Rattaan

Ok, while refilling my coolant I had the engine running, heater full blast on hot, and radiator cap off standing there with extra coolant in hand. I filled the level to the top when it sucked more coolant in to the engine from the cap. I ran the engine for about 10 minutes while doing this. When Everything was completely warmed up, after at least 10 minutes of running/topping off, I put the cap on, and turned the engine off. I just went back out to see if it had cooled enough to work on and found that the upper radiator hose has flattened out. Is this supposed to happen? I thought coolant was supposed to be sucked back in from the overflow tank? Am I right and I have a problem occuring or am I just completely wrong and need more explaination? Let me know what's up please, it's kinda making me wonder if the new radiator cap isn't right.

Bruce

I'd go have it checked or buy another one, while your at it if you havent replaced the lower one you might as well knock that out. Good luck with your car.

Rattaan

Well, that's the thing, it's new. A new radiator cap, new thermostat, new upper hose and new lower hose. I just finished completely cleaning out the coolant system with the Zerex cleaner and flushing it all clean. I'm also kinda wondering what's up with the idle speed since doing this because it's gone up about 100rpm? Anybody? Really I just wanted to know about the cap and if coolant should flow readily back into the system from the overflow tank?

Digi7ech

iTrader: (1)

The hose shouldn't flatten out. That's why there is the springs inside to prevent the flattening.

You might have ha it filled to the top with coolant but that's at running temps and not cold(contraction due to heat loss).

So far my Rad Cap would only open up when there was positive pressure but I never sat there and checked for it sucking in coolant.

I recommend to just fill it up while it's at it's coldest(in the morning/or haven't turned it over in a couple hours).

Open the Cap closest to the engine(on the Water pump neck) and fill from there. If your Rad has the bleed screw on the side then use it to help drain any air.

When it fills to the top close it off and hand squeeze/pump one of the hoses to free any trapped air.

Open it up again and top it off.

This will fill it up to it's max during cold meaing it will have plenty of coolant during hot or cold situations.

Another thing to look into would be that flattened hose.
Get the car to running temp and rev the car from the engine bay and check to see if it collapses. If it does then you should bring it back and ask for a new one.

Rattaan

The hose I took out had no spring in it. Does plain water expand and contract more than 50/50 coolant does? This is starting to become more confusing than I origianlly thought. I looked on that "how stuff works" site just for the heck of it and comparing mine to that I was correct that coolant should flow both ways. But how does it flow back into the engine without enough vacuum(enough to squeeze the hose but not to pull it past the cap) ??

HAILERS

I've seen that problem on another type of car. Went out in the morning and noticed the top hose collapsed. The problem was that the overflow hose that goes to the overfolw tank was stopped up at the entrance to the overflow tank.

Pull your overflow hose off where it attaches next to the radiator cap. Blow into the hose towards the overflow tank. It should flow freely and blow bubbles in the tank. If not.....unstop the obstruction in the line or the overflow tank.

Then again its possible its the radiator cap. It might be allowing water to flow out of the radiator into the overflow tank....but for whatever reason not letting that water return to the radiator from the overflow tank back into the radiator. Either way, the hose is collaped due to the water cooling in the radiator and there not being anything to replace its volume when it was warm, which causes the hose to flatten out/suck in/collapse/whatever.