99 QX4 Bad Oil Leak and Air Issue

[Huskyhunter]

So I just bought this 1999 QX4 from an auto dealer near me this last weekend. It's in tip top condition on the inside and the paint is good enough. I didn't notice when I bought it that it had an oil leak. I cleaned the engine bay and I couldn't tell where it was coming from. It's leaking from somewhere on the left side of engine (standing in front of the car) either underneath the alternator or right next to it. The alternator is clean, it also looks like its leaking from in the middle and just getting everywhere. That is the main issue, another issue I have is with the heat/AC in the cabin. When the car is cold the air blows like a tornado, but when the car warms up it just stops working. I've looked at some things for this and it seems like it might be the Blower Motor Control Module / Resistor down by the blower motor. Any advice or help is appreciated.

[McFalconPunch]

The oil leak is probably the oil cooler behind the oil filter. Its a common issue on the 3.5/4.0L engines. I can't recall if the 3.3L has the same setup, but it would be a good place to start. What you can do is clean the areas down with brake cleaner, and check it after a couple days to pinpoint the leak.

[onespiritbrain]

Valve cover? My passenger side valve cover on my 01 3.3L Frontier leaked like a sieve. Easy enough to replace the gasket.. driver side is not the same story, there's lots more to take off, but still manageable. I opted to tighten the driver side valve cover in as many places as I could reach even though it wasn't leaking... don't do that.. started leaking 10 times worse than the passenger side.

 

Anyway.. is the oil leaking down on to the exhaust manifold? Does light smoke occasionally come from the engine bay and your heat/AC air smell like burning oil with recycle is off?

 

For the heater/AC air issue, I'd do the climate control diagnostic. I'll find it in the FSM for you..

On page 357; section "HA", start the "self diagnosis mode". Then go to page 383 for the blower motor.

 

 

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[Huskyhunter]

Valve cover? My passenger side valve cover on my 01 3.3L Frontier leaked like a sieve. Easy enough to replace the gasket.. driver side is not the same story, there's lots more to take off, but still manageable. I opted to tighten the driver side valve cover in as many places as I could reach even though it wasn't leaking... don't do that.. started leaking 10 times worse than the passenger side.

 

Anyway.. is the oil leaking down on to the exhaust manifold? Does light smoke occasionally come from the engine bay and your heat/AC air smell like burning oil with recycle is off?

 

For the heater/AC air issue, I'd do the climate control diagnostic. I'll find it in the FSM for you..

On page 357; section "HA", start the "self diagnosis mode". Then go to page 383 for the blower motor.

 

 

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It doesn't smoke off the manifold, it does smell pretty bad after highway driving but i haven't noticed any smoke. I will take a look at the valve covers but I think it may be lower than that because the top half of the engine is pretty clean.