Disco 2 Blowing exhaust manifold, again. Probably need new cylinder head; what am I looking at?

Naf623 said:

Its bloody heavy enough lmao, but yes fair point.

I was literally searching "machine shop", guess it pays to be more specific lol. One of those places opens early and is an easy detour on my way to work. I'll drop in for a chat in the morning; thanks!!

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Good for you! Glad to help. It often pays to get to know the guys who work in your local parts shop like Motabitz or Halfords or whatever there is down your way. They always seem to know where you can get things done. Also on industrial estates the same types of businesses tend to congregate. Once you've found one you often find others, like tyre guys are often near guys who refurbish wheels etc, paint guys know guys who do bodywork, who know guys who do welding. I found the nearest decent and cheap Land Rover repair guy near me because I needed a replacement anti-theft wheel nut and my tyre guys told me about him 2 streets away. He also sells decent secondhand parts too. (He didn't have a replacement weheel nut though!) Almost all guys who work in the motor repair trade in one way or another have a project, as soon as they know you have one too, they start to care. I get trade rates on all my casr parts from the local Motabitz basically coz i know the guys really well, mind you I do buy quite a bit off them! With an LR it comes in handy!

Not just me going through this at the moment then. I share your pain.
I am in the process of swapping the exhaust manifold on my son's D90 TD5. The nuts had been sprayed with penetrating fluid every day for a week and all was going swimmingly until the top stud of the front cylinder - which sheared just inside the head. Looking at the bit that came off it had already failed over 2/3 of the way through, so it was never going to come off cleanly.
I spent about 2 hours a day for 3 days drilling it out using various techniques with depressingly slow progress. Centre punch to set the start and went from there. Reverse thread drill bits did nothing but make a small patch shiney, so I abandoned any idea of using an Easy Out. Cobalt drills of increasing diameter turned slowly with plenty of cutting fluid and frequent stops slowly, slowly removed metal. When I went to a 7mm bit I used the old manifold as a template to keep the drill centered. I got down to about 1mm of stud left and a small bit has actually gone through. However, even working as carefully as possible the hole has been ovaled and will now need a helicoil to repair. I came to the conclusion last Thursday that if I carried on I was going to do more damage and started looking for a specialist. I found a mobile guy working the London area who trades as ThreadDoctor. He has more work than he knows what to do with, but is booked in this Thursday. Hopefully by Friday the final Wurth replacement stud will be in place and I can put it all back together along with the new pyrometer in the end plate. I attach a photo for amusement and sympathy.....OK just amusement then.

Hi @Si Click, fell YOUR pain too, same stud as went on mine. I don't know at what stage your pic was taken but although it looks a bit oval, I'd a thought you could have drilled it round and then rethreaded it to the bigger size, but then I am not standing right next to you holding the inspection lamp, while you do the swearing! There is of course the elephant in the room of how much wider you can redrill the hole before getting into an oilway, coolant wayor even a fuelway, on a TD5 head. I somehow feel a ThreadDoctor would not necessarily be easily to hand in York but then I haven't done a search and they may travel a fair distance. OP may want to search for that. Forgot they existed, if I even knew! Fingers crossed for the end result!

Well the place this morning was unhelpful, and to be honest pretty rude. Wasn't impressed by the guy's attitude at all. Instantly just said "not interested", as if me even asking was a waste of his time.

Have tried messaging a few other places advertising cylinder head re-manufacturing in the area, but none are close and all want me to get the head off and take it for them to take a look at. Which I understand; but that's much easier said than done. I have a week's holiday at the end of the month; looks like I'll need to get my garage to remove it, and use a loan car from them to take it some places...

So sorry to hear that. Tells you all you need to know about them and in this case they either don't think they can do the job, or do not want to risk trying, failing and being charged for any ferk-ups they cause along the way, or else the job to them is too small and they don't think it is worth it for the money.

Although I have taken loads of heads off engines, including some quite complex ones, I have never done a diesel, especially a TD5. It ought to be quite straight forward but I don't feel qualified to give you more specialist advice.
If you have a tame garage, can't they get the head off and get the work done for you? You can be certain it'll be a heavy and awkward beast I'd a thought.
Anyway, keep us posted, and the very, very best of luck.

Stanleysteamer said:

So sorry to hear that. Tells you all you need to know about them and in this case they either don't think they can do the job, or do not want to risk trying, failing and being charged for any ferk-ups they cause along the way, or else the job to them is too small and they don't think it is worth it for the money.

Although I have taken loads of heads off engines, including some quite complex ones, I have never done a diesel, especially a TD5. It ought to be quite straight forward but I don't feel qualified to give you more specialist advice.
If you have a tame garage, can't they get the head off and get the work done for you? You can be certain it'll be a heavy and awkward beast I'd a thought.
Anyway, keep us posted, and the very, very best of luck.

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Absolutely, and I understand that. But he could have said it better. Much as he's most convenient for getting the manifold refaced, its not likely i'll actually take it there now.

At this point the info I'm getting back says that it'll need spark eroding out of the hole, at a cost of over £200 more than likely. Seems easier to get one of the replacements I linked above and just get it swapped over.

Naf623 said:

Absolutely, and I understand that. But he could have said it better. Much as he's most convenient for getting the manifold refaced, its not likely i'll actually take it there now.

At this point the info I'm getting back says that it'll need spark eroding out of the hole, at a cost of over £200 more than likely. Seems easier to get one of the replacements I linked above and just get it swapped over.

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I agree about the rudeness, he could have just said, "I'll reface the manifold for you but we don't do jobs like rethreading, BUT "I know a man who does" ." Did you link replacement heads? I haven't followed the links. Even then, at £200 + it is still cheaper than taking the head off, buying a new one then putting it on. I am assuming here they do the hole in situ. (Must search "Spark erosion" wonder if it like using a plasma cutter.)

Stanleysteamer said:

I agree about the rudeness, he could have just said, "I'll reface the manifold for you but we don't do jobs like rethreading, BUT "I know a man who does" ." Did you link replacement heads? I haven't followed the links. Even then, at £200 + it is still cheaper than taking the head off, buying a new one then putting it on. I am assuming here they do the hole in situ. (Must search "Spark erosion" wonder if it like using a plasma cutter.)

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No, anything I could get done to it now will need the head removing anyway. So given that I have to get that done anyway, and I'm not confident that it's a guaranteed fix (especially with the extra hole that shouldn't be there) for the £200 I can get a second hand head for, I feel that's probably the way to go.

Just watched some videos on it. Quite interesting, but I think you might still have to take the head off and give it to them. Thread Doctor only covers the Home Counties but they seem to be able to do Spark Erosion onsite, so you may be lucky. At the moment I'd be taking my time over all this as the ideal solution may take a while to figure out. As you said, you can still drive the car. Even getting the manifold refaced and putting it back on after the suggested mods, you will probably find it'll run a lot better, even with the Heath-Robinson bolt/stud in place. After all it is only one stud out of ten. Personally, that is what I'd do. Manifold first then worry about bolt/stud later.

Naf623 said:

No, anything I could get done to it now will need the head removing anyway. So given that I have to get that done anyway, and I'm not confident that it's a guaranteed fix (especially with the extra hole that shouldn't be there) for the £200 I can get a second hand head for, I feel that's probably the way to go.

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Understand how you feel but do take care over secondhand heads, as other posters have said. you don't want to end up back where you started.
One plus with the second hand head being on is that you could then play around with the original head off the car, you might even find a more satifactory DIY solution, like some sort of a strap you could position to hold the end of the manif in place, using other existing bolts, or even studs placed in holes you have drilled in other safe places on the head. There would be no loss if you fecked it up except your time. It'd be handy to have engineering drawings of the head to see where all the fluidways go so you could drill safely into the head. The strap could be made out of steel or billet ally and follow the shape of the contours of the end of the manif.
In the old days, B and A series BL engines used combination inlet and exhaust manifolds and they were held to the head by nuts on studs that did not even go through holes in the manifs at all in certain places, they just had bridging pieces that tightened the manifs down, so this last idea is not as bonkers as it sounds. note the absence of holes except for the ends of this image of an MGB exhaust manif
The inlet manif sat around the centre pipe of the exhaust manif, entirely held on with bridging pieces.
I have a twin carb B series engine and with its manifold and the exhaust manifold the fitting is quite intricate!

So you could drill a hole or holes around the edges of the manif and then put in stud-big thick washer-lockwasher-nut. But you'd have to know where to drill the holes! "Big help", I know!

Stanleysteamer said:

Just watched some videos on it. Quite interesting, but I think you might still have to take the head off and give it to them. Thread Doctor only covers the Home Counties but they seem to be able to do Spark Erosion onsite, so you may be lucky. At the moment I'd be taking my time over all this as the ideal solution may take a while to figure out. As you said, you can still drive the car. Even getting the manifold refaced and putting it back on after the suggested mods, you will probably find it'll run a lot better, even with the Heath-Robinson bolt/stud in place. After all it is only one stud out of ten. Personally, that is what I'd do. Manifold first then worry about bolt/stud later.

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That bodged stud is stripped now though, so it's offering no hold at all. My only chance to get anything significant done would be the last week in November, and I need the car for Christmas, as well as making deliveries most nights, and getting to appointments, including that last week in November.

Everybody, including a guy who it sounds like might be able to do spark erosion locally, want the head off first. I can't do that at home. Then if I try and that doesn't work, it means waiting for anther head to arrive, and everything just being a right mess. I also worry that even if the erosion does get the stuff out, the bodged hole will mean that enlarging and retapping the proper hole might not work either. At least with a replacement head I should have something decent to start over with.

Naf623 said:

How wary would people be of any of these?

https://www.ebay.co.uk/itm/Land-Rov...Defender-years-1998-2002-HRC2880/193105546202
https://www.ebay.co.uk/itm/Land-Rov...scovery-Defender-years-1998-2002/233028874625
https://www.ebay.co.uk/itm/LAND-ROV...0P-TESTED-CYLINDER-HEAD-COMPLETE/123920511393
https://www.ebay.co.uk/itm/Land-Rover-Td5-15p-16p-cylinder-head-Discovery-Defender-year-2003/174069464785?_trkparms=aid=888008&algo=DISC.CARDS&ao=2&asc=20131227121020&meid=15a8fa425357445e9eed33daac7ee8b5&pid=100009&rk=1&rkt=1&sd=233028874625&itm=174069464785&pmt=0&noa=1&pg=2047675&_trksid=p2047675.c100009.m1982

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Just had a good look at these, the one at £325 has the same problem as yours! And I think you'd still need to have the lightest of skims on the one you get anyway to be sure of a good seal, although many people will say this is a big no-no. (You can pocket the piston heads if really necessary, a guy near me who races TD5s does this.) I REALLY feel "better the head you know". Sorry to be such a downer. I did once buy a secondhand Dolomite Sprint head and those things warped for an absolute pastime, and it was OK, but i was bale to go and look at it, pre eBay by decades. But I think I was lucky.

Naf623 said:

That bodged stud is stripped now though, so it's offering no hold at all. My only chance to get anything significant done would be the last week in November, and I need the car for Christmas, as well as making deliveries most nights, and getting to appointments, including that last week in November.

Everybody, including a guy who it sounds like might be able to do spark erosion locally, want the head off first. I can't do that at home. Then if I try and that doesn't work, it means waiting for anther head to arrive, and everything just being a right mess. I also worry that even if the erosion does get the stuff out, the bodged hole will mean that enlarging and retapping the proper hole might not work either. At least with a replacement head I should have something decent to start over with.

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Sorry mate, have to disagree with you. Even if the bodged hole eventually becomes bigger, which it is bound to do, it can still be drilled straight and tapped properly. Then you just have to drill out the hole on the manif which is also not a problem, then you put in a bigger stud and Bob is your uncle. At the end of the day, it is your decision, and we support you all the way, it's a "balls-out" journey anyway. The very best of luck with whatever you try.

Stanleysteamer said:

Sorry mate, have to disagree with you. Even if the bodged hole eventually becomes bigger, which it is bound to do, it can still be drilled straight and tapped properly. Then you just have to drill out the hole on the manif which is also not a problem, then you put in a bigger stud and Bob is your uncle. At the end of the day, it is your decision, and we support you all the way, it's a "balls-out" journey anyway. The very best of luck with whatever you try.

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What I mean is that if either is enlarged then they'll start to encroach on each other; or can one be plugged up to provide strength for the other?

Stanleysteamer said:

Just had a good look at these, the one at £325 has the same problem as yours! And I think you'd still need to have the lightest of skims on the one you get anyway to be sure of a good seal, although many people will say this is a big no-no. (You can pocket the piston heads if really necessary, a guy near me who races TD5s does this.) I REALLY feel "better the head you know". Sorry to be such a downer. I did once buy a secondhand Dolomite Sprint head and those things warped for an absolute pastime, and it was OK, but i was bale to go and look at it, pre eBay by decades. But I think I was lucky.

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Not sure what makes you think it has the same issue? The £325 is tested and (briefly) guaranteed; one of the others has a stud stuck; but that can be drilled out, unlike the original hole on mine due to the two drill bits broken and stuck in there.

So I'm thinking my best option now is to get her into the garage for them to get the head off. Then I can get someone in to have a proper look and see what can be done. If nothing much, then I'll have to go with one of those replacement heads.

Naf623 said:

So I'm thinking my best option now is to get her into the garage for them to get the head off. Then I can get someone in to have a proper look and see what can be done. If nothing much, then I'll have to go with one of those replacement heads.

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Im sorry for all of your problems but dont loose heart, there are loads of ways to skin this cat, I worked in engineering for quite a few years and have done alll kinds of fixes when needed, one way would be to plug and re drill, drill it bigger and tap it then thread some alloy bar screw it in using locktite bearing fit, then cut it flush machining or filing it, then mark it and re drill original size.
Sounds complex but not that hard.
My number one tip would be to let someone experienced look at it it might not be quite so drastic as you think.
Taking the head off is not so hard for an experienced DIY mechanic but a bit daunting for someone who as not done it before, there are threads on here ( including my own) which may give you a feel for it, and there are people who will gladly offer advice if you get stuck.

have a look
https://www.landyzone.co.uk/land-rover/at-last-the-big-td5-job.349420/

raywin said:

Im sorry for all of your problems but dont loose heart, there are loads of ways to skin this cat, I worked in engineering for quite a few years and have done alll kinds of fixes when needed, one way would be to plug and re drill, drill it bigger and tap it then thread some alloy bar screw it in using locktite bearing fit, then cut it flush machining or filing it, then mark it and re drill original size.
Sounds complex but not that hard.
My number one tip would be to let someone experienced look at it it might not be quite so drastic as you think.
Taking the head off is not so hard for an experienced DIY mechanic but a bit daunting for someone who as not done it before, there are threads on here ( including my own) which may give you a feel for it, and there are people who will gladly offer advice if you get stuck.

have a look
https://www.landyzone.co.uk/land-rover/at-last-the-big-td5-job.349420/

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Nowhere near crazy enough to consider trying it myself at home haha. I'm pretty much a beginner with doing anything on my car. So far I've only changed the front brake disks myself. I do intend to get onto more; but I don't think this should be step two lol.

How much work, time-wise, is removal/refitting of the head? Just to try and get an idea what my garage might charge me for it.

Naf623 said:

Nowhere near crazy enough to consider trying it myself at home haha. I'm pretty much a beginner with doing anything on my car. So far I've only changed the front brake disks myself. I do intend to get onto more; but I don't think this should be step two lol.

How much work, time-wise, is removal/refitting of the head? Just to try and get an idea what my garage might charge me for it.

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I would say a profesional garage could take it off in 4 - 6 hrs and put it back in 6- 8 but I would be guessing, maybe someone has had a head gasket done and could tell us more accuratly.