1985 Z31 TURBO Headgasket and Exhaust Manifold questions.

[Stormhelix]

Hey there friends!

In short:
I have slight headgasket leak, and an exhaust leak at the manifold. If i take everything off the top (throttle body, valve covers, etc), Can i get the exhaust gasket off without pulling the engine? And do my headgasket without much trouble?


Long verison:
I have a 1985 300zx z31 turbo, I bought it for very, very little money, it has 131k miles original. Stock everything in bay except the intercooler. I noticed my coolant was a dark yellow even with a new flush. So i concluded it was a headgasket leak. I want to do it myself because I, like many other people, I am BROKE. I have a complete engine gasket set, timing belt, New head bolts (was told they warp once put in to lock it in.), a torque wrench, and a socket set (also jacks and jackstands).

Can I do everything in my bay (headgasket, flex tube gaskets, Manifold gasket, valve cover gasket) without pulling the engine?

I also have a exhaust manifold leak (got a new one, sanded down the grum off the gasket covering area, and aquired new gaskets.) I Noticed i have 2 stud and nut (think thats what they are called) broken off in the block. I cant get the tapped out because my wallet is quite empty. I heard from another Z tech that you don't need all the them for it to seal. (I have at least one complete stud and nut for each cylinder exhaust pipe on the manifold.)
Is that true?

lastly, If the First inquire is true, about being able to do it in the engine bay, Could i get a step by step guide (or a link to one) on taking apart my z31 VG30ET? / doing a headgasket?

I have little to no experience with open engines (below the valves). I do have experience hooking engines back up to harnesses. I do have lots of tape, will take photos, and i am alright with electrical.

Useful additional information:
-What to watch out for when taking the VG apart.
-Tips/Tricks
-How much oil the engine could hold at one time (for oil drain bucket sizing)
-basically anything else!

P.S I do not have a car manual. Unfortunately.

Any help at all is appreciated.

Thanks, Alex.

[ezb57e]

I think you should re-examine your conclusion that the head gasket(s) have a problem in the first place. Coolant color? Really? Is it just rusty?
Are you losing coolant?
Don't make work for yourself.
Which side manifold are we talking about? I assume you have obtained a NEW one and not some warped junk.
The manifold, especially the right, will be a PITA and if you are going to the trouble of taking it off, do it right and get all the studs in. They are actually pretty easy to remove once you get everything out of the way and get access to the stud, but they do take some technique and experience, or you will wind up with a broken extractor in the old stud piece, then you really have a problem.
The engine should have less then 5 quarts of oil in it.
Head bolts are reusable if they have not exceeded the stretch limit.
I think you need to slow down a bit here.
Good luck

[evildky]

No better way to learn than by doing!

I do agree you might be a bit hasty in your diagnosis. You might have a boatload of stop leak gunking everything up thats showing up even after the flush. Part of why I hate that crap so much it's nearly impossible to get it all out! Now if you have a milkshake in your oil or are blowing exhaust out your coolant overflow by all means you have a blown HG. Also the radiator in these cars being low and angled as they are, tend to be impossible to flush out all the gunk.

[Stormhelix]

Hello guys. Thanks for the reply.

I agree, I am a bit hasty to do my headgasket. Therefore I will just try to get the last stud and nut (one behind the manifold near the flex tube) off and try to pull it before I try to attempt a headgasket.


It is the right side manifold (As far as i know). But id like to do both, and the flex tube gaskets also.

So as I said before, 2 stub thread ends are stuck in the block. And I have atleast 1 complete unwarped stud and nut for each pair of bolt holes. (atleast they dont look warped.)

Any tips to getting that PITA manifold off? Do i have to take the turbo off? Would it be easier to just take the throttle body off? Is easy to do the valve cover gaskets? (i want to clean them and paint them also).

Also, Ive heard that the Manifold gasket bolts are torqued to 17-20ft/lbs? Is that correct?

I have a used manifold off a 86 turbo z31 with 80,000 miles. Ive leveled/sanded the gunk off the gasket end and its smoother than a babies bottom.

thanks, Alex

[Stormhelix]

I think you should re-examine your conclusion that the head gasket(s) have a problem in the first place. Coolant color? Really? Is it just rusty?
Are you losing coolant?
Good luck

Hey there.

My coolant is a dark yellow, sort of milky? not straight up milkshake though. I am not loosing coolant as far as I know. Coolant level has kept even. Not sure what rusky coolant looks like in these cars. The radiator has some rust towards the bottem, Could that be the cause? I Have all new radiator hosing (upper and lower piping) due to a tubing leak on the way back from buying the car. The old tubing was holding a redish gunk on the inside of it.

[ezb57e]

I meant the LEFT would be harder as it has the turbo.
Used manifolds can warp along the centerline of the bolts, and put a shearing force on the bolts. In fact, that is what often causes them to break. Its not that they are pulling up on the nut, there is often a sideways force. That is why used manifolds are a bad idea.

[Stormhelix]

Hey.

So yes, I am doing the left side. Where is a good place to purchase OEM parts? Ive seen many Nissan part stores, but haven't found a one with reviews. I've seen that a new manifold costs around $250.

thanks, Alex

[ezb57e]

No better way to learn than by doing!

That reminds of one of my favorite sayings: "Experience keeps a dear school, but fools will learn in no other".
There are many resources out there to help you, and you have tapped into at least one here, but I would not expect folks to walk you through the job online.
Get a manual somehow and read it. Its the single best thing you can do, learn for yourself. There is a lot of bad and/or erroneous advice online.
I would not dive into this without some thought and preparation. Think ahead and be ready for setbacks or unexpected situations such as more broken studs and frozen bolts/nuts/studs.

[chkootje]

hello,

i am wondering if you finished the job already, and how well did it go?

currently i am also taking apart my 1986 turbo so if your not done already, maybe we can help each other out a bit.s,

[AZ-ZBum]

P.S I do not have a car manual. Unfortunately.

Any help at all is appreciated.

Buy a car manual.

Haynes.

Less than $20 at any automotive parts store.

Don't be stupid.

[Pitts]

From doing several head gaskets (mostly on GM's) and dealing with broken exhaust studs, I can personally say pulling the heads onto a bench to remove the broken studs is a much easier (and typically time saving) method. The head has to come off for the new gasket anyway right? Also allows you to use carb cleaner to clean up around the area of the valves. Make sure you drain all the coolant you can before removing the heads otherwise coolant will go into the cylinders and cause more issues/work to be done. Don't use any copper spray on the head gaskets. They can clog cooling pathways. Due to the amount of work that already has to be done, also do the timing belt, timing belt tensioner, and water pump. You already have to do 2/3 of the work to pull off the heads. Just another hour of work for you and you will be in good shape for some time.