Broken exhaust manifold bolts. It WILL happen to you!

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Dec 16, 2025 | 07:00 PM
  #11  
Quote: It is 58.5mm long. Or about 2.3 inches.
Thanks. I'll measure when I get home. Is this the length including the head of the bolt with its 16 point star socket?
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Dec 16, 2025 | 07:05 PM
  #12  
Quote: Thanks. I'll measure when I get home. Is this the length including the head of the bolt with its 16 point star socket?
no problem. And no, that's the measurement of the body+threads without the head.
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Dec 17, 2025 | 01:23 AM
  #13  
Quote: no problem. And no, that's the measurement of the body+threads without the head.
About 1/2
About 1/2" snapped off
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Dec 17, 2025 | 04:51 AM
  #14  
Great info Sal. Curious why one couldn't just run a conventional manifold bolt instead of that over engineered one. I will take a look at mine on the p300, since it likely has the same type of bolts. Keep us posted if u come up with a kit. If i find something feasible, i will let u know first.
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Dec 17, 2025 | 05:26 AM
  #15  
Quote: I will take a look at mine on the p300, since it likely has the same type of bolts.
Well, this is a sobering thread. Ralf, you get at a question I was wondering about. Sal’s comment was about P400s. Will this issue affect the P300s as well? Maybe we hear about it in P400s because they are more common. But as a P300 owner I’m hoping this doesn’t happen as often to this engine.
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Dec 17, 2025 | 05:36 AM
  #16  
Quote: Well, this is a sobering thread. Ralf, you get at a question I was wondering about. Sal’s comment was about P400s. Will this issue affect the P300s as well? Maybe we hear about it in P400s because they are more common. But as a P300 owner I’m hoping this doesn’t happen as often to this engine.
Had 130K miles and a lot of vibration being applied to the vehicle, if it's a problem it should be evident on mine. When I get into work today, I will check the parts catalog to determine if they are the same part number bolts. If that's the case, setting up a preventative maintenance schedule to replace them before they break preferably with something more robust would be a good point of valor
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Dec 17, 2025 | 06:01 AM
  #17  
Correct me but P300 manifold looks completely structurally different.
Less area, volume and less forces on bolts.
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Dec 17, 2025 | 08:51 PM
  #18  
Quote: About 1/2
About 1/2" snapped off
What are the chances you could just buy a replacement bolt that is the same diameter but shorter? Just leave the broken bit entombed in the engine, and use a new bolt to secure the manifold? There looks like enough threaded length remaining on the broken one to give you a secure connection with a new one of the same length as the remaining thread?
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Dec 17, 2025 | 11:28 PM
  #19  
Quote: What are the chances you could just buy a replacement bolt that is the same diameter but shorter? Just leave the broken bit entombed in the engine, and use a new bolt to secure the manifold? There looks like enough threaded length remaining on the broken one to give you a secure connection with a new one of the same length as the remaining thread?
My suspicion is that this is the one bolt I've found. It was a bizarre freak chance that allowed me to find it dangling from the under armor. Had I not seen it, and found it I'd be none the wiser. No noises that I can hear. There is 1/2 " remaining in the block so it would be a pointless endeavor IMO. The instructions for the disassembly alone reads like a tangental side quest in a Tolkien novel. Where can you even go to get this fixed. Dealership is obviously a non-starter. A local independent may be able to do it I suppose. Willing to do it without GTFO pricing is another ball of wax.

Perhaps it's just 1 bolt out of 13 that's failed. Some vehicles putter along just fine with broken manifold bolts. I think that when we look back in another 5 years, much like other LR models, this will be an infamous and common failure the brand will be known for. Failures like these, in engines so young, is, I suppose, synonymous with the brand.
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Dec 18, 2025 | 01:47 AM
  #20  
This looks to be a p400 I6 issue. The exhaust manifold is part of the cylinder head casting on the p300. The turbo bolts on to the cylinder head with a square 4 bolt pattern. No speciality bolts.


The I6 looks to have the exhaust manifold as part of the turbo and uses those fancy bolts to attach it to the head. Procedure includes chasing the threads with a tap and 5 stages of torque specs per bolt! We will definitely be inspecting the I6 engines that come in the shop for exhaust manifold bolts broken. Thx Sal for the info. Curious if any of the bolts that were not broken had any issues being removed conventionally?

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