd, and the threaded hole I refer to needs to be blanked off.

thanks Neil
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Post by NewcastleFalcon »

Here are the pictures. The threaded hole is M10, and goes in at least 1-2cm. The two bolts are the positions for the bottom two bolts of the idler pulley mounting plate. Water pump to the left, and "brassy round thing" adjacent to the threaded hole. Lower picture shows idler pulley on its mounting plate. The large drilling in the mounting plate fits over the "brassy round thing" and the metal plate covers the threaded hole.

Image

Image


I am thinking along the lines of cutting down a M10 bolt and cutting a screwdriver slot in the end to plug the hole, although a neater way would be to use a grub screw if I knew where to get them quickly.

Is this hole likely to tap into an oilway? Does anyone know what a "piston oil jet spray tube-bolt-turbo models" is-Page 2B.3 Haynes manual. I am just wondering if this may have anything to do with my mystery hole.

One thing I also discovered was that my injection pump sprocket only has one timing hole. Haynes suggests this is applicable to 2.1 litre models, mine is a 1.9td as far as I am aware.

Not that any experienced members of the forum would do this-but I did spend about 1.5 hours retrieving my second and totally unnecessary M8 timing bolt from behind the injector pump sprocket having dropped it when ferreting about for the non-existant hole.

Thanks Neil
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