Having issues with the cap i have on the filler neck. I recently removed the AST and put on a elimination kit. Im currently using the filler cap and its allowing coolant overflow into the reseviour. Ive read several posts about using a low pressure cap instead of the filler cap. I just would like to see if anyone has any similar issues or tips on how to fix this. I am using the Evan NPG+ coolant and would like to keep it at zero pressure as for what the coolant is intended for.

 

I use a regular pressure cap with the seal removed NPG + also. No problems here

 

So you removed the rubber ring and left the springed piece?

 

You need to retain the outer seal and remove the center one for the coolant recovery to work at zero pressure.

 

yes and yes

 

Here's a pic of my setup. I've removed the lower rubber ring as suggested. Once the engine gets hot coolant starts filling the overflow tank. Any more advice? What if I eliminated the overflow tank all together?

 

You need to keep the engine full (almost) to the top to avoid trapped air and possible overheating problems. Just because Evans does not boil, does not mean it doesn't expand. The expansion pushes coolant out of the engine, and it needs to be stored so that it can be pulled back when the engine cools.

So, IMO, you still need the OF tank.

Dave

 

well maybe I have air in my system. Every time I remove the coolant cap there's about 2 cups of coolant missing. I would've thought the system would pull coolant from the overflow tank but it does that exact opposite....

 

+1

Its normal for coolant to flow into the overflow tank when it gets hot. the liquid expands and that is what the OF tank is for.

 

Do a coolant system pressure test to look for leaks. Rent one at your local autozone with the adaptor for import cars.

It is normal for the level to be lower a bit once the car cools but 2 cups seems like a bit more than I'd expect.

FYI - I used to have an upper rad hose like you are using. It would suck in air as the car cooled b/c I could never get the clamps tight enough for it to be sealed properly. The pressure tested brought this issue to light. I replaced it with a factory hose w/ factory clamps and life was good. Those worm clamps suck. They loosen up after a few heat cycles and don't maintain correct pressure on the hose.

 

thanks for the info. I'll do as recommended and report back.

 

I did the same to mine. Just removed the spring but kept the rubber ring to make it seal. I love the Evans! I run about 40degrees cooler on average.

 

So I did a pressure test today. To my surprise not even a minor leak. I kept 11lbs on it for 15 minutes and not the slightest drop in pressure. Any advice on what to do from here?

 

Check the tubing, nipples, etc. between the cap and the overflow tank. It sounds to me like the coolant is either leaking out before it gets to the tank, or not getting drawn back once it does. This indicates a probable leak in this area.

It is also possible that it doesn't leak/lose coolant until it gets warm.

Dave

 

When I ran Evans I ran a 7psi cap instead of running 0. The problem I had was at high RPM the lower radiator hose would suck itself partially closed and restrict flow. Running 7psi put enough pressure in that hose to keep it properly flowing.

And it sounds like you probably do have a leak somewhere between the nipple at the cap and the overflow tank. Check especially at the tank where the hose goes in, seems that is a very common spot for a leak.

 

You just need a new radiator hose.

 

That is a logical next step. Looking at the pic, it doesn't seem like there is a hose clamp on the hose going to the overflow tank. I bought new hoses and hose clamps to the overflow tank when I did my AST elimination.

 

At this point the issue may be solved. With no pressure on the system the overflow tank fills when the car gets to operating temp...when it cools the level goes back down....opinions?

 

I am having the same issue.

I just deleted the AST and every time the car cools there is a bit of water missing.

no coolant leaks in the engine.