I have a rookie question. I need to remove the intake plenum on a 93 300ZX NT to get to a cooling system leak. Do I detach the throttle assembly or should it come off with the plenum. Any other advice on removing the plenum would be appreciated.

Just disconnect the throttle and cruise cables under the center cover. If you don't want to remove the plenum, just do the water hose bypass at the rear where the pipes are, and that will eliminate any flow though the hoses under the plenum. That whole setup is not useful in any way unless you drive the car in sub -40 weather for extended periods of time.If you do pull the plenum, I'd still highly recommend the water bypass routine.

WOW if I don't have to remove the plenum that will make my weekend (week, month...). Do you know where I could find a diagram or something on how to do the bypass. Sorry to sound so stupid (but I am). If I can eliminate that leak without removing the plenum that would be awesome. THANKS!!!

I'm not home right now, but when I get there and root though my tech bulletins I've saved over the years, I'll email it to you. Turns a 10 hour job into a 1/2 hour exercise.

That would be AWESOME! [email protected]

i would also enjoy that tsb if possible [email protected]

im actually in the same process jus about to take the plenum off, a couple hoses and stuff left could u just post the link here???

It's really pretty simple. At the back of the engine a little toward the PS of center are 2 pipes that feed the heater core. On those pipes there are 2 nipples (on each one) that supply water to and from the plenum lines. Disconnect them from the plenum feed lines and just connect them together on each pip with a short piece of hose. That's it on an NA.

I look at this in the morning. If you have pics please send

Hey Zwicked,

I am planning on by-passing these same hoses. Could you please forward any pictures / info available for this process. It would be greatly appreciated!!!

I'm trying to learn how to repair my own car by reading these forums and other guides.

I'm a little confused by all of the responses.

Everyone seems to be trying to bypass the two plenum feed lines.Why is this? Is everyone here trying to find a coolant leak or what is the motivation?

It appears to be a bit of a design overload by Nissan. My understanding is that these lines are really only needed on a vehicle that is going to be operated in -40 degree temperatures on a regular basis.

The cost and time of replacing them is not worth it if you are not in that type of climate. To replace you must remove the plenum which requires a great deal of time and cost.

Blocking them off, I understand, does not require removing the plenum. I am just trying to get more specific instructions for this process.

I was under the impression, by the previous posts, that you had this instruction. Sorry for the misunderstanding.

great write-ups here :http://s95014253.onlinehome.us/63104/6901.html

Thanks clickdoc for the response,

But this isn't what I am looking for. I want to eliminate the hoses located under the plenum.

Ray

a1a2keyw,

Did you get the problem fixed with the leaking hoses?

Ray

i know i gave you the carbon canister -- look to the left & click -- he has posts on everything !

Great help. Thanks!

Yes I did, thanks to a lot of great help from zwicked. I have some great pics that he sent me that really helped if anyone needs them. I have a 93 non-turbo.

I would certainly appreciate a copy of the pictures you received. My email is [email protected].

Thanks so much,

Ray

I was wondering if I too can have those pics. I am getting ready to do this on my 300zx.

Thanks

[email protected]

I was wondering if I too can have those pics. I am getting ready to do this on my 300zx.

Thanks

[email protected]

I hate to bother you as well, but I am also getting ready to do the same. If you could also send me what you have on bypassing the coolant lines without removing the plenum I would be so grateful.
Thanks
[email protected]

glendonr1 wrote: ↑

Sun Aug 28, 2022 7:58 pm

I hate to bother you as well, but I am also getting ready to do the same. If you could also send me what you have on bypassing the coolant lines without removing the plenum I would be so grateful.
Thanks
[email protected]

You're replying to a 14 year old post. You might get an answer, but I wouldn't get your hopes up.

Search for 300zx plenum coolant bypass. the diagram has been posted numerous times and is hosted on the 300zx wiki by CZP.