[mopar4u]

91 voyager 3.3
I'm gonna use the prestone flush n fill kit to back flush the entire system including the heater core. It says I need to open the petcock on the bottom of the radiator while back flushing. I don't recall seeing a petcock on this radiator. Is there one and i'm just not seeing it? If not what should I do, could I do this flush with the lower radiator hose disconnected?

also wondering which hose is the inlet hose for the heater core?

 

[RickMN]

There is a petcock on the radiator. It's black plastic, so it's a little hard to find. The inlet to the heater core always come off the top of the engine (where the coolant is hottest)

 

[Rick99]

There is a petcock on the radiator. It's black plastic, so it's a little hard to find. The inlet to the heater core always come off the top of the engine (where the coolant is hottest)

Rick-- I've had three vehicles since I started working on my own vehicles, and the petcock on all three of them has never worked. I can turn them, but nothing comes out. Am I missing something? Do I need to turn them and pull them out or something? I ended up siphoning the radiator and then pulling the lower hose (messy).

Mopar4u-- sorry for the sort-of hijack, but I'm sure you'll want to know this information when you go to do this.

 

[XDGT03]

yes, you do have to pull it out some. Actually, I did not have to do that before fluid started coming out but it does not thread like the old metal ones. There is the plug which has a course thread on it and has a nib so it kind locks when fully seated. There is a big thick gasket that I think is red on mine. It takes a couple of turns to get it fully unthreaded but then you need to pull.

 

[vabear]

Flush

I have a '96 3.3 and the petcock is a PITA as the "O" ring tends to break when removing the plug(dealer techs have sane problem) so I drop the lower coolant hose (radiator to block) and drain her that way (yes I do have to remove the splash shield), but I never have to buy a new "O" ring.

 

[mopar4u]

so, back to my question, can I simply remove the lower hose and still use the prestone flush and fill kit or do I have to just use the petcock?

 

[Rick99]

I have a '96 3.3 and the petcock is a PITA as the "O" ring tends to break when removing the plug(dealer techs have sane problem) so I drop the lower coolant hose (radiator to block) and drain her that way (yes I do have to remove the splash shield), but I never have to buy a new "O" ring.

Yeah, I defaulted to that method, but I try to syphon as much as I can from the radiator first to reduce the mess.

 

[vabear]

Flush and Fill

Pull the lower hose off of the block (ensure radiator cap and coolant overflow bottle caps are off) and let her drain, when empty do your flush and fill, always using the lower hose trick to drain the system. I sometimes drain her, reattach hose fill her with water and flush, run the engine with heater on (this is your flush) re-drain and then fill.