End-all Be-all plenum thread
Professional
Joined: Jun 2017
Posts: 180
Likes: 1
1996 Dodge Ram 2500 2wd 5.9 V8 VIN Z 120,000 miles
Truck had no CEL but had 40-45 mph shimmy indicative of a random misfire. Did coil, cap, rotor, wires, plugs, wire reroute as per TSB. United Motor Products tune up kit and coil (lifetime warranty) with Champion plugs from RockAuto ($73 with tax and shipping). Number 8 and number 7 spark plugs had white ash buildup. The rest were fine. Cleaned throttle body and IAC valve with a little B-12 Chemtool. Replaced idle purge vacuum line 'cause it was shot (bigger of two rubber hoses on throttle body). Replaced PCV. Truck runs like new... for now.
While I had the throttle body off I looked down into the Intake manifold and there it was (cue Psycho music)... the oily residue from a blown plenum plate gasket. Explains the ash buildup on number 8 and number 7 plugs.
I just ordered a new aluminum plenum plate from this guy on ebay:
https://www.ebay.com/itm/DODGE-360-M...ty!14424!US!-1
and a Dorman 615-310 from here:
https://www.ebay.com/itm/Engine-Inta...012.m1985#rwid
Had a 10% coupon for ebay which paid my NY sales tax ;(
Total for plate and gasket kit was $95. Will install soon and give update.
P.S. Thanks to everyone at this site. The info is worth a million. -M
Truck had no CEL but had 40-45 mph shimmy indicative of a random misfire. Did coil, cap, rotor, wires, plugs, wire reroute as per TSB. United Motor Products tune up kit and coil (lifetime warranty) with Champion plugs from RockAuto ($73 with tax and shipping). Number 8 and number 7 spark plugs had white ash buildup. The rest were fine. Cleaned throttle body and IAC valve with a little B-12 Chemtool. Replaced idle purge vacuum line 'cause it was shot (bigger of two rubber hoses on throttle body). Replaced PCV. Truck runs like new... for now.
While I had the throttle body off I looked down into the Intake manifold and there it was (cue Psycho music)... the oily residue from a blown plenum plate gasket. Explains the ash buildup on number 8 and number 7 plugs.
I just ordered a new aluminum plenum plate from this guy on ebay:
https://www.ebay.com/itm/DODGE-360-M...ty!14424!US!-1
and a Dorman 615-310 from here:
https://www.ebay.com/itm/Engine-Inta...012.m1985#rwid
Had a 10% coupon for ebay which paid my NY sales tax ;(
Total for plate and gasket kit was $95. Will install soon and give update.
P.S. Thanks to everyone at this site. The info is worth a million. -M
Registered User
Joined: Oct 2019
Posts: 9
Likes: 0
From: NY
Noted. I use the truck mainly on weekends for home projects and whatnot... I drive it like I'm an old man (which is not too far from the truth
).Do you think the Dorman gaskets will hold up for a while, or are they complete garbage?
Administrator
Joined: Apr 2010
Posts: 87,510
Likes: 4,226
From: Clayton MI
Get good gaskets, and be happier.
Registered User
Joined: Oct 2019
Posts: 9
Likes: 0
From: NY
lol I replaced the intake on my old Mercury Grand Marquis 2 years ago. That was an all plastic design that some genius came up with to save weight and get better MPG with a body on frame, full size V8 car. It's hard to get good gas mileage when your vehicle is dumping all of your coolant through a 1/4 inch crack in your plastic intake and you are dead on the side of the road.
Anyhow...
You are correct. I sure don't want to do it twice. Will get a Fel Pro set.
TY for the advice.
Administrator
Joined: Apr 2010
Posts: 87,510
Likes: 4,226
From: Clayton MI
lol I replaced the intake on my old Mercury Grand Marquis 2 years ago. That was an all plastic design that some genius came up with to save weight and get better MPG with a body on frame, full size V8 car. It's hard to get good gas mileage when your vehicle is dumping all of your coolant through a 1/4 inch crack in your plastic intake and you are dead on the side of the road.
Anyhow...
You are correct. I sure don't want to do it twice. Will get a Fel Pro set.
TY for the advice.
Anyhow...
You are correct. I sure don't want to do it twice. Will get a Fel Pro set.
TY for the advice.
A tank would last forever.Good Decision.
Registered User
Joined: Dec 2016
Posts: 18
Likes: 2
From: SPRING HILL FLA.
The universe is in dire straights
Well ,the Powers have decided and chosen me to undertake the task of correcting a" EVIL" so sinister which if left unchecked will cause pain and suffering to be exhibited throughout all of Mopar World. The task I have chosen is known as, "THE DREADED PLENUM DISPLACEMENT ". If left unchecked forces that are well known by those who have chosen to fight this nemesis ,that two dissimilar metals ,forced to work in a violent and hostile environment , cannot exist . So it is with a heavy heart, the proper tools, and a special alloy, that I attempt to correct this problem with the help and the council of " Master Hughes" that I attack and destroy the " EVIL ONE " ,and bring joy and harmony back to our fair world once more. Wish me luck and a speedy return my fellow warriors...........BLAMBRAM
Administrator
Joined: Apr 2010
Posts: 87,510
Likes: 4,226
From: Clayton MI
Well ,the Powers have decided and chosen me to undertake the task of correcting a" EVIL" so sinister which if left unchecked will cause pain and suffering to be exhibited throughout all of Mopar World. The task I have chosen is known as, "THE DREADED PLENUM DISPLACEMENT ". If left unchecked forces that are well known by those who have chosen to fight this nemesis ,that two dissimilar metals ,forced to work in a violent and hostile environment , cannot exist . So it is with a heavy heart, the proper tools, and a special alloy, that I attempt to correct this problem with the help and the council of " Master Hughes" that I attack and destroy the " EVIL ONE " ,and bring joy and harmony back to our fair world once more. Wish me luck and a speedy return my fellow warriors...........BLAMBRAM
Registered User
Joined: Dec 2016
Posts: 18
Likes: 2
From: SPRING HILL FLA.
the dreaded plenum fix
Well,my fellow warriors, the saga continues,having taken off the plenum to do the repair ,as usual ,a bolt broke in the front so that was a pita ,was able to get the bugger out and cleaned up all the crud and carbon from the plenum ,installed the new plate ,gasket and bolts ,set it in and bolted her up, then as the force was starting to move to the center,Lo and behold,the book I have says to make sure that the gaskets are installed with the proper orientation , Now i could swear that I saw an R on the one that I placed on the right side and being a little **** retentive ,the force said to me" Luke I am your," oh wait that was some other story, its gonna bug you to death, so with much trepidation I remove the plenum and the gaskets are exactly the same . So having rechecked everything again I reassembled the plenum and torqued it down in the sequence of 12 i.p/24 /36 /48/72 and then finally 12 f.p . stay tuned my fellow travelers,for the next episode ,of "The Dreaded Plenum Fix"
