Qctech

The MAF can be cleaned with electrical contact cleaner spray before wasting money on a new one. What you want to check first is all your vaccum lines for leaks and then remove the inlet to the throttle body and see how dirty yout TB is. Sometimes, carefully cleaning your TB will do away with the hesitation you are talking about.

I rechecked mine. It is totally doable without removing anything else and will just take your time and to have all the gasket (1) and o-rings(2) available. Empty the radiator and lines. Loose both lines completely at the oil cooler, then take the main center bolt out. You can them pull the oil cooler out. Once you do that and remove the oil cooler , there are 2 allen type bolts out side and one inside that you have to remove to get the base out and change the rear gasket. Clean , put the gasket and o-ring and reinstall. Torque as per the manual, reconnect the lines, put coolant in your radiator and you should be good to go. You should be able to do it in one hour, 3 hours max.

Well, for me it was easy because I removed the oil pan(which involves removing the transmission and almost all the front suspension) and I removed the seals with the pan out. I had read of people changing them in site. It is difficult due to the small space but is not impossible. It have a main bolt running thru it, then 3 additional allen bolts(2 outside and one inside once you remove the main bolt.) You need the service manual for this to properly appreciate where the bolts are. You have to drain your radiator first because when you disconnect the 2 lines it will rain on you. Your smell of burning oil can be because of this, because as long as it is slowly leaking , it will go thru your frame and end up at some point getting to your exhaust and it will burn there. I dont know what tools you have available so it will all depend on that and your patience and skill to dedicate 1-3 hours to it. I think it is worth the time and you will eliminate another leak.There are 3 seals to change. One that goes to the base, one big o-ring and a smaller one. Ill try to find an illustration to post for you.

Well, synthetic helps up to a point. But if the sludge have reached the piston rings, it is kind of harder to remove from them and will take a few flushes to clean it completely. I think you should still try the seafoam or any of the other flushes I mentioned if you still have missing oil. Seafoam is the milder and safer flush. If you are not inclined to do a full engine swap I would not recommend to do the full diesel fuel flush. I have done that when I was willing and able to do and engine change if that failed. The automatic transmission oil mixed with regular oil flush is also milder and could be done relatively safely. Take in mind that any flush have the capacity of dislodging sludge material that could block something else(like an internal oil passage), so that is why with flushes you should go slow, take your time and do it several times at certain intervals. You should also download the manual for your vehicle and check the part about crankcase gases ventilation and check that all those lines are not blocked. In other cars(like toyota corolla), I have found that when the vent of the crankcase get clogged with sludge, those gases stay in the engine and cook the oil(aluminum is a heat sponge), then that cooked oil is what becomes sludge. Have you even used frying oil a few times and it starts becoming black and then solidify in chunks??? That is exactly what happens inside your engine when the crancase can not breathe this gases out. It becomes an oil pressure cooker and something have to give. I keep mentioning the compression test because that will tell you if your piston rings are worn out to the point of leaking, in which case there is nothing more to do but to measure the cylinders and install oversized rings. You could relatively easy remove the heads, measure the cylinders , do a light honing with a drill and attachment and reinstall bigger rings without touching the crankcase area. Assuming of course there is nothing wrong with your crankcase bearings.

Thanks for this post. it helped me a lot.

Hey thanks. I think you are referring to the carcomplaints.com website. The major thing I read there about the 2005 was the transmission failing due to the bad design of the transmission cooler inside the water radiator. This is not new. Honda odysseys had that same problem for years and other makers still do. It baffles me that most people can not buy a 50 dollars or less external cooler and just install it and connect the 2 hydraulic lines and have what otherwise is a good truck with a powerful engine. If I find a cheap , failed transmission 2005 I will buy it , fix it and keep it. Mine turned to be be a 2003.

Hey guys, thanks for the welcome. The pathfinder I bought was shown as a 2005 on the creaiglist ad, but it was a mistake. When I finally went to check , it is a 2003 LE , and I bought it anyway. I already changed the rear main oil seal with all the associated pains of lowering the transmission ,exhaust, forward differential,cv joints , front suspension ,etc. The only thing now is a little problem with the idle that it had already when I bought it, and the fuel level that is not working on the gauge. I will get into those problems next. I just also found out that it have the problem with the passenger side strut tower corrosion. It seem as per the service bulletin that is non repairable(for nissan standards), but it is repairable for me if I decide to do so. I got this truck cheap , so I could give it to the dealer and start the painful process of dealing with Morley and try to get the blue book price for it, or just fix it myself with better reinforcement than the silly patch nissan uses and just keep it. So far I am thinking about keeping it. There is a 2001 near me being sold cheap also, but after reading all the problems the 2001 have with the IACV , I am rethinking about it.

Your exhaust is designed by the manufacturer to give the proper pressure feedback to the engine to maintain certain compression/fuel mileage. It is a complex system and explaining how exactly it works would be out of the scope of this answer. What you have to know is that an improper exhaust system will affect your milleage negatively and in extreme cases even your engine, because it may not be create the correct backpressure and cause problems in you pistons. And no , it is not a dumb question. Proper exhaust design and performance is an engineering task. The only fix on your case would be to buy a new compatible muffler and have it installed.

Do a compression check as others have suggested. I read somewhere of a few cases of engine sludge.If this has happened, your piston rings will stick and probably let oil pass thru them in a certain position. Your oil will burn slowly if it is in only a few cylinders. You could do some sort of internal cleaning. There are several ways, from seafoam to using a quart of transmission oil on you engine oil to using diesel instead of oil and doing a 20 minute run and then flush. If your pistons sludge get unclogged you might solve your problem. Also the oil cooler next to the oil pan leaks unto the front crossmember and goes to the frame before dripping to the ground so you might have all of your truck covered in oil underneath and not a drop in the floor. I have cleaned several engines with both mechanical and liquid flushes and they have not only survived but eliminated the missing oil problem. Also check if your engine is breating properly and the crankcase gases are exiting properly, which many times create the sludge when they dont get exhausted.

The oil cooler is on the engine, attached to the oil pan. It is a water to oil cooler. Water from the radiator gets into this little donut , that carries oil from the oil pan to cool it and then return to the engine. It have 3 seals and they become crackers and start leaking. That oil cooler gets all black covered in oil and just looks like part of the oil pan but is not. When you clean it is shiny aluminum color. When it leaks is slow and the oil gets right into the front engine cross member and goes down the whole frame, making it less traceable. There is also a trasmission cooler inside the water radiator. It is a tube that just goes thru the lower part of the radiator. When it leaks internally, it mixes water with your transmission fluid and kills the transmission, specially in the 2005 and newer models. The engine oil cooler is in both auto and manual. The transmission cooler I think is only on the auto. Hope this helps.

Are you refering to what is called in the manual as the stabilizer connecting rod? Because even as they have a hex key, they also have nuts on both sides. I completely disconnected and retorqued them with no problems or I might be confusing it with something else. You should be able to torque them just using 2 wrenches and no hex key.

I am new to the forums, getting a 2005 pathfinder and willing to learn more about it. Thanks for the great forum.