@Saltek Motorsports Did you have to remove the exhaust manifold to get access to the broken studs? If you did remove them, did you have any problem extracting unbroken bolts? How much work is needed to be able to inspect for broken bolts?
Just spreading the word. If you're hearing a rattle/ knocking during cold starts on your p400 defender, your exhaust manifold bolts are broken. Unfortunately im seeing a lot of defenders with this issue. It's a job I do not recommend for a DIY person unless you have professional tools and a welder. I just got done doing this on our Defender where 6 out of the 13 bolts were broken. Took 3 days.
Why is this happening? The exhaust manifold bolts are made from inconel and are stretch to yield. After the the torquing process they only see about 15-17 ftlbs of torque. And unfortunately you can't tighten more as they just stretch without providing more clamping force. Inconel is great for high temperature but not great with vibrations. After some time of expansion and contraction due to the engine heat cycles, they break. And to add insult to injury, they are loctited with make extraction more difficult. Welding nuts to them seems to be the best method to remove them.
We are going to come up with new hardware for this but for the meantime. Replace with what's available. As soon. As you hear a rattle, get it done before you end up like us with half of your bolts broken which will only add to the labor.
Only way to see the broken bolts are by removing the heat shields around the manifold. The gasket has a heat shield intergrated to it making it difficult to see without removing the shields surrounding the manifold. 4 broken bolst on the left sife of the manifold/turbo. You can see the top one sitting on it's side 2 broken bolt on the right side Its not pretty but it worked. Getting our mig gun in there was a bit of a challenge for some of the bolts. May be time to invest in a flexible gun.
Already happened to me. Cold start whistling that would go away after the engine warmed. Dealer finally figured it out and found loose bolts - and two that had sheared off that the were unable to extract for less than 20k. Insanely annoying sound but will trust Sal to fix this one
BEYOND annoyed to find this today on mine with 31k miles on it. Was changing front diff oil and this was on top of the skid plate. Unacceptable mileage for a failure like this.
Sounds like it is grand time for an exhaust manifold bolt recall. At 31k miles, I would let the dealer fix it under warranty @nashvegas
I wonder if it is also happening to the P300s?
Sounds like it is grand time for an exhaust manifold bolt recall. At 31k miles, I would let the dealer fix it under warranty @nashvegas
I wonder if it is also happening to the P300s?
It's not happening to p300 because the exhaust manifold is part of the cylinder head. So there are no exhaust manifold bolts. As far as a recall, I doubt it. At least in the US they will only be focused on recalling something based off of it being a safety issue. There is a possibility there would be a class action, which potentially could cause JLR to implement something
Sounds like it is grand time for an exhaust manifold bolt recall. At 31k miles, I would let the dealer fix it under warranty @nashvegas
I wonder if it is also happening to the P300s?
I was trying to prepare for costly repairs that might arise by doing the scheduled maintenance but this is another level. Bolts that break on their own in engine is nuts. No pun intended. I wonder does this happen more to people who off road?
So after a fun weekend of four wheeling in Utah, the last two times I have started the defender I am getting a metal rattle on a cold start. It lasts about 10 seconds. I am thinking this means I have some broken manifold bolts. Is there any other way to diagnose this problem other than taking apart a bunch of stuff?
Also would this possible lead to bad O2 sensors. I have replaced 3 in the last 9 months and now have a fourth that is needing to be replaced. Though this fourth one is one I replaced last year. I have about 60k miles on the defender.
@Saltek Motorsports Did you have to remove the exhaust manifold to get access to the broken studs?
If you did remove them, did you have any problem extracting unbroken bolts?
How much work is needed to be able to inspect for broken bolts?Would the use of a $99 endoscope make this task easier/trivial?
