Cooling System Issues

[VaTechZHP]

Car has been throwing an intermittent low coolant light, but the car hasn't budged at all from center (I know its not very accurate) over the past few weeks.

I topped it off with some coolant, only to then realize it had dumped out while I was at work one day.

Today, I actually spent some time messing around with the car and figured I'd take a look at the cooling system to see what was going on.

The car was warm from just driving and when I took the top off, I didn't see much in the expansion tank, so I added some to the high level (even thought that indication is cold)

While letting the car adjust and kick out any air that might be in the system, the expansion tank seemed to be "volcanoing" out a bunch of coolant/water mix.

I let this go on for some time and didn't see any change. The coolant would overflow out of the top and what would seem like pulsating with a lot of hissing like there seemed to be a lot of pressure in the system while the car was hot and running.

I have since turned the car off to let it cool down for while and then will recheck the level to see where it settled and then see what happens tomorrow.

Any suggestions on things to check? The entire system was replace last summer, but it might look like the upper radiator hose is weeping a bit which I'm planning to replace shortly.

Here is a video of what the car was doing. Click the image and it might work? I've never tried to post a vid before!



Thanks!

[kayger12]

It's a pressurized system, so I would expect it to do that with the cap removed. Don't see any issue with it.

I would imagine you either have a crack in your expansion tank or a bad hose at the connection to the tank.

What brand exp tank did you have installed when you did the overhaul?

[VaTechZHP]

That is my guess. I'm going to start with the hose since its easier. They were an off brand (cheaped out for some reason...) but I think I'm going to replace them with some oem parts and see how that works out, unless I can get some cool looking silicon hoses!!! (likely not going to go that route...)

Thanks!

[Avetiso]

It's a pressurized system, so I would expect it to do that with the cap removed. Don't see any issue with it.

I would imagine you either have a crack in your expansion tank or a bad hose at the connection to the tank.

What brand exp tank did you have installed when you did the overhaul?

+1

[VaTechZHP]

Well I just ordered a new upper OEM hose from ECS tuning along with a couple of other things for a few other cars of mine. I drove the car into work today to see what would happen and the needle was bouncing around a lot between the lower hash mark and the middle, and I had no heat the entire way in (about 20mins)

Seems I'll be parking this car for a little until the new parts come in, swap those over, bleed the system, and hope for the best!

[alexandre]

Bleed the system - there's an air pocket somewhere.

[Dave_B]

Yep, no heat = air in the system.

Turn the heat in the car set to 91, on the lowest fan setting. That causes the coolant to circulate the heater core where most likely the air pocket is trapped.

May take a time or 2 to do this. Took me 4 "bleeds" to be mine just right.

[aurelius]

And bleed air thru plastic screw on upper hose.

Depending on where you're seeing coolant residue on the upper hose, the bleeder screw could also be the leak source when the coolant is at normal running temp. Be sure the o-ring is still there and count the number of turns it takes to to remove the screw so that you do not over-tighten when replacing.

For more on how to avoid breaking the head off that screw, CLICK HERE.

[VaTechZHP]

Thanks Aurelius,

I'll take another look and see if I can figure out where its leaking from. So far, the car seems to have fixed itself. Heat is fully functioning again, and coolant light has been off for some time now. I do have a replacement upper hose that should be at home to put in if I notice any additional leaks.

Thanks again everyone for the help!

The car has been running great and looks much better now that it has been washed!

[Dave1027]

It's a pressurized system, so I would expect it to do that with the cap removed...

Why can't you have the cap off while running the engine? I know you can't if it's hot because of expansion. But should be ok when cold.

I have been trying to learn this cooling system lately. It is looking like I received my zhp with the coolant over filled. I had some coolant leak out and I refilled. So if I understand correctly, the the top of the float stick should be at the rim when cold? Exactly what does the bleeder cap do? I would think it would be a bad idea to crack open the bleeder when the coolant is hot. I tried that and pressure began to escape. I would assume the system would not work correctly that way so I opened it again when cold to equalize the pressure.