redbull343

Hey everyone mike from PA here. Looking to get info, well more in depth info, on the oil consumption the JK 3.8 liter engines have. A few guys I know that have that engine were complaining of a engine tap/ knock (because of low oil) and was curious. They looked into it at a couple jeep shops and the guys were saying something about, when the engine was built the installers put the piston rings in upside down. They go through about 3 quarts of oil in around 3000 miles. Does anyone have any thoughts about this and a way to fix it. He wasn't sure if he should swap engine, trade it in, or buy something different. ( I'm tryin to keep him a jeep a guy )

airforce26yrs

As the 3.8 gets some miles on them they tend to burn oil. It is a known problem. Chrysler says 1 quart in 750 miles is normal and won't do anything until they reach that point. some have their engine replaced under warranty for this problem but it is a long process. If you are burning a quart in 750 miles then Chrysler does an oil consumption test to prove it and after that fixes the eng. Some do not have problems, others do. I am currently burning about a quart in 4000 miles on mine, but keeping an eye on it. The problem is not only in Jeeps, but in anything with the 3.8.

rob_engineer

Lots of threads on this topic. Some were successful replacing the PCV and trying different weight oils.

JK_Crawler

The main issues I have seen have been PCV valves that are stuck or cylinders that are out of round. My 08 had the PCV get stuck at 50k and I replaced it, problem solved. Within the last 3 oil changes I have noticed the engine being 1.5qrts low between oil changes (I change my oil every 4k), I have been using 5W-30 conventional oil since I bought it with 41k miles. The jeep currently has 80k miles and the engine is holding up great compared to others on here (fingers crossed), I make sure I check my oil every time I get gas. Being a mechanic I have seen to many nightmares due to people not checking their oil.

Steelblu08

I used 5w20 since day motor just shelled itself at 65.5 k miles cam and rod bearings gone but due to oil issue

redbull343

Yeah I completely understand JK crawler , I'm a mechanic to and do the same stuff. I'm about to check my pcv valve, just cause it does have 90k on it. Then at my next oil change in gonna switch over to 5w-30. My buddy has a 08 I think and is starting to knock and carry on and the shop he took it to said something about the rings on the Pistons and what not. So it freaked him out and he had been thinking about stroking the engine or replacing it. I'm tryin to tell him other things to try before he puts about 7500 into it and he could have fixed it for less.

rob_engineer

if I had an 08 and $7500 available I would trade in the 08 and use the $7500 for a down payment on a new or newer jeep.

SoK66

It seems a consistently sound move is to change to a heavier oil as early in a 3.8's life as possible, and to observe a shorter change interval than the recommended 6k miles. Long term the specified 5w-20 just doesn't provide enough viscosity to protect the engine under the loads the JK's weight etc puts on the engine. The 3.8 was designed for 10w-30 and nothing was ever done to the internals, clearances, cooling, etc to warrant the change to 5w-20. All the new factory reman 3.8l engines come with 10w-30 requirement.

Ryan0260

X2, get a '12 or newer with a 3.6.

redbull343

Well yes of course if I had that money available too or if he did I think he would ... But it would have to be a loan