nickl

Hey all,

Just noticed after a 30 min city trip that my upper rad hose is not hard.

Rad is new as is cap & water pump. Can't say I have noticed this before...

I am thinking the cap is not pressurizing? Temp of engine is OK & not losing any coolant. Top hose should be hard when engine is hot, right?

djb383

Yep, it should be but up in your area, it could be cooling off quickly enough (engine off) for the pressure to drop. Do u notice coolant level in the bottle rising a bit when hot and dropping a bit when cold? Have u removed the rad cap (ENGINE COLD) to make sure the system is full of coolant?

kojoff

Mine isnt always hard after driving.. (that just sounds weird saying it). Guess it just depends on how hard you drive.

95THORxj

mine is hot & hard after driving awhile. sounds like the beginning of a b rated **** movie i had in highschool!!!

nickl

It would only be high 50s here today in the rain, but you can open the rad cap 5 minutes after driving for 30 mins in the city-no steam, nothing.

nickl

& it is full of coolant. I should add that my e-fan is running all the time too as I need defrost on currently.

djb383

Where is the needle on the temp gauge (when warmed up)?

nickl

its @100C or 212F.

nickl

Nobody has any ideas?

2Evil4U

you'll only build serious pressure above boiling point. otherwise it's just thermal expansion of the fluid. I wouldn't worry about it.

nickl

It is running fine, my buddy noticed it & thought it strange-suspected rad cap wasn't making pressure (16lb cap).

djb383

Check it after driving a bit (normal engine temp), with the engine still idling, hoses should be firm. CAREFUL, hot too. If hoses are not firm, engine hot and idling, I'd suspect a bad cap or the cap is somehow not sealing properly.

nickl

Hoses are hot, but you can squeeze the hoses flat.

I put on a prestone cap today, will see if that makes any difference.

I wonder whether the newish rad has a manufacturing defect that causes it not to seat with the caps properly. Not much can be done about that I guess.

djb383

It's gotta be the correct cap for the specific rad. It sounds like the cap is sealing on top of the rad ok (coolant would be leaking out if it wasn't) but possibly the rad cap is not sealing farther down in the neck of the rad (the pressure release portion of the cap).

nickl

This is what I was thinking too, but this is the suggested rad from the parts shop. Everything else lined up fine but it is a chinese one....

Sadly the replacement rads don't come with caps you must get the cap separately.