Throwing out coolant

[WhiteFinish]

Hej Guys,

I seem to have some issues getting my car to rev above 4000 rpm. (might be some setting in megasquirt, don't know)

Anyways... when I tried to rev higher it bounces back. But also throws out coolant through the burp tank.

Anybody idea's why the coolant is coming out?

[Evo_Spec]

i think that means you need a new rad cap? no idea, that's just a guess

[WhiteFinish]

Why a new radiator cap ? Shouldn't it leak underneath there than?

[wytbishop]

I would say that the unability to get it above 4 grand and the coolant thing are probably not directly related.

The revving issue seems like a timing thing to me. is this a recently assembled engine...or have you done headwork or something? When the timing's off the advance or retard gets worse as the engine speed increases until the spark is so early or late that the engine effectively stalls and slows down.

Small bits of coolant overflowing might just mean a bit of air in the cooling system. Big gurgling coolant overflow problems are usually indication of a head gasket leak. Combustion gasses getting into the cooling jackets and forcing coolant and big air bubbles past the rad cap.

[WhiteFinish]

This is a video during normal stationary



I'll try to take one after reving more, there you'll see it spilling out more.

[wytbishop]

Is the overflow bottle full?

[mikeinaus]

x2...

how old is your rad cap? if its worn out it wont let the cooling system build pressure.

[WhiteFinish]

No, far from full.

No idea how old the pressure cap is. I'll try to replace it, see what it does.

[davmac]

Exhaust gas flowing into the cooling system through bad head gasket or worse would explain everything. You would also be running hot or overheating. But presence of exhaust gas in the coolant system is easy to test for with a combustion gas tester like the ones sold at NAPA part 700-1006.
Coolant would be pretty hot and under high pressure to push into the overflow to begin with - so I agree the pressure cap may be bad. It is easy to test and cheap enough to replace anyway. Also pull the cap off the overflow and check the cap and tube that sets into the overflow tank. It must be blocked if coolant is coming out of the overflow tank when it is less than full. You don't see coolant coming out of the overflow tank unless coolant is flowing violently from the radiator or the tank is full.

[WhiteFinish]

Also pull the cap off the overflow and check the cap and tube that sets into the overflow tank. It must be blocked if coolant is coming out of the overflow tank when it is less than full. You don't see coolant coming out of the overflow tank unless coolant is flowing violently from the radiator or the tank is full.

What do you mean by this ??
So one way it should flow in, but only flow out if more than half full. ?

[Evo_Spec]

the coolant shouldn't be coming out the overflow tube unless your coolant tank is actually full, so he's saying to check your overflow cap and and the tubing to make sure there's no blockage forcing the coolant to flow out rather than into the overflow tank

[davmac]

Exactly. The tube dripping coolant is just a vent to air and of course will drain coolant if the tank overflows.

Is the car over heating?
Is it possible the radiator overflow is hooked up backwards? The tube from the radiator neck should connect to the overflow tank cap where there is a small tube that runs into the overflow tank. There should be enough coolant in the tank to cover the end of the tube.

[mikeinaus]

are the hoses on the resevior hooked up the right way? the hose that goes to the rad cap is supposed to be connected to the large straw that goes to the bottom of the resevior, while the other nipple is just a vent slightly below the cap...

[Mooneggs]

If your thermostat is bad and is not opening, you won't get circulation and it will push it out the overflow tank (just had this happen).

[WhiteFinish]

Thanks guys, I'll try this stuff in the weekend !

The thermostat is good. When checking the lower radiator hose it will be warm after the engine warmed up. So that's working fine.