Intake Manifold stuck

[seintg123]

I'm trying to remove the lower intake manifold, but it is stuck to the block. I've already removed the upper plenum, fuel rail, hoses, and the 8 mounting bolts (4 outer bolts, and 4 inner nuts). I can't pry the manifold off. I need some advice. I have a 1998 Pathfinder with 3.3L V6.

[ARKQX33V6]

What's happening?

[seintg123]

Nothing. I've removed every connection that I can see, and I've sprayed the 4 inner guide bolts with lots of lubricant, but the manifold will not budge.

[ARKQX33V6]

Do you have the manual, and describe what you have in front of you, are the heads on or off, how deep are you going, what is the final outcome that you are doing?

[seintg123]

I'm trying to remove the lower plenum (intake manifold). I've removed the upper plenum and gasket. I've removed the fuel rail. The lower plenum is still there, w/ 2 gaskets underneath, attached to the engine block. I'm trying to replace the knock sensor.

[seintg123]

Here is a link to a few pics.


Sorry the image isn't clearer. The lower plenum is the thing with the blue rags stuffed into the holes. That's what I'm trying to remove to get at the knock sensor.

[Towncivilian]

Fixed your images for you. They're very small though.

[seintg123]

Thank You. I'm still trying to figure out how to get images on this forum. Here is another link to the same pics. Hopefully they'll be bigger this time.

[ARKQX33V6]

seintg123, if you have a service manual can you scan the blow up page that shows exactly what you have ( the blue rags stuffed in) and send me a copy.

I have blow your pix to 300 % but detail is missing.

Al

[email protected]

[seintg123]

Here are pics of a blow up diagram from the shop manual




The object (intake manifold) in the center of the close up pic, is what I have the blue rags stuffed into

[Pathfound49]

Odds are that a previous owner had the intake manifold off before you owned it and decided to use a permatex gasket maker in place of a factory gasket when re-installing the manifold. I made that mistake when replacing a fuel injector on my '91 Maxima. Needless to say, it was a real pain in the butt to get off when another injector crapped the bed.

[ARKQX33V6]

Did you get my e mail?

[seintg123]

I got it, thanks. I'll give it a try and let you know

[ARKQX33V6]

Just be careful with that mallet, a weighted dense lead, lead fill, or dense rubber may just do the trick, you are looking to release the gasket between them, then use a sharp edge carefully. Dig it out without harming the metal either side of the gasket.

It may need a soaking to soften the gasket and adhesive.

[DARTHANIAN]

I realize this is an old thread. Hoping OP can post back on the outcome.

I've got the same issue going. I've done everything i can think of to release this lower intake manifold. I've hit it, pried with bars been spraying with penetrant, i even went and bought a 2ton engine hoist all it did was lift the front of the car. I am thinking the studs have electolysed to the intake manifold. Sunday, while i had the hoist with pressure on it, i heated up the intake and studs, still will not release from the engine. I'm going to keep scouring the internet but i am and looking for any other thoughts or ideas. My next thought is to try and drill along the studs with an 1/8 drill. I bought a bolt/stud extactor set but smallest size was to large and wouldn't grab the stud, double nutting wasn't successful. Going to search for a stud remover that will fit as well. This is my sons car he purchased all i want to do is replace the stupid knock sensor. I don't want to but i've also considered doing the relocation hack, though trying to avoid since i've already got it torn down, and it's not a proper repair.

97 Pathfinder SE VG33E engine.

[Rogue One]

I realize this is an old thread. Hoping OP can post back on the outcome.

Unfortunately seintg123 hasn't logged in for a full ten years, so there's a good chance that he won't reply.

[A1218]

I realize this is an old thread. Hoping OP can post back on the outcome.

I've got the same issue going. I've done everything i can think of to release this lower intake manifold. I've hit it, pried with bars been spraying with penetrant, i even went and bought a 2ton engine hoist all it did was lift the front of the car. I am thinking the studs have electolysed to the intake manifold. Sunday, while i had the hoist with pressure on it, i heated up the intake and studs, still will not release from the engine. I'm going to keep scouring the internet but i am and looking for any other thoughts or ideas. My next thought is to try and drill along the studs with an 1/8 drill. I bought a bolt/stud extactor set but smallest size was to large and wouldn't grab the stud, double nutting wasn't successful. Going to search for a stud remover that will fit as well. This is my sons car he purchased all i want to do is replace the stupid knock sensor. I don't want to but i've also considered doing the relocation hack, though trying to avoid since i've already got it torn down, and it's not a proper repair.

97 Pathfinder SE VG33E engine.

I recently did this job, along with injectors and some other components done while everything was off.

There is a 10 or 12 mm bolt that goes through somewhere around the timing cover at the front and into the neck area of the lower intake. If I can remember correctly…

It is there and you may not notice it. But right under the base of the top timing cover belt. Take a good look.

[DARTHANIAN]

There is a 10 or 12 mm bolt that goes through somewhere around the timing cover at the front and into the neck area of the lower intake. If I can remember correctly…

I did see that, first i removed that bolt still no luck then i removed the water inlet housing as well, still no luck. The manifold is stripped down i've removed rear water block also. It should basically be held on by gasket tension at this point. So frustrating.

I've ordered a different stud remover kit, the harbor freight kit didn't work. Also ordered replacement studs. Hoping if i extract these, it will be the issue.

[A1218]

There is a 10 or 12 mm bolt that goes through somewhere around the timing cover at the front and into the neck area of the lower intake. If I can remember correctly…

I did see that, first i removed that bolt still no luck then i removed the water inlet housing as well, still no luck. The manifold is stripped down i've removed rear water block also. It should basically be held on by gasket tension at this point. So frustrating.

I've ordered a different stud remover kit, the harbor freight kit didn't work. Also ordered replacement studs. Hoping if i extract these, it will be the issue.

That’s odd.

Aside from the 4 nuts from the studs. Did you take out the 4 hex head bolts?

Mine was a bit held down after removing everything but gave it a little wiggle and shake and it came off. Check everything good and make sure nothing is still connected thats holding it down.

Did you remove the coolant bypass hose?

[DARTHANIAN]

Just for internet and posterity updating this so others who search can find information.

All the things you mentioned were removed yes.

As i thought all along, the intake manifold studs had seized to the intake with corrosion and electrolysis. I bought some special stud remover sockets from amazon. After removing the studs, intake manifold came out with no issues, I purchased some studs ahead of time to replace in case i ended up breaking some, or threads are damaged from the remover. Anyway, now i just gotta remember where all this stuff goes 3-4 weeks later for this 6hour job. :\

PS i will be and recommend you do to, install some anti-seize on just about everything. #2 spark plug felt like it was going to break off in the head, they have never been changed.

[A1218]

Just for internet and posterity updating this so others who search can find information.

All the things you mentioned were removed yes.

As i thought all along, the intake manifold studs had seized to the intake with corrosion and electrolysis. I bought some special stud remover sockets from amazon. After removing the studs, intake manifold came out with no issues, I purchased some studs ahead of time to replace in case i ended up breaking some, or threads are damaged from the remover. Anyway, now i just gotta remember where all this stuff goes 3-4 weeks later for this 6hour job. :\

PS i will be and recommend you do to, install some anti-seize on just about everything. #2 spark plug felt like it was going to break off in the head, they have never been changed.

Glad you go through with everything. Always helps to take some pictures as your dismantling.

Luckily I didn’t run into anything seized. And I’ve changed my spark plugs a few times already so I never had them seize.

But what I did do several days leading up to the job was spray all nuts and bolts accessible with PB Blaster. I guess that played a factor.

The only issue with my job was when I was putting things back together. I stripped a hex bolt on the lower intake on the back right side. Luckily I got a longer bolt and there were more threads below. The moment I had heard those threads pop my jaw dropped. I was using a torque and I’m not sure why it didn’t work. I ditched it after that and tightened by feel.

[PNWPathfinder]

I'm with you Darthanian, same rig...a knock sensor replacement has turned into a major overhaul. Fortunately my intake broke free without a hassle (after I found the "hidden" timing cover bolt connected to the LIP)

My timing belt kit and other parts came today...just waiting on the water pump now. Working on getting the Crankshaft Position Sensor changed out now (!!!)

It's been apart now for a few weeks waiting on parts (longer than I'd like)...now I've got to get it back together this weekend without ending up with spare parts lying around

I picked up the online shop manual though. very handy!

[AZhitman]

Anytime you run into something like that, heat is your friend. Any electrolized stud can be torch-heated (or, get access to an inductive coil tool) to red hot. Allow it to cool, then do the double-nut removal process.

Usually, the heating / cooling breaks the bond at the thread surfaces due to the difference in expansion / contraction rates of dissimilar metals.

[DARTHANIAN]

Anytime you run into something like that, heat is your friend. Any electrolized stud can be torch-heated (or, get access to an inductive coil tool) to red hot. Allow it to cool, then do the double-nut removal process.

Usually, the heating / cooling breaks the bond at the thread surfaces due to the difference in expansion / contraction rates of dissimilar metals.

Agreed. I did that, and tried to double nut remove. When you put the double nut on it's to close to the top to hold, when you put at the bottom of the stud there is no way to get a wrench on with a decent amount of torque. I bought a new torch specifically for this with nice n hot map gas. Didn't even flinch this stuff. Maybe i should have videoed the removal. my middle and 4th finger on my left hand has blood blisters from the knurling on my ratchet pulling these studs out. I thought for sure I was going to break them.

I don't think i posted about it here, but i broke the egr tube connection off trying to remove the pipe that connects to the exh manifold it, would not break loose. long story short trying to get it done etc and didn't have heat at the time. I soaked the head of the pipe down with PB an other penetrants over a 2 weeks period while fighting with manifold. Had to use nipple extractor to remove the broken nipple (2 different styles) from the pipe. Glad that worked, didn't want to deal with swapping that part out and possibly breaking off in the exh manifold, ugh.

[AZhitman]

Wow. Those projects test your willpower for sure.

I suppose it's the unintended consequence of building a motor that's just well-designed and robust... Years and years of trouble-free use, BUT when the time comes to do something invasive, it's damn near impenetrable.