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Sedans Nissan Altima Nissan Altima Engine Failures
495 messages, Last post on Nov 06, 2009 at 9:53 AM
You are in the Nissan Altima Forum. Your Hosts are pat & karens
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Replying to: aguarino (Feb 14, 2008 3:55 pm)  .......
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Replying to: altimavq35 (Feb 14, 2008 4:16 pm) |
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Replying to: electricdesign (Feb 12, 2008 8:17 pm) I just bought a 2002 Altima in january with 90K miles and in the first week heat stopped working.......after 3 weeks i had the engine problem and thank god i had the extended warranty so they changed the whole engine.........now i am in a doubt.... should i keep the car or not? ............any suggestions.....please help Thanks once again |
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| ASJ YOURSELF THESE QUESTIONS....HOW COMFORTABLE DO YOU FEEL WITH THE CAR? IS THE CATALYTIC CONVERTOR CHANGED? IS THE WARRANTY GOING TO STAND UP FOR ANOTHER ENGINE? DO YOU WANT TO DRIVE IN FEAR OF THIS CAR FAILING YOU AGAIN? ARE THERE ANY OTHER CARS ON THE MARKET THAT YOU YOU WOULD CONSIDER HASELL FREE? IF THE ANSWER IS "YES" TO ANY OF THESE FIND ANOTHER CAR | |
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Replying to: electricdesign (Jan 28, 2008 8:43 pm) Thanks for all the detailed postings and pictures. It’s nice to have you here, knowing the inside of this Nissan engine and the problems with the oil consumption. I have an 02 Altima I purchased new and now has 100,000 miles. Have religiously changed oil and filter between 3-4,000 miles. Have had all the recalls done at the dealership when notified. Car was good to me for five years, requiring routine maintenance and normal wear parts. No significant oil consumption. Mileage got into mid 90’s in late 2007, car started to run rough occasionally, like when there’s condensation in the fuel. Problem was intermittent. Used isopropyl in fuel, but that didn’t fix it. Also, the heater started blowing cool when idle, which made me think low water or weak water pump. Took to my Goodyear mechanic, a good guy and capable mechanic. Looked at computer codes, suggested changing gas cap to clear the codes and radiator cap to see if that improved the heat . He also backflushed the heater core and it got better for a few thousand miles, but it still continued to run rough occasionally for short bursts of time. Then the excess oil consumption started. Maybe 1 quart / 1,000 at first. Took back to Goodyear January, 2008. Replaced PCV valve, but no change in consumption. Back to Goodyear again February, checked water for trace carbon, but zero. Checked oil for presence of water but none. Compression check yielded 149, 151, 150, 149 which he thought was OK (do you agree?). Did leak down test and pressure held good. Pulled the plugs but they were dry, with a little white powder residue. Replaced plugs. Mechanic found oil in line leading from PCV valve so he replaced the valve again in the unlikely event that the new one he installed the first time was bad. Car is now using about 1 quart / 200 miles. Mechanic thinks he should remove valve cover to see if oil return ports are clogged, allowing oil to accumulate in top side of engine, filling to the point where the PCV is located and allowing oil to escape there. I decided to call the local Nissan dealer to ask the Service Manager if this problem has presented with other cars. She indicated that she has seen a couple with excess oil consumption, that the cat was the problem causing the cylinder walls to score. When I asked her if a compression check should confirm her suspicion, she indicated that it may not (what do you think?). I don’t understand this, but she’s the mechanic. She said that if the cat was indeed my problem, a rebuilt engine was the only fix. So, my question to you – is there any merit in pulling the valve cover and checking the oil return ports, or is it a foregone conclusion that I have the dreaded catalytic converter problem? I called Nissan North America to see what they know, but they won’t talk to me until I have the problem diagnosed by their dealer. They said they would entertain Goodwill Assistance, but they needed dealer-provided diagnostics first. Your advice, sir?
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Replying to: scttcrssmn (Feb 28, 2008 11:18 am) Since you seem to have read all my previous posts, I may refer to them during this post. Your oil comsumption of 1 quart in 200 miles is horrendous, a very serious problem. Referring back to my posts about my daughters 2002 Altima 2.5S, I just recently confirmed that you oil consumption now is about 1 quart in about 3000 miles, which is very good. Before I worked on the engine and had the head rebuilt, it was consuming about 1 qt every 1500 miles. I am now supposing that the oil consumption has improved due to having the head rebuilt and having new seals installed on the valve guides. I think that most of the oil was being sucked past the valve guides. The valve guides and springs sit in "pockets" in the head that hold oil, so the top of the valve guide with the seal basically run submersed in motor oil. So it is my belief that the valve guide seals are critical on this engine. Another thing that struck me about your engine was that the cylinder compressions were so close together, that is a good thing. They seemed a little low to me, but otherwise good. The eveness of the readings is very important. Pulling the valve cover is a very simple issue, just a few screws to take out and a few hoses to remove, and a few wires to take loose. Put it back on with a new gasket to prevent leaks. You gave a lot of good information, but here's a few things to closely check. 1. Check the cooling system for any sign of external or internal leaks by doing the following: A. Do you have to add any coolant to the coolant resivor? I have suspisions about your cooling system because of the occasional miss and also because of the heater not heating. It acts like gas bubbles are getting into you cooling system, the gas rises to the top and into the heater hoses, making less or no heat. It possible for gas to seep or leak from the engine into the cooling system, and when that happens a small amount of coolant goes into the cylinder causing a temporary miss in the engine, usually on a cold start and lasts a short time. B. With the engine running, watch the coolant resivor for any trace of bubbles rising inside the tank. I was able to find the combustion leak on my daughters car by doing this. If you see small bubbles that continue to rise in the coolant resivior, it may mean that combustion gas is moving out of the radiator and into the coolant resivior. These head gaskets are very prone to leakage and the heads are very prone to warp if they have ever been overheated. 2. Check out the exhaust system completely. With engine running be sure you get plenty of exhaust gas out the tailpipes. This will confirm that either of the Cats is not clogged up. When the exhaust is cool, disconnect the exhaust pipe from the precat, at the spring connector connections, and inspect the inside of the precat, looking through the bottom opening. You should see a clean unbroken screen. If not, the Cat is shot. If the lower screen is busted or gone, then the material may have moved down the exhaust pipe to the 2nd cat, and you would be getting a service engine soon light that says bad cat. Unbolt the precat and the exhaust manifold assembly from the engine head, hold it upside down over a clean table and shake it to see if anythihng comes out. Nothing should come out. If anything comes out, the cat is probably shot. If the screens are busted in the cat and the material has moved out of the cat, you can clean out both the cats to make sure that they are unplugged. If you put it together this way, the engine will run fine, but the service engine soon light will remain lit, due to the non-performance of the cat. The precat is monitored, the 2nd cat is not monitored. 3. Please post what codes were displayed. 4. The compressions seems fairly good and even, but the only way to tell the condition of the cylinders is to pull the head, and that is a last resort for now. Please do what you can of what I asked in the preceeding and then we will go from there. Good Luck, E.D. in Sunny Florida
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I have been viewing these boards along with Accord forums, closely watching both cars. My wife is purchasing either an Accord 4 cyl or Altima 4 cyl by early April. Reading these forums on both cars is getting us nervous. Is the same engine/cat converter set up still used on 08 4 cyl Altimas or has this engine been motified? We tend to keep our cars long term. It would not suprise me if it was the same set up since these cars would be long out of warranty. Any advise. Thanks
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Replying to: electricdesign (Feb 28, 2008 9:23 pm) I suspected the head gasket at the onset of the oil consumption problem. But I instructed the mechanic to ensure this was the problem before spending the money to replace it. He did the carbon test on the coolant and found zero trace and concluded there was not a head gasket problem. I have added water to the resevoir a couple times in the past weeks, which still points to a head gasket. I will observe for bubbles as you suggets and let you know. The engine has never overheated, at least not yet. Like you, my mechanic also thought it was a good thing that all four cylinders had compression that was +/- 2 PSI of each other. I'm guessing he used a plug gauge, not a threaded guage, which may explain why the readings are lower than expected. I'll confirm his method and let you know. My mechanic also mentioned the importance of valve guide seals. If you remember, he would like to open the valve cover to see if I have a plugged oil return port that is causing the oil to accumulate in the top side and leak out the PCV valve (by the way, what do you think of this theory?). He also indicated that the valve guide seals have an umbrella shape, designed to shed oil coming from the top side, and if the oil was accumulating, the oil would rise under the guide seal and possibly escape. This sounds different than your description of the seals, which you indicate is submerged in oil. Can you say if his theory has merit? I've used him for years and he's very reputable, but perhaps he's not seen this engine torn down like you have. One thing I forgot to mention in the previous post, the engine oil is black, real black. It gets black very quickly, even after a complete change. And it stays black, even though I'm replenishing it with a fresh quart every 200 miles. How difficult is it to get the precat and exhaust manifold unbolted from the head? In the past, I've had bad luck with head bolts - they are usually pretty stuck and I'm afraid of twisting one off. I'd like to disassemble the precat and inspect it for integrity and see if any material inside is loose. And will the 2nd cat disassemble pretty easily? If either cat is shot, I'll have to replace because PA tests annually for emissions. But I don't want to replace the cat if I've already damaged the cylinder walls badly. I guess I could clean the debris out of the cats and run them "empty" for a while to see if that solves my oil consumption problem before replacing with new cats. I'm a weekend mechanic, more of a do-it-yourselfer, and not sure I should attempt to take the cats apart at home. And finally, please help me understand how a bad cat causes cylinder wear and oil consumption. Does a clogged cat cause the exhaust and cat chemicals to back-up into the engine? Does that corrode or wear the cylinder walls? Since I'm now using 1 quart / 200 miles, does that sound to you like it's too late to save it? And if I'm burning 1 quart / 200 miles, whether it's from scored cylinders, bad head gasket, or leaky valve guide seals, why don't I have a sooty black carbon buildup at the tail pipe? Thanks for taking the time to read. Hope your weather is better in FL than here in NW PA.
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Replying to: boating (Feb 29, 2008 8:02 am) 1, not every altima, actually a pretty small amount, suffer from the oil consumption problem. 2. It is almost exclusive to the 2002 model year 3. The QR25DE engine was first used in 2002. There were, like with anything else new, some issues with it. those issues have been taken care of. 4. then engine itself is solid. its the cat, actually the precat, that was causing the problems. If your not really interested in the altima, or are just looking for a reason not to buy one, then don't get one. you'll just worry about it all the time. But, If you really like the car, and are really interested in one; I wouldn't let the problems with the first year of the 2002-2006 (3rd generation) redesign featuring a brand new never before used engine keep you from getting one. |
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Replying to: scttcrssmn (Feb 29, 2008 10:48 am) I'm really busy tonight, so I'll answer the rest of your questions tomorrow. Many of the questions that you ask are answered in my previous posts from #75 until now. I'll address just one issue right now, the valve seals, and this could apply to most engines, but especially to this one. Your mechanic is saying the same thing I said, it's just your interpretation that is different. Yes the valve seals are unbrella shaped, I knew that, and 99.9% of them are, because they fit over and cover the end of the valve guide like an umbrella, this is a very normal and usual fit. But imagine if an umbrella gets submersed in water, it wont do you any good, you'll still get wet! In other words, if you are under water, an umbrella won't do you any good, unless it's seal tight around you. And as I said before, the valves, guides, springs & seals are located in pockets in the head, so the valve seal runs largely under oil, and does shed oil that falls from above it, but most of the oil is running down the sides of the pocket down to the valve guide. This valve guide depends more on the seal itself fitting tightly onto the stem. As the valve seal gets old from age and hardens from the heat, the valve stem slips up and down on the seal and the seal between the valve and valve seal becomes less of a good seal, it gets loose. Once oil can leak between the valve and the valve seal, it can reach the valve guide where vaccum around the intake valve can suck some oil through the valve guide and into the combustion chamber on the intake stroke. It takes a special tool to remove the valve springs from the head, that why it needs to be done by a professional machine shop. The bottom line is you may need valve seals, and the best way to do that is to pll the head off and get it professionally rebuilt like I had mine done, then there is no more problem. I suppose that you looked at all the pictures of the teardown and rebuild of the engine that I linked in previous posts. You can also download those pictures, they will be very helpful if you need to tear down your engine. But before tearing down anything, we need to do all the diagnostics first. I'll answer more later. Yes, be sure the oil drain pockets in the head are clear and open. More to come soon. E.D. in Sunny Florida
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