I just started getting some blow by in my 92 with a 5.0. everybody is saying i have a blown head gasket but i don't think i do because there is no smoke coming from the exhaust and my oil is not milky. any ideas?

 

I know a bad PCV valve will cause blow-by though I'm not sure how severe it will be. My 95 5.8L was soaking the breather element (in the air filter housing) with oil and the bottom of the oil filler cap always had the milky white crap on it. Both these issues were fixed by changing my PCV valve.

 

I'd replace the pcv valve too.

If you have a blown head gasket, you'll either see oil in the coolant, coolant in the oil, or at least some pressure in your cooling system.

You say the oil isn't milky - is the coolant cloudy? With the truck idling and up to operating temp, do you get bubbles in the overflow tank when the thermostat opens?

 

The pvc creates a vacuum in the crank case pulling out the contaminates and burning them, no pvc will cause pressure in the crank case thus pushing the atomized oil throughout the intake system, more so through the hose that goes from the valve cover to the breather. If the pvc is good your rings are going bad, bad rings cause compression to bypass them creating a pressure in the crank case, causing the same symptom as the bad pcv valve.

 

Yep. I know it's a different animal, but I just replaced the Chevy LT1 engine in my Caddy for the same reason. Had a lot of crankcase pressure (oil blowing out everywhere - even the dipstick tube) but nothing was getting into the exhaust (wasn't smoking). I replaced the PCV, knowing in my gut that it had to be something more serious. The PCV didn't help. A compression check revealed that the problem was the #7 cylinder.

 

where is the pcv valve on the 5.0 engine?

 

I have the 5.8 so I don't know for sure but they are usually in a hole in the valve cover, or connected to it by a vacuum line or tube. Mine is on the passenger side valve cover, close to the firewall. I'm sure someone else will chime in soon to confirm. If not, the local parts store guys should be able to point it out to you (or else they shouldn't be working at a parts store!).

 

Buddhaman - PCV valve is on top of the passenger side valve cover, at the rear, tucked up under the air plenum. Hard to see, better found through the touchy-feely method.

 

Once you replace your PCV, open up the oil fill while it's running. If you get smoke out of there in puffs consistent with the cylinders firing, you've got trouble. That's the way mine was. It created LOTS of pressure.

 

ok i'll probably do it tomorrow and let you guys know how it goes