Coolant over flowing
 

Everytime I drive my car and it gets hot the coolant overflows out of the overflow bottle. For and overflow I have a greddy catch can and the nipple that goes to the water neck has another hose on the other side in the catch can to "suck up" coolant. When I stop the car the coolant in the overflow is boiling like theres no tomorrow. Could I have a bad cap that does not hold pressure and releases to much coolant?

Re: Coolant over flowing
 

Most likely you got it, replace it and let us know.

Re: Coolant over flowing
 

Yeah, sounds like it's the cap. Question is how long have you driven it while it's been boiling over hot?

Re: Coolant over flowing
 

Ive driven it like 3 times when thats happend. Each time I fill it up before I go the next time. Its been broken so I havent driven it much. Thanks guys Ill go buy a new one.

Re: Coolant over flowing
 

Could be a popped head gasket too.

Re: Coolant over flowing
 

I have a metal head gasket

Re: Coolant over flowing
 

I'd drain all the coolant and oil and see if there's any mixing of the to. If there is you at very least gonna need a new HG. From there the head could be warped. And draining the fluids is a cheap way to find out wtf is wrong, if anything.

Re: Coolant over flowing
 

Any white milky substance on the bottom of your oil cap? Any brown swirls in your coolant?

Re: Coolant over flowing
 

I just changed the oil like 100 miles ago and there was nothing odd about it. The coolant in the overflow is green. And the head was rebuilt(and surfaced was smoothed and stuff) last year and probably has about 600 miles on it.

Re: Coolant over flowing
 

You could do what I did this weekend and run the hose out through the hood and watch when the coolant blows out. Mine blows like crazzy under boost so Im assuming its a head gasket.

Re: Coolant over flowing
 

And your point? Was your block and deck both machined flat?

Usually when a DSM HG goes, it blows between a cylinder and water channel. I haven't seen one go near an oil galley, and I have blown quite a few over the years! That is why you usually don't seen anything funny in the coolant, you just end up blowing it out.

Re: Coolant over flowing
 

But wouldnt I just be looseing coolant and smoking? I do smoke a little at WOT in first gear but I was told that its just because of the breaking in of the rings and stuff. My block(800 miles ago) was decked last year when I rebuilt it and the head when I got it machined(600 miles ago). Have a mitsu metal HG copper sprayed and ARPs.

Re: Coolant over flowing
 

I would start by renting a coolant system pressure tester from a parts store. Check your cap and pressurize the radiator and see if they both pass. If the cap is bad replace it, if the radiator/coolant system doesnt hold then move on to a leak down tester and keep looking.

I didnt realize people copper sprayed metal head gaskets. I thought that was only done with the stock composite one. If so I just learned something new.

Re: Coolant over flowing
 

Did you retorque the head studs after a few heat cycles? How long does it take to start blowing out coolant? Try babying it the next time you take it out and see if it takes the same amount of time if you are nice to it.

The radiator cap is the first to try, after that start checking for a bad HG.

Re: Coolant over flowing
 

Got new cap and beat on the car a bit and no coolant overflow.

Re: Coolant over flowing
 

Got new cap and beat on the car a bit and no coolant overflow.

Re: Coolant over flowing
 

You are lucky if that fixed the problem. I have neer been that lucky.

Re: Coolant over flowing
 

Woohoo! nice work! Gotta love the cheap fix.

Re: Coolant over flowing
 

Heck yah! When I went to the store and put the new one on it felt totally different then the other one. It took a little force to "clip" it on where the old one was easy. Now I just gotta fix all the other problems

Re: Coolant over flowing
 

Just be happy this didn't happen to you. some serous detination blew the fire rings in the head hasket. notice there oval now instead of round, and blown between the clyinders. the stock head gasket saved me though no damage to the pistons cylinder or head.