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Heater core\cooling system questions

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turbosam6

My cars suck
Joined
Jul 24, 2001
Messages
3,356
Well, it looks like my intake may not be leaking after all. We pressurized the system, and after messing around with a stat housing that was a pain to seal, we think the heater core is leaking, cuz you can hear something hissing back there. We pressurized the system to 15 psi, cuz thats what the cap is rated for. We then bypassed the heater hoses, to isolate the heater core. Didn't hear any hissing at 15 psi then. We only left the pressure on for a minute, then bled it off. So looks like a new core is in order, my question is, did we do this testing right? Is the pressure supposed to stay on for awhile, or not? I couldn't hear any hissing after the core was bypassed, but is that good enough? Thanks
 
Your post is not too clear?

If you bypassed the heater core and still cannot hold pressure, there is a leak somewhere. Pressure should hold period.
 
Leakin??

If the core is leaking, you should see the coolant running out of the bottom of the heater/ac box...OR, it's running into the passenger side floor! Check the carpet to see if it's wet...

The psi should stay for a considerable time....Are you using a rad pressure testing pump or air pressure from a compressor??
Should be using a rad tester.. once it's pumped up to 15, it should stay there...UNLESS there's a leak!:eek: :eek:

Check the oil too..
IF you can hear the leak, it's GOTTA be a big one!!!Lotsa fluid is going somewhere!! NOT GOOD!!
 
OK, I'll rephrase. We installed a new intake on the car. I filled up the coolant, drove around, all seemed well. I started looking over everything, and saw coolant around the front of the intake. I thought it was a poor seal on the intake gasket, even though we did it right. So we pressure tested it, and found the stat housing was leaking really bad, and the coolant was running down across the front of the intake. So we finally get that to seal up, and pressurize the system to 15 lbs. You could hear hissing from the heater core area, so we bypassed the heater core. We then put pressure back up to 15 psi, and didn't hear anything, but only left the pressure on for a minute or two. My heater core never leaked before, inside or outside. Maybe the pressure from the test opened something up, because I doubt my car ever see's 15 lbs. It runs cold. We DID use a radiator pressure test kit, where it screws on in place of the cap. I'm wondering if we should do a longer test, or if this is satisfactory. I guess we will replace the core, but I"m going to test it by itself before, just in case it was the valve or something, like I said, it never leaked before. How long should we leave the pressure on? I bypassed the valve also when I bypassed the heater core. So to summarize, with that stuff bypassed, you can no longer hear any leaks, but the pressure was only on for 1-2 minutes, and I don't know if thats long enough to call it good.
 
I re read that and I don't think I got my point across-bear with me guys, I'm sick. Mind is a little foggy. My main concern here is the intake gasket and cooling system, not the heater core, I can diagnose that easily. I checked the oil a lot, and it is clean, and the level is the same, so no reason to suspect coolant in the oil. Thanks
 
Ok you said when you bypassed the heater core and valve, the hissing stopped. then why are you concerned with the intake if it stopped hissing when the heater was bypassed? Sounds like a heater core or control valve..... :rolleyes:
 
Because we just installed this intake, and the t stat housing did not want to seal. I don't know that just because I can't hear it doesn't mean its good. Again, screw the heater core, I'm worried about the motor.

Heater core-$30
My motor-$$$$$way more
 
Hi

Sorry to hear that your under the weather. Just put the pressure tester on for about 5-10 minutes and observe if you have any pressure drop. If there is. Look around externally and if none is found loosen the drain plug and watch for what forms on the plug since coolant will settle to the bottom as long as it was not mixed with the oil. If none then pry either air going past the control valve or a heater core leak. Good luck and take care.

Steve:)
 
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