96 850NA Wet Weather Misfire & Stall

[FLXC90]

Get that timing cover open then. Another leak that was shown on the forum recently was a diverter valve for the piston squirters that screws into the face of the block and has a copper crush washer. In any case, oil and timing belts don't mix for long.

[eriscentro]

I'll look into it later today. The front exhaust seal replacement is essentially a TB job with some fun added on, correct?

[cn90]

- FRONT Cam seals are known to leak after 140K-150K. You will see oil at the bottom of the TB cover and CV boot and subframe. Info in the Timing Belt Serp Belt DIY I wrote a while back.

- OEM seal is Corteco, about $8-$10/each.

Re: Ignition department, this is what I use:
- Iridium spark plug by NGK (info in forum)
- Bougicord
- Cap/Rotor: Bosch only.

Once you tune-up the ignition dept, you should not have the "misfire when wet" issue.

[cBobs94850T]

This same thing happened to me, the solution was a new cap and rotor.

[erikv11]

I'll look into it later today. The front exhaust seal replacement is essentially a TB job with some fun added on, correct?

Yep, that's right.

The fronts don't leak very often but they don't last forever either, I have had to change just a couple. The rear seals are much more common to need changing because they blow out easily under PCV-related pressure; that is the reason they usually go rather than the seal going bad.

[eriscentro]

I'll look into it later today. The front exhaust seal replacement is essentially a TB job with some fun added on, correct?

Yep, that's right.

The fronts don't leak very often but they don't last forever either, I have had to change just a couple. The rear seals are much more common to need changing because they blow out easily under PCV-related pressure; that is the reason they usually go rather than the seal going bad.

Unfortunately the mechanic who did my TB last year didn't change the seals. I'll have to tackle it around thanksgiving when I have access to tools and space.

[erikv11]

You still want to track down the actual leak before you dive in. In now way at all do the front cam seals fail predictably at any given mileage or age. On most of the P80 cars I have worked with, they are fine. Don't change 'em until they start to leak. You may have a leaky one but you may not, a couple other possibilities have been suggested.

[eriscentro]

This evening I pulled the spark plug cover and the timing belt cover. I found a lot of oil pooled by the plugs, so I sopped it all up. I have no idea when the filler cap gasket was changed last (has to be 4-5+ years), so I picked up a new cap at the local auto parts store. My old gasket wasn't rock-solid or brittle, but it certainly seemed far harder than the new one. With regards to the leak, I noticed that much of the oil was over by the interface between the spark plug area and the front (seemingly leaky) cam. I have pictures from months ago and there doesn't seem to be a big difference between now and then. If anything, it's slightly more oil. Thankfully, the TB looks dry.
I'll check on the distributor later this week/weekend. Didn't have the time today.

[erikv11]

Yeah this is what I was talking about, it sounds like the oil may be coming from the oil cap, not the cam seal. Clean up the oil up top, see if the leak accumulation goes away. Good chance the cam seal is fine.

[firestarterpro]

I had this problem plague me all last winter. All I had was a vacuum leak.... A sneaky one in the accordion-like air filter housing to the throttle body.

I changed spark plugs, Mass Airflow Sensors, paid shop diagnostics, etc... but it was hidden in the crevice. I sealed it with several clear UPS label pouches while I waited on my replacement in the mail.