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5.9l basic mods

14K views 12 replies 8 participants last post by  98sst 
#1 ·
Hi everyone. I just picked up a 2002 ram quad cab 2wd with the 5.9l motor with 80k miles. Couple of questions for those that are in the know.

First are their any known problems I should look out for with the truck/motor. I heard of some type of intake leak when they get up in mileage but no idea what it is or how to diagnose.

Secondly what type of base mods are working to increase power and mileage. Things that come to mind

CAI- had good luck with K&N
Cat back exhaust- whats economical?
Plugs/cap/rotor/wires- what's a good combo?
Thermostat- any benefit to lowering the thermostat
Electric fan vs clutch fan
Read something about changing to all synthetics. Really worth the investment for the cost? Which fluids are people replacing besides motor oil?
Underdrive pulleys?
Not looking to change gearing
Chip/programmer-reading lots about hyper tech

Thanks for any help
 
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#3 ·
one thing about switching to synthetic oil. If you have any leaks...even ones that aren't bad enough to drip yet, they will turn into a hose once you put that synthetic in there...lol
Also, going to an electric fan. Its not worth your money, you may free up 5hp, if that, plus, you then lose the reliability of a clutch fan. (as long as the motors turning, it will stay cool) But, whatever you do, don't buy a replacement clutch for it from Autozone or Advance. The clutch seems to lock constantly, and not slip, and that does take power away, and makes your gas mileage suck. So...one thing I would actually buy from Mopar if I were you (if it ever needs replaced)

The rest of you list, though, looks good.

As far as the thermostat...put a 180 in it. Engines are more efficient at lower temps (to a point)...

and, exhaust, 2.5" duals out the back....whatever muffler you choose. I'm a Flowmaster fan, but, choose whatever you're into.

Also...something that I hear makes a big difference on the 5.9s is a new cam. So...thats an option, and, most cams are about $100.

as far as the intake leaking vacuum. Mine is doing it now, so badly I can hear air rushing. But, supposedly, if you take the air cleaner off, and look into the intak, you can see oil residue on the inside if its bad.
You can either replace the plenum gasket, or get one of those after market intakes (quite pricey)...but say they will take a .5 second off your 1/4 mile time, and give you about 4-5 mpg more.
 
#4 ·
Good options. I'm also interested in a cam, but if your like me, your incapable of installing it yourself and it'll cost more. I'm unsure of where to install it.

Personally, I run a K&N CAI, Air Raid TBS, Magnaflow muffler with 3 inch piping all around, custom long tube headers, Jet power control module, and taylor ignition cables. My truck is fairly fast for a worn out 5.9.
 
#6 ·
I could handle the cam install. Built a few motors in the past though it would be my first time installing a cam without having the motor out. Wasn't thinking of cam change only because I assumed you would need to then upgrade rockers pushrods and all the rest which is where the $100 cam turns into a $1000 cam lol.
 
#7 ·
haha...yeah, I've never installed one in the vehicle either, but, these trucks have a lot of room if you take the radiator/fan shroud out...nothing but a big hole in the front...lol

But, you shouldn't have to do that, especially with a 80k motor. Maybe throw some new lifters in there, and check all the other stuff out...but, it should all be fine.
There are a lot of cam places (Hughes Engines is a good one that specializes in Mopars)...that you just tell them what you have, what you want it to do, and they'll grind one for you.
 
#8 · (Edited)
Doing a little more reading and thinking and wanted to see if anyone had some more specific info on a few things.

180 t stat anyone have a preferred manuf/model#

Spark plugs I see people talk about some e-diamond something or another and others say to stick with a truck plug. Personally not a big fan fancy plugs but would like to hear from some with personal exp on either.

Rotor just a stock replacement with brass inserts the way to go or a performance rotor?

Coil I think I read a accel coil anyone have a part number?
 
#12 ·
dont waste money on a jet thermostat, autozone sells the 180* stat cheap

the 5.9L dont like fancy plugs, use copper core plugs i prefer champion truck plugs. just dont use platniums or anything like that. bosh seems to be the worst in the 5.9 in my experience

summitracing was having a hell of a deal on their brass cap and rotors. but anykind will work. use a 8mm+ plug wire

accel coil for 90-97 5.9L P/N 140021
adapter for 98-03 5.9L P/N 140021AH
 
#10 ·
quick note about the coil. make sure that if you get the accel that you get the wiring harness adapter or else it will not fit....learned that the hard way..mine is sitting in the box yet cause i didn't get it and ran out of money lol but go to summitracing.com and look at their "generic" cai and headers and such..they cost A LOT less and are actually name brand. like i got my cai for like 229 and it was actually k&n. and i went with hypertech t stat. works well as far as i can see. and for headers i went with summit brand and the only thing that i have to complain about it that you can hear the exhaust pulse..but that's just cause the pipe gauge is too low. but they were 154 for both..can't beat that.
 
#13 ·
Yeah I got a 180 this week for cheap as hell. Easy to install also. Didn't notice a big change in power but well worth it with 117k on the clock. Cant afford to have problems!
 
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