[leesonic]

This weekend, we had a reprieve in the cold spell we've been having in Southern NJ. Yesterday when I did the work, it was around 59F, and today it was 52F. Not bad for December/January.

My Focus has been taking a long time to heat up in the mornings since around early November. My commute to work is around 21 miles, add 10 miles if I have to take my daughter to school, and the temperature gauge would only be 1/4 of the way up around half way into my journey. I figured the thermostat was stuck open, so I set about fixing it. There are a couple of YouTube videos that I used to plan my attack. One shows the removal of the grill and passenger side headlamp, the other shows removing the hose at the bottom of the radiator.

I started out by putting my car on ramps. Some people don't like them, I've never had a problem with them. The underside of my front bumper is a scratched anyway (not from the ramps), so running it up them doesn't worry me.

First things I removed was the grill, the passenger side headlamp, and the plastic undertray. Tools you will need for this are trim removal fork (or two flat screwdrivers) to remove the pushpins for the grill, 10mm socket for the headlamp, and an 7mm socket and flat screwdrivers for the undertray. One tool I find useful is a 90 degree adapter, this can be mounted in a cordless drill or small cordless impact to remove the 7mm screws. Another tool that is useful is a pair of very long nose pliers. The pair in the picture I bought at a car swap meet tool stand years ago.

With all that stuff out of the way, you can finally see the beastie in question. Well, not that much, but you can certainly see the pipes going to it. Some of these housings have a sensor on them, some don't, mine didn't. I ordered both types from RockAuto (they were Motorcraft), and will be sending back the one I didn't use.

Open the radiator drain valve, and drain the coolant. Old paint buckets are your friend here. Remove the radiator cap to allow the coolant to drain faster. In fact, remove it, and throw it in the trash. New Motorcraft ones are available at RockAuto.

My coolant looked good after 12 years and 186,000 miles, but I was planning on changing it anyway. It's about time. I used Zerex G05 which I got from my local Advanced Auto. I got the undiluted stuff, and mixed it with some distilled water from my local grocery store.

Though not immediately obvious here, but the large hose is detached from the thermostat housing elbow. Those long nose pliers I mentioned previously proved to be a great help. I would consider them an essential tool in order to do this job. The blue thing on the left is a Harbor Freight flashlight.

The power steering return line is in the way though, so this needs to be disconnected. Hey, consider it a chance to replace the power steering fluid (or some of it) that's also 12 years old. I caught what I could in an old yoghurt pot, not pictured. I also removed the hose from the bottom of the radiator, and moved this hose down and out the way as best I could. By this time, I had also removed the radiator header tank, two 10mm bolts on the top. I rinsed mine out in my slop sink with nothing more than hot water, and it came up clean.

 

[leesonic]

And here were are. Both hoses are now disconnected from the thermostat housing. Again, use of the long nose pliers helped here. Once these are off, you can remove the three bolts holding the housing in place, these have 8mm heads. Some crafty selection of extensions are needed on your ratchet, just to get in with the lack of space.

Once the three bolts are removed, the thermostat housing can be wiggled out of place through the headlamp hole. It took me two hours to get to this stage. I was expecting it to be stuck wide open, but there was enough of a gap there to allow coolant through before the engine had a chance to warm up. Inside the housing on the engine, it all looked clean inside.

Reinstallation is the reversal of removal, as they say in the shop manuals. If you clean the heads of your thermostat housing bolts up with a wire brush, this will make them easier to see to get your 8mm socket on. You can pretty much get all three of them installed just using your fingers. You'll be working semi in the dark here, but they should all go in far enough so they won't fall out before you get the ratchet on them to tighten them up. There is a torque figure of 89 in-lbs for these bolts, but I just snugged them up with my 3/8" ratchet.

Hose clip re-installation is also the reversal of removal. Remember, those long nose pliers are your friend, but it's still going to take a few attempts. If you followed these instructions, it will be the bypass hose first, followed by re-attaching the big hose to the bottom of the radiator, and then to the thermostat. Remember to re-attach the power steering return hose if you removed this, and top up the power steering reservoir.

Refilling with coolant will take a little time, the small opening in the radiator burps more than me after eight pints of beer. Take your time, and eventually, the level will not drop any more. Re-install your header tank, attach it's hose to the top of the radiator, and install your radiator cap. Fill the coolant reservoir up to the cold marking on the side, and refit the cap.

One final check over, and it's time for a test drive. Maybe re-install your headlamp so you don't attract any attention from the Police, and you can refit the grill and undertray too.. If all is well, you should be rewarded with a temperature gauge like the picture below. This happened in only 2.5 miles or 5 minutes of driving. Heat inside the car was warm and toasty like before.

The following day, check the level in both the radiator and the header tank. Top the radiator up all the way, and add to the header tank to the cold level.

 

[NHSammy]

great job and super post ! Changed the therm on our Town and Country last week. Took me 30 mins all in. Darn Ford make it tough sometimes.

 

[pbfoot]

Great write up!

 

[Cr0ssF0cus]

Gonna be doing this either before Focus Fanatics Dragon Takeover OOOOOR if I am lucky when I get my Cossie knockoff manifold which will probably give a bit more room to do this and probably just knockout PCV while I am there too.

 

[2003focusowner]

Great write up! How long did the entire process take? I need to change mine as well.

 

[2003focusowner]

Great write up! How long did the entire process take? I need to change mine as well.

 

[PeteB]

@leesonic I take it you are the same person on AudioKarma? I'm Pete B there.
Seems like your location is the same so ....