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Thermostat replacement

64K views 16 replies 12 participants last post by  ShinsenTuner 
#1 · (Edited)
Hey guys, I had to replace my thermostat because of a reoccurring CEL.
(P0128 coolant temperature is below the thermostat regulating temperature)

I decided to go ahead and take a few pictures while replacing it.

Overall its a very simple and to the point replacement. It can be a pain to access all 3 of the bolts that are holding the thermostat down. Its a little easier if you remove the hose that's connected to it, as well as a few pieces that create more space for your hands.

Tools/Parts needed:
12mm wrench
10mm wrench
pliers
flathead screwdriver
bucket (to catch the coolant)
THermostat part # 19301 PNA 003 its part #3 in this link

STEP 1

Start car and turn the heat all the way up, then turn the car off.

STEP 2:

Jack up car

STEP 3:

Remove bumper

STEP 4:

Remove lower splash shield

STEP 5:

Loosen the drain bolt and place the bucket under it.
Take off the caps off the top of the radiator and reserve tank.

Remove the reserve tank drain plug and place a bucket under it.


STEP 6:

Use pliers to remove the metal clamp off the hose that connects the radiator to the thermostat. There is a clamp on each side of the hose.
Go ahead and remove the hose to allow more work space. (be careful because a little bit of coolant will come out of the hose, so have a bucket ready)



STEP 7:

To allow more space for my hands I removed this metal/rubber bracket.
It has 2 x 12mm bolts holding it in place. (circled in red)
I also disconnected 2 wire clips from the metal mount (inside red square)


STEP 8

This step is where you need smaller hands.

I used a 10mm wrench to remove the 3 bolts.
(Some more coolant dripped down while removing the last bolt.)

The hardest part about this is getting to the bolts, it only took one full turn to loosen the bolts so I could take them out the rest of the way with my fingers.





REINSTALL IN REVERSE ORDER.

The only thing you might want to do is place the hose on the thermostat before reinstalling it.


WHEN REFILLING THE RADIATOR WITH COOLANT:

STEP 1
Make sure both plugs are securely placed back
STEP 2
Refill coolant into radiator up to the base of the filler neck.
STEP 3
Install the radiator cap loosely.
STEP 4
Start the engine, and let it run until it warms up (keep the heat on full blast) (the
radiator fan comes on at least twice).
STEP 5
Turn off the engine. Check the level in the radiator
and add more coolant if needed

IF YOU WANT TO TEST YOU THERMOSTAT BEFORE INSTALLING NEW ONE:


CAPACITIES SPECIFICATIONS
 
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#3 ·
I did this yesterday and it basically went as described :thumbsup:. Here are a few things I noticed:

  1. (Step 3) You don't have to remove the front bumper. Maybe it makes access a little easier, but I had no trouble removing the splash shield with the bumper still in place.
  2. (Step 5) The reserve tank drain plug is much higher than the radiator drain plug. I decided to syphon the coolant out of the reserve tank to avoid making a big mess (ironic considering what was about to happen).
  3. (Step 6) Not much coolant came out of the hose that connects the radiator to the thermostat, maybe a few drops.
  4. (Step 8) Reaching the thermostat bolts definitely the hardest part of the job. It sucked. As soon as the thermostat was loose, probably 3/4 cup of coolant poured out from behind it, judging from the mess on the floor :thumbsdow.
  5. (Reinstall) I put the hose on the thermostat afterward because it was a little easier to reach the bolts with the hose off.
  6. (Refill Step 2) When refilling the radiator, don't fill it up to the top. As the coolant heats up and expands, it will overflow. In retrospect this is kind of obvious, but I learned my lesson the hard way. The floor was already a mess though...
  7. (Refill step 4) Be sure to keep the heater on max heat during the bleeding process, since air is trapped in the heater as well. I forgot to do this and there were strange results.
  8. (Refill) Don't forget to refill the radiator reserve tank. Of course, it doesn't do much unless the radiator cap is tightened/pressurized, so don't expect to see fluid movement during the bleeding process.
Thanks for the DIY!
 
#4 ·
While you've got your coolant drained, you should check your fan switch. All you have to do is pull the clip off and short across the two pins with the ignition on. If the fan kicks on, you're good to go.

Found out that mine is shot and wish I had check this while I already had the coolant out. At least it's winter ...
 
#5 ·
Just did this over the weekend

I have to say, that was the greatest pain in the @$$ to do. I have big hands and couldn't get in there from the bottom. I ended up releasing the radiator and condensor bolts, removing radiator hoses and pulling the radiator and condensor as far forward as the condensor would allow. Then I unbolted the reserve bottle and worked mainly from the top. In the end, many hours later, got it all done.
 
#6 ·
Yeah. It's a simple install, yet a pain in the ass
 
#8 ·
Technically, it's possible, but you'd have to secure the radiator hose out of the way and then probably pull the intake manifold and work from the top in order to have enough room to do anything.

Working from the bottom /with/ the hose pulled, I raged and raged about how little room I had to work with.
 
#9 ·
Forgot a step

Go on ebay and order 30 splash guard clips for 6.00. I broke like 4 and acura wants like 4-5.00 EACH for them.

Even with 2 different gearwrenches accessing the 3 bolts was a god dammned nighmare. Took me like 4 hours to do this simple job. If you dont have a ton of patience this is NOT a job for you.

COOLANT: I just did a regular drain and refill. Its regular maint anyway so why not just get it over with?
 
#10 ·
I did mine in 1 hour! Didn't have to take off the front bumper or loosen the radiator brackets. None of that bs. Just a waste of time if you ask me. The only thing I did extra was remove the trans bushing bracket, and the connector bracket for space. Easy fix and install.
 
#11 ·
I changed my t-stat because my MPG was going to hell from the temps not getting hot enough. *your guage will LOOK like its reading full hot but an obd2 scanner will tell otherwise* I think I was only maxing out at 160 degrees where it should be like 180-190 even in winter. PLUS-I bought the KD tools set of TWO pliers for removing the clips which makes life SO much easier when doing friends' TL, accord atf drain and refill. Those effing splash guards are a pain. KDT41840 for both pliers. Dont go cheap, get both. The angled one is super handy for getting high in wheelwells.
 
#14 ·
No. The thermostat sits below top of the radiator, so you'd have to drain at least a third of the coolant so it didn't immediately spit out the top of the lower radiator hose when that's disconnected from the old thermostat. Then, you'd have to finish the rest of the job with that hose in your face, which will not be pleasant.

Just drain the coolant. It's not that much more work.
 
#15 ·
Just finished replacing my thermostat. My car was blowing cold air when idling and only hot when driving. Thanks to TypeSinVA and this DIY I now have heat again :thumbsup:

I was able to complete the job in about 3.5 hours, here are a few tips for the next guy...

- I did not remove the bumper, just the splash shield. A bunch of clips broke in the process and I believe the part number for them is either 91503-SZ3-003 or 91506-S9A-003. Ordering a bunch of each from amazon. ;)
- I removed the hose and the "trans bushing bracket" for more room. No need to remove the wiring harness.
- I worked from underneath, with my legs under the car as opposed to out the front (or side). This allowed me to reach the top bolt with ease. It seemed almost impossible at first to get too positioned any other way.
- I only used my 11mm wrench to get the job done on those bolts. It was too tight to fit my gear-wrench or ratchet. I was only able to turn those bolts with my wrench a tiny bit at a time when taking them off. Spray them with penetrating lube when putting them back on and you'll get them on in minutes.


good luck to the next guy.
 
#16 ·
I replaced my thermostat awhile back. Had to also replace the plastic component it mounted to. This was due to the fact the previous owner put loc-tite on the bolts when he mustve replaced it awhile back :firemad: Had to use right angle grinder with drill bit to puncture plastic enough to break the thermostat off. Then I could get to the bolts for the part it bolted to.

I got both replacement parts from the dealership fairly cheap. Most OEM shit like this I'd rather go to dealership and pay the $10 extra dollars than get aftermarket :rain:
 
#17 ·
Did this DIY two weeks ago. The top bolt on mine was stripped by a previous attempt at doing this from the last owner. 3 hours later, lots of yelling, access to a lift, and my knuckles all cut up later - it is done.

Car now runs smoother, heat is actually hot, and the car gets great gas mileage.
 
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