Found Cooling System Problem - now what?

[turbojimmy]

Holy crap.

If you recall, my new engine has been running "warm" since I put it in. I say "warm" because it's not "hot" as in overheating, but it very sensitive to outside temps and gets to operating temp almost instantly. The hottest it's gotten is 205 or so on a 95 degree day - but I have a 160 degree stat. Haven't really figured out why until today.

I'm not sure why I've haven't done this in the 600 miles I've driven the car, but when I got home today after a 100 mile trip I parked it and figured I'd see if there was any coolant system pressure. Gauge shows 190 degrees. I had noticed that the overflow level wasn't moving around much, so I got a rag and turned the cap one notch expecting a blast of (hot) antifreeze out the cap. Now I'm thinking I have a timebomb. Turned it one notch, maybe the rubber seal is stuck and it's gonna blow. Turned it one more to remove it and.....there's no cooling system pressure AT ALL. Zip. WTF is that about?

If the thermostat was stuck shut, would the car still stay cool enough not to overheat from the bypass?

Rad is full, overflow tank is halfway between add and full (doesn't move when hot, obviously). No steam from the tail pipes, no oil in the coolant or coolant in the oil. No bubbles in the rad or overflow tank.

This is freakin' me out.

Jim

 

[Buick Beginner]

Just my 02

I got a book from the library called "Cooling System Basics" it's very interesting, got a video from the library by the same title. If I can get smart enough, fast enough I'll send you some info. In the mean time, go by your local library, you might be surprised. That book was printed in 1998, so the info is up to date. - BB

 

[turbojimmy]

Re: Just my 02

Originally posted by Buick Beginner
I got a book from the library called "Cooling System Basics" it's very interesting, got a video from the library by the same title. If I can get smart enough, fast enough I'll send you some info. In the mean time, go by your local library, you might be surprised. That book was printed in 1998, so the info is up to date. - BB

Thanks for the reply - I'll check it out.

Couple other thoughts.....

Could it be as simple as the cap? It's new, but maybe it's not working? Wouldn't it puke antifreeze out of the expansion tank if the cap was just letting it all blow by? With the cap on, if I squeeze the rad hoses, the expansion tank fills up. Did I just answer my own question? Or when I squeeze the hoses do I get the 16 PSI required to blow past the cap?

Jim

 

[1ARUNEM]

Couple of things..

If the T stat is stuck, the car would overheat very quickly (and get much hotter than 205 degrees).

Secondly.. If you have the cap on tight, the system is not ALREADY pressurized and you squeeze the hose, it should NOT be anywhere near enough pressure to push the fluid back to the overflow.

I'd change the cap for $5 first and see if that yields any positive results..

HTH..

 

[Jimn8or]

Another thought....
Ensure that your hot water shut-off isn't 'frozen' in the closed position! Simple check, be under the hood when someone inside the car turns on the A/C and watch the valve. If she moves, great, it's fine...if it don't, this could be the source of yer problem PS: make sure the vacuum line is attached to this valve too!
HTH
Jim

 

[turbojimmy]

Just bought a new cap - same thing - no pressure. Looks like the heater valve is operating okay, too - thanks for the info.

Jim

 

[turbojimmy]

TTT

So what does the pressure in the cooling system do for me. It reduces the boiling point, right? It also makes it run cooler? Or will I still have a run hot problem even if I solve the pressure problem?

Jim

 

[John Larkin]

Try this for free. Drain down about 2" of coolant from the edge of the neck. Start the car, leave the cap off and see when the coolant starts coming through the tubes. That's when the thermostat opens. At least you'll know if it's opening.

 

[FJM568]

Pressurized cooling system increases the boiling point...

Are you losing any coolant at all??? What kind of cap did you buy??? If Stant, take it and throw it as far as you can one way and run as fast as you can in the opposite direction!!! Got to GM and buy OE cap...I think the one that I got from them for my car was only like $6 or $7, not much more than aftermarket, but better quality...

I'm not sure, but I think someone like Autozone may have cooling system pressure testers for rent...Get one and try to pressurize your system and listen for leaks...You may just have a pinhole leak that is bleeding off steam and not leaking any coolant or a loose clamp on a hose somewhere...

After you drive it and warm it up, park it in a quiet area, shut it off, and pop the hood and see if you can smell and anti-freeze and listen for hissing or whistling...

99% of the time, the T-stat sticks shut causing overheating, but may actually stick open occasionally, taking longer for the engine to warm up...

 

[turbojimmy]

Thanks for the info and tips.

I'll try draining it down a bit first to see if the 'stat is working.

And I'm not losing any coolant at all. Level hasn't moved since I filled it for the first time. I don't get any antifreeze smell at all. I park it in the garage every time I'm done with it and am sensitive to every smell. Still smells like paint drying. Nothing else.

Yes, it's a Stant cap. The old Stant cap worked fine, the new one does the same thing. I'd rather have the OEM one. You have a part number by any chance?

Thanks again,
Jim

 

[FJM568]

According to the 44w parts book - #6410427 for all 82-87 g-body cars...