AndyF07

Active Member
Hi,

I have a P38 2002 4.0 Thor. After 165k miles I think the head gasket has developed a small oil leak near the front on the drivers side. Very minor at moment and no issues at all and she runs perfectly. However I assume at this mileage it is only a matter of time before head gaskets need doing so I think I'll just get on with it.

I am looking for recommendations on a head gasket kit. I am assuming OEM is the way to go rather than aftermarket but there is such a large selection on the market and want one that can be trusted?

From reading up ARP bolts seem to be far easier to use than stretch bolts. Is this people's experience? Again any brand recommendations appreciated.

I would prefer not to go through the hassle of getting the head skimmed as would like her off the road for as short a time as possible. The engine has no problems and never overheated etc. Have you guys had any problems just cleaning and refusing?

One thing I have neglected is the oil vapour separator. It is completely solid and impossible to get out of the valve cover whithout removing and drilling it out. The additional pressure build up can't help with the leak. Has anyone ever changed it over and had leaks stop?

Thanks for any help and advice.
 
Hi,

I have a P38 2002 4.0 Thor. After 165k miles I think the head gasket has developed a small oil leak near the front on the drivers side. Very minor at moment and no issues at all and she runs perfectly. However I assume at this mileage it is only a matter of time before head gaskets need doing so I think I'll just get on with it.

I am looking for recommendations on a head gasket kit. I am assuming OEM is the way to go rather than aftermarket but there is such a large selection on the market and want one that can be trusted?

From reading up ARP bolts seem to be far easier to use than stretch bolts. Is this people's experience? Again any brand recommendations appreciated.

I would prefer not to go through the hassle of getting the head skimmed as would like her off the road for as short a time as possible. The engine has no problems and never overheated etc. Have you guys had any problems just cleaning and refusing?

One thing I have neglected is the oil vapour separator. It is completely solid and impossible to get out of the valve cover whithout removing and drilling it out. The additional pressure build up can't help with the leak. Has anyone ever changed it over and had leaks stop?

Thanks for any help and advice.
If the breather is blocked it will try and push oil out at any weak point. I'd fix the breather and see if it fixes the leak.
 
If the block is good then ARP bolts put significantly less stress into the block and generally supply a much more consistent torque.. not all stretch bolts are identical.

No need to skim the head or the block if its straight

If you've got an oil leak, it's not going to get any better, though symptoms may go away at least for a while if you fix the breather
 
+1 on ARP Studs. I used them on my 4.0 rebuild a few years ago. Got mine from Real Steel in West Drayton. For head gasket kit, I used an Elring kit.

Not sure if Thor is the same, but I simply hammered the old one out, and installed a new one. The covers are easier to clean if you un-screw the internal baffles.

1729784907095.png
 
If the breather is blocked it will try and push oil out at any weak point. I'd fix the breather and see if it fixes the leak.
Thank you. I will do the breather first but will need to get to the hg at some point too. Been reading rave and looks fairly ok ;)
 
If the block is good then ARP bolts put significantly less stress into the block and generally supply a much more consistent torque.. not all stretch bolts are identical.

No need to skim the head or the block if its straight

If you've got an oil leak, it's not going to get any better, though symptoms may go away at least for a while if you fix the breather
Thanks @kermit_rr . Definitely going on the ARP route. Will fix the breather in next day or two. Have some time off in a couple of weeks so may get after the head gasket then. Will just leave the rear main seal which I imagine is fun on a driveway in December :)
 
The HG really aren't that hard to do..
There's a exhaust manifold bolt on the drivers side that's really hard on the rear cylinder.. made easier with a wobble joint on an extension to get round the steering gubbins.
Don't forget to undo the coil packs, they are in a bracket bolted on to the inlet manifold
 
rear manilfold bolt from cylinder 8 is a ball ache with the steering shaft in the way, you can drop the shaft out the way or remove the arch liner, up to you really.

IMG_2023-07-23-15-34-18-909.jpg


They're also bi hex so make sure you have the right socket before you start.

hardest part of the job in my opinion is getting the heatshields off the manifold you'll more than likely have to butcher them off, no real loss though just heatwrap the manifolds.

IMG_2023-09-11-20-10-31-251 (1).jpg


There is a ground wire on the passenger side cylinder head which can cause a slight snag when removing the head..

ARP bolts are essential to a quick painless installation its a no brainer.

Elring gaskets are oem and the best.

And also worth noting you oil leak is more than likely the valley gasket end seals, not the headgasket. :)

coolant galleries are at the front and rear of the block :)

IMG_2023-07-23-15-33-52-009.jpg
 
rear manilfold bolt from cylinder 8 is a ball ache with the steering shaft in the way, you can drop the shaft out the way or remove the arch liner, up to you really.

View attachment 328806

They're also bi hex so make sure you have the right socket before you start.

hardest part of the job in my opinion is getting the heatshields off the manifold you'll more than likely have to butcher them off, no real loss though just heatwrap the manifolds.

View attachment 328807

There is a ground wire on the passenger side cylinder head which can cause a slight snag when removing the head..

ARP bolts are essential to a quick painless installation its a no brainer.

Elring gaskets are oem and the best.

And also worth noting you oil leak is more than likely the valley gasket end seals, not the headgasket. :)

coolant galleries are at the front and rear of the block :)

View attachment 328805
Thank you @Henry_b for your detailed advice, really appreciated. Good news is have already had the heat shields off all be it they have less bolts now than they started with lol. It doesn't look too bad a job. I did the valley pan six months ago so pretty sure it's ok and have tracked the (very slow) leak in real time to an exact point from the hg and can't see anything coming from above it. Would be over the moon if it turns out to be something easier :) Thank you again!
 

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