I did the headgaskets on my 04 g35x. The car is running and driving now but the head gaskets aren't sealing 100% still. I purchased a low mile engine and I plan to install it over the winter. That's what I wanted to do in first place but my friend convinced me to replace the head gaskets instead.

I have my suspicions why it isn't sealing 100% but it's not conclusive. The heads weren't warped and the gasket surface seemed fine when I removed the heads so I'm really not sure what the problem is.

this is the engine running after the repair and getting the air out of the cooling system

The engine does run good and doesn't overheat by I know it's not sealing perfect.

 

How do you know it's not sealing properly?

 

I mean for the other guy. I wanted to know if OP was going to keep going on

 

There is a small amount of oil in the overflow. Not sludge but like little crystal flakes most likely from the combustion gasses pushing through. When I squeeze the rad hose to open the pressure relief in the rad cap, bubbles will come up through the overflow.

Once I get the used engine in, I'm going to take it apart again on the stand. I hope it will be more telling the second time around. If I find the time, I'm going to completely disassemble it and do the HR mod with gaskets. The engine only has 74,000 miles and only overheated in the shop once when I was changing the coolant for maintenance. We shut the car off right away as my friend was in the car revving it when we were attempting to bleed the system. I think that little mishap landed me in this problem. Needless to say, I think these engines are way too sensitive.

It runs great now and it'll get me through the summer without any problem and I'll deal with it over the winter.

 

Holy **** lol. I was going to take the timing chain etc off this weekend. It is more of a project car now. I do have lots and lots of vehicle repair experience and its not that scary for me... Im just newer to the vq engine than anything hence the post to get a close of how far I need to ventur. Thanks for the heads up guys. I'll probably reassemble the engine now and ..... Install a new coolantemp sending unit and call it a day hahaha.... Then sell it or something. BTW I've got all of the tools required for assembly or a car.. Except for a 60$ torque wrench.. I swear its pro ably not even the head gasket. No signs of leakages from either coolant or oil in each others reservoir.

 

Your going to sell your G and get what? Well, glad you have some experience in the mechanic world.

 

Not some experience, "lots and lots".
If it's a "project car" now, why not get to the root of the problem over time?