1998 Ram 1500 5.9L oil burning

I have a '98 Ram 1500 with the 5.9L in it. Has a 163K miles on it. I know it is burning oil and not leaking it. I've already replaced the PCV valve. It is going through oil at about quart a week or about every couple hundred miles. It seems to have plenty of power but does idle a little rough when idling. Runs good other then that. The shop I had it at, said the only way to determine the cause of the oil burning is to tear in to the motor. My guess would be either valve seals are bad, or intake gasket is leaking. I've gathered that the intake gaskets are a problem on the 5.9's. My question is, is there a way to determine the cause without taking and tearing in to the motor and spending a bunch of money just to find the cause. Also the oil turned black after only about 300 or so miles after changing it. I just recently bought the truck last month and hate to get rid of it already. But I don't have a ton of money to through at it, nor do I know any record on previous oil changes, tune ups or any other maintenance done to the truck. What do you all recommend I do. I'm trying to spend as little money as possible and prefer to spend nothing or close to nothing to atleast find the problem of the oil burning.

Sounds like the engine is heavily sludged for the new oil to turn black so soon after an oil change.
I acquired a 1979 Malibu that did the same thing and it turned out the passages on the heads that allow the oil to return to the crankcase were clogged. This allowed the oil level on top of the heads to submerge the valve guides and oil get into the intake ports & get burned in the combustion process. It had oil fouled spark plugs also.
After pushing the sludge through the drainback passages with a long narrow stick (like a 1/4" diameter wooden dowel 2 ft. long so you won't lose it if it slips from your hand), the oil was able to drain correctly back into the crankcase and stop the excessive oil loss. I use Valvoline, a full bodied premium oil.....use the mfg. recommended viscosity. Valvoline also has a Max Life oil for higher mileage engines.

I'm not able to do much work on my own vehicles as I'm disabled. So I tend to have most work done by a local shop. What would you recommend I have them do to help?

By the way shortly after I bought the truck, I had to have both oxygen sensors and the catalytic converter replaced due to all of them being bad, don't know if that's related the oil burning or not.

If you're burning a quart a week, there's a tell-tale sign to look out for; blue smoke coming out of the tailpipe. If the smoke is coming out when you first start the engine and goes away in 15 minutes or less, it's the valve seals. If the smoke is intermittent and random or just constant, it's the piston rings... specifically the oil rings, not necessarily the compression rings. Although a compression test might be a good idea anyway.
If it is the valve seals, it shouldn't be too catastrophic. The valve seals themselves aren't usually very expensive, but the cylinder heads will have to come off and therefore you will need new head gaskets, which also aren't that expensive, but the labor on that might get a bit pricey.
If it's the piston rings, that's a different story... the engine will have to be taken apart completely, you'll need the piston ring set, a full gasket set and while you're in there you definitely want to replace the main bearings and maybe the rod bearings too. It may actually be cheaper to just get a replacement engine if the piston rings turn out to be the problem.

First off #1, is the Check Engine light on?



Valve springs and seals can be replaced with the heads on the engine. That's why a special air fitting was developed to screw in the spark plug hole and air applied to hold the valves shut in place while you make the change.
An older friend told me 35 years ago a poor boys racer trick. He would remove the sparkplug on the compression stroke, put a couple feet of small rope in the sparkplug hole then bring the piston up until the rope stopped it then with the rope holding the valves closed, remove weak valve springs and install stronger springs......RIP Jimmy

Your shop needs to remove the valve covers and check for clogged drainback holes.
If the oil drain back holes are clogged, new valve cover gaskets will be the only parts cost then the labor charge.

no the check engine light is not on. The valve cover gaskets was already replaced by the shop as they were leaking when I bought it. They did not mention anything being wrong at the time. I noticed online that there's been a common problem with the intake manifold gasket on the particular engine and that can cause a lot of problems. What do you guys think is the possibility of it being bad?

Do they report an oil loss with the bad intake gasket?

yes a loss of oil seems to be very common with the intake gasket failing. I spoke to the shop today though and they said the intake manifold gasket is one the things they checked and that it was fine and that the oil loss im experiencing is either from valve seals or piston rings.

Sounds like the next move then is to let them install valve seals or sell the truck and start over. Given the price of even getting a good junkyard engine and having it installed is pretty pricey.
Did the seller make any written guaranty on the truck when you bought it?

no i bought the truck from a private individual with no kind of warranty