91 240sx. DOHC motor.
Nothing special done to it.
stock clutch fan

I replaced the radiator about 2 years ago due to the old one having a nice crack.
Cooling has since been flushed maybe twice.

I replaced the thermosdat multiple times, with multiple brands (from autozone, advanced, even nissan oem) it would still overheat.

I then changed the temp gauge. didn't fix it.

I thought maybe it was just the sensor? nope.. because my overflow would be boiling over..
I changed the radiator cap.. still would boil over and run super hot.

So then I took out the thermosdat hoping it would solve it.. it did for a time.

Now the exact same thing happened to me yesterday that happened to me at dday 4 and 5..

I drove to Ocala with the people that met up at the rest stop.
Got to ocala, checked the coolant.. it was fine and clear, no oil..

I drifted the whole day, needle stayed right on mark, never overheated.. even with running for a good half hour parked with the a/c blowing (it was friggen hot.. I needed a/c )

Before we left, I checked the coolant again, and again, it was fine.

Drive home, and after about 60 miles of driving, the needle starts to climb... then goes back down like nothing happened.. ( I was thinking it was because I got stuck behind a big truck with not enough air going through my radiator, but it cooled down after I got away from the truck)... but that wasn't it...

then the needle shot up to the roof luckily less than 1 mile from the 75 and 52 exit..

I got off the road to let it cool off.. after a bit I did what a lot of people don't recommend, but i've done lots of times... I had a large towel that I put over the cap while I turned it ever so slighty to release pressure... after about 2 minutes of steam rushing out.. the cap was off, and my radiator was empty. It took the full gallon of 50/50 coolant that I had on hand.

As far as I can tell.. hoses are all good, all cylinders have OK compression, engine bay never smells of coolant.

Sorry this was long winded.. just lay out all the facts.
So what would cause all of my coolant to turn into steam??

 

Heat?

By instantly dropping the pressure of the superheated fluid, it will want to change phases on you. I think.

That doesn't tell you what is causing the build up of heat though.

 

water pump and fan clutch any play or shavings there?

 

get an electric fan, and see if it gets better.
i run a ford taurus electric fan, that fits the 240 radiator perfectly, and looks near stock since it has sort of a shroud.
20$ from cophers, and just run a relay to it.
my car runs colder than the clutch fan, and havent had a problem yet.

 

That was going to be my next purchase.

Thanks for the tip for which car to take it from.
I was also thinking of a late 90s altima since they have a KA in them, but the Taurus would do just fine.

Also forgot, waterpump is new and clutch fan seems to be fine.

 

did u intall the water pump up yourself? and if so could u have installed it incorrectly?

 

Is that even possible?

yes, myself.. yes, it was installed correctly

 

actualy yeah it is... one little slip up and it's going ot give u problems

 

1. If you're gonna do the towel trick, at least release pressure from the bleeder valve near the thermo sensors.

2. I made 3 stops coming back from DDay Wasn't overheating, just running an S13 temp gauge sensor which behaves different than the S14s - just playing it safe and chilled at the public stops.

3. Coolant into steam huh? And you're running true 50/50? (True 50/50 is no good in FL. 85/15 water/coolant would be best for cooling & street use)

4. You have a leak in your hoses somewhere. Pressurize the coolant system and you'll find it.

Jesse

 

Well the coolant that was in there wasn't 50/50, what I added to it now was 50/50 (it was the premixed stuff)

Before it was mostly water... probably like 90/10

how do I pressurize the system?


Thanks for the help.