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Intake Manifold gap


Leo94
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Okay so my Terrano wasn't running right and would barley start and because im new to these engines i decided to have a look inside the throttle body and go on from there. It was pretty dirty so i decided to remove it and give it a good clean. Having a look at the first picture

Mixtureheater.jpg

(Picture courtesy of MY1PATH)

 

The little hole under the throttle body was really dirty and all clogged up as well as many different parts of the throttle assembly so i took it apart as much as i could and cleaned passages, plates, inside the body etc. As i was about to install it i also saw that the EGR Passage to the EGR valve was in no better condition either and abit of the gunk fell inside the intake manifold. Now i didn't want to run this stuff through the engine so i decided to remove the intake manifold. I removed the top eight bolts (4 allen, 4 hex) removed all the visible vaccume/coolant pipes etc. Once all that was removed i tried removing the intake manifold and it didn't budge one bit. In the process of trying to remove the intake manifold one of the bolt spacer/washer fell behind the engine. At first i tried to get to it with my fingers but the pushed it in further so i used an inspection camera and too my surprise i found a pool of coolant in a large gap under the intake manifold (The bolt fell in that pool). The pool can also be seen through the front of the engine between the timing cover and fan belt cover.

Block.jpg

Now my first question is: Is this pool normal, is the coolant there because i loosened the manifold bolts and it leaked into that gap. Second is: how do i remove the EGR valve because when i remove the two bolts at the back of the EGR valve i removed fine the other removed the whole stud and cant be removed because the Firewall is in the way. Thanks in advanced :)

Edited by Leo94
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I understand this a common problem on the VG 30. When I did my timing belt and water pump etc.. last fall, the guy at Factory Nissan in TX ~ I think mentioned that there is a coolant pipe with a rubber connecting hose, that runs underneath the intake manifold. That is prone to leak and drive people crazy trying to locate the source. Because it runs under the manifold, it especially hard to locate hence most people ignore it until it turns into a gushing leak.

I would look a little closer at that as a cause.

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Cheers, Ill have a look and post pictures if i find any causes. Also apart from those 8 intake manifold bolts do you know if there's anything else holding on the manifold from moving?

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No I don't. I would imagine that after a few years, and miles. the manifold may take a 'determined' effort to remove. I would look at a repair manual or FSM to determine that you have all the bolt's and fasteners removed, and there is nothing hidden which could hold you up from removing this.

 

Cheers

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They can get stuck on pretty good. On mine the gaskets were pretty much sealed to everything and tore apart when I removed the manifold, that'll cost you about $35 if yours do too. A few taps with a hammer will break it loose and with some wiggling it'll lift off. The coolant line under the intake connects towards the front to the thermostat housing and at the rear to a heater hose. Even if those aren't leaking, take it out anyways and make new gaskets with RTV so you know they will never leak. If you didn't drain the coolant you're going to have a hell of a mess when you pull that manifold off and probably fill the intake chambers in the head with coolant. I've done it.

 

Another place they leak coolant is the 90 degree bypass hose and that can spill a lot of coolant into the valley or down the front of the engine. Replace that too while you're in there.

 

How good of condition is the mixture heater in? Over time they get brittle and break up sending chunks of porcelain into the engine. If yours is in anything but perfect shape I'd knock all that crap out of there and seal it up.

Edited by Kingman
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I'm still having alot of trouble removing the manifold and i cant find any spots to hit it without hitting on something else. Are you sure its just those 8 bolts? or am i missing something. I cant seem to find any FSM for this specific engine (VG30I) i can only find the one for the VG30E which has a different intake manifold. As for the mixture heater as far as i can see its in a pretty decent condition.

Edited by Leo94
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Nope if you read in my first post youll see

Second is: how do i remove the EGR valve because when i remove the two bolts at the back of the EGR valve i removed fine the other removed the whole stud and cant be removed because the Firewall is in the way.

So yeh i haven't managed to remove it yet

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A 1 1/16" or 1 1/8" wrench to get the big nut off holding the tubes together.

Big nut where is this located on top or behind the EGR valve because i also removed the small bolt over the passage?

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Right on the back of the EGR valve. It's what connects it to the tube running to the driver side exhaust manifold.

The one with the steel line? I haven't removed it yet because i still have that problem where one bolt comes off and for the other bolt the whole stud comes off so its easier if i remove the intake manifold first then i will remove the EGR. Of course i will remove the line running to the manifold but right now my main issue is to get the intake manifold to at least come free.

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  • 4 weeks later...

This might sound abit stupid but do you have to remove the spark plugs to remove the intake manifold because with it still on the block its hard to see where the manifold meets the head/block

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