Quote:
Originally Posted by Speedy
Man, some of the stuff you guys post is just.....bad. I'm not knocking on you guys but unless you know how to work on a car it's best not to give advice on what to do. The test kit puts nothing "IN" the car. If you watch my video I posted you'd see that.
Second, the radiator hoses will not have pressure in them when the car is shut off.
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Speedy, I suggest you take a look at my build thread before saying things like I dont know how to work on a car. But to be fair you assumed, as did I with how this test was done.
Also I disagree, a car that does not have any issues will not have pressure when the car is shut off... but one that is pushing combustion gasses into the cooling system will retain the pressure. Its a telltale sign of head gasket issues, along with forcing air up through your coolant reservoir and making a mess.
When a cooling system is working normally no combustion gasses can make its way into the system. Thus its a closed system where when the car cools off the water 'shrinks' so to speak and the system pressure is relieved, thus the upper rad hose returns to its normal self, it may even turn into a bit of a vacuum in which coolant from your reservoir is sucked into the cooling system for the next heating cycle (say if you have a small leak or whatever). However if you have the system being pressurized by the engine it will retain some of this pressure even after the engine has cooled because of the way the rad cap works. Sure it will bleed off some of the pressure, but because air can be compressed much more than liquid it will stay in the system and the rad cap will only bleed off enough pressure to satisfy its internal spring load. Thus once the pressure in the system drops below this spring pressure it will stay, assuming it doesn't leak back into the cylinders, which is why IMO if you want to test for leaks just do a leak down test of the system. I would go as far as to pull all the plugs, apply a pressure to the cooling system and wait say 30mins, then crank over the engine and see what (if any) cylinder has coolant in it.
Speedy - Its well known that an pressurized cooling system is almost always caused by a head gasket leak. When the car is running it can be sometimes hard to tell because the rad cap will be working overtime to compensate for the pressure changes in the system. But once the car is off and has been for a bit the system will stabilize and it will be easier to tell if you have a stiff hose.
What you could also do is a compression test of each cylinder, a cylinder with a leaking head gasket would have a lower compression than the rest of them. Or just take a look at your plugs, a plug burning coolant will look different than the other 5.
Mhcoss - I get what your saying, but something is obviously wrong one way or another. Doesn't matter what test you tell Nissan you've done, they will still do their own testing and disregard your results guaranteed.
Just trying to help you out, and despite what speedy thinks I do know my way around a engine.
I do wish you the best of luck, I still think the best advice is going to the Infinity dealer to see what they have to say.