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Diagnosing Oil Leak - Small Hole,Rear of Engine.
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Author:  theeld [ Mon Jan 08, 2018 2:02 pm ]
Post subject:  Diagnosing Oil Leak - Small Hole,Rear of Engine.

I am attempting to diagnose an oil leak that has been created after doing the full top end maintenance (head gasket, rockers/lifters, head studs, etc)... I believe I have located the source of the oil with a mechanics mirror, however it is at the rear of the engine as such not exactly ideal visually. I havent been able to find any good reference images of the rear of the engine, So I am not sure what I am looking at back there. The oil seems to be emanating from a small hole at the rear top of the Head. The photo below (best I could find on web) shows the area that looks to be seeping oil. I circled the area in Red. There are two small holes in this area, one above the other. To me it appears that oil is seeping from the top most hole. What are these?? If anyone can provide me a better high res photo of the rear of the head/intake area that would help as well.

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Author:  papaindigo [ Mon Jan 08, 2018 2:16 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Email me and I can provide a somewhat better image of the back of the engine. If I was to guess though I'd suspect the oil is more likely coming from a) the rear cam "seal" or b) the valve cover gasket both of which are just above that point.

Author:  APC9199 [ Mon Jan 08, 2018 3:02 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

I hate, no, LOATHE chinese tools to the point that I will pay double for an American version. That being said, I own one of the "borescopes" from harbor freight and it is worth its weight in gold (fools gold, maybe) when I need to inspect an area like that. I highly recommend picking one up if you can, or order one from Amazon with good reviews. Seriously, there have been times I don't know how I could have done without it.

On another note, did you remove the cam position sensor from the intake when you did the rebuild? If so, it might be worth taking it out and checking to make sure it's sealed properly. It is directly above that area on top of the intake, so it could feasibly leak down to the area you're seeing oil. It would be pretty easy to check and confirm before doing to much else that costs a lot of time and/or money.

Author:  theeld [ Mon Jan 08, 2018 4:47 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

I did find a better image to mark up. I am almost certain it is at the spot marked (Red Arrow) in this photo, as with the engine running can watch it ooze directly from this hole with my mechanics mirror. There are two smaller holes, the lower one is the one that a bolt appears in the reference figure. The oil appears directly from the upper hole. I see some diagrams in the Parts Fiche refer to a cylinder block plug, but from the diagrams cannot tell if this is what this hole is for.

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Author:  geordi [ Mon Jan 08, 2018 7:31 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Image

The spot in question you are looking at, is either a freeze plug or a blind threaded hole.

The bad news, is that the cylinder head will have to be removed in order to do anything with this, because obviously access to this location is minimal at best. I can see where the freeze plug may back onto the oil gallery for the lifters, which suggests that this is definitely a pressurized port.


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Author:  theeld [ Sat Jan 13, 2018 4:05 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

So at this point since as I just did all the valve/head/timing belt bulletproofing, does anyone have an idea what would be less expensive to do? Remove intake/head again and replace all the gaskets gaskets (maybe head studs again as Im not sure if the new ARP one are to be reused after head removal). Or would it be more simple/less costly to pull the engine with the head and such intact??

Author:  geordi [ Sat Jan 13, 2018 9:15 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

ARP studs can be reused. I would not have an issue with reusing the head gasket as well if it is the two-hole size, just spray it down with copper kote after making sure that you give it a good scrape with a plastic razor to remove any loose coatings. This is a laminated steel gasket and should easily be reusable IF it has not been compromised. The coating is no big deal to recreate, and I coat even the new ones before assembly. Spray all 4 surfaces (block, head, both sides of gasket) until they are solid coppery goodness.

Have you replaced the valves in the head? If not, then that could be a good reason to do all this again. Yes it sucks, but better to have that freeze plug sealed now than risk it blowing out later under pressure.

Author:  WWDiesel [ Sat Jan 13, 2018 9:44 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

If you end up re-pulling the head, you could always remove the metal plug that is leaking that you have identified, tap out the hole and screw in a tapered threaded plug coated in some Permatex Form-A-Gasket No. 1 Sealant or equivalent. It will never leak again! :idea:

Author:  theeld [ Sat Jan 13, 2018 9:47 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Yes, All valves/rockers/lifters were replaced as well at the service.

Author:  theeld [ Tue Jan 16, 2018 9:00 am ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Considering that all gaskets have just been replaced, In the event that the head needs to be removed again, which ones should be considered "one-time use" and which should be considered reusable. They are all brand new but of course have all been torqued once.

Some that come to mind:
Timing belt cover gasket,
Turbo gasket
Valve Cover/Intake Gasket
Injector crush rings/o-rings/bolts (1st time they reused the old ones and my injectors leaked)
Thermostat gasket

If there are any others that would be problematic, would appreciate pointing them out as well.

Author:  flash7210 [ Tue Jan 16, 2018 9:55 am ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Timing belt cover gasket-- reusable but mostly useless
Turbo gasket-- reusable
Valve Cover/Intake Gasket-- reusable
Injector crush rings/o-rings/bolts-- replace all the crush washers and o-rings
Thermostat gasket-- get a new one

Head gasket-- probably reusable if you coat the surfaces with some sort of sealer

Author:  geordi [ Tue Jan 16, 2018 10:16 am ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

flash7210 wrote:
Timing belt cover gasket-- reusable but mostly useless
Turbo gasket-- reusable
Valve Cover/Intake Gasket-- reusable
Injector crush rings/o-rings/bolts-- replace all the crush washers and o-rings
Thermostat gasket-- get a new one

Head gasket-- probably reusable if you coat the surfaces with some sort of sealer


Completely agree with all of this. The only change I would make is on the o-rings for the injectors. If they are not cut up they can be reused, these are not a critical seal they are just for debris blocking and to keep the injector centered. Definitely have to replace the crush washers however.

The intake elbow gasket is not really reusable either, but if you have the elbow kit now, you can just leave the connection attached to the valve cover. That and the thermostat are the only two paper / fiber gaskets. All others are metal seals.

Author:  Mountainman [ Tue Jan 16, 2018 6:38 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Why in the world would there be a freeze plug on an oil gallery? If you wipe it clean you're certain it's not coming from the cam seal, or more likely because you had the top off, the rocker cover gasket?

I've never heard of an oil gallery have a freeze plug :dizzy:

Author:  theeld [ Tue Jan 16, 2018 9:32 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

From what Ive dug up, I cant come to any other conclusion. The plug from parts fiche, matches up with the oil galley that supplies the lifters from the oil flow diagram. I ordered the part just to look at it. I can literally see it coming out of this hole with my mechanics mirror and my endoscope camera. The cam seal looks dry.

Image

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Author:  theeld [ Mon Jan 22, 2018 10:34 am ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Does anyone know whether the "hold down bolts" for the injectors are stretch bolts (aka one time use only)??

Author:  Mountainman [ Mon Jan 22, 2018 11:18 am ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

theeld wrote:
Does anyone know whether the "hold down bolts" for the injectors are stretch bolts (aka one time use only)??


They are not tty

Author:  WolverineFW [ Mon Jan 22, 2018 4:57 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

I don't know why anyone would re-use the head gasket after doing all that work to get at it. Asking for a dose of Murphy's Law IMHO.

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Author:  GordnadoCRD [ Mon Jan 22, 2018 5:53 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Mountainman wrote:
theeld wrote:
Does anyone know whether the "hold down bolts" for the injectors are stretch bolts (aka one time use only)??


They are not tty

True. They are not tty. However, the FSM recommends replacing them each use. The torquing causes the bolt threads to deflect a little. Each use causes them to deflect a little more. Each deflection puts more and more of the force to be transferred to the threads in the (aluminum) head, and each re-use causes the likelihood of stripping the aluminum threads to increase exponentially. New bolts and their flat threads /\ help keep the aluminum threads flat as well.

Author:  papaindigo [ Mon Jan 22, 2018 6:59 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Perhaps but I cannot imagine that the torque on those steel bolts in an aluminum head is high enough to cause any deflection of the steel bolt threads. Then again for new bolts doesn't cost anything to speak of.

Author:  geordi [ Mon Jan 22, 2018 7:13 pm ]
Post subject:  Re: Diagnosing Oil Leak - Small Hole,Rear of Engine.

Those bolts are only supposed to get about 28 pounds of torque. That is really not that much, and certainly not enough to cause any effect on the steel. If you said that it was possibly changing the aluminum, I might buy it… But you cannot change the aluminum so I have to say this seems to be a little silly.

However it is standard practice for European vehicles to recommend complete replacement of just about any fastener that is removed for any reason. I have no idea why they do this, but Volkswagen is well known for this. And they are not the only ones.


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