Anyone NOT have a blown plenum gasket?
Champion
Joined: Feb 2009
Posts: 3,416
Likes: 4
From: Bay Area, CA
Sad...but true.
Rookie
Joined: Jul 2007
Posts: 85
Likes: 0
From: Idaho
Plenum Vacuum test
(1). Start the engine and allow it to run long enough to reach operating temp, then turn it off.
(2). Remove the breather hose from the air cleaner assembly and attach a vacuum/pressure gauge to the end.
(3). Remove the PCV hose from the manifold vacuum port and PCV valve. Plug or cap the port and valve.
(4). Turn the engine on again and allow it to run long enough to stabilize crankcase pressure.
(5). Observe the pressure gauge. A slight pressure is fine, but a noticeable vacuum indicates the manifold is drawing a vacuum in the crankcase through a failed plenum gasket.
Ok, Yesterday, @ 156K!
(1). Start the engine and allow it to run long enough to reach operating temp, then turn it off.
(2). Remove the breather hose from the air cleaner assembly and attach a vacuum/pressure gauge to the end.
(3). Remove the PCV hose from the manifold vacuum port and PCV valve. Plug or cap the port and valve.
(4). Turn the engine on again and allow it to run long enough to stabilize crankcase pressure.
(5). Observe the pressure gauge. A slight pressure is fine, but a noticeable vacuum indicates the manifold is drawing a vacuum in the crankcase through a failed plenum gasket.
Ok, Yesterday, @ 156K!
Veteran
Joined: Oct 2008
Posts: 313
Likes: 0
From: The NEW Mexico
If you have a 5.2 or 5.9 v8 engine in your 2nd generation or early 3rd generation ram it is likely that the plenum gasket is blown because it is a design flaw. If you notice poor performance, poor gas mileage, burning oil, pinging (spark nock) under acceleration, blue smoke coming out of the tailpipe on startup, or oil pooling in the intake manifold, there is a very good chance the plenum gasket is blown. The only way to tell for sure whether or not it's blown is to do a vacuum test.
Out of all those mentioned, the poor gas mileage is definatley there....however, if its because of the effeciency of the motor or this issue, who knows. I have been getting about 10.5 latley.
Administrator
Joined: Jul 2007
Posts: 24,686
Likes: 21
From: South Georgia/East Florida
I never had the issue with my '98, but sold it at 4 years old with 68,000 miles on it.
I'd ask the guy who bought it, or should I say who's mommy and daddy bought it for, but he got a little fiesty playing off-road after owning it about a month back in '02. Lost control on a sand bar and sunk it in a river. I believe when they got it out it was classified as DOA and I'm sure went to a salvage yard.
I'd ask the guy who bought it, or should I say who's mommy and daddy bought it for, but he got a little fiesty playing off-road after owning it about a month back in '02. Lost control on a sand bar and sunk it in a river. I believe when they got it out it was classified as DOA and I'm sure went to a salvage yard.
I never had the issue with my '98, but sold it at 4 years old with 68,000 miles on it.
I'd ask the guy who bought it, or should I say who's mommy and daddy bought it for, but he got a little fiesty playing off-road after owning it about a month back in '02. Lost control on a sand bar and sunk it in a river. I believe when they got it out it was classified as DOA and I'm sure went to a salvage yard.
I'd ask the guy who bought it, or should I say who's mommy and daddy bought it for, but he got a little fiesty playing off-road after owning it about a month back in '02. Lost control on a sand bar and sunk it in a river. I believe when they got it out it was classified as DOA and I'm sure went to a salvage yard.
Administrator
Joined: Jul 2007
Posts: 24,686
Likes: 21
From: South Georgia/East Florida
For what I sold it for I wish I'da kept it. Today, it would be a mean a$$'d, lifted, stroked, weekend warrior with about 38" Baja Claws on it!!!
Champion
Joined: Aug 2009
Posts: 3,015
Likes: 8
From: Western NY,
from what I read there are actually two design flaws working against you...
1 they used bolts that were slightly too long for ther depth that they drilled and threaded for on the plenum gasket so it doesnt sandwich the gasket and hold it as well.
2. they made the belly pan out of steel and the manifold out of AL alloy...they expand and contract at different rates.....that being said I have yet to test mine but the po may have done it...140k and doesn't burn oil so...
1 they used bolts that were slightly too long for ther depth that they drilled and threaded for on the plenum gasket so it doesnt sandwich the gasket and hold it as well.
2. they made the belly pan out of steel and the manifold out of AL alloy...they expand and contract at different rates.....that being said I have yet to test mine but the po may have done it...140k and doesn't burn oil so...
Professional
Joined: Nov 2009
Posts: 158
Likes: 0
From: bellefontaine ohio
107,000 and no leaks, but who knows what the PO has done, it has weird things replaced on it, like the 4 and 6 cyl spark plugs being different than the others, and one AC line new and the other not to the condenser, but when i get some spare cash its getting a hughs plate and keggar mod
Record Breaker
Joined: Jan 2009
Posts: 2,222
Likes: 4
From: NB, Canada
this describes my truck perfectly.
Haven't checked down the TB yet but I already know what I'm gonna find..... I was mostly concerned about the smoke on startup, mine does this randomly and I was hoping it was the plenum also.just to clarify, does the spark knock created by this sound like normal ping or more pronounced? mine sounds kinda like noisy lifters or somethin sometimes, usually after a while of driving, but not constantly...
