The cooling system presure

[krot84]

Helo guys.
I have a problem, first of all I recently replaced my radiator cap for one that says 0.9 BAR and i began to notice that my radiator is loosing it's coolant, i noticed it by openig the radiator cap a couple of times before i start the engine in the morning.
Is there a specific radiator cap that i should use, i mean what's the minimal/nominal presure it should be able to hold ?

The thing is that the old cap looks pretty worn down and it doesn't say what presure it can hold, however i don't loose coolant with that cup.
Please i need your advise :-(

[Huffer]

Most radiator caps for stock vehicles keep the system pressurized between 13-15psi. This can raise the boiling point depending on the mix of coolant/water an additional 35-40 degrees. A 50/50 mix of anti-freeze and water has a boiling point around 265 degrees. Add to that a radiator cap that holds 13psi and now you have coolant that won’t boil until 300 degrees .

http://www.smart-service.com/blog/2009/ ... ad-gaskets (http://www.smart-service.com/blog/2009/09/prolonging-subaru-head-gaskets)

The cap you have - 0.9bar - is the same as a 13psi cap.

I would look for leaks other than your radiator cap.

[krot84]

Huffer you now somehow the leak began after i replaced my cup to the new one and i noticed that my cup and beneath it has a brown/orange sludge.

[Huffer]

1. Why did you replace your radiator cap?
2. Have you inspected your coolant overflow tank for oil, bubbles, or both?

[krot84]

1. I went to a garage replacing an AC HP hose and the mechanic told me that the cap is worn out so he replaced it for me.
2. I didn't, it's kinda hard to do so because i can only see that the tank is full of lequid as it should to.
BTW how do you inspect your tank for oil/buubles ?
P.s
If you like I can add photos of the new cap and the old one.

[02_Legacy]

What probably happened is your old cap didn't hold pressure so when you got the new cap now your cooling system is pressurized to 13 PSI and something cannot hold that pressure so it started leaking. You should have your cooling system pressure tested so you can find the problem.

[krot84]

That makes sense, however if i use ether the old cap or the new one the temperature keeps the same (the dial is in the middle).
For a conclusion what does it help me if the system is pressurized or not ?

[02_Legacy]

Huffer explained it earlier.

Most radiator caps for stock vehicles keep the system pressurized between 13-15psi. This can raise the boiling point depending on the mix of coolant/water an additional 35-40 degrees. A 50/50 mix of anti-freeze and water has a boiling point around 265 degrees. Add to that a radiator cap that holds 13psi and now you have coolant that won’t boil until 300 degrees .

So under normal operation your operating temp should be around 200 degrees. But if something happens and you start overheating, or even if you are running it hard on a hot day you could reach the boiling point than your coolant becomes steam and your engine dies.
If you are not going to fix it just keep a close eye on your temp gauge. But like I said before I recommend taking it to a shop and they will pressurize the system and find the leak. Or at the very least test your coolant to make sure you are at a 50/50 or better mix.

[krot84]

Yes i think i'll take the car to a garage tomorrow and let you know what's the result.

[krot84]

Alright then, I went to a garage, did a cooling system pressure check and noticed that the water pump hose is leaking (Part# 807615081), so I decided to replace both the water pump hose and the outlet radiator hose (Part# 45167AA030).
The parts were ~$15 together - aftermarket.
A replaced them myself, filled the coolant.
I've been driving for a day now and the temp is fine (right in the middle) and there are no leaks, the only thing that bothers me is that the inlet hose feels a little too hard when i put a little pressure on it with my fingers, I can't tell if that all the time hard but sometimes when i start the A/C it turns soft again.
Is that fine ?

[krot84]

Somebody please, i need your help.
Is that ok that my inlet hose feels preaty stiff when I press on it with my fingers ?
I'm looking for a 500 mile drive next week, and i don't want anything do go wrong...

[Huffer]

It's fine. They're new hoses, you want them to be firm.

[krot84]

they're stiff when the engine is running and it's in his normal operation temperature.
I've done some reading and some say that there could be a problem with the head gasket.
How can I find it out for sure ?

[Huffer]

Compression test on the cylinders would tell you if there were any major leaks, also a loss of coolant without any leaks would be a tell-tale sign.

Oil and bubbles in the coolant overflow tank combined with a rising temp gauge when the car is sitting idling are usually excellent indicators of HG failure.

Be careful not to be looking for problems that aren't there.

[krot84]

Yeah I'm aware of this fact.
Unfortunately I'm too pedantic about my car :)

[krot84]

Well, I came back from my trip and I have to say that everything went out just great.
I had put a 44K just before I took off.
The fuel consumption was ~16Km/Litter - I don't know how much it is i gallons/Mile but it's pretty economical.
My water temp was steady during the whole drive - just a little beneath the middle of the gauge.
For a conclusion I'm very satisfied with the car.

[Wiscon_Mark]

Uh, yeah, that's 37 MPG. Wow.

Kinda makes me want a 1.8L

[krot84]

Uh, yeah, that's 37 MPG. Wow.

Kinda makes me want a 1.8L
Inspite of that i want a 2.5 GT.
Too bad it was never imported to Israel. :cry: