I have an 88 Sentra that I would like to get fixed if it isn't too costly. I was driving home and as I got in the turn lane and decelerated all of the sudden a very loud tapping noise started when I downshifted (it sounded like the lifters to me). After I made the turn, the engine had no power to speak of and would not rev very high (no tach, so I don't know what the RPMs were). I was only a couple of blocks from home, so I limped into my driveway, where it sits now.
My first thought was the timing belt, and from what I have read on this forum, if that is the case, then more than likely my valves are bent.
Is this worth trying to fix? It has almost 175k miles on it. The timing belt has never been changed on it. If the valves are trash, what does a new head cost (ballpark), and how hard is it to change. I am fairly inept when it comes to working on cars.
Location: Car is Richmond, VA but I'm in Orlando, FL
Posts: 450
could've been the timing belt, but it shouldnt run at all if it broke completely. If it slipped a couple notches you could have some power (minimal) and the tapping noise would be the piston/valve interferance. At this point your valves are probably bent if that is the case. It'd be pretty labor intesive to replace those and the timing belt. Even though parts are fairly cheap, excpect like an 8 hour labor charge.
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I'm with 87SXS12. A failed rod bearing will knock and rob your engine of power. You'll step on the gas and it just won't want to go. Eventually the engine will seize.
A compression test will tell you which, if any, cylinders have bent valves. You'll need a compression tester. You can get one at a parts store for around $20. Good enough for the amount of use you need it for.
Check the oil, if it looks grey and smears grey in your fingers you've wasted a rod bearing and it's all ground up and in your oil....also getting passed around all the other moving parts in the engine.
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to do a compression test you need a compression gauge(any auto parts store should have one and might even rent you one), it checks the compression of each cylinder to see what/where your problem is, but I don't know if you should do this if your engine makes alot of noise when running, you might end up messing it up even more. Maybe a leakdown test would be better since the engine doesn't have to be running, and it will tell you a little more about where the problem may be. Those are the only two things that I can think of to do without actually tearing into the engine. Well you could also see if the cam timing is off, without going too far into dissassebly, you will need to take off the top half of the timing belt cover which also involves unbolting the pass. side motor mount and alternator bracket but it's not as painful as it sounds. Get the engine to top dead center by lining up the first timing mark on the crank pulley and see if your cam pulley marks are lined up like they should be. Here's a pic of the cam pulley at TDC- http://community.webshots.com/photo/...93868992sCViSG .
Thanks for all of the suggestions. It sounds like whatever the problem is, it isn't going to be easy for a novice to deal with. At this point, I'm not sure that it is worth tackling.
to do a compression test you need a compression gauge(any auto parts store should have one and might even rent you one), it checks the compression of each cylinder to see what/where your problem is, but I don't know if you should do this if your engine makes alot of noise when running, you might end up messing it up even more. Maybe a leakdown test would be better since the engine doesn't have to be running, and it will tell you a little more about where the problem may be. Those are the only two things that I can think of to do without actually tearing into the engine. Well you could also see if the cam timing is off, without going too far into dissassebly, you will need to take off the top half of the timing belt cover which also involves unbolting the pass. side motor mount and alternator bracket but it's not as painful as it sounds. Get the engine to top dead center by lining up the first timing mark on the crank pulley and see if your cam pulley marks are lined up like they should be. Here's a pic of the cam pulley at TDC- http://community.webshots.com/photo/...93868992sCViSG .
whoever heard of doing a compression test with engine running??
I have an 88 Sentra that I would like to get fixed if it isn't too costly. I was driving home and as I got in the turn lane and decelerated all of the sudden a very loud tapping noise started when I downshifted (it sounded like the lifters to me). After I made the turn, the engine had no power to speak of and would not rev very high (no tach, so I don't know what the RPMs were). I was only a couple of blocks from home, so I limped into my driveway, where it sits now.
My first thought was the timing belt, and from what I have read on this forum, if that is the case, then more than likely my valves are bent.
Is this worth trying to fix? It has almost 175k miles on it. The timing belt has never been changed on it. If the valves are trash, what does a new head cost (ballpark), and how hard is it to change. I am fairly inept when it comes to working on cars.
Thanks for your help.
go to auto parts store buy a compression guage..come home. raise hood remove all four plugs, put compression guage in no 1 cyl and crank engine. record reading, and so on down the line, if you have a dead cylinder it will show up on the pressure reading. good compression is over 120psi.
go to auto parts store buy a compression guage..come home. raise hood remove all four plugs, put compression guage in no 1 cyl and crank engine. record reading, and so on down the line, if you have a dead cylinder it will show up on the pressure reading. good compression is over 120psi.
hey! unplug coil wire. You dont want to get zapped!! and 120 is very very low. 120 is to low. shouldn't be under 160. 150 at the very least, as an oil burner. hehe, i have 185 on all four holes
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