Leaks everywhere
 

I bought a 2002 Montero sport. I noticed that wherever i go, there's a trail of oil ledt from under the car. There is a "multiple mis-fire detected" code, but no check engine light. Where can the oil be ;eaking from? will lucas additive work anymore at this high mileage?

02 Montero Sports typically leak from their valve cover gaskets, the rear camshaft covers, and the front cam seals on each head. This is not a design flaw--those gaskets and seals are just 16 years old and have hardened. This leak on the (US) passenger side often leaks onto the alternator, causing it to fail. Replacing these three seals requires taking off the upper and middle intake manifolds (3 sections). Not a tame job at all, but I just did it successfully, working very slowly, in 10 hours or so. I did my timing belt, relevant pulleys, belt tensioner and water pump, plugs and plug wires at the same time and also replaced the three oil seals on the front of the engine while I was there--the two camshaft seals (behind the cam gears) and the main crank seal (on the crankshaft behind the crank gear and behind the crankshaft position sensor).

While you are there, clean your throttle body, your idle air control passages, your EGR valve and passages, and your PCV valve.

The other likely source of oil leaking is from your rear main seal, on the crank shaft, where the engine mates with the transmission. I don't know when I will get to mine.

Lucas additive will not likely work. It almost never does in my experience.

I have to agree. I have an 02 Montero Sport that I have gotten really good at changing the alternator. That pesky valve cover leaks right on to it and in a few months bam it goes bad. I'm in the process of tearing this thing down and I want to change every single seal I can to stop the leaks. Currently it has just been way easier to swap out an alternator.

Ol leaks here too: The oil dip stick tube is a 2 piece unit. Mine seems to have lost the seal where the two hales join. I have not changed it yet btw,so no use to ask me how to.

Just adding my 2 cents on the topic. Previous posts on replacing valve cover gaskets and spark plug tube seals are right on topic. Unfortunately main rear seal is a big PITA... You can replace front crankshaft seal if it leaks there. Camshaft seals and the gasket on the cam shaft position censor is also very good candidates for DIY work.

As far as multiple random misfires - I've experienced that condition on my '01 Monero Limited. Replacing spark plugs and wires did not fix the condition. I finally traced the root cause of misfires to leaky valve stem seals. The old seals hardened and were letting in too much oil into combustion chamber. The amount of oil was, as you can imagine, not metered. This would "upset" the fuel/air mixture and result in uneven combustion/power generation. I finally replaced my valve stem seals and the misfires went away. This is not an easy job that is an easy "add on", but it might be worth considering.