Bought a 2003 montero limited today, inspected the car and it seemed fine. Oil was full, coolant was full, was not mixing.. Valve cover gasket looked to be leaking, no big deal. Test drove it and there seemed to be no issues. I went under and checked the bottom of the engine as best I could before signing the papers and was off on my way.

About 15 minutes into my 40 mile drive home I noticed the temperature start spiking up past normal & dropping back down. I pulled over in the middle of the highway in downtown chicago (very fun) and checked everything out.
the car was dripping oil towards the firewall (about 1 drop per 5 seconds) and smoking around the exhaust manifold on the passanger side. Started the car back up and it sounded perfectly fine, got off on the next exit and pulled over onto a sidewalk. Called the insurance company, they wanted $500 for a tow home. Cops showed up and all that..
I ended up leaving it in a parking garage right next to where I was pulled over.

Flash forward 2 hours & numerous phone calls to u-haul to try and rent a trailer which they could not locate for the life of them. I called a tow truck company by my house and they were willing to get the car home for much cheaper than $500 so I had no choice since chicago parking garage rates are rediculous.

Now the car is home and I was able to check it out more. I pulled the following codes:
p0171 = too lean cylinders 1-4
p0431 = drop in catalyst activity bank 2
p0155 = o2 sensor bank 2 sensor 1
p0161= o2 sensor bank 2 sensor 2
p0456 = evap system leak
p0117 = engine temp sensor low input

topped off the coolant (4 water bottles full) and noticed its leaking BAD.. I cant see where its coming from but from underneath it streams down towards the front of the oil pan.

this is going to be a FUN FUN FUN project but if anyone knows common areas for coolant leaks on this 3.8 L engine please let me know. I appreciate any thoughts or inputs.

 

Sorry you are having trouble. Don't despair, sh*t happens. The items on the front of the engine that may cause coolant leaks are thermostat housing, water pump, front crossover pipe and the radiator hoses. There are multiple gaskets there - thermostat housing cover, thermostat to water pump, water pump to engine, etc. Any one of those could have gone bad. There are also several small hoses running coolant to and from the throttle body on top of the engine, but you would see them leaking.

Two ways to diagnose where the leak is coming form. If, as you say - it leaks without pressuring the system, open the radiator cap and keep pouring water in until you can trace where the leak is. You can just use water for now instead of coolant until you get it patched - less mess to deal with and you don't waste coolant. If the leak does not show when engine does not run - top of radiator, close radiator cap, start the engine and watch where it starts to leak once system builds up temperature and pressure.

The codes you have can all be connected to the fact that your engine was not getting right temp readings when it was running. Focus on fixing leak first. Then, reset the codes and deal with them later if they come on again.

 

Tried to update this thread, not sure why but nothing posts.... found the coolant leak, fixed the oil leak. here's a youtube video for help
-Oil leak = camshaft O-ring
-Coolant leak = bad water pump (waiting on parts)
-Replacing front main crankshaft seal + camshaft seals for good measure

 

Firstly, your montero is beautiful! And yeah mine has the same oil leak from both o rings.. mechanic says cost is $800 just for that. And the temperature seems to spike from time to time

 

Wow! that sucks, but glad it worked out for you. I've been nursing my 2001 along for years. That Montero is killer looking. I haven't seen many in black.
Awesome choice!
Thanks for the video. Nice job and the format with subtitles is great.
If you have any CEL codes later on, especially EGR, search my nick. I've battled and won the PO400 issue twice.

 

The rear cam O rings on my truck got replaced when it was time to do the timing belt replacement, the drivers side was starting to leak so it wasn't to messy. But if you are mechanically inclined you can diy this.

 

Rear Cam Seal O-ring leaks- FIXED! - 4x4Wire TrailTalk

The pics. don't work anymore but the idea is there, this link is for a 3.0 but should be similar.