No coolant flow to heater core.
Thread Starter
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
No coolant flow to heater core. What would cause me to have no coolant flow to my heater core?
My heat has never been the same since I swapped the 5.3L into my El Camino, it blows out hot for a couple minutes and then is only luke warm. I finally got pissed off enough to pull the heater hoses and check it out. The heater core is not blocked. But when I put both heater hoses into a bucket and started the car I noticed that there is no flow from the engine, if I rev it up the coolant starts to trickle out of the hose but thats it. The coolant level is full and I am not running dex cool. Before I put the engine in I flushed it out and have been running prestone extended life antifreeze for a year now. What would stop the coolant flow? Bad T stat? Waterpump worn out??
My heat has never been the same since I swapped the 5.3L into my El Camino, it blows out hot for a couple minutes and then is only luke warm. I finally got pissed off enough to pull the heater hoses and check it out. The heater core is not blocked. But when I put both heater hoses into a bucket and started the car I noticed that there is no flow from the engine, if I rev it up the coolant starts to trickle out of the hose but thats it. The coolant level is full and I am not running dex cool. Before I put the engine in I flushed it out and have been running prestone extended life antifreeze for a year now. What would stop the coolant flow? Bad T stat? Waterpump worn out??
Heater control valve maybe stuck closed? Just a guess, but I dont think coolant flows through there unless the heat is on, and when the heat is on the heater control valve opens and allows it to flow through the heater core. Ron
Thread Starter
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
I did put the heater control valve back in after the conversion, but I checked it and it is working perfectly. It will flow as much water as my garden hose can put out which is a lot more than my motor can currently put out 
.
Where is the heater core in a truck/f-body, above or below the level of the engine? The only thing I can think of right now is that since my heater core is above the level of the engine, and is the highest point in the system that mabey the motor is not designed to push water that high
?
. Where is the heater core in a truck/f-body, above or below the level of the engine? The only thing I can think of right now is that since my heater core is above the level of the engine, and is the highest point in the system that mabey the motor is not designed to push water that high
? 
GB,
I don't know if I can help with your situation, but I'm getting ready to plumb the hoses in my LM7 Supra. Does it make a difference which engine heater hose fitting (5/8 or 3/4) goes to which port on the firewall?
The Toyota shows the heater outlet being on the driver side, and the inlet on the passenger side. I'd have to think if the flow were reveresed that maybe this would impede the heater's operation.
I can't find a heater hose or flow diagram for an LSX vehicle.
I found this here:
https://ls1tech.com/forums/showthrea...ht=heater+hose
Sounds like a similar sitaution, most think it is a blocked heater core, but that would not account for the lack of flow.
EDIT
BTW, it's like 80 degrees here today
, but our "winter" will be here soon.
I don't know if I can help with your situation, but I'm getting ready to plumb the hoses in my LM7 Supra. Does it make a difference which engine heater hose fitting (5/8 or 3/4) goes to which port on the firewall?
The Toyota shows the heater outlet being on the driver side, and the inlet on the passenger side. I'd have to think if the flow were reveresed that maybe this would impede the heater's operation.
I can't find a heater hose or flow diagram for an LSX vehicle.
I found this here:
https://ls1tech.com/forums/showthrea...ht=heater+hose
Sounds like a similar sitaution, most think it is a blocked heater core, but that would not account for the lack of flow.
EDIT
BTW, it's like 80 degrees here today
, but our "winter" will be here soon. Last edited by V8 Supra Builder; Dec 23, 2006 at 03:27 PM.
