Difussion3

Hi all, I've been having a problem with my cooling system. A few weeks ago I realized that my reservoir tank was empty, so I added some water to the max line. After another week or so I popped open the hood and noticed it was empty again, so I added water again. At this point I knew this shouldn't be happening. These past 2 weeks I noticed that when I pop open my hood, the water somehow leaks from the top of the reservoir tank. The reservoir cap is always wet and its surroundings are wet also.

On Tuesday I was driving and noticed some steam coming out of the passenger side of the hood. When I opened the hood the reservoir cap was wet and I'm assuming the coolant is coming out from the top. Later that day I opened the radiator and had to top it off with water, it took about 36oz or so to top it off. Plus I put more water in the reservoir. Friday, I drove around a lot and by the end of the night I noticed steam again coming out from the hood. I opened the hood and noticed the same thing, water all over the reservoir/cap and dripping down. I also noticed that the water in my reservoir was bubbling/boiling. So I turned off my car and I heard pressure being released. The water boiled for like 15 more seconds and stopped.

So my question is, what do you guys think is happening?? Why is the water/coolant so hot that it's boiling in my reservoir. I don't believe any of the main big hoses has holes in them which would cause my car to loose coolant. I'm pretty positive it's not my head gasket since it was changed about a year ago, or less. When I bought the car it had about 81k miles on it. I asked the man who sold it to me what he had done it it and told me the waterpump and timing belt were changed at about 65k. He gave me a receipt to go with it. Can it still be the waterpump?? Can the thermostat cause this??

Your help is appreciated. Thanks.

TheOtherDave™

First off, have you bled the coolant to make sure you don't have air trapped in the coolant passages?

Before assuming the gasket has failed, I would confirm that:
a) the radiator cap is maintaining pressure
b) the thermostat is opening fully and
c) that the thermostatic fan switch is functioning. The radiator fan should be coming on as coolant temp hits 202° to 205°F.

Also, when you pin the throttle, is there any condensing steam coming out of the exhaust?

It is possible that the new head gasket was improperly installed or that the head bolts weren't properly torqued. Both would lead to coolant seeping into the combustion chamber, causing the symptoms you describe.

Difussion3

Thanks for responding Dave. I haven't bled my coolant yet... on Thursday I ordered a few parts for my car. The parts include a new radiator cap (maybe the old one doesn't hold pressure anymore), a new reservoir cap (cracked), the hose inside the reservoir tank, the hose leading from the radiator to the reservoir, and the joint that attatches both hoses mentioned above together...

I noticed today that the reservoir cap is cracked... would this explain why the reservoir cap is always wet when I open the hood? And that water is always spilled all around that area? Could this be the problem??

Also, the radiator fans are functioning correctly. Once the car is at operating temperature, they do turn on fine. When you say pin the throttle, do you mean tapping it a little?
Well when I get the parts in sometime next week, I'm going to replace them while flushing out the existing water in the radiator and filling it up with 50/50 mix coolant. Hopefully this fixes my culprit.

Lynxs1981

Sounds like you could possible have a bad radiator cap that's not holding pressure. As to the reservior cap being wet, the crack could cause this. Also if the coolant is boiling in there, it could just be boiling out of the vent in the cap.

TheOtherDave™

It could be a contributing cause. But so long as the siphon hose (which connects to the reservoir cap is under the water line and the radiator cap holds, the reservoir shouldn't be pressurized much if at all.

My only other concern is that coolant could be seeping into the cylinders.

Sorry about that. h:
By pinning the throttle, I mean pin it to the floor.
Full-throttle acceleration through at least a full gear.

Some head gasket leaks won't become apparent until the combustion pressure inside the cylinders remains high for a long period of time.

And I can't believe I forgot to ask this earlier... but I assume you've checked the oil to make sure there's no coolant contamination?

If you can rule out a blown head gasket, that's great.

Difussion3

I did an oil change about 3 weeks ago and didn'd notice anything. Ill run my car today and check my dipstick to see if I see any residue in it.

I'm really hoping that with flushing the radiator I can rule out a hose leak. I'm just crossing my fingers that its something simple like a bad radiator cap not holding pressure. I'm going to be really upset if it is the head gasket, since I had it replaced about 1 year ago.

Ill be keeping you guys updated. Thanks for the help.

Difussion3

So I checked the oil in my car today and it looks clean. No milky or green color in it. But, I decided to open my radiator cap to see how much coolant was missing found these two pieces broken off the cap. A black piece laying on the bottom of the radiator opening and a spring. So what do you guys think?? Is this what is causing my problem??

TheOtherDave™

That's the spring that is supposed to maintain pressure within the coolant system.

Since a head gasket leak is ruled out, I'd say you've solved it.
I'll bet the new radiator cap and proper coolant mix will do the trick.

Difussion3

So I changed all the parts I mentioned, drained my old coolant/water & flushed it with radiator flush. I refilled everything with fresh 50/50 mix and it seems to have done the trick... I ran the car yesterday and opened the hood and no leaking coolant from the reservoir. So believe your right Dave, the radiator cap did the trick :rockon: