LB7: No cooling system pressure???

[770JOHNNYW]

so i was driving the other day and noticed a coolant smell coming through my a/c vents. I assumed i had pushed an injector cup out but when i stop and shut the truck off i had zero pressure in my system. My upper hose is cold and at any time even if i have been beating on the truck i can walk out and pop the cap of my coolant tank...the truck never runs hot for that matter wont break 200 degrees. i pressurized the system last night and it slowly dropped from 16 psi to 10 psi over night. I dont see any loss of coolant an the truck still has rediculous power...any ideas?? motor may have 500 miles on it

 

[Mike_S]

How strong is the coolant smell? You could have a heater core leaking inside the truck.

 

[770JOHNNYW]

Its not horrible but it is coming through the vents so its there and its not all the time either... I assume its not a cup because I'm not pressurizing anything! And its almost to early for a head gasket to pop.

 

[770JOHNNYW]

Do these heater cores leak in the floor? Mines not I don't think

 

[Chevy1925]

Do these heater cores leak in the floor? Mines not I don't think

It wont leak on the floor, it will leak out the little tube the A/C evap water drains out of. If its only leakin a little, you will still get a strong smell but may not see any dripping out. Your pressure drop is not that bad. 6psi with a change in temps is about right (the colder it gets, the less pressure there will be in the system). Turn your heater on and see if the smell gets worse when your drivin.

 

[770JOHNNYW]

thanks...the coolant smell dosent seem to get worse or better with the heater on. that would make sence with the coolant drop because i put the tester on it while it was hot. will this cause the seytem not to build any pressure at all? It just started recently the hose would get stiff after i drove it but not anymore. Man i hope a heater core fixes this thing!!!

 

[Chevy1925]

thanks...the coolant smell dosent seem to get worse or better with the heater on. that would make sence with the coolant drop because i put the tester on it while it was hot. will this cause the seytem not to build any pressure at all? It just started recently the hose would get stiff after i drove it but not anymore. Man i hope a heater core fixes this thing!!!

could but you would have to be loosing a good amount of coolant to not build pressure. You might look at testing/getting a new coolant resi cap. if its gone weak, it will let pressure out and give a coolant smell as you drive if your vents are on outside air, not recycle.

 

[770JOHNNYW]

could but you would have to be loosing a good amount of coolant to not build pressure. You might look at testing/getting a new coolant resi cap. if its gone weak, it will let pressure out and give a coolant smell as you drive if your vents are on outside air, not recycle.

ill try a different cap this afternoon...im not seeing any coolant on the ground. Thanks for the help

 

[Mike_S]

could but you would have to be loosing a good amount of coolant to not build pressure. You might look at testing/getting a new coolant resi cap. if its gone weak, it will let pressure out and give a coolant smell as you drive if your vents are on outside air, not recycle.

Thats the next thing i was thinking too, given that if any coolant is vented its dumped right in front of the heater box on the firewall. I would also recomend the cap, start with the cheap stuff first!

 

[770JOHNNYW]

Well the cap fixed it im back to building pressure and pressure tested the truck cold held 16psi all night!!!

 

[GMC_2002_Dmax]

Just don't break it before the end of the month, I'll do that for you.......:thumb:

 

[770JOHNNYW]

Just don't break it before the end of the month, I'll do that for you.......:thumb:

Im hoping i can keep you the hell away from this thing!!! we may just work on the 1st dsp position and stay the away from race tunes:roflmao: