Found radiator cap was bad, damage?

[Bigsyke]

Bought a 350z a few days ago, drove fine but I really didn't give it a full 100% inspection before the purchase. Well I put about 200 miles on it, and a few redline bursts here and there.

Tonight just for fun I decided to squeeze my upper radiator hose after a long 60 mile drive in about 90f weather....Upper radiator hose had no pressure. Funny thing is, I have had no coolant loss from what I can see, radiator was full, reservoir was fine. I did notice the cooling fans kicked in alot, but I dont think low pressure in the system would cause a higher temp, unless there was fluid loss --which there wasn't. Put on a 1.2bar cap from my Twin Turbo Z, and it seemed to hold pressure.

The car runs perfectly, acceleration is a bit on the lacking side for a Z, but it sounds great. Could running with little to no pressure actually cause damage to the heads on a vq35de, if the system was always full?

 

[RiceCake]

Pressurization raises the boiling point, so, logically this bit of physics was defeated.

Worst case scenario I can see with that is the coolant boiling. Boiling coolant can cause hot spots and possibly cavitation issues but with all the additives in coolant, this is typically a non-issue. The coolant also raises the boiling point, so if it even boiled in the first place is a good question to contemplate.

So, did it cause you a problem? Highly unlikely. Some people run around without the rad cap on fully to diagnose issues, others run around with a rad full of only water, which lowers the boiling point and about accomplishes the same thing.

You're fine.

 

[Chris142]

It never got hot enough to boil so no damage done. Old cars had a no pressure cooling system anyway. carry on.

 

[TFB1]

I run my '98 Grand Marquis with the pressure cap loose because it has the failure prone plastic intake manifold, been this way three years with zero issues... Prior I ran a '93 with a seeping radiator tank for at least three years, no issues on that one either...

 

[sasha]

the 350z would have tripped into limp mode if the temp shot up to the danger area. no harm done, enjoy the car.

 

[supton]

My father had the cap loose on the Astrovan for a few years. Had a cracked tank, and with the cap loose it would not pressurize. Lost less water that way.

 

[circuitsmith]

The radiator cap stopped holding pressure on my '88 fuel injected Accord.
The only symptom is it would boil over a little after stopping the engine but only after driving fast on the highway.