This 2002 Ford Focus engine, 2.0l DOHC 4, now resides in a VW Vanagon Syncro. Thanks to Bostig.com.

For all practical purposes the engine functions exactly as it might in a focus. So my story is relevant to this situation.

I had the engine in the vehicle for over a year when this problem occurred. After an eight hour drive i noticed coolant dripping on the ground. I could not locate the source and the overflow tank was still full. I thought it a faulty clamp and cold weather (i have seen this before). Continued on my journey. Eventually the thermostat housing failed completely. I replaced it. Some test driving, new one fails. Strange that mine were melting, not cracking.

Bostig.com sells an aluminum housing. Much more robust. Dumping all coolant from head at highway speed could certainly destroy an engine worth the $$. No more problem.

Noticing discoloration on the now aluminum t-stat housing I investigate further to find a leak at the joint where the exhaust header meets the catalytic convertor. The leak was like a narrow jet of hot air pointing right at the thermostat housing. Duh! I am not sure the original plastic housing lives very long due to the high temps from being close to the header. The aluminum will work with the engine in the car as far as I know. Good insurance.

Also check for leaks around head to cat connection. Some extra heat shielding may also be good insurance if the exhaust decides to have a leak while you are on a journey and can't fix it immediately.

I have a 2002 Ford Focus with the Zetec motor, 2.0l 16v DOHC. I bought it used in '05 from Ford dealer with app. 50,000 miles on it. I had them modify the exhaust (Magnaflow), add low-profile wheels, and put an alarm system in at the time of purchase and I bought an extended warranty (which was an ABSOLUTE WASTE OF MONEY to the tune of approx. $2,000). I now have 134,000 miles on it and have had relatively few problems. I absolutely LOVE my car but I absolutely HATE Ford mechanics and from what I'm reading, all dealership mechanics are the same, regardless of maker. Here's what I've found.

I am a 47-year-old female. Until recently, I knew how to check my water, oil, watch the fuel gauge, check tire pressure, and had a very simple, generic understanding of how motors work. Shortly after purchasing the car, I had an incident where the car wouldn't start. I took it to the Ford dealer I bought it from and was told the alarm system was interfering with the starting system. They assured me the problem was fixed, and I took my car home. Little did I know at that time that their "fix" was to remove my alarm system. About a year later, I again had a starting problem. On my way to the dealership, my teenaged-son pointed out to me that my alarm system was missing. Until that point, I hadn't noticed that when the trash truck would come to pick up the trash every week, my alarm wasn't going off (always went off when the trash truck came by). When I arrived at the dealership, I inquired of the mechanic as to what had happened to the alarm system I purchased from them and they had installed in my car. The head mechanic very patronizingly informed me that my car did NOT have an alarm system. It was called an anti-theft system. It took me no time at all to snap and lose control at the condescending manner in which he argued with me over the alarm system. After completely losing my control and cussing him out, he threatened to have me removed from the facility. I then asked him to check the records. He couldn't find anything relating to an alarm system (how convenient!). I then told him to talk to the salesman who sold me the car. The salesman was very clear about the sale he made to me and told the mechanics that they had indeed installed an alarm system in my car at the time of purchase. They quickly and without apology reinstalled the alarm system. Then, in order to "fix" the no-start problem, they informed me that all they would be able to do was cut the wires to the alarm. Although that did "fix" the no-start problem, it also left the alarm system and all its wiring dangling down beneath the dash for my feet to tangle up in every time I drove the car (manual transmission).

Next the clutch went out. I again took it to the dealership and had the clutch rebuilt to the tune of approx. $900+. This, naturally, was NOT covered under the warranty I purchased. The next thing to come along was the check engine light. Again, I took it in to Ford at which time they informed me that my O2 sensor was bad. I forked out another $500 to have this fixed, again not covered by warranty. The next morning when I got in my car, the check-engine light was on again. I took my car back in to the dealership at which time they now wanted another $800+ for a new computer, also not covered by warranty. When I asked them if perhaps my O2 sensor wasn't really bad, they assured me that it was but that the computer was bad as well. I refused to fork over anymore money to them and drove my car as it was until it came time to smog it for registration purposes (California - gotta love it!)

Since that time, I came upon a friend, a very good, trustworthy male friend, who is extremely mechanically saavy. He located a computer for me at a wrecking yard for $40. It needed to be reprogrammed with my VIN# by the Ford dealership. I took it in and they wanted to charge me this and that and the other for switching the good computer for the bad. The computer simply plugs into the system behind the glove box. My friend had come along with me and told them if they were going to charge me more than the $99 to reprogram the computer, then he would switch them out for me right there and they could push my car into their service area. They told him it wouldn't be necessary and they switched the computers out and reprogrammed the new one for the $99 quoted over the phone. My friend then took a look at my car and pointed out that the wiring running between the computer and the O2 sensor was not secured and had been resting against a part that would get hot during operation. This had caused the insulation to melt off and the wires to short out the O2 sensor and the computer. He simply spliced the bad wire, reinsulated it, and secured it off the hot part. He also showed me where the O2 sensor was that they had replaced (right in the front under the hood, takes about 5 minutes to switch out), and pointed out that had I paid them the $800 to switch the computer, I would have been right back in the next day with the new computer shorted out and probably the O2 sensor as well as they had not fixed the underlying problem. The check-engine light has not come on since that time.

Now my car won't start on its own at all (I have to push start it), there's a leak at the thermostat housing, and there is brake fluid leaking down my clutch into the driver's side floorboard. My dad told me to take it in and have it repaired. I refused his offer as I will NOT spend nor let my father spend hard-earned dollars on certified ASE mechanics. Instead, I have researched and read, read, read up on as much as I could about my car, the motor, etc. I'm finding that, with the wealth of information available at my fingertips via the internet and the services offered by the local parts stores, including mechanical know-how and free rent-a-tool programs, along with my Chilton's book, that I am just as capable - no, MORE capable than these so-called mechanics with their ASE certification. What a joke!! My mechanically-inclined friend has fabricated his own vehicles all the way from the frame on up, yet has no certification. Yesterday, I switched out the thermostat housing all by myself. My friend stopped by as I was finishing it up and looked over my work, gave me the nod of approval, which made me feel very proud of myself. I DID IT!! Next I'm tackling the no-start issue, and then I'll jump on the clutch-fluid problem. I also noticed oil leaking around the valve cover, so I'm going to replace the valve cover gasket and change the oil myself as well.

The point? Who would have thought a mother of 7 and grandmother of 2 could do it? If I can do it, anyone can do it. No one has to be treated like an idiot when something goes wrong with their car. I have been enjoying myself so much that I can't wait to get back under the hood of my car. I only wish I would have taken things into my own hands much sooner so that I could have maintained my car appropriately. I just read a blog where someone paid $330 for the dealership to replace their therm. housing. I did it for $45.00. I'll take a garage mechanic over an ASE certification any day! You'd be surprised at how simple some of the repairs and maintenance for your car can be. Here's to saving big bucks AND getting the job done right. Good luck to all of you!!

i bought this car in 2009 . i bought it from jd byrider here in Tampa and in the beginning i saw that the car would go to red on the thermostat so i told them about and supposedly they fixed it .. but throughout the 2 almost 3 yrs of having it this has been a reoccurring problem . looking up past complaints on the car it seems it must be the thermostat housing .. but since October the car has been giving me problems . first i noticed a slow leak after the first time i brought it to the mechanic that is suppose to work on my car because it is under warranty. then 1 wk later the car wouldn't start and i had to bring it back to them and that ended up being the coil thats on the engine. so each time i always told them about the car still over heating. as usual when ever i was in idle it would over heat. recently i noticed that i was spending about 20 dollars a week on coolant. and yesterday it was boiling hot and it spewed out boiling hot water into the air. so now i will keep u posted because m bringing it in on Monday to see what comes of this... FORD PERIOD<< SUX

My 2002 Ford Focus (~75k miles) started leaking antifreeze after a normal drive. By the next day, the radiator was empty (all over my garage floor). After a cursory examination under the car, I pinpointed the problem to be the housing on the right side of the engine. I took the car to a mechanic, and the mechanic determined that the thermostat housing had cracked. Apparently, this is fairly common because Ford uses a plastic housing and O-ring for this component...which is then attached to the engine block. The housing for the thermostat costs approx $100 from Ford, while the labor cost me an additional $125. I ended up having the upper and lower radiator hoses replaced ($90 for the hoses, $125 for the labor).

This is my wife's car. I noticed a few drops of coolant on the garage floor one day after she left for work. When she got home, and after the engine had cooled down, I got the flash light and promply located the leak. It's coming from the thermostat housing. I've had this happen before with one of my other vehicles, only there was no crack in the housing itself. The problem was the thing that sticks out from the housing, it was leaking. I believe there is an o-ring there? Anyway, she puts about 325-350 miles on the car per week and I only have to put coolant in about every three weeks or so. It has never over heated. I've looked and repairing this myself will be a piece of cake. To everyone out there. Don't take your car to the dealership for this repair! You can do it yourself with a little patience and a few tools.

I had a slow coolant leak on my Ford Focus 2002. I just kept topping it up for several months until one day it started to overheat and I took it to (they call it Crickshank Ford - I call it Crookshank Ford in Toronto).

They initially said they couldn't find the problem, but that they thought it was the thermostat and possible the housing (a $400.00 job) and could I leave the car overnight and they would test it in the morning. After some more testing in the morning they said they still could not find the issue but were still sure it was the Thermostat and housing. So I said what choice do I have but to rely on the "professionals" and gave the go ahead. I was then called back about ten minutes later and was told it was definitely the Thermostat housing as it was leaking as we were speaking.

Great right, well not so fast. After driving home that night it was fine, but after driving home from work the next day and backing into my parking spot I got out of my car and saw coolant all over my condo parking area and a pool under my car. I went back to the Crookshank dealership and had them take a look and they said they didn't see anything wrong. So I went back home and sure enough the next day the same thing happened and I went back to the garage again, and was told once more they couldn't find anything wrong, but I went with one of the mechanics for a test drive and the car did overheat.

Mechanic thought it might be a sensor or a problem with the fan. Ford asked if I could leave the car and they would take a closer look in the morning. The next day I was told it could be the Fuel pump at $460.00 and if that didn't fix the problem then they would have to change the radiator at another $360.00 with taxes that would be about $1000.00. I said this was unacceptable as the car did not have this problem prior to my bringing the car to their garage and went home without doing the recommended repairs.

The next day I went back to work and sure enough when I got home and backed into my spot and got out of my car there was a trail of coolant and a puddle under my car. I went back to the dealership and was once again told they couldn't find the problem but the manager of the service department would drive the car home and they would see if he had the same problem when he drove back to the garage in the morning. By the way he said he would call first thing in the morning, at around 3 in the afternoon and not receiving a call I call the dealership and was told they had located the problem and it was a hose that was leaking. Another $165.00 and about 2 days of missed work not to mention the 4 hours in three days of cleaning coolant off of my condo parking, I complained that I should not have to pay the $165.00 as the problem was not there prior to my bring the car to Ford in the first place. The service manager said that it may have been since they had replaced the thermostat and housing there was more pressure in the system, but the mechanic and I had the system pressured up to 22 pounds and there was no leak.

I think the problem may have been "just" the hose all along. I also complained that if I had replaced all the recommended parts at about $1000.00 my car still would not have been fixed, seeing as it was a hose that supposedly had blown (but only after driving home and backing into my parking spot). I asked how it was that these Ford service garages which charge over $100.00 an hour, I think it is $110.00 could justify this fee if they are not even able to resolve known issues with Ford vehicles. I was told that most issue are very straight forward and not this difficult to diagnose.

Well I ask you as Ford does not have an answer, if these technicians can only diagnose very straightforward issue then why in the world should we pay such a hefty premium and bring our cars and trust to a Ford service garage? I am very frustrated and will be contacting Ford Canada directly but do not expect much from them either, but will let you know.

I noticed that there was a drip of antifreeze, but nothing major until the car was idling for about 20 minutes and the temp went into the red. I was able to get the car home, then found there to be no coolant. A little googling found the common issue of the cracked thermostat housing. Sure enough, that was the problem. Bough the parts from partstrain.com for about ~$150 and installed them with the help of my brother. A tight place to install the housing, but just move the hoses around and it can be reached. The old housing blew a ring seal where it interfaces with the engine block. Replaced the thermostat while I was in there to be on the safe side.

So, the day before I was going to drive this thing 130 miles to the airport, I noticed my dog peed under the front end of the car, parked in my driveway. By early evening, since it did not dry, I checked it and saw it was not pee. So, I drove my reliable Toyota 4Runner to the airport the next day. A week later, I was home and popped the hood on the Focus and saw the coolant reservoir was empty. I searched online and saw that the main cause of an idle coolant leak in a Focus is the thermostat housing. I went to Ford and bought one (probably could have got it cheaper online) and a gallon of coolant.

It is too easy to replace yourself. The only annoying part was draining the remaining coolant. There is no way to direct the flow, at least not on my model. As soon as you unscrew the plug, it shoots out everywhere--I took a coolant bath.

Follow these instructions: http://www.focushacks.com/?modid=59&ht=Replacing%20the%20thermostat%20and/or%20thermostat%20housing

Took about three hours with a self-done flush and fill after the housing was replaced. Don't pay a repair guy.

Same as other complaints regarding the thermostat housing. It's a bit annoying. The main problem is that you have plastic bolted right on the head so over time is just dry rots. I had the exact same problem in my 98 jetta.

Btw, I can't believe someone else getting a dealer quote for ~$1100!! No wonder Ford is having financial issues... when the economy gets tough not as may people are going to fork over $1100 for a <$100 job!!

Easy to change. Make sure to buy the replacement housing before taking the old one out, as it most likely going to fall apart.

Anticipating a huge repair bill, I decided to fix this thing myself. The puddle of coolant in the driveway was obvious, but it took a long time to determine the exact point of the leak. Observation indicated it was above the transmission housing and none of the hoses or connections were dripping. When searching around using a flashlight, I spotted indication of corrosion on the lower bolt holding the thermostat housing to the engine block. Getting enough tubes and brackets out of the way to remove the housing was very tough, but I did get it out and discovered the channel that holds the "O" ring gasket was broken out for about 1" of the internal circumference of the housing. That allowed coolant to blow out between the housing and block when under operating pressure.

The nature of the repair is very simple. It is a remove and replace operation, but all the tubes, wire bundles, and distributor module mounted around the housing made it a nasty job. I had to remove 8 to 10 fasteners just to change a housing that is held by three bolts and three hose clamps. Most of the cost of this job at a shop will be consumed by labor involved simply getting to the problem part.

If you need a thermostat housing changed, find a patient friend who is a good wrench man with a couple of hours to share. Spend $65 for a new housing and gasket, and take your friend to dinner when he is done.