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Should I replace only the leaking valve cover or both?

XK8 / XKR ( X100 ) 1996 - 2006

Should I replace only the leaking valve cover or both?

 
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Old 05-22-2019, 06:58 AM
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Default Should I replace only the leaking valve cover or both?

I've got a small leak at the rearmost bit of the driver's side valve cover. Interestingly, the drop falls in one specific spot and does not coat the length of the metal plate underneath the cover, in other words, the rest is dry. I do get a faint burnt oil smell when the car is driven spiritedly and during these summer months. The passenger side valve cover is not leaking at all. Regarding changing the valve cover gaskets, should I change them both, or should I only do the leaking side?

I am apprehensive to doing both as that could potentially introduce a new leak where there was none. Is it ok to only do one?

Also, who makes the best valve cover gaskets for the 4.2 engine? I would not want to re-do this job. I do plan on using a thin strip of RTV the length of the valve cover to ensure against leaks.
 
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Old 05-22-2019, 10:06 AM
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I would just do the leaking side. There is always a chance of the plastic cracking, but I would only use rtv at the timing case joint as per the manual. I have never replaced a 4.2 gasket, so I don't have an opinion on what to order.
 
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Old 05-22-2019, 11:49 AM
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In my experience, the OEM seals and gaskets are superior to the aftermarket items. Replace the spark plug boss seals as well so oil doesn't find it's way into the spark plug wells and cause a coil unit to short.

Do not use any sealer on the gasket or head mating surfaces except for the areas near the front of the engine where the heads and timing cover meet.
 
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Old 05-22-2019, 12:07 PM
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Thanks! In that case I will only buy the leaking side gaskets and seals.

Sorry for this barrage of questions, but I was also considering the octopus hose, and the upper radiator hose (I already did the lower) and the valley hoses. Should I do those concomitantly with the valve cover gaskets? What other hoses should I also change while I'm at it? Does removing the supercharger also involve changing more gaskets?
 
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Old 05-22-2019, 02:41 PM
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Originally Posted by giandanielxk8 View Post
Thanks! In that case I will only buy the leaking side gaskets and seals.

Sorry for this barrage of questions, but I was also considering the octopus hose, and the upper radiator hose (I already did the lower) and the valley hoses. Should I do those concomitantly with the valve cover gaskets? What other hoses should I also change while I'm at it? Does removing the supercharger also involve changing more gaskets?
You suddenly appear to have a lot of time on your hands. My guess is that the exams must be over.

Graham
 
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Old 05-22-2019, 02:56 PM
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Replace them both. The gaskets are the same age. And when you starting getting oil in the spark plug wells and short a coil or 2 what are you saving???
 
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Old 05-22-2019, 04:30 PM
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Originally Posted by GGG View Post
You suddenly appear to have a lot of time on your hands. My guess is that the exams must be over.

Graham

Not quite, I've got a final on Friday, and classes end on the 26th of June. I'm just looking for summer projects and would like to get the parts ahead of time. I did, however, finish a few classes so I do have a little more time.


Originally Posted by Brutal
Replace them both. The gaskets are the same age. And when you starting getting oil in the spark plug wells and short a coil or 2 what are you saving???


True. However, I'm not looking to save money on this, only headaches. I see your point about the age of the valve cover gaskets. In spite of that, the nature of the driver's side leak leads me to suspect that this isn't an age related leak. Maybe a P/O already had them changed and there's a microcrack on the valve cover? Sadly, I don't have the service history from the P/O at hand to confirm this. It's all speculation.
 

Last edited by giandanielxk8; 05-22-2019 at 04:35 PM.
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Old 05-23-2019, 04:36 PM
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I just remembered that my valve cover bolts look a little rusty. What's the part number for them?
 
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Old 05-24-2019, 02:02 PM
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Replacing the gasket on the side of the dip stick isn't straightforward, I've been putting it off for years.
 
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Old 05-25-2019, 08:10 AM
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Originally Posted by RaceDiagnostics View Post
Replacing the gasket on the side of the dip stick isn't straightforward, I've been putting it off for years.
Yeah, I remember it was a bit of a headache when I was change the tensioners for the XK8.
 
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Old 05-25-2019, 09:44 AM
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I noted that there is some talk of oil in the plug wells shorting coils.
Motor oil is not conductive because it contains no charge carriers. Oil in the plug wells is not causing coil shorting.
If water with salts in it has entered the wells, the coils will short.
 
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Old 05-28-2019, 10:04 AM
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Originally Posted by oldmots View Post
i noted that there is some talk of oil in the plug wells shorting coils.
Motor oil is not conductive because it contains no charge carriers. Oil in the plug wells is not causing coil shorting.
If water with salts in it has entered the wells, the coils will short.
not going through oil. Oil causing the boots to swell and break down and then spark is easily finding a path to gound not the plug. Just like the old days of spark plugs wires getting oil soaked and then firing to the engine. One of the reasons before i quote a misfire for a coil fault i pull the coil on older engines and many times find the wells have oil in them so quote gaskets along with new coils
 

Last edited by Brutal; 05-28-2019 at 10:08 AM.
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Old 06-03-2019, 07:26 AM
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I would base my decision to replace one or both on the reason for changing one.
Once you find the exact cause of the problem, you can make a good decision.
If it's age related deterioration, replace both, assuming they are the same age.
If somebody screwed something up or something broke, address only that.
 
 
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