It seems i do have a head gasket leak, i removed the starter and noticed that the area behind it is wet as you can see in the pics. It's leaking outside, not inside, thats not that bad right? I need to change it and all the good advices are more than welcome, i have never done that..

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240zgoldie.blogspot.com

You could try cleaning that area very well, then re-torquing your head to see if it stops. That might save you a tear-down and a week off the road.

Most important is to check to ensure the fluids have not mixed. Oil spots in the radiator or chocolate milkshake in the oil change the whole game.

Frank

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1970 240Z

Do i loosen the bolts and torque or just tighten them? No oil spots on the radiator nor swiss chocolate on oil.

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240zgoldie.blogspot.com

Personally, I would simply tighten them down to factory spec torque. Be sure you use the correct tightening sequence, and just turn them down as if you were applying final torque (which you are).

My manuals are in the garage ~ do you have the correct sequence and torque specifications available there? I could get them for you if you don't (just as soon as I find my missing MasterVac hoses ~ you're #2 on my 'help list' )

Frank

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1970 240Z

Also Rev, be sure that leak is coming from your headgasket and not a tiny hole in that heater line. If it's a slow drip from the carb heating line, there's no need to mess with the head (and you'll still have the leak after you retorque everything).

Wrap a dry cloth around the heater line in that area, then run the car and see if the cloth gets wet.

Frank

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1970 240Z

I do have the FSM. I need to buy a torque wrench or loan it from someone

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240zgoldie.blogspot.com

NO. Don't just torque them down. Pull each bolt one at a time, clean it really good, spray brake clean in the bolt hole and spray it out with compressed air, then oil the bolt threads and re torque. remember one at a time. It will cure the issue most likely. I did this to mine last year to stop the water from leaking on the outside. It's 100% perfect now. Also if the bolt is real rusty and don't clean up, don't use it, get another one.

There's the voice of more experience (Paul is an automotive shop teacher). Listen to him.

Frank

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1970 240Z

If you do need to pull the head, you need to make absolutely sure you properly wedge the timing chain tensioner before you remove the cam sprocket. That's really the only hidden hazard of the job, and it's a common mistake.

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71 on a rotisserie, two more in pieces in my shed...and a 69 1600 waiting for me to get to it

I'll get proper torque wrench for loan tommorrow, BUT we have companys "summer opening" party so got to do this on saturday. Hope that screw cleaning helps!

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240zgoldie.blogspot.com

Also keep in mind that those head bolts, as with a bunch of the REALLY IMPORTANT bolts (main bearings, rods) in the L6 engine are torque to yield. This means that once they've been torqued the first time, they've already been stretched the most that they should be, and the metal is considerably weaker. Makes it more likely for the end of the head bolt to stretch further, leading to a head gasket leak or even worse snapping off inside the engine block. The remedy for this of course is getting new bolts... I've read (and heard) multiple different sources recommending that you change the bolts every time the engine is rebuilt/head comes off.

It's possible that the head came off that engine several times during its life, and the same bolts were used every time to put it back on again. Some people insist that it's fine to reuse the bolts, and don't have problems with it. However, there's always a breaking point somewhere. Coupled with thousands of heat cycles from running the car and shutting it down, they may be failing...

Keep that in the back of your mind as well, for it's within the realm of possibilities.

By the way, is the head surface above the gasket completely dry? Is the only wet area on the block and below?

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-Chris

If they were torque to yeild bolts, there would be warnings in the manuals to use new head bolts, and I have never seen such a warning for a Z car, or most Jap cars I have done. I just finished my Acura and no warnings, so reused the headbolts. Now I'm doing a Chevy Venture and it warns to use new head bolts, So I got NEW head bolts for it. Also torque to yeilds usally have you torque them down, then turn an additional 90 degrees. Not so on a Z. I did exchange some of mine for ones that had no rust on them,but that's it, and so far so good,have more than 5,000 miles on it, took it up to 8 grand and all is good.

Yes, that's the only visible wet area, why?

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240zgoldie.blogspot.com

I'm sure he was considering a cracked head, which would leak ABOVE the gasket line.

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1970 240Z

Okey dokey. Ordered all the gaskets just for sure, i will change them some day eventually, EVEN the torque-trick will succeed. Needed a new PVC hose, it was actually quite cheap (15$ braided) compared to master vac hose (89$ braided)...

Weather man says there is wave of hot air coming this weekend, hope i get Z running!

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240zgoldie.blogspot.com