Engine Coolant cap stuck. Any ideas?

[akeeeno]

I want to add some engine coolant to my car but when I take the cap off, I get this... Any ideas? I can't seem to get it out easily.

[danielsatur]

With the cap off, is there a piece of cap stuck in the coolant reservoir tank?

Caution - Coolant can get very hot!
Add 50/50 mix to the cold line on your coolant reservoir tank.
If you don't know what color to use, prestone makes an extended life 50/50 mix for all colors.

[akeeeno]

Originally Posted by danielsatur

With the cap off, is there a piece of cap stuck in the coolant reservoir tank?

Caution - Coolant can get very hot!
Add 50/50 mix to the cold line on your coolant reservoir tank.
If you don't know what color to use, prestone makes an extended life 50/50 mix for all colors.

Yes, it looks like there's a piece of the cap stuck. Is this something I pry off? Twist off? The underside of the cap looks normal though, I have no clue if and how part of this cap got stuck..?

[danielsatur]

Doe's it look like a coolant strainer, or a broken cap?

You might need to drill a small hole in the stuck piece in the coolant tank, so you can poke something in the hole and pop it out.

[pfofit]

I've had these guys break on other gm's. If it's not opened up enough, the internal o-rings dry up and hardens and coolant crusts up the cap and cause the lip that on the piece that is stuck in the reservoir to let go and all you get is the upper part.

I normally wet the o-rings with a smear of something when I open one up to prevent what you have. Since you have it now, they can be a bugger to release and be careful not to break the reservoir.

It sometimes helps if you can get a bit of light oil between where the leftover cap and reservoir meet. Stick a flat blade between the two in several places and let a bit of oil wick in or run down the blade and then let it sit a bit to work in. This will only lube the upper o-ring. Then work around the perimeter with the blade tip ever so slowly lifting it up. Do not try and pry it up in one go on one side. Two blades on opposite sides is better and if you have an extra arm then three. The trick is straight up, slow and easy, like a gear puller. However a bit of rocking may be necessary if there is a whack of crusty bits at the bottom o-ring.

Good luck

What it is suppose to look like and what your up against.

[sparcx]

i almost had a similar problem this morning. cap would get stuck about half way. Luckily i realized that i might break something if i twisted too hard.

I tried again tonite after the car had mostly cooled down but still slightly warm and it finally turned the last bit.

Wonder if it's time to get a new coolant reservoir cap just in case.

[danielsatur]

Being made of plastic, and heat damage, it's probably worth replacing befor it does break.

[pfofit]

Originally Posted by sparcx

Wonder if it's time to get a new coolant reservoir cap just in case.

You'll find that if you clean it up and lube the o-rings it'll spin on an off in a breeze.

[sparcx]

Originally Posted by pfofit

You'll find that if you clean it up and lube the o-rings it'll spin on an off in a breeze.

thanks... i might try a little dielectric grease and see if that helps for now

[vegastvt]

hi i have a similar problem on my volvo s40 2007, any tips

[Meztrov]

Hey guys, I was super worried because I might of melted my cap onto the tank, but in the end I got it open and here's how...

If it's just too tight.

Then, seriously, just heat the car up, by either idling/revving OR driving it until hot.

hen turn the car off and wait for 20 minutes (not enough for the car to fully cool down).

Go ahead and wear a glove and covering your face (nothing happened to me, but safety first), slowly open the coolant cap (remember lefty loosey). Loosen the cap only about a quarter of a turn, and never fully or even till pressure escapes. Then you should leave it, wait till it cools down fully, then it'll be safe enough to fully open the reservoir cap.

I got mine open after work, when I got home, went upstairs cooked something to eat, came back down, and did as described above. Haven't checked on it yet. Will do in the morning when I go to work again, I'll just add some anti-freeze. It's ratio is consistent of mainly water at the moment. After my car overheated on the way to work a week ago, because I didn't put the cap back on properly the pressure boiled over, spilling antifreeze all over the engine.

If that doesn't work. Buy a wrench that fits around the cap and wrench it open that way, but try to do this slowly so you can assess the situation and not cause further damage. UNLESS of course it tells you specifically to push down before twisting.