On my 97 TA, I noticed that the line going into the passenger side of the TB at the very top was cracked where it went to the TB. I followed the hose to the back of the Passenger side valve cover where you would install a crankcase breather. What would cause oil to saturate that line and get into the TB? I checked the PCV Valve and shhok it and it sounds fine, I just replaced it a year ago. Any ideas? Or is this normal?

 

Are you talking about the hose that goes from the valve cover to right next to the TPS? If so, I had the rectangle top plate off of my intake a couple weeks ago, and i noticed a good amount of oil in there as well. I would say its normal.

The hose i'm referring to is the large one to the left of the TPS in this picture.

http://csce.uark.edu/~jgbertr/rb/tps.jpg

 

Yeah thats normal......I put a breather on the valve cover and threw that damn mess making thing away. Plugged up that port on the TB of coarse.

 

Pretty common to find oil there. If you want to keep the pcv system intact (no breather) and stop the oil problem, you can install a Deutsch BF412 breather. Check this out.

 

jkipp84,
Where would I buy one of those breathers? My engine is approaching 130,000 miles so it sure couldnt hurt to install one.
Would Pep Boys, Auto Zone, or Discount(Advance) Auto have them?

 

Autozone has it under Breather Filter, BF412
Stupid web site won't let you select something not made for your vehicle.

 

Yup, thats the hose, the large one on the top next to the TPS. Strange how they say it's a high mileage LT1 problem? I just got a new LT1 installed 16,000 miles ago? I'll give that breather a shot. Is this unusal for a low mileage LT1?

 

Mr. Kevlar,
I don't know if theres supposed to be some kind of filter in the stock breather fitting, but mine is just an empty elbow. I'm actually surprised theres not more oil getting sucked into my intake.

I would say there will always be oil getting sucked in there if the average LT1 is configured like mine. It must get extreme on high mileage cars though.

 

That line should not fill with oil, because it isn't exposed to vacuum at the TB, and it is intended to flow filtered, MAF metered air from a port in front of the TB blades to the passenger side valve cover. That is the air the vacuum in the PCV valve pulls through the crankcase and lifter valley, and out the bottom of the intake manifold. In a healthy engine, air should be flowing from the TB to the valve cover, so no filter is necessary, and no oil entrainment is possible.

When you get into a problem, it MAY be a plugged PCV valve, that is allowing crankcase pressure to build up, or excessive blowby on the rings, creating more crankcase gasses than the PCV system can handle. In that event, the system is designed to reverse flow, and vent the crankcase through the valve cover line, into the TB. When I pulled my engine apart for the stroker build at 65K miles, there was no oil in the line or in the top of the TB.

It might also be a problem of "some" vacuum building up in the line at WOT. That would occur if you have a dirty air filter, or some other pressure loss in the air feed system before the TB. That would allow a small vacuum to develop at the line's TB port, and some vapor to be pulled through the line to the TB.

 

ok tell me if what did was bad:

i took the hose off, plugged the hole in the TB, and placed a little breather filter in the valve cover?

 

Injuneer,
I just replaced my PCV valve, so that can't be a problem. my engine has almost 130k on it, so there very well could be worn rings and blowby. It's funny you mention the air filter, it still seems to be flowing ok, but it's a K&N FIPK CAI, and when i touched the filter element from above I rubbed black dirt off on my finger.. It's probably about time to clean and re-oil it. It only has about 32k on it and K&N only recommends cleaning them about every 50k or so.

 

I'm interested in this as well because I have a breather on EACH valve cover (they are the chrome gm bowtiw covers) and left the TB hose in place. Haven't noticed any excessive oil consumption or oil accumulation in the TB. Should I remove the hose and block the TB tube or just leave everything as is??
Thanks!

 

I am in the middle of fixing my intake leak and noticed that my intake had an oily film on the inside as well. The car has 76k and had a new PCV valve installed when I bought it with 58K. For a couple of bucks, I may just buy one and use it as a precaution.

 

Your "breathers" are allowing "unmetered" air into the combustion chambers, forcing the PCM to make corrections with the long term fuel trims. Air that enters through the breathers gets dumped into the intake manifold via the PCV valve. And, if you didn't block off the line from the valve cover to the TB, you could be pulling some air through the breathers to the TB, adding more unmetered air.

Nothing that the PCM can't correct for, but I've yet to understand why you need a breather with a closed PCV system on a healthy motor. I still run the stock closed system on my 800HP nitrous motor, with no problems.

 

Injuneer,

From a performance standpoint, should I remove the 2 breathers (I can install them for car show purposes) and leave the valve cover hose to the TB in place or remove the hose to the valve cover, block the TB tube, and leave the breathers in place?
Thanks!