Whats going on with my coolant?

[1fast97gsx]

I'm running a fully built 6 bolt block with about 4000 miles on it now. One day I noticed my coolant reserve was empty so I kept topping off my coolant until it finally stabilized somewhere in the middle. After driving around a few days I noticed it's empty again. I once again filled it up. Later that night I went out and did some hard 3rd and 4th gear pulls to do some tuning and once I got home I noticed a little puddle under my car. I pop the hood and see the coolant reserve is overfilled and coolant was draining out of the overflow tube. I don't know a whole lot about cooling systems, but I'm not getting any smoke out of the exhaust and have no external leaks, so what's causing this coolant level to change like that? Basically the reserve tank fills up only after I beat on the car a bit. Maybe this is normal?

My initial thoughts were a bad headgasket. I did however shave both the block and head and installed a brand new headgasket along with a brand new set of arp headstuds using the proper torque sequence. I did a compression test and my numbers are perfect. Also there's no signs of oil in my coolant or vise versa. Thoughts?

 

[1gdsmNI]

I had a similar problem recently and it ended up being a combination of the thermostat and temperature sensor.

 

[1fast97gsx]

that was another thing I considered. If it was a headgasket there would be signs of oil in coolant, coolant in oil, or at least compression numbers that aren't damn near perfect imo. I will try and replace those things and see if it takes care of it.

 

[EclipZ]

the radiator cap is a good thing to replace while you are at it, that could be your problem.

 

[1fast97gsx]

Kinda bringing this back from the dead, but my car has been broken for a while and I just got it going again. The problem is still there with a new rad cap and thermostat. I notice my lower radiator house feels kinda "mushy" and I can feel signs of coolant on the outside of it, but would a leaking lower hose also cause something like this? The problem is only there if I really beat on the car for a while, and it never gets to the point where I loose a lot of coolant and overheat or anything ... the coolant loss is minimal, but I still want to take care of it.

 

[Car Cannibal]

What are your coolant temps after you get on it?

The rad will boil over if it gets really warm and you might not notice it spilling out on the road or after you leave the car.

Most likely you were adding coolant due to only filling up the rad and lines when the block got put back in the car. The thermostat was not open to fill the block with water when you added it the very first time. I start the car with the cap off and wait till the thermo opens and bubbles out all the air while adding water as the block and system need more.