I'm having head gasket replaced along with resurfaced heads on my 97. The shop told me the heater core is clogged and I should fix the heater core before putting motor back together or the heater core could cause another head gasket issue. Does this sound accurate or could it just mean the heater may not work properly after it's put back together?
Heater Core Question
- Thread starter westtx_cruiser
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Uhh...no. Unless its leaking and the loss of coolant overheats the vehicle.
Yes
When I got my 80 years ago, my front heater was "OK", my rear was almost completely plugged. I was able to clean both without removing but the rear took quite a while.
- Thread starter
- #3
What was your process of cleaning them?
^this
I dont remember the chemical but it was fairly mild. I cleaned out my overall cooling system, added a mild flush chemical and drove for a week. I ran straight water for this.
Most of the process was a length of clear hose and a plastic ball valve. Unhook the heater and flush one direction then the other, back and forth until It came out clear. I hooked it back up, added more water and chemical. repeated each week for three weeks.
The fourth week, almost no discolored water came out of the core. The next year, I flushed out the system and manually flushed both cores to see if any much was stuck in there. All good.
Most of the process was a length of clear hose and a plastic ball valve. Unhook the heater and flush one direction then the other, back and forth until It came out clear. I hooked it back up, added more water and chemical. repeated each week for three weeks.
The fourth week, almost no discolored water came out of the core. The next year, I flushed out the system and manually flushed both cores to see if any much was stuck in there. All good.
Thermocure
this thing made the radiator and the heater core / rear heater act like new.. Give the rig 6-8 mins and the heat is going to make you sweat. there is a proper procedure to using this so flush with distilled 3-4 times, then pour this in with distilled and drive for 1-2 hours. drain asap and refill with 50/50 red
I will second thermocure for rust. It cleared up a severe cooling system rust problem for me. For mineral deposits it’s hard to beat CLR.
"The shop told me the heater core is clogged"
@westtx_cruiser
How did the shop diagnose that? Was there no heat coming from the vents when the HVAC slider was pushed over to full heat? Was the cooling system full when that was checked? Had anyone added any type of cooling system or block/head gasket sealer to the radiator?
Did the shop tell you they found anything blocking the heater hoses?
IME the small bypass hoses can block up (if sealers have been used) so check the bypass hose that runs from the top of the radiator to the outlet pipe on the engine. Also check the small water hoses that run to and from the Throttle Body to see if they're blocked with anything (head gasket sealer for example). And if any of those are plugged then the heater core may also be plugged.
If a head gasket sealer was used and they you start flushing the system you may break loose that hardened sealer and those pieces/particles can block the smaller passageways. And if that's the case you might be better off removing the radiator to clean it off the vehicle, or just replacing the radiator along with all the heater circuit water hoses.
Point is, when deciding how to clean your cooling system it also depends some on if you or the PO dumped any type of sealer into the cooling system previously.
If anyone used a radiator stop leak or mixed different types of coolant you may have a greasy sludge blocking passageways. In that situation the Thermocure may not work well unless/until you remove the gunk using a type of cooling system cleaner designed for removing greasy sludge. There's a bunch on the market, just read the labels until you find one, then follow the directions.
If head gasket sealer, sodium silicate, was added to a rusty system previously then the Thermocure may cause all that sealer to break loose (because it's stuck to rust which the Thermocure will remove). Then all that hardened sealer (if it had been added to the system to stop a leak), can break loose and start clogging things up, IME
FWIW
@westtx_cruiser
How did the shop diagnose that? Was there no heat coming from the vents when the HVAC slider was pushed over to full heat? Was the cooling system full when that was checked? Had anyone added any type of cooling system or block/head gasket sealer to the radiator?
Did the shop tell you they found anything blocking the heater hoses?
IME the small bypass hoses can block up (if sealers have been used) so check the bypass hose that runs from the top of the radiator to the outlet pipe on the engine. Also check the small water hoses that run to and from the Throttle Body to see if they're blocked with anything (head gasket sealer for example). And if any of those are plugged then the heater core may also be plugged.
If a head gasket sealer was used and they you start flushing the system you may break loose that hardened sealer and those pieces/particles can block the smaller passageways. And if that's the case you might be better off removing the radiator to clean it off the vehicle, or just replacing the radiator along with all the heater circuit water hoses.
Point is, when deciding how to clean your cooling system it also depends some on if you or the PO dumped any type of sealer into the cooling system previously.
If anyone used a radiator stop leak or mixed different types of coolant you may have a greasy sludge blocking passageways. In that situation the Thermocure may not work well unless/until you remove the gunk using a type of cooling system cleaner designed for removing greasy sludge. There's a bunch on the market, just read the labels until you find one, then follow the directions.
If head gasket sealer, sodium silicate, was added to a rusty system previously then the Thermocure may cause all that sealer to break loose (because it's stuck to rust which the Thermocure will remove). Then all that hardened sealer (if it had been added to the system to stop a leak), can break loose and start clogging things up, IME
FWIW
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Recently bought a 97 lx 450 and the blower is pumping out air but its always just at outside temp.... car maintains proper temp during driving but need that heat to work here in the midwest. Gonna start with a clean like this and see if that does the trick unless anyone else has other suggestions????
Thanks
Thanks
Check that the lever on the heat control valve on the upper firewall just above and behind the valve cover is connected to a short cable. Should be an eyelet on the end of a cable attached to the lever. Then check to see if it moves at the valve when you move the HVAC temp slider. Ignition key needs to be On or engine running for the slider motor to work.
See @Kernal reply above.
Sounds like your heater valve is not being actuated and/or your blend doors are not actuating.
The LX versions have a climate module that does go wonky and they are NLA, but some have repaired them. Do the easy stuff first, like checking the valve and making sure the cooling system is properly topped off.
Got this all connected back and slider seems to be working but still blowing cold. I have friday off so Im planning on trying the ole radiator flush. Coolant levels are good but looking a bit murky