Loose bolt on head - spraying oil

[Driver+Passengers]

To the right of the rightmost top intake manifold stud is a sensor, to the right of it is a bolt that I found to be loose. Any ideas?

I've just ran a few miles with the bolt removed, and it's spraying oil all over my nice clean inlet manifold, rocker cover, etc...

It bolts into aluminium - the threads are (now) stripped. The bolt's been loose before, and when snugging it up, it kept turning and brought three threads worth of swarf out with it.

Whatever it is that it's bolting into is at the front of the block, under the front most end of the head, and from the driver's side looks like it goes a little way back, ie along the front of the block. It's just under the coolant outflow stub.

Going to look at some 'sploded diagrams, but need to know:
- what is it threading into?
- why is it spraying oil?
- what's the best remedy?

[westonwarrior]

cant answewr the first 2 but the only remedy that I know of is to get it helicoiled

[briwy]

If the bolt isn't holding anything on/down Matt it could just be a plug for the oilway after it was drilled.

Possibly drill and tap it again slightly larger diameter and Locktite the bolt in. Otherwise as WW says helicoil. Main thing is keep any drillings, swarf etc out of the oil. If its blowing oil out hopefully it will have pushed any crap out with it.

[widdowson2008]

If it's this one

- what is it threading into? The block
- why is it spraying oil? The front pair of bolts (one at each side of the head) is the oil return from the rocker chamber back to the main oil sump. (I think - almost 100% sure)
- what's the best remedy? As WW said - Helicoil, but not sure how you would do it without removing the head first.

[widdowson2008]

If the bolt isn't holding anything on/down Matt it could just be a plug for the oilway after it was drilled.

Possibly drill and tap it again slightly larger diameter and Locktite the bolt in. Otherwise as WW says helicoil. Main thing is keep any drillings, swarf etc out of the oil. If its blowing oil out hopefully it will have pushed any crap out with it.

Definitely not a plug briwy. It's one of the bolt set you get with a new head. Got pics if you want them.
Through the head at that point is 100mm, and that is before you get to the threaded part, so you would need a tap at least 130mm long. Not saying it's not possible though - just a bit risky if the tap snaps off, cos that would mean HEAD OFF.

[briwy]

It was just with Matt saying that it bolted into alloy that made me think it might just be a plug Steve. Is it the same as the other head bolts that come with a new set?

Must admit it looks more like a head bolt, not sure it why it would be letting oil out though if that's the case. I agree if it goes into the block its likely a helicoil is the only option but might still mean the head off I guess.

[Driver+Passengers]

Thanks, folks.

I think, from the service manual, it's one of the two front "A" bolts - different head from the 'numbered' bolts.

I'm pretty sure it's not going into the cast block - both by location, and by what I stripped out. I was working by candlelight, but I think whatever the fuel pump bolts into is the same piece that this bolt meets at the bottom of the head. I'll get it back on the ramps to have a better look. I will run the engine tomorrow with a sheet of newspaper over the engine to confirm the source.

After doing the rocker cover gasket (no more than a week after doing my first oil change EVER), I was just saying earlier this evening that it would be fine to have an opportunity at some point to get my head off. Well, well...!

[Driver+Passengers]

Diagram 1010C (http://lushprojects.com/bongopartsmk2/c ... mgno=.html)

Part 10-271 is the head gasket. The lower left hand end of this shows a narrow, transverse opening. Above it is the head, below is not the block (1030C http://lushprojects.com/bongopartsmk2/c ... mgno=.html), but some part presumably bolted to the front that I've yet to identify.

The YouTube video (BongoBrainstorming-Session13 Finally prying the Head off out.WMV shows the block under the head...

(What a fantastic set of videos, I've just sat and watch pretty well most of them - you should watch them even if you're not planning to replace a head!!)

Anyway, the view we get in the image above is not quite good enough. This makes it look like part of the head. Whatever, if Steve's right, it's the "oil return from the rocker chamber back to the main oil sump". That would qualify as an oil source.

There is gasket between the two surfaces, but this joint is only being held by one bolt, hence oil must be managing to work its way around the gasket and out the hole. So simply plugging the hole is unlikely to help. It would stop oil coming out the top, but not continuing to seep out past the gasket and weep. Admittedly it's going to increase oil path resistance, but it's not a solution, is it?! I'm therefore still looking to identify the part in the diagrams that connects the head to the sump and completes the oil return path.

At half two in the morning, I'm going to opt for an Irwin Quick Grip approach to fixing this, though I will sleep on it...

[Driver+Passengers]

Someone else with this bolt missing and oil coming from the hole...

viewtopic.php?f=3&t=32381

To quote that thread, "it fits into the aluminium case on the front cover of the engine".

[widdowson2008]

This is a better pic of the block with head removed. Red arrow shows bolt in question and the vertical rectangular slot just below the bolt hole is the oil return (from head) cavity.
Pic is from spenners head change done recently.

[Driver+Passengers]

This is a better pic of the block with head removed. Red arrow shows bolt in question and the vertical rectangular slot just below the bolt hole is the oil return (from head) cavity.

Thanks, Steve.

Can you confirm if it's part of the block or bolted on?

The diagram at http://lushprojects.com/bongopartsmk2/c ... mgno=.html would suggest the latter but perhaps with gasket and channels for fluids - ie can't take it off unless drained. If this is so, then it's head off.

[widdowson2008]

Just been having a closer look at the pic and it definitely IS a separate bolt-on and not actually part of the block casting. Can't see an easy way to get to repair the thread other than head off. (bummer )

Think this may be the bolt-on part - item 10-500 (top right). You can just make out the return slot at the top.
http://www.lushprojects.com/bongopartsm ... o=.html#18

[Driver+Passengers]

Just been having a closer look at the pic and it definitely IS a separate bolt-on and not actually part of the block casting. Can't see an easy way to get to repair the thread other than head off. (bummer )

Wonder if it's a through hole (looks a bit like it, both in this pic and the youtube screengrab). If so, might be scope to get a nut on the other end of it...

[widdowson2008]

Just been having a closer look at the pic and it definitely IS a separate bolt-on and not actually part of the block casting. Can't see an easy way to get to repair the thread other than head off. (bummer )

Wonder if it's a through hole (looks a bit like it, both in this pic and the youtube screengrab). If so, might be scope to get a nut on the other end of it...

Would be nice, but no, not a through hole.
Think this may be the bolt-on part - item 10-500 (top right). You can just make out the return slot at the top.
http://www.lushprojects.com/bongopartsm ... o=.html#18

[widdowson2008]

Bit more info.

This pic shows the head bolts. When we took them out, we arranged them on a piece of cardboard in the pattern that they came out. The ones at the right of the pic are the bolts in question. They are smaller in diameter than the main head bolts BUT are the same(ish) length, and a shorter thread.