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Head gaskets and exhaust studs on a 91 4WD


darkflounder
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First, a quick introduction. Not only am I new to this board, I'm new to Pathfinders. Just got mine this past weekend.

 

Girlfriend had the above mentioned 91 4WD automatic. Had an exhaust leak and wouldn't pass CA smog, so it's been parked in her apartment complex parking space (covered) for the past two years. My car got totaled in an accident, and she offered me the Pathfinder for free. Just had to pay the past registration (never had a non-op) and get it running.

 

Dropped in a new battery this past weekend and drove it home (with the legal temp op permit), about a 35 mile trip. Apart from the exhaust leak, it drove very well.

 

Got it home and realized that it wasn't the cracked exhaust manifold as I thought, but a busted exhaust stud. After some searching, I found this board and realized that it's a common malady of the Pathys (as well as the non-functioning fuel/heat gauge and the power locks unlocking themselves).

 

So, here's my plan. Gonna take the top-end of the engine apart. Replace the exhaust studs, the timing belt and all the top-end gaskets. I'm not familiar with working on the Pathfinder, so is there anything I should be on the look out for? Any tricks or tips?

 

I figure after the back registration, parts and tools (need a new torque wrench anyway), I'll have a grand into it. It's got almost brand new tires, very good interior (just needs a bit of cleaning), no rust (at least, that I've found yet) and about 150k miles. I'm assuming I got a good deal, but I'd like some validation.

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if you're tearing the heads all the way down...make sure u do valve seals and both cam seals...probably would want to replace or at least reseat the valves (lap them in)...for the head bolts you'll need a 10mm hex head socket to put on a 3/8 or 1/2" drive especially for retorquing them...i suggest a scotchbrite on a drill to remove the head gasket residue (don't use any metalic abrasive pad...thats bad for aluminum heads b/c it will impregnate it with that material and could cause problems)...replace all seals...do a water pump while your there...I cant remember if the 91 is MPFI or TBI...if its TBI the job is much easier...MPFI is a lil more work b/c the intake is awkward...hmm do a tstat and all hoses especially that one hose that tends to bust and then its a PITA to replace later (i havent had this happen but i think slick has a write up on this)...aside from the head bolts there are 2 cross sloted 10mm bolts that help hold the heads on...when you have all the head bolts out and it breaks loose and you cant get it off these are still in place...take them out before forcing it or you could have a bad day

 

if you look further down in the past 2 weeks i have a quick youtube video on removing studs which if you installed a body lift or just jacked the truck up and removed the tire and fender liner you could probably do without doing a full top end rebuild...i assume you will burn the gas in the tank out and after that i would suggest a fuel filter replacement...you'll also probably want to take that manifold nad have it machined back to true since it will be warped or buy a set of pacesetters (i think they have the CA smog stamp...

 

Where in CA are you...if youre close to 93505 I could possibly give you a hand if you need it

 

finally :welcome: and others will chime in...also someone will chime in about search...its a brute to use but with practice it gets better...glad to have ya around and hope ya get it all worked out

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Welcome to the boards, I just finished up the same exact job about a week ago. The fuel rail is a bit of a pain when trying to pull the intake off, kind of a catch 22, one won't come off till the other and vise versa. Hardest time I had was actually getting some of the coolant hose's off for the heater. Expect to break some vacuum lines and find some cracked hoses. I had an easier time pulling the starter completely out to get at the flywheel when you go to take the crank pulley off. I can't really think of any good tips at the moment, if I do I'll post them up. Oh and if you haven't yet, get your self a tap and die set. Cleaning up the threads will make your life a lot easier when it gets to reassembly. Good luck and let us know how it goes!

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if you look further down in the past 2 weeks i have a quick youtube video on removing studs which if you installed a body lift or just jacked the truck up and removed the tire and fender liner you could probably do without doing a full top end rebuild...i assume you will burn the gas in the tank out and after that i would suggest a fuel filter replacement...you'll also probably want to take that manifold nad have it machined back to true since it will be warped or buy a set of pacesetters (i think they have the CA smog stamp...

It's currently stock height, but I'll look into pulling out the fender liner. If I can get a good angle on the head, I might end up going that route and save myself some time. I did find out that the girlfriend had the timing belt replaced within the last 30k miles or so. So, I should be ok on that for the time being. Maybe I'll deal with tearing down the top end when I can get the heads rebuild.

 

Where in CA are you...if youre close to 93505 I could possibly give you a hand if you need it

I see you're in Cal City. I grew up in Ridgecrest, but right now, I'm up in the bay area (San Jose). Hope I can find some good 4x trails around here like I had down in the desert.

Edited by darkflounder
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I see you're in Cal City. I grew up in Ridgecrest, but right now, I'm up in the bay area (San Jose). Hope I can find some good 4x trails around here like I had down in the desert.

there are a couple members by you (including me) froggy is in SJ, andrew (sc88) is in santa cruz, and i am in the bowels of hell (near stockton). i could help you out.

if the t-belt was changed in the last 30k miles, leave things alone, also, my truck had 6 out of the 11 broken studs and still passed...... can you post the smog results, betcha we can get it to pass.....

depending how bad the studs are broken (ie: something to grab hold of or snapped off flush), is to how nasty a job it can be. must admit, these are the times a BL is handy lols.

also, as far as wheelin, yeah, we can show you a few great spots. :beer:

 

 

 

*edit* i've done said stud job 3 times..... and have all the tools you'll ever need lol

 

 

also, mark lives about 1 mile from me, here's his stud write up http://www.nissanpathfinders.net/forum/index.php?showtopic=16196

Edited by Slick
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OK, I'm rapidly running out of motivation to take the top-end apart.

 

So, anybody got any tips on getting the left-hand exhaust manifold out of the vehicle? I can't figure out how to get at the inside two nuts on the manifold flange. Can't seem to get at them from above, and the axle is blocking them from underneath. Maybe from the side, through the fender liner?

 

At least the two broken studs are at the front of the engine, so they should be easier to get to. They do appear to be snapped flush with the block, but it's difficult to see with the manifold still in the way.

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When I replaced my manifolds and the six broken studs I had, I removed the front tires and the rubber fender liners. Made things a lot easier. I also used 12" long drill bits (one 1/8" pilot, the other just under the 8mm stud diameter) to drill out the broken studs. Everything I put back on was stainless steel except for the new manifolds. I made the entire exhaust from 2" stainless downpipes> into> 2.5" main exhaust. Used stainless sheet metal clamps instead of u-clamps, etc.

Edited by Rallybob
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yes, take the wheel off. much easier. also, while yer fixin studs, make sure to upgrade them so this doesn't happen again. here's the p/n's for everything you need to change them

 

Nissan 14037-V5005 Lock Washer for manifold studs 1.88ea

Nissan 14039-W1500 Nuts for manifold studs .65ea

Nissan 14065-V5004 Manifold Studs 3.21ea

 

 

you're in CA so pricing should be same as mine.

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thanks slick...I needed those PNs I used napa studs on my 87 and had no issues with them but the napa in cal city doesnt have studs big enough...

 

At least the two broken studs are at the front of the engine, so they should be easier to get to. They do appear to be snapped flush with the block, but it's difficult to see with the manifold still in the way.

 

hmm i want to say we used a wrench to break them loose and then some extensions with a swivel through the fenderwell but that was over 5 or 6 years ago...the last time i pulled any headers or exhaust the engine was out of the truck

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OK, I'm rapidly running out of motivation to take the top-end apart.

At most, do a compression test and odds are everything is fine. I wouldn't touch the heads unless there is a problem or you are doing serious engine upgrades...

 

B

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yes, take the wheel off. much easier. also, while yer fixin studs, make sure to upgrade them so this doesn't happen again. here's the p/n's for everything you need to change them

 

Nissan 14037-V5005 Lock Washer for manifold studs 1.88ea

Nissan 14039-W1500 Nuts for manifold studs .65ea

Nissan 14065-V5004 Manifold Studs 3.21ea

you're in CA so pricing should be same as mine.

 

Thanks for the part numbers, but the prices were different at my dealer. Granted, it's in the heart of the Silicon Valley, so I'm not surprised.

 

Nissan 14037-V5005 Lock Washer for manifold studs 3.76ea

Nissan 14039-W1500 Nuts for manifold studs 2.32ea

Nissan 14065-V5004 Manifold Studs 5.18ea

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