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

Right front as in from sitting in the seat facing forward?

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

Attachment 145883

Attachment 145884

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.

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.

I would try tightening the cap on the chain tensioner. If that's where the oil is coming from it's likely loose.

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.

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.

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 ?

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.

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 ?

Matthew 7:7

Ok Mike, I guess that response means you don't

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.

Again, in other words, you don't know.

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.