I have a 1999 Dodge Ram 1500 Van - 3.9L, V6

Been chasing a bad MPG prob. Ultimately I have diagnosed the issue as a bad plenum gasket. (many, many repairs have be done and many causes ruled out) I got a look into the throttle body; oil in there. Cats bad and I dont wanna replace it until the exhaust isnt blasting burnt oil into it. hope I can hit these repairs in the next couple weeks.

Although my van doesn't seem to suffer from the direct symptoms of a bad head gasket (not losing coolent or oil; not mixing) I can see some leakage on the engine; a small, small amount. but its there.. I don't feel it's too bad but if I'm going to replace the plenum anyways should I keep going?

**please keep in mind that neither time or money is on my side right now. both will be in 4 or 5 months and Ill have a complete shop to hold up in. I also need the van to get me a good 4k miles between now and then; and i'd rather no do any further damage.

I just wanna make sure that if I replace only the plenum (with the aluminum Hughs kit), that I won't have to totally redo everything again if I decide to really dig in and replace the head gaskets this summer.

if doing so is the way to go what should I expect for extra time it will take? ANy huge expenses assuming I dont have to have the heads machined.

ps- again, if time and money wasn't such a big deal i wouldnt be asking, I'd just do it.

thanks in advance.

 

You won't have to redo the plenum, but you will have to R&R the intake again.

 

Like alloro said, you will have to re-do the intake again.


One word of advice. I have done the intake and heads on my v6 (the eight is the same just longer heads)...
When doing the intake, take off the mounting bracket for the alternator. It is a long, triangular aluminum piece. There are 5 bolts. Four are easy to find, the fifth is south of where in alternator mounts and is recessed. It took me about an hour to find this one the first time I did this job with taking this bracket off...


The reason I recommend taking this bracket off as it is really hard to put the intake on straight with it in the way. You cannot get your hand under the front of the intake with the bracket on. With the bracket on, you have to hold the intake (which is about 16 lbs) and do a down, front, down, front maneuver to get it in right. At the same time don't knock off your intake gaskets!!! It is a real, real pain in the *** if you don't take off the alternator bracket.


Also there are front and rear intake gaskets that just sit there, and it is really easy to knock these off without the intake coming straight down on them. I want to stress that the intake has to come straight down on them. Any angle will knock the off or twist them. It wont seal and you will have a huge vacuum leak.


Good luck - let us know if you have more questions. If you decide to do the heads, let us know because there are a few gotchas there too.

 

thanks for that tip- I took everything out I could, even that bracket- it's annoying enough working in a van without being crowded out by everything.

also an update - I ended up starting another thread about the head gaskets after they started leaking. i changed the intake and they sprung leaks. from here I just went for it.

https://dodgeforum.com/forum/dodge-r...ant-wtf-2.html

 

hope to have the heads back form the machine shop tomorrow...

 

If I'm not mistaken, the intake manifold and gasket design was one of the more common things to go bad on these engines and was sort of a fatal flaw. I'm dreading when I have to do this repair.

 

Could be - ive learned that much of the gasket and vacuum leaking is caused by the crappy plenum pans they put in. Which are almost guaranteed to breakdown from what I have read.