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97 Nissan Altima RPMs too high
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bankshot
Novice
Jul 13, 2009, 10:38 AM
Post #1 of 5
(4947 views)
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97 Nissan Altima RPMs too high
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I have a 97 Altima with auto transmission. 128K miles. Over the past 6 months the RPMs have been inconsistent at higher speeds. Use to be that at 55 mph it would be about 1800-2000 RPM when the overdrive kicked in. Now it is at 2500 RPM at 55 mph and the overdrive is kicked in (it is still doing 3 shifts and then shifting to overdrive as it always did). Problem is that at 65 mph it is at 3000 RPM and to sustain that on a climb, it goes to over 3500+ RPM for extended time and overheats the engine. I have cleaned the throttle body thoroughly, had the transmission checked and all looks good there, also had the computer codes checked for any errors even though the check engine light is not on. No error codes in the computer. My friend who has done some mechanic work thinks the torque converter is not working correctly and thinks it might just be a sensor not working correctly to kick it in appropriately. Any ideas on this? The Nissan dealer wants $95 to diagnose it and I'm not too confident they'll figure it out either.
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Loren Champlain Sr
Veteran
/ Moderator
Jul 13, 2009, 10:41 AM
Post #2 of 5
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Re: 97 Nissan Altima RPMs too high
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bankshot; I'd agree with your friend. Doesn't sound like it is actually going into lock up. But, as far as the overheating, it shouldn't be getting hot at only 3000 rpm.
Loren
SW Washington
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bankshot
Novice
Jul 13, 2009, 10:46 AM
Post #3 of 5
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Re: 97 Nissan Altima RPMs too high
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It doesn't overheat at 3000 rpm, only when I have a long climb at 65 mph plus and try to sustain that and it gets to 3500 rpm or higher for quite some time, then it overheats.
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Loren Champlain Sr
Veteran
/ Moderator
Jul 13, 2009, 10:50 AM
Post #4 of 5
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Re: 97 Nissan Altima RPMs too high
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bankshot; Still shouldn't be overheating. I'd address the transmission problem, first, but you may be having cooling system issues as well that weren't apparent before. With the symptoms, the radiator, water pump, and thermostat would be suspect.
Loren
SW Washington
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wsmith82
New User
Aug 18, 2009, 10:05 AM
Post #5 of 5
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Re: 97 Nissan Altima RPMs too high
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bankshot,
lets start with your shifting issue - this could be a number of things
1. Loose slip rings on tranny - easy way to check this is to start the car up after it's cooled down to 70 degrees F or below. if the car seems to require more throttle to move the same distance as when it's warm then you will need to have the tranny dropped and have the slip rings tightened/replaced (about $1k at cottman).
2. Transmission overheating - as with all things, heat is your enemy, ESPECIALLY with transmissions. you may want to look into an aftermarket transmission oil cooler, JCWhitney sells them online for around $50 and takes about 45 min to an hour to install.
3. Bad sensor or solenoid - usually shows with ECM error codes, but may need to drop the tranny to verify. this could include a bad solenoid or just a bad wire to it.
Now, to touch on your overheating issue. The transmission could be causing the problem. When your tranny isn't running correctly, it gets hot. This can than put a strain on your engine by trying to pull too much power, which ultimately overheats it. Engines are pretty basic things and when they overheat it can only be from so many issues. They are: Bad water pump, missing belts, clogged/cracked radiator, clogged coolant lines, blown head gasket, bad thermostat, or BAD TRANSMISSION.
The good news is these are all easy to test. If your car is losing coolant than it's a bad water pump, radiator, or head gasket. If your not leaking fluid but overheating, it could be a missing water pump belt, clogged radiator/coolant lines, stuck thermostat, or a bad tranny.
obviously, start with the cheaper things and work your way up.
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