I've been noticing a growling rattle only upon acceleration and found out last night that it wasn't the muffler or fuel pump but seems to be coming from the area around the exhaust manifold. There doesn't seem to be any loose metal parts in that area but the sound is somewhere in the vicinity of the Oxygen Sensor/Exhaust manifold. The sound isn't there on idle... almost seems to come on at a certain level of engine vibration.

there also seems to be more oil residue on the engine from below the valve cover gasket all the way down to the oil filter (which looks to have black oil gunk all over the top of it.

Any ideas about what's going on?

would oil spew from the exhaust manifold gaskets (they look pretty cracked).

I'm gonna clean it up (since I spilled ATF all over it too -during my ATF flush) and try to isolate where it's coming from but the rattle makes me wonder.

I don't think it's coming from inside the engine (I hope!)

any thoughts or philosophical ramblings will be treated with the utmost respect.

jack
--
Bad Blue, '86 245, 250,000 mi., Columbus, Ohio

Just a thought and philosophical rambling.....
Check your Motor Mounts. They caused my pipes to rattle as you described when they went bad. Also the Pre heater hose my be cracked right at your exhaust manifold, that will rattle as the engine revs or winds down.


--
'75 Jeep CJ5 345Hp ChevyPwr and two motorcycles: it wasn't Volvos safety , it was Longevity that sold me

Probably, as rhaire said, a heat shield.
Possibly the oil leak has affected the rubber of the motor mount on that side. When the mounts sag, clearance of the exhaust system to the body changes, and you can get contact and rattles. In the worst case, the oil filter can scrape the crossmember and rupture. They usually give some kind of warning first, though.

The source of the noise might possibly be a heat shield on or around the exhaust system. Sometimes an additional bend will quiet a suspect.

The oil would not be coming out the exhaust gasket. More likely would be a leaking cam cover, oil filler cap or perhaps the cam seal. Cleaning everything up and then waiting for new leakage to show up might help identify the source.

If you are not familiar with the flame trap and associated plumbing on your car you should do a search on "flame trap" and read the wealth of informatiion concerning that device. Also read the 700/900 FAQ's concerning flame trap/ crankcase ventilation. Pressure build up in the crankcase can cause oil to be forced out of any of the seals and even blow the seal out which is a real day spoiler...

Randy

I am familiar with the whole flame trap/crankcase ventilation issue...
flame trap, throttle body, etc. was cleaned last year around August as I tried to eliminate an acceleration problem ...

maybe it's time for another flame trap cleaning/replacement?

until recently the car hasn't lost a drop of oil, which I was pleasantly surprised about considering it's age.

would the "filler cap jiggle test" confirm that I had too much crankcase pressure?

I would prefer not to spoil any more days with blowing out seals!

thanks for your input!

will update about leak source and rattle source.

jack
--
Bad Blue, '86 245, 250,000 mi., Columbus, Ohio

>would the "filler cap jiggle test" confirm that I had too much crankcase pressure?

Possibly, I don't use that test, seems I remember that several people have indicated the plastic oil filler cap jiggle test is not totally reliable. The older metal caps seem to meet the rigors of the jiggle test from what I have read.

Randy