98 bad seals and (I hope not) burning oil

[r0llinlacs]

I have a 98 Montero Sport LS V6 with 200,000 miles. Got it real cheap and couldn't pass it up. It has a misfire and it seems to burn oil but I'm not 100% sure if it's burning because I know it's leaking through the valve covers. I don't think the previous owner did much as far as maintenance and repairs. I've read that the valve cover gaskets and rear cam gaskets are notorious for going bad and they definitely are bad on mine. I read that the rear cam seals go bad and leak on the cat which kind of makes it hard to tell where the oil smell is coming from but sometimes it looks like the exhaust is smoking until the engine warms up. With that said I just want to know if there's anything common with these trucks I should know as far as losing/burning oil besides seals? Anything serious mechanically like piston rings, valves, etc?

Also, as far as the misfire goes, what is common with these trucks? I wouldn't be surprised if it has all original plugs, wires, injectors, coils etc. but is there anything more serious I should worry about? Are valve problems common?

I checked it with a snap on scanner and it didn't show any codes at all, which is weird. The check engine light isn't on and the bulb hasn't been pulled because it turns on during the ignition bulb check.

It's just the combination of oil problems with a misfire that make me worry that it's something more serious.

Any feedback is appreciated!

[russiankid]

For the oil leaks, I would put money on the valve covers an rear cam seals. Rear cam seals are easier to do than the valve cover gaskets because you have to pull the intake manifold off to get to the valve covers. As for the misfire, I would not be surprised if the spark plug tube seals are leaking on the valve covers which filled the tube with oil and thus a misfire. When you do the valve covers, change the plugs and wires while you're at it.

[r0llinlacs]

I've read that these engines burning oil is uncommon so I really hope it's just seals. Valve cover gaskets, cam gaskets, spark plug gaskets I believe come with the valve cover gaskets, spark plugs, wires, coils, will all be done at the same time. No sense in taking it apart more times than you have to. I'm just worried about dumping money into it and it not fixing the misfire. Basically I'm just worried that the misfire is mechanical and not electrical.

[russiankid]

If the vehicle was maintained somewhat in its past, most likely you're just burning oil on the exhaust. If it were burning oil you would have blue smoke coming out of the tail pipe. Also, no sense in replacing the coils unless they are bad. They are probably the easiest thing to change out under the hood aside from a battery or a rad cap...haha.

[r0llinlacs]

Jan 29, 2015 12:52:57 GMT -5 russiankid said:

If the vehicle was maintained somewhat in its past, most likely you're just burning oil on the exhaust. If it were burning oil you would have blue smoke coming out of the tail pipe. Also, no sense in replacing the coils unless they are bad. They are probably the easiest thing to change out under the hood aside from a battery or a rad cap...haha.

Lol that really is the problem, I don't think the previous owner did much at all. It was pretty much trashed and wasn't running when I got it. Needed an alternator. Oil dipstick was bone dry. It was literally spraying gas out of the top of the gas tank. Rear U-bolt plate that the shock mounts to was broken so the shock was dragging everywhere, and she said she drove it like that for a long time! All of this has been fixed so next on my list is the oil problem and the misfire.

The rest of the car is solid. 4wd works great, transmission shifts great, rides great, doesn't overheat, hasn't been wrecked so to me if it's not something serious it's definitely worth fixing.

I will have to get out and do some more fiddling today. I haven't had a chance to smell the exhaust when it looks like it's smoking.

[russiankid]

So from the sounds of it the seals are just leaking. I had done the valve cover gaskets on mine one, and I am not sure if I didn't torque the covers down enough but they kept leaking. Almost 2 years later I tore it apart again, put in new gaskets with the right stuff sealant and hasn't leaked since. I would suggest using some so you won't have to do it again.

[r0llinlacs]

Jan 29, 2015 13:43:56 GMT -5 russiankid said:

So from the sounds of it the seals are just leaking. I had done the valve cover gaskets on mine one, and I am not sure if I didn't torque the covers down enough but they kept leaking. Almost 2 years later I tore it apart again, put in new gaskets with the right stuff sealant and hasn't leaked since. I would suggest using some so you won't have to do it again.

So the rubber gaskets leaked?

[russiankid]

On mine yes, but that was mostly my fault. The original gaskets were hard as a rock and leaked a lot.