rut row shagggy, I hear a knock on the 87..
 

ok, I'm getting the 87TD brought up to snuff for myself. I noticed the oil pressure drops below 1 at hot idle... not a good thing, but not scary, the oil filter shaft orings were brittle and could have accounted for this. but I hear a knock also. Roy said to pull the tensioner arm out of the equation before condemning the vacuum pump or looking deeper... well the belt is off the car, and the knock is still there and pretty loud with the fan not turning... I'm getting worried.
the tensioner arm is pretty loose, and grindy feeling. so, I'll be getting a new one anyway, but on to further discussion. how should the shaft of the arm feel? smooth I assume? both my parts car and the TD feel the same, grindy.
I like the water pump design on the 93, there's a nice boss to brace an allen wrench against to take off the fan... the 87 has no boss. very difficult to get that nut off!
I've pulled the vacuum pump off the 93, and it has the open bearing style...
I'll put it in the 87 if the 87 is worn out, but I'll keep my eyes open for a newer one. I wish you could order just the pivot for the pumps... that's all that really needs to be changed.

The knock on one of my '87s was the vac-pump cover rattling, ... crimps had worn and were loose. Wierd.

The oil pressure doesn't sound optimum, but I don't know that it's out of spec.

I wish I were finished with everything else and just running my engine looking for noises, ...

Factory Says,"Oil Pressure at idle may drop to .3 Bar"
 

(But, me I'm freaking out @ .7 Bar)

my TD hovers at 2 bars or a little less at idle.

heh, no. I'm nowhere near finished with anything on this car.
I decided to not drive it until I had addressed all concerns with the car. (the joys of owning multiple MB's and cars in general:D)
first thing I did was pull the oil filter shaft, and install new o-rings. (that is sooo cool what they did on that oil filter! I love being able to pull the shaft first, and then the cover just pops off. awesome! too bad it's so hard to get at with all the lines in the way. the bolt head has some damaged points from heavy hands pushing without the right wrench... :mad:
my VP is original:eek: and the crimped cover scares the crap out of me. I hope it's just the cover rattling, but it sounds like it's coming from the lifters... possibly an injector, but I will pull the VP anyway, and change it before it causes any issues. I'll check the chain stretch while I'm at it.
since I'm in there fighting that )@#&) Fan clutch, I figured I'd go full tilt and get everything out of the way.
anybody have a new belt tensioner they can tell me how it's supposed to feel?

Belt tensioner should feel smooth, not crunchy. IIRC you can remove it / check and clean, might be fine with a little cleaning and fresh lube?

I've been unfortunate enough to replace two.

it looks like sealed bearings, and I have play side to side on both of mine... I kinda figured crunchy was not the norm... just hoping. on the large hard drives and many printer motors I overhaul, the motors are crunchy feeling out of the box. something about being stepper motors with indents for exact rotational feedback to the controllers...