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  #1  
Old 12-18-2017, 11:36 PM
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1971 250 2.8L Oil leak

I've got a 1971 250. I believe it's the 2.8L. On the right front, just below the head, there is a stud with a nut that looks to be about 24mm maybe. I'm not sure what it is but it's leaking a substantial amount of oil.

Can anybody tell me what it is or what it's for ?

Any what is the fix for this leak ?
Thank you all, Fredd

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Old 12-19-2017, 05:59 AM
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Right front as in from sitting in the seat facing forward?

If so then you are probably referencing the chain tension-er.

1971 250 2.8L Oil leak-20056433259_tensioner-breakdown.jpg

1971 250 2.8L Oil leak-20056434251_chain-tensioner-installed.jpg

Could be as simple as snugging the bolts/nuts or replacing the gasket. Do NOT, repeat, NOT use a silicone gasket sealer on the mating surfaces.
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Old 12-19-2017, 11:01 AM
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Can you post a photo? Anything would help. If it just shows the general area, even if it is covered with oil, there is a good chance someone has seen this sort of leak before.

Worst case: I once tried to track down a leak like this that defied finding. I finally pulled the radiator and the A/c parts, as well as the fan. That way I could see everything.

But prior to this I hosed the area off at a car wash.

Then I found a crack in the aluminum housing that bolts on to the front of the engine. It looked as if the chain had rubbed a hole in the casting. I don't think it did but that's what it looked like. It was really just a crack but it was up high and gave the impression oil was leaking from just under the head but not from the valve gasket.

A bit of JB weld and all was well.
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Old 12-19-2017, 11:02 PM
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I would try tightening the cap on the chain tensioner. If that's where the oil is coming from it's likely loose.
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  #5  
Old 12-20-2017, 09:04 AM
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Mike D: Great Job ! You nailed it ! Much appreciated.

Chain Tensioner housing, Cover, crush ring and o-ring. So I take it there is no gasket ?

If I feel the need to remove and reseal, will everything from the housing to the piston come out the side as one intacted assembly ? Or will I have to pull the Valve cover to R&R correctly ( if necessary) ?
Are the pieces held in place by just the load of the tension spring ?

Is this Hydralic tensioner with no adjustablity ?

In the future I will post photos. I just noticed how to do it.
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Old 12-20-2017, 09:38 AM
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One piece assembly. Bit of an oxymoron as the tensioner itself can be broken down into its separate components (pic #1).

Should be just the "O" ring on your model.

Hydraulic, adjusts itself with oil pressure.

If you pull the assembly apart to clean/inspect components you should "re-pressurize" the piston assembly before initial start-up.

Not a big deal. Submerge the assembled unit in a container of oil and compress the plunger until air bubbles stop and resistance is felt.

Can be a bit of a bugger to refit due to the shortness of the mounting studs.
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Old 12-24-2017, 08:51 PM
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Ok Mike D.

I pulled the valve cover off this engine.

1. If I remove the two nuts holding the tensioner housing to the side of the block, and I pull the tensioner housing out, the whole assembly is going to stay together intact ?

2. Do you have a close up of the bolt that goes in the front of the head to hold the tensioner arm in position ? the tensioner arm has a spring loaded shaft. The bolt that goes in the front must have a pointed tip to hold the tensioner arm centered ?
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Old 12-25-2017, 07:22 AM
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The tensioner unit will come out as one piece. It can be further dis-assembled into its individual components for cleaning, inspection. etc.

No need to pull the guide rail. The tensioner is self locating.
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Old 12-25-2017, 08:37 PM
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The bolt hole in the front of the head, if you look in there, you can see there is a contical locating hole in the tensioner arm axle. The bolt that goes in must have a point on it to fit the contical hole. Do you have a shot of the original bolt ? Or an exploded view of these parts maybe ?
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Old 12-26-2017, 07:51 AM
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Matthew 7:7
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Old 12-31-2017, 09:41 PM
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Ok Mike, I guess that response means you don't
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Old 01-01-2018, 08:50 AM
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No, my response meant you should do a "search" yourself. Successful results are dependent upon the amount of effort you expend. You'll learn more and gain a much better understanding with a more complete research than asking about one step at a time.
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Old 01-07-2018, 11:50 PM
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Again, in other words, you don't know.
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Old 01-08-2018, 12:21 AM
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Update: I pulled the valve cover, A/C compressor, thermostat housing, and Chain tensioner.

Replaced the o-ring and reinstalled everything.

What a mess. Oil leak fixed.

Thanks to all that offered help.

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