Nissan 720 Intake Manifold Gasket

Jun 11th, 2002, 12:10 PM

Has anyone replaced an intake manifold gasket on a 1985 Nissan 720 pickup? I can't find the correct torque specs for the bolts. Something seems to be tweaked a bit on my engine because the gasket does not seal fully in one spot and drains the coolant into the air intake directly below. I tightened the bolts from the middle of the intake out to each side and to approx. 40 NM (I can't get a torque wrench in there to be sure). Any ideas?

Jun 11th, 2002, 02:34 PM

Well andya@usa from what I read in my trusty Haynes Manual the torque specifications for your intake manifold should be 12 to 15 ft-lbs.

Jun 11th, 2002, 02:40 PM

Does your trusty manual have any info on the order to tighten the bolts in? (center out, left to right, etc?)

Thanks for the reply!!

Jun 11th, 2002, 06:51 PM

No prob andya@usa, here is the order:

work from the center toward the ends and work up to the final torque in three or four steps.

Jun 11th, 2002, 07:27 PM

That's what I did (although I tightened them up a bit much) and the stupid thing still pours water out around the 3rd cylinder. Is the intake or head warped?? Should I just load it up with gasket sealer?

Jun 11th, 2002, 10:47 PM

Ok, this is the direct transcription from what the Haynes Manual says:

The intake and exhaust manifolds on the engine share a common gasket. To prevent air leaks and possible damage to the valves, the gasket must be replaced whenever either manifold is removed-the manifolds must be removed and installed together. The engine must be completely cool when this procedure is done.

So, are you using a new gasket or reusing your old one? Since you said you torqued down the bolts with the correct measurement, my guesses would be that your gasket is to thin (or warped) or your intake is warped over the third cylinder thanks to the increase in temperature becuase of improper colling. The most probably though is that you probably just need another head gasket. Also is your engine an L20B, or NapsZ24? If it is a Napsz you have to make sure the chamfered side of each washer is facing the engine. Also the torque specs are the same as is the tightening procedure.

Jun 12th, 2002, 11:47 AM

It's the Z24 engine. I used a new gasket and the engine had been cool for at least 24 hours before I started work on it. The old gasket failed when the thermostat went out and caused the engine to overheat, so I have really bad feeling that something warped and that I will need the pieces machined to get the gasket to seal correctly.

Jun 12th, 2002, 10:04 PM

Sorry to hear that. I hope it's a warped intake instead of a head though. Keep me posted if you need more help.

Jun 13th, 2002, 11:18 AM

After some tinkering I've managed to get the thing to seal correctly, but now it won't start. I'm pretty sure it's because the coolant leaked into the air intake when the gasket didn't seal the first time. Any ideas on how to get water out of an engine? (or is this even a problem?)

Thanks alot for the info, it solved many of my problems!

Jun 20th, 2002, 02:38 PM

Just a quick note to finalize the post! Finally got the truck started. Ended up pulling the plugs and cranking it a bit to blast the water out of the engine, then let it sit with the hood open for about 6 hours. Put everything back together and then had to replace the starter because the old one could barely turn the engine over (although it would start it when it didn't have water in it). Anyway, after just a little bit of cranking with the new starter it fired up and ran fine! I turned it back off and changed the oil (which came out like light colored chocolate milk because of all the water in it). It's been running fine for a few days now and the coolant is still at the top of the radiator!

So, to sum it up: After 8 hours of messing with it and a couple gaskets ($3 apiece) and a new starter ($50), it's running fine. Hopefully I'll never have to do that again!

Thanks for all the help!