Thinking
Senior Member
Joined: Apr 2014
Posts: 6,246
Likes: 797
From: Indiana
Originally Posted by Salvador Rodriguez
i have a 98 f150 with a 4.6L. My issue is that the truck starts but when it is put in drive or reverse it stalls out. Have switched out a lot of the throttle area. Body, idle valve, Hoses. Checked vacuum leaks and nothing seems to fix the problem. I was told by a friend of mine who thinks it could be the torque converter. But I’m not sure. I just want to get this truck fixed ASAP.
Thanks.!
Thanks.!
So flushed the core, poured the Prestone radiator flush into it, let it sit for 20 mins, flushed again. Switched hoses, flushed again, switched back (heater core outlet -> hose and heater core inlet
-> hose dump into bucket) and flushed for about 8mins.
Never saw a ton of gunk or discolored coolant/water at all like lost people claim to see. But the water pressure coming out was pretty equal to the hose going in. Once coolant was flushed it was clear water the entire time (minus when it was the Prestone coming out). So now I have heat when I'm driving/higher Rpms but while sitting in the drive thru idling the heat started to fade. Took off and the heat went back up.
So failing water pump or semi clogged heater core?
-> hose dump into bucket) and flushed for about 8mins.
Never saw a ton of gunk or discolored coolant/water at all like lost people claim to see. But the water pressure coming out was pretty equal to the hose going in. Once coolant was flushed it was clear water the entire time (minus when it was the Prestone coming out). So now I have heat when I'm driving/higher Rpms but while sitting in the drive thru idling the heat started to fade. Took off and the heat went back up.
So failing water pump or semi clogged heater core?
Senior Member
Joined: Apr 2014
Posts: 6,246
Likes: 797
From: Indiana
Originally Posted by jprevat
My bet is on water pump. I would rather change that than the heater core any day. lol
Now an XLT in Colorado
Joined: Aug 2016
Posts: 5,977
Likes: 3,170
From: Colorado
I don't know about confirming, but I agree that it's likely the pump. It makes perfect sense. Insufficient flow at idle, better at higher RPM. I'd expect the engine temp to be higher (or too high) as well, but with the cooler weather, that might not happen.
Senior Member
Joined: Apr 2014
Posts: 6,246
Likes: 797
From: Indiana
Originally Posted by OhioLariat
I don't know about confirming, but I agree that it's likely the pump. It makes perfect sense. Insufficient flow at idle, better at higher RPM. I'd expect the engine temp to be higher (or too high) as well, but with the cooler weather, that might not happen.
