spoolin93r1

every since i installed my new engine, the coolant system has always been able to take more coolant after a couple days of driving, but never been a whole lot. here lately, i've heard the coolant buzzer 3 times after the car has sat and restarted. i never see any puddles under the car, there's no bubbles in the coolant neck when running, and there's no oil in the coolant. anyone have any clues? it doesn't have any smoke from coolant on startup either. i'm running a PWR radiator mounted upright due the the Apex fmic. i still have stock AST also (i know i know)

CCarlisi

Mine did that twice:
1st time: when I installed the PWR radiator and FMIC. It took a solid week before the system didn't need to be topped off anymore.

Last time: when my motor developed a coolant leak.

CCarlisi

Mine did that twice:
1st time: when I installed the PWR radiator and FMIC. It took a solid week before the system didn't need to be topped off anymore.

Last time: when my motor developed a coolant leak.

spurvo

How is the level in your overflow tank doing? Going up every time you fill the filler neck? Might be small coolant system vacuum leak making it not draw all the coolant back into the engine on cool down. I'm talking about a very small leak that would only occur when cold. Monitor your coolant overflow level for a while and see what it does. Then get a coolant system pressure tester from NAPA and find that leak! Maybe...

spoolin93r1

i've never noticed the level in the overflow, it might not be gettin in there. how would i fix that?

spurvo

What I mean is this: When the engine get's hot, it builds pressure in the cooling system. This pressure will reach the point where the pressure cap allows coolant to expand into the overflow tank. This pressure cap is supposed to 13 lbs for our cars, post recall. The pressure cap is the one on the AST, just behind the intercooler towards the driver's side of the engine, NOT the one in between the alternator and the air pump. Anyway, this expansion is normal. When the engine begins to cool down, the coolant literally shrinks in volume, which creates a slight vacuum in the coolant system. The pressure cap has a valve in the bottom of it that allows coolant to come BACK into the engine with very little vacuum required. Thus, the fluid that expanded into the overflow tank while hot gets drawn back into the coolant system and you don't need to add coolant.

But, when there is a small so called "pinhole" leak in the coolant system, this can provide an alternate path for the vacuum situation in the coolant system at cool down to be relieved, namely by allowing air into the system. With repeated heatings and coolings, the system loses enough coolant to make the buzzer go off. These leaks are often small enough to not show any visable trace of coolant, or maybe only a light greenish "dust" around the leaking area, making these very difficult to positivley diagnose. This is compounded in our cars by the 28 possible locations where this could occur via 14 hoses. Leaking water pump bearing seals will also exhibit this behavior.

The fix is to place a coolant system pressure tester onto the engine and pressurize it when cold to about 15 psi (clamp the AST outlet hose to keep it from releiving the pressure through this route). Then go hunting for leaks. You'll probably find it Then replace that hose, or just go proactive on its *** and replace ALL the hoses, though this can end up giving you more leaks than you started with

Anyhow, if the coolant isn't going out the tail pipe (blown O-ring) and isn't going on the ground (hose leak of larger than pinhole nature), then it's likely going into the overflow tank, so monitor it's level. It should have a level when the engine is completely cold, and the coolant should return to this EXACT level after a heating and cooling cycle. If the level is higher, then it could be the pinhole.

spoolin93r1

cool, glad you could help, i'll keep an eye on it this week. i'm just worried because i need to drive it to chicago this weekend and i don't want it goin nuts on me