jaz50

Last winter, I changed the heater valve on the back of eng block due to no heat. My heat worked last winter but now its not. The valve is fine. Im hoping that just the Tstat is stuck now and hoping for heat after this.

Theres a rubber seal already on the new Tstat, not the separate gasket Im used to. Should I be applying a thin layer of blue silicone in addition to the rubber seal? These cars take awhile to burp?

3.2TLc

Hey Jaz50, what all did you replace last year besides the heater valve ?

A good place to start is to pressure check the cooling system. The T-stat can be checked, but if in doubt....buy the original Honda two stage T-stat, which is specifically engineered for our TL's motor. Be careful to orient it properly with the pin up when installing. The O-ring rubber seal is normally all that is needed, unless the mating flange surfaces are in bad shape.

If the coolant wasn't replaced recently, get a top quality brand and refill with a 50/50 mix after draining out the old. There's a drain plug on the rear of the motor block in addition to the rad's petcock. If the hoses are old, consider replacing them at this time, along with the rad cap.

After everything's tightened back up and the rad is topped off with new coolant, make sure that the heater temp control and blower are both set on high, turn the motor on with the cap loosely on and run until motor warms up to normal operating temp with the rad's fan activating. The trapped air from the higher heater core will normally bubble and purge out with the cap carefully removed during this process of burping.

Turn off motor, then check rad and reservoir again, adding coolant as necessary. Replace and fully tighten rad cap, run motor to temp again, check for leaks, let cool and recheck levels again. If you don't have heat now, you may need to inspect the heater valve cable located underhood near the center of the firewall. It may need to be lubed and exercised to free it up ?

01tl4tl

thats about it
make sure valve is really open for full HOT and cabin fan on
open car doors!

burping is a little more that as stated
please follow owner book method carefully- some idle time till fan cycles, use of 2000 rpm and fan cycles etc are detailed

no book? free download www.owners.acura.com need cars VIN to register as owner

temp should run stable at 1-2 lines below half

make sure the res bottle cap- hose inside it, is attached firmly/snug on fitting
It drops off and no transfer = cooling problems

victus1

Do not use any sealant on that tstat gasket. It's designed to seal the tstat housing as is. Make sure you get the oem tstat and it must be lined up properly with the mark indicated.

Also, make sure you clean & lube that cable on the heater valve with some motor oil (not wd40). It's known to seize up with dirt.

fsttyms1

With the key in the run position have someone turn the temp control from cold to hot and you look at the calve to see if the valve is being pulled open. If not then look under the dash to see if the cable/motor there is moving.

jaz50

Thanks for all the input. Ive checked all the aforementioned steps off my list except the Tstat, which I hope to do this week. I already have a Stant which has the bleeder on top so not sure why using an OEM is such a major difference (not looking to save a couple of dollars, just curious).

Some other parts I swear by using OEM but what makes the OEM Tstat that much better?

3.2TLc

Hey Jaz50, while you may very well be able to install the "Stant" T-stat.....and be ok, but why chance a $20 part that is so critical to your TL's motor ? Honda has used a specifically engineered two stage T-stat in their performance motors for what I'd assume is a meaningful purpose to open at different temperatures.

Most of the time aftermarket parts are manufactured to OEM specs, I'm unsure if the "Stant" has this two-stage feature or not. You could research their product line and if you feel comfortable, then use it at your risk !

But, in closing......for a few bucks more, I'd go with the real McCoy and rest assured that I attempted to retain the purpose of Honda engineering in a hot alloy motor.

01tl4tl

one of the few oe parts I would use is the t stat
something special about them,,
you know how picky the TL is about certain parts, certain gas stations etc

jaz50

Returned the Stant to Pep Boys and bought and picked up an OEM Tstat, flushed system. Had sporatic heat while I was burping system but now I have nothing again as Im driving it. Upper & Lower hoses both hot. Rear hoses going to core seem to be hot too so everything up front seems to be in order. Even though theres no smell or leak, Im now suspecting core.

Thoughts?

victus1

Disconnect the input & output hoses from the core. Put a garden hose in one inlet and see if water comes out the other. There are youtube videos showing this technique to flush out and unplug a core.

fsttyms1

make sure core isnt plugged.

3.2TLc

One quick thing to check is to make sure that the heater valve cable is properly adjusted and fully opening the valve itself. Remove the cable and work the valve's lever mechanism by hand. You'll know if you have flow through the valve when open if you can feel the hose being hot on the firewall side after the valve.

Hopefully the heater core can be backflushed if it's clogged up. It's a pain to replace the core.

jaz50

10/23 update; had some time this morning so I flushed the heater core & re-burped system... so far so good, the heat seems to be back on. fingers crossed. Thanks for the help guys.

Paymar

Hi there, I've been struggling to fix this same problem. My control cable does not move the valve - it's stuck in the cold position and all heater core hoses are cold. I removed the cable and manually opened up the valve and both heat core hoses get hot - so I believe this tells me my heater core isn't plugged and the heater control valve is OK. Why am I not getting heat after I do this? The heater core must be hot if the output hose is hot. Is there a valve for the air flow that needs to open up? HELP!!!!! It's getting cold.

3.2TLc

Hey Paymar, I think that you've located your real problem......The heater control valve or the cable ! You can "force the valve to open" which proves that your heater core is functioning properly. It could be as simple as lubing or adjusting the control cable. Does the valve seem to move freely by hand ? It may be gunked up or binding as well !

Paymar

Thanks for the reply.... when I disconnect the cable and move the valve manually, it moves freely. I definitely think my valve is OK. I think that I should get heat when I disconnect the cable and manually move the valve as the Heater Cores input hose and output hose are both hot. Does the cable only hooked to the Heater Control Valve or does it simutaneously move this "air blending valve" that I've been reading about in other threads?

3.2TLc

You may need to go explore on the opposite side of the firewall as to where the cable originates.
I'm really unable to give you any info on that, sorry !

Paymar

It connects to what looks like the air flow mixer valve. It's under the center console. The cable hooks to a white piece of plastic that looks like a boomerang.
Anybody know how to make that thing move? I tried to manually move it and it won't budge.
I've sprayed both ends of the cable and it didn't help.
Anyone have any further suggestions?

3.2TLc

Try working the climate control settings while watching the cable for any movement.

Paymar

Hi there... I've tried doing that and the no movement at all. I've tried to lubricate it and help move it along and not luck.
There must be a seized motor that moves that cable or it has a hold current on it. Does anyone know if there is a way to manually move that valve - I believe it's the air mixer valve (it's the one under the dash board on the other end of the cable)? If I can move it manually, I believe I'll have heat. I can leave it in the heat position all winter.

3.2TLc

The climate control has a self-diagnosis feature. Try using it by turning the key on, then push the "Auto" button and next the "Off" button, keep pushing both buttons .......if there's a problem, the digital "temp indicator" will show an error code. It will be a "letter" code. If nothing comes up, then just turn the key off and the system will go back to normal mode.

Does the AC work ? Check fuses #3(7.5A) located in the driver's side kick panel box and the #13(7.5A) located in the passenger side's fuse box. Also, if the AC isn't working then check the underhood relay box, #54(40A). Some things to look at, Good luck !!!!!

Paymar

Thanks to all who responded. My problem turned out to be a bad Air Mixing Motor. There are a few threads people can read on this site that are helpful. Bought one out of a junk yark for $10 and my heat is back on.

3.2TLc

Thanks Paymar for posting your results.
This info is good for any others who may experience the same problem with the climate control and heater.