replaced plenum and still leaks
#1
12-23-2007 | 01:46 AM
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replaced plenum and still leaks
well about 5 thousand miles ago i replaced my plenum plate with a hughes kit. It was fine for until i started getting pinging again. I look down into the tb and theres oil back in my intake. There is no telling what happen. I put it on at night. Can i just buy a replacement gasket from a parts store? Also i overtorqued the bolts on the plate cause my torque wrench fouled up. I can just go to lowes and buy grade 8 bolts to fit it right?
#2
12-23-2007 | 02:37 AM
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RE: replaced plenum and still leaks
Well if you don't mind a bit of down time, search for a welding shop that can just aluminum weld that puppy to your intake and your leak problems will be over for good.
Usually the Hughes kit is good for 50K miles +, so as you said, maybe you overtorqued it.
Usually the Hughes kit is good for 50K miles +, so as you said, maybe you overtorqued it.
#4
12-23-2007 | 10:03 AM
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RE: replaced plenum and still leaks
when the blown plenum gaskets first started appearing in the mid-1990s
there were several good reviews from people
who used this product instead of a gasket:
http://www.permatex.com/brand_right_stuff.htm
I have never head a forum post where this 'Right Stuff' failed in plenum duty
and several posters have said it is incredibly tough to remove after it sets up.
there were also posts about being sure to bottom tap the threaded holes for the plenum plate to make sure you can torque the bolts down without them bottoming out. If any of the holes bottom out, even the Hughes replacement plate can't hold properly...so using a bottom tap and them screwing all the bolts to the manifold as a test before installing the plate is worth doing
there were several good reviews from people
who used this product instead of a gasket:
http://www.permatex.com/brand_right_stuff.htm
I have never head a forum post where this 'Right Stuff' failed in plenum duty
and several posters have said it is incredibly tough to remove after it sets up.
there were also posts about being sure to bottom tap the threaded holes for the plenum plate to make sure you can torque the bolts down without them bottoming out. If any of the holes bottom out, even the Hughes replacement plate can't hold properly...so using a bottom tap and them screwing all the bolts to the manifold as a test before installing the plate is worth doing
#6
12-23-2007 | 10:25 AM
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RE: replaced plenum and still leaks
what does oil in the pan look like? i looked down my throttle body and saw dirt and what looked like stringy hair all going to the center of the pan, it wasnt hair but the way the dirt attached itself to the pan thats what it looked like. What is pinging?
#7
12-23-2007 | 10:58 AM
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RE: replaced plenum and still leaks
i apoligize for posting this same link for the 1000th time, but its got some good pics.
https://dodgeforum.com/m_735291/tm.htm
oil gets into plenum from 2 sources. one is the oily air sucking in from the pcv in the valve cover gasket through the manifold port. it will stain the plenum plate over time. this is normal. i guess you could put a filter on this to clean it some.. the second source is not supposed to happen, and its from a leaking plenum gasket at the bottom of the manifold. the low pressure inside the manifold is like a vaccuum cleaner constantly trying to suck air and oil out of the engine's lifter valley. when you get a little leak, then in it comes. this unmetered air leak causes a lean fuel/air ratio, leading to higher piston temperatures, and pinging.
http://en.wikipedia.org/wiki/Spark_knock
dark stain on the plenum plate is normal. puddles of oil, typically in the rear, are not. there is a vacuum test you can perform to check for plenum leak. unplug pvc hose from manifold and cap the port. plug the pvc hose with a golf tee or bolt. disconnect opposite side valve cover hose at breather. start truck. feel for engine vacuum on that hose. there should not be any. if there is, then the plenum is sucking air from the crankcase (which its not supposed to do), and you can feel some vacuum at the vave cover breather port.
https://dodgeforum.com/m_735291/tm.htm
oil gets into plenum from 2 sources. one is the oily air sucking in from the pcv in the valve cover gasket through the manifold port. it will stain the plenum plate over time. this is normal. i guess you could put a filter on this to clean it some.. the second source is not supposed to happen, and its from a leaking plenum gasket at the bottom of the manifold. the low pressure inside the manifold is like a vaccuum cleaner constantly trying to suck air and oil out of the engine's lifter valley. when you get a little leak, then in it comes. this unmetered air leak causes a lean fuel/air ratio, leading to higher piston temperatures, and pinging.
http://en.wikipedia.org/wiki/Spark_knock
dark stain on the plenum plate is normal. puddles of oil, typically in the rear, are not. there is a vacuum test you can perform to check for plenum leak. unplug pvc hose from manifold and cap the port. plug the pvc hose with a golf tee or bolt. disconnect opposite side valve cover hose at breather. start truck. feel for engine vacuum on that hose. there should not be any. if there is, then the plenum is sucking air from the crankcase (which its not supposed to do), and you can feel some vacuum at the vave cover breather port.
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#8
12-23-2007 | 11:09 AM
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RE: replaced plenum and still leaks
ORIGINAL: dhvaughan
i apoligize for posting this same link for the 1000th time, but its got some good pics.
https://dodgeforum.com/m_735291/tm.htm
oil gets into plenum from 2 sources. one is the oily air sucking in from the pcv in the valve cover gasket through the manifold port. it will stain the plenum plate over time. this is normal. i guess you could put a filter on this to clean it some.. the second source is not supposed to happen, and its from a leaking plenum gasket at the bottom of the manifold. the low pressure inside the manifold is like a vaccuum cleaner constantly trying to suck air and oil out of the engine's lifter valley. when you get a little leak, then in it comes. this unmetered air leak causes a lean fuel/air ratio, leading to higher piston temperatures, and pinging.
http://en.wikipedia.org/wiki/Spark_knock
dark stain on the plenum plate is normal. puddles of oil, typically in the rear, are not. there is a vacuum test you can perform to check for plenum leak. unplug pvc hose from manifold and cap the port. plug the pvc hose with a golf tee or bolt. disconnect opposite side valve cover hose at breather. start truck. feel for engine vacuum on that hose. there should not be any. if there is, then the plenum is sucking air from the crankcase (which its not supposed to do), and you can feel some vacuum at the vave cover breather port.
i apoligize for posting this same link for the 1000th time, but its got some good pics.
https://dodgeforum.com/m_735291/tm.htm
oil gets into plenum from 2 sources. one is the oily air sucking in from the pcv in the valve cover gasket through the manifold port. it will stain the plenum plate over time. this is normal. i guess you could put a filter on this to clean it some.. the second source is not supposed to happen, and its from a leaking plenum gasket at the bottom of the manifold. the low pressure inside the manifold is like a vaccuum cleaner constantly trying to suck air and oil out of the engine's lifter valley. when you get a little leak, then in it comes. this unmetered air leak causes a lean fuel/air ratio, leading to higher piston temperatures, and pinging.
http://en.wikipedia.org/wiki/Spark_knock
dark stain on the plenum plate is normal. puddles of oil, typically in the rear, are not. there is a vacuum test you can perform to check for plenum leak. unplug pvc hose from manifold and cap the port. plug the pvc hose with a golf tee or bolt. disconnect opposite side valve cover hose at breather. start truck. feel for engine vacuum on that hose. there should not be any. if there is, then the plenum is sucking air from the crankcase (which its not supposed to do), and you can feel some vacuum at the vave cover breather port.