Heater core no coolant circulation, but not plugged

[llamavan]

Well, look at it this way ... what's the cost of aftermarket headgasket PLUS OEM headgasket PLUS doing the job twice?

Just go OEM. It will save you waaaaay more money than you're fussing over right now.

Gwen

[coronan]

My felpro failed after 2 years.

[timsrv]

Well, look at it this way ... what's the cost of aftermarket headgasket PLUS OEM headgasket PLUS doing the job twice?

Just go OEM. It will save you waaaaay more money than you're fussing over right now.

Gwen

[Filippo]

Update: it wasnt the head gasket. I tested it and no products of combustion in my coolant. I borrowed a pressure tester and found a pin hole in the hose from the heater core. As the engine heated it moved coolant into the resevoir, as it cooled it drew air in from the hole instead of coolant from the resevoir. Air pockets gathered in the core and didnt allow proper circulation. Problem solved....i hope. The head gaskets must be tough to not habe failed under these conditions.

[Busyboy]

I am having the same issue. Van runs fine for awhile then the heater in the front stops blowing hot and the van overheats. I have replaced the water pump, new belt with correct tension, replaced and later removed the thermostat. Disconnected rear heating route, checked the flow valve in the heater hoses, flushed the engine and hoses and heater core, replaced the radiator, replaced the fan clutch, and added a 2nd aftermarket fan. I removed the air conditioning fan and condenser to allow more air flow to the engine. I dont see any external leaks. I ordered a block leak tester to check the head gasket but i dont see oil in the water or any white smoke. Im running out of ideas of what it could possibly be. Any ideas or suggestions?

Okay now, 2 things.
How does the radiator look on the outside front? If the face is blocked by those fluffy balls from cottonwood trees you'ld never see it, happened to me so I blew high pressure air through to clear it. Simple stuff but ya have to look.
But if there's a clue after it's after "awhile", Meaning obvious it's blowing or leaking or burning out the coolant lowering the fluid level to the point the heater core goes dry, thus no heat inside and then the engine gets hot.

I just want to see someone pull the heater core. I had a mouse plug the plenum up with carpet fiber and I'll be danged if I can figure out how to get it cleared without pulling the entire dash apart again.

[Filippo]

Even though i had no signs of head gasket leakage, i finally went ahead and changed it out. That was the problem. Hot gases from combustion were crossing into the coolant, super heating and pressurizing it. It forced the coolant into the reservoir and eventually the level would drop low enough to not have an adequate amount to reach the heater core

[Ace MM]

Wondering if the rear heater has anything to do with it. Does it work?

I recently replaced the thermostat and flushed the system but still didn't have good rear heat.
Tapping on the metal line around the flow switch, 1 sprung a leak.
I had to cut the rotted corner off. There was a lot of debris trapped in that low corner that wasn't touched in the flush. I re flushed from the back and fixed the tube.
Good heat in the rear and stays 181* all day.



If there was any oil in that frothy green coolant, it would be an obvious head gasket. The color is indicative of an issue.

I use the Toyota red coolant in all my Toyotas.
Ill never felpro HG again! Anywhere else I would.

[ingmire]

Hey guys<br><br>just left the house 1 mile drive and my temp gauge is almost at the ceiling! I turn the air to maximum heat and it was coming into the cab cool.. which I've never experienced. Is this a thermostat symptom?<br><br>thanks for any advice

i was 24oz low on cooolant. Things seem to be good now anyone know how to delete this post?

[Grappler]

First thing I'd check once everything's not hot is your coolant level, not just in the overflow tank but under the actual pressure cap. A lot of times, this symptom is indicative of air or exhaust gas circulating instead of coolant.

Once you ensure it's all the way filled up, you can more easily determine if it's a leaky hose (see: hose of death threads) a radiator leak, or exhaust gas seeping into the system from a gasket break and expelling the coolant (that would be apparent if there's bubbles in your overflow tank after running)

Note: I realize this sounds like potential doomsaying, but I will say the first time this happened to me it was a bad radiator cap, so it can just as easily be something simple!

[bushcat]

If the rear heater core is clogged, could that affect heat in the front? I removed the controls for the back and I've flushed the front heater core and I still get pretty weak heat. I know they are weak in general but mine seems especially weak. It's warm but if I was in snowy conditions, I'm not sure it would defrost in an hour.

[timsrv]

Rear being clogged wouldn't effect the front unless the clog was in the common return line (unlikely). If your heater is not blowing hot, the 1st thing to check is the coolant temperature. It should be ~180° F or so. If the coolant isn't getting hot then the heater won't get hot either. If that's the case then replace the engine T-stat. If the coolant is hot, then get under the front of the van to make sure the cable controlled heater hose valve is open. If it is, then check the duct doors to make sure they're opening/closing correctly. If all that checks out then the next most likely issue is a clogged heater core. Tim