OK. The stethosscope (plastic hose with steel bar at in one end and small funnel at the other) seems to indicate that the racket at the front of the engine (85 TDT, 220K) is coming either from the Hyd. Oil Pump or from the Vac. Pump. The oil pump sits right atop the vac. pump so whichever is making the noise, the ohter one is picking it up.

The stethoscope makes it very clear that the tapping does not originate at the timing chain.

Didn't finish.

I'm assuming that bearings are going bad. What should my next move be?

Thanks.

Roll up your sleeves, break out the tools, and remove parts to find the problem. Your type vacuum pump will sometimes have bearing failure with pieces of the bearing entering the timing chain area resulting in very bad things. I suggest you find the problem as soon as you can - further damage can be very expensive to repair compared to fixing it at the stage it is at now.

My $0.02 Worth!
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.

I have read of the bearings in the timing chain housing and the ruined engines that can result.
It will probably be a few days before I can get to it. Until then, she sits.

I have read of the bearings in the timing chain housing and the ruined engines that can result.
It will probably be a few days before I can get to it. Until then, she sits.

I had the same type of sound on my 85 300 SD. I pulled the VP. The roller on the swing arm was shot and the swing arm was running and wearing on the motor. Luckily the balls of the bearing made it to the oil pan with out incident. I would have a set of hex sockets and multiple varied extensions as someof the cap screws are a little hard to reach.

__________________
87 300SDL 220K
85 300SD 218K
82 diesel Chevette 440K
85 subaru 4WD turbo
83 4.1L buick powered cutlass THE TOY

Does anything get removed to make room for the v.p. coming out? I'll pick up a set of hex drives for the socket.

zbenz -
did you rebuild or replace the v.p.?

My quess is that it is the Vacuum Pump. I think it is pretty rare that the hyd. pumps pack it in. As to the rebuild or replace issue the answer is simple. Replace it. Even if rebuilds are available the downside here for an Ooops rebuild is not worth the $$ you'll save (if a rebuild is even available). I can't speak to the '85 but having just replaced the VP on my '87 and looking at my '85 I'd guess only the belt and maybe fan shroud need to be removed. You could remove the radiator but the time you'd save R&R the VP probably equals the time it takes to R&R the radiator. FYI, I threw a towel over my radiator so I wouldn't wack it by accident as I was removing the VP. The whole job took about 2-3 hours. Good luck.

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

I needed the car the next day and didn't want to do any more damage. So I drove up to Autosports Unlimited they had a used one. As to the R&R I removed the fan and shroud, the tube from the vp, and the bolt from the fuel filter that retains the vp hose. A hindsight note it would have been a little easier to do had I removed the belts also. Don't use ball style hex sockets they can and will slip and strip the bolt. I had one do that and had to wire weld my socket to the bolt to get it out Other than that glich I'd say 2-3 hours is about right. As said before cover the radiator for safety (I use a tray from a restaurant). Happy wrenching

__________________
87 300SDL 220K
85 300SD 218K
82 diesel Chevette 440K
85 subaru 4WD turbo
83 4.1L buick powered cutlass THE TOY