[Mag]

So I have a 2002 sentra spec V that is starting to act up.

Six months ago the SES light came on, and it was a misfire on the 3rd cylinder.A day after the SES light went away, so I ignored it.

Recently the Engine shakes violently when I try to start the car, and it cranks 2-5s before it starts, and the SES comes on again. Also there is a loss of coolant. The coolant in the reservoir becomes empty after one month. Other than that everything is good, I don't feel a loss of power and gas mileage is good too.

I brought the car to a shop, the guy said it could be a lot of things, could be a spark plug, coil pack, head gasket, fuel pump, motor mount....

I just replaced the 4 plugs 3 months ago, so they wont be the problem. I don't want to start replacing all these parts until the problem goes away.

So what do you think the problem is? Which part should I replace first? Do you think there are more than one problem?

Thank you

 

[i68k]

your symptoms sound very much like it could be a possible headgasket failure, so first things first, you need to figure out where your coolant is going. how is your oil level, are you losing oil as well? hopefully you dont have the stock precat. all the misfire and unburned fuel are corrosive to the precat. read this, it applies to your vehicle:
http://www.b15sentra.net/forums/showthread.php?t=135241


if your coolant is leaking onto the ground, as long as you keep your oil and coolant level your good to go, just find and fix the leak. as temp gets warmer out, leaks tend to popup. if your coolant is really low, you may get air in the system, which causes the temp needle to rise and drop relatively quickly, purging the air out fixes this.

if your coolant is being burned, or it is mixing into your oil, you have a bad headgasket. you may see some milky stuff in your oil, or oil in your coolant. best way is to do a compression test, then a leakdown test, to check the integrity of the headgasket. if your headgasket is bad, this would explain all your misfires/shakes/fluid loss.

if youre over 100k miles, and you havent replaced/rebuilt your coilpacks, its possible they may be reaching end-of-life, this is a good time to rebuild them. also, you have an 02, you should be priming your fuel before startup, to avoid the long crank times. another possible item is your crank and cam sensors could be missing signals, these are common problems, which cause misfires on startup usually. ever see your rpm gauge drop to zero while driving? these may or may not be the problem, but could cause your symptom if it is not your headgasket, so rule out your headgasket first.

 

[Mag]

I think we have discussed about the header =[ I'm in california, I just don't know what to do.

I think I'm going to replace the headgasket first and see how it goes. So what esle do you sugesst I replace while the engine is apart? I don't want to take the engine apart again for other stuff. Parts aren't expensive, but labor is, so I would like to replace all the old parts as I'm already there.

Thanks i68k, your always there to help people out!

 

[Jeff Kleb]

I have a lowly GXE, but it still seems as though a failed head gasket could be the cause (or perhaps one of the causes) of your problems.

Good luck!!

 

[i68k]

you should check your headgasket before replacing it, do a compression test, then leakdown test to find out if it is your headgasket, so you dont do pointless work.

for the rebuild, you should definately use the 08+ headgasket and headbolts. you should also consider the rebuilding the bottom end as well, particular the piston rings, and if you do the bottom end, you can consider a jwt bsr.

as for your rebuild goals, im not sure what else youll need aside from rebuild kits/greases/cleaners, etc. this would depend on your goal output for the motor. most likely your pistons/rods/etc are still reuseable. but if youre trying for the 300hp, you might want to consider internals now for your rebuild, like s1/c cams, frontier pistons, etc. if you are going above and beyond a normal overhaul, you can visit b15u.com, theres a lot of information about aftermarket internals, what fits, what works best, etc

 

[ten-sec Spec]

you should check your headgasket before replacing it, do a compression test, then leakdown test to find out if it is your headgasket, so you dont do pointless work.

for the rebuild, you should definately use the 08+ headgasket and headbolts. you should also consider the rebuilding the bottom end as well, particular the piston rings, and if you do the bottom end, you can consider a jwt bsr.

as for your rebuild goals, im not sure what else youll need aside from rebuild kits/greases/cleaners, etc. this would depend on your goal output for the motor. most likely your pistons/rods/etc are still reuseable. but if youre trying for the 300hp, you might want to consider internals now for your rebuild, like s1/c cams, frontier pistons, etc. if you are going above and beyond a normal overhaul, you can visit b15u.com, theres a lot of information about aftermarket internals, what fits, what works best, etc

this ^^^^^

 

[Mag]

A shop is willing to replace the head gasket for $500 and a valve job for $500. Is this fair? Should I do the valve job also?

 

[i68k]

im guessing youve done a compression test?

if that is your total, parts+labor cost, that is fairly cheap for a shop. you have an 02, you should also consider your bottom end, as youll most likely need to replace the rings. with all the hard starting, and vibrations, you may need to hone the cylinders also, this way you can examine the pistons, rods, and rest of the bottom end while its apart.

 

[Mag]

This is the cheapest I could find, but I am not sure if they know how to work on the car and get the job done correctly. This shop is really cheap compared to others in south cal, other shops quoted 1000 to 2000 for just replacing the head gasket.

I really need a reliable mechanic....