goofy cooling and heating

[badcamelot]

Start car up and drive to work, within 4-5 mins cars engine temp starts to rise. In the past once the gauge needle reached the L or A on the gauge the heat was warm to hot, but awhile back it would only blow cool air, then I noticed that the gauge would quickly climb up to about the N on the gauge and stay there briefly then quickly drop back to the A on the gauge and hot air returned. You're thinking thermostat, so did I. I have replaced the new one I bought thinking perhaps I got a dud, but the latest new one produces the exact same thing. No fluid is visibly leaking from the water pump, no squeak nor any other sound coming from pump. The radiator was a little low (perhaps a quart) when I replaced the thermostat last. Im stumped. The 'mechanics' of the heater core operate in accordance with the gauge, but 'electronics' of a faulty gauge wouldnt stop the heater core working correctly. The is no coolant smell present in the car either, and no sign of anything leaking after the car has been parked.
Any ideas?

 

[93rev2sev]

Low coolant. I guarantee it.

 

[badcamelot]

I filled it when I replaced the thermostat on sat. Sunday morning got in car to go to work and exact same problem.

 

[93rev2sev]

Fill it moar.

 

[zach44102]

Have you realesed all the air out of the system?

 

[93rev2sev]

Realeast*

 

[badcamelot]

I'll try, thanks

 

[badcamelot]

Few times in life we are given the invitation to say "told you so" but your guarantee of low coolant gave me pause, so I checked again and it swallowed a whole bunch. If you meant by asking about releasing the air, had I attempted to push fluid through and force air out, I believe so. After pouring coolant and water in it would burble down into the radiator and I would squeeze the upper radiator hose and sort of pump (but surely squeezing the upper hose isnt going to push coolant through the thermostat, is it?). Im unaware of any other method....Im willing to learn if you have a suggestion. But now sir for your moment in the spotlight, go ahead and tell me....
I guess the next question, where did all the coolant go? Perhaps now is when closer inspection and monitoring of the pump comes in to play, but I changed to radiator cap some time ago with a 13lb one. I had a choice between 16 and 13, couldnt find anything in print, so went with what seemed the best choice.

 

[TopGunnYFZ]

Check it again in a few days and keep your eye out for puddles. My gf car developed the samething crossover is leaking. Slow leak and easy to overlook!

 

[frosho]

First, ditch the 13lb cap and get a 16 in there. The cooling system is designed to work at 16 psi. That might explain where some of your coolant has been going (out through the overflow). As for working the air out of the system, squeezing the upper rad hose should help. Make sure to do it while the car is idling though. The "pulses" that you create by squeezing the hose will help to dislodge air pockets in the system.

 

[93rev2sev]

I usually have to fill and refill at least 2 times after I drain coolant, pumping the upper radiator hose the whole time. Even if I let the car run while I'm filling it, somehow, enough air gets trapped to where the water pump can't circulate coolant at idle. Once the RPMs get up and stay up at about 2500, the water circulates. This is evidenced by the temp needle dropping like a stone all of a sudden while you're driving.

The 13lb cap didn't hurt you here because you probably never got to 13 lbs. See, the coolant expands when it gets hot and pressureizes the system. once that pressure exceeds the pressure of the spring on the radiator cap, air and excess coolant get pushed out, into the overflow bottle. If there's too much air, though, the coolant wont expand enough to overcome the radiator cap.

 

[badcamelot]

2 + 2 does equal 4! Thanks guys for your advice and help.

 

[badcamelot]

Update: coolant leaking out (a quick successive drip) at the bottom of the radiator on the drivers side.....now I know where all the coolant went, just need to figure out where it is coming from. Hoping the radiator itself isnt damaged.

 

[frosho]

There is a drain down there on the driver's side. That could be loose/leaking. Other possibilities include the upper radiator hose and the radiator end tank. Stock radiators commonly fail at the crimp connections with the end tanks. If you end up needing a radiator, consider this all-aluminum unit: http://www.genesisautoparts.com/product/all25274X2192aa.htm

 

[badcamelot]

I found a small crack just under the bolt where the electric fan shroud bolts to the radiator. Im reading lots of things online about products and ways to fix. Im a bit worried about pouring fix a leak chemicals into the radiator for fear of gumming up something like the pump or thermostat. JB Weld make a stop radiator leak product, has anyone used that before? I was contemplating using E-6000 on the outside then putting in soem of this JB Weld 'perm o leak' or something. Any thoughts?

 

[NORMAN]

AutoZone radiator with limited lifetime warranty is only $99.99 plus tax.

 

[badcamelot]

Update, the crack was not that significant, but it was cracked on the plastic portion. I tried JB Weld (sorry this stuff sucks and has never worked on anything Ive tried) and stop leak stuff. Neither worked. I used to work for an acrylic fabricator and called him. He told me only welding the plastic (there is a specific name but I can neither pronounce it let alone spell it) by plastics people who know how and have the tools to do so. It was removed and during the removal the coolant adapter for the tranmission line was so rusted that upon attempt to remove/replace the adapter collapsed and then the whole fittingcracked and now spins. So the old radiator is toast. Fortunately I still had the one from the donor car I scrapped and use now.
Filled, refilled and topped off a couple of times. Problem - I hope - solved....now I just have to exchange the atx that is slipping really bad. Gonna try to do so without removing engine, just support engine and then drop out subframe and atx! Wish me luck! Never done it before, but with this forum even a dunce like me can!