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Ford Focus 2.0 SOHC (SPI) thermostat cooling issue

17K views 7 replies 3 participants last post by  djzx3 
#1 ·
Greetings all. I have a 2000 Ford Focus that I recently inherited with 92K on it. Everything works fine except the car will not get up to temp. Easy right, new thermostat and problem solved. Well, I could've only been so lucky. Since I've had the car I replaced all three motor mounts (passenger side, dog bone, & trans mount) because the car vibrated terribly and put brakes on the car. I am a seasoned "backyard mechanic" and have done head gaskets, replaced tranny's, etc but am not a seasoned pro. Those bigger R&R tasks usually take me a couple of days because I'm a perfectionist, do everything by the service manual and also clean everything I take apart. There's a little background about me so you know i'm not a bumbling idiot.

When I changed the thermostat out (had to remove air cleaner box, battery tray, ignition mount, etc) I was surprised to find the housing was made of plastic. I replaced the thermostat with a Stant 45990 "Super Stat" since my car had the letter "P" for the 5th and 8th VIN digits. Well, in my opinion the 45990 did not fit very well into the housing. It was pretty loose actually. The factory thermostat fit very tightly into the housing. And... with the 45990 installed my cooling issue was NOT solved. The car still barely gets to the bottom range of the temp gauge while driving. If I let it sit and idle it will get up to normal temp but does not hold once you start driving. It is not leaking anywhere and the housing seemed ok.

Thus I figure, 1 of 2 things is going on. The factory thermostat really was bad and the loose fit of the new "Super Stat" is allowing too much water to go by or my thermostat housing has somehow become warped over time and is not allowing the thermostat to seat properly. To the best of my knowledge it's a mechanical system and there are no electronic servos or PWM devices regulating coolant flow so my problem has to be at the thermostat. Anyone have any experience with this particular issue? My next step is to return the thermostat and replace the whole housing.

Thanks in advance for your time and knowledge!
 
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#4 ·
No, the site I checked showed both and in fine print, it showed the 45978 and 34979 for the vin 3, which is the dohc. It should hold the coolant from flowing until the engine gets to the temp and opens so if there's any opening for the coolant to bypass, it won't heat up. Does the engine seem to get hot other than the gauge? The gauge could be wrong too.
 
#5 ·
Vin 3 is the Zetec IIRC, but either way, the Zetec and SPI are almost identical, The only difference is the heads,and a few exterior motor parts. Put a 195 in there, 180 doesn't even make sense with a stock focus motor, I know people who build performance motors whether it be Duratec, Zetec, or SPI, they don't use 180 unless they have a turbo or supercharger going on, or a lot of N/A parts.

So 195 is what I'd put in, but your going to find out when you actually get to a store(autozone, Advance auto parts), that they got three options, 180, 192, 195, either 192 or 195 will work fine.

I'm actually using 180 in my Duratec 2.3l right now, and 195 in my Zetec. I'm running a little colder on the D23 because I'm starting to put more and more mods on it, and for how I drive it, being colder will help in my case.
 
#6 ·
Re: SOLVED - Ford Focus 2.0 SOHC (SPI) thermostat cooling issue

I noticed that not many people post a solution to the problems they post here. Annoying! I didn't want to be one of those people so here's the result/solution that worked for me...

My particular car, a 2000 Focus with 2.0 SPI Single Overhead CAM (SOHC) came with a stock 4-port thermostat housing. After trying 2 different thermostats advertised to fit my car that ended up not fitting I opted to return the thermostats that didn't fit and go with the RH169 housing for $48 from rockauto.com. Evidently there are some thermostat parts issues for that 4 port thermostat housing.

The RH169 housing comes with everything you need (Housing, Thermostat, new Temp Sensor, and the o-ring type gaskets. You don't need to use anything from the old housing. This was nice. However, and MOST IMPORTANTLY the RH169 housing only has 3 ports but there is a solution. Ford offers a hose kit to compensate for this and the part you will want to order to go with the RH169 housing is Ford part number 3M5Z8K012BA. It fits perfectly so you don't have to cut and splice the old hose. After installing the new housing and the new hose all was well.

Engine temp is good and I have heat again on my 35mi drive to work. Better yet, I have about 5 mpg better fuel economy too! Running your engine cold causes the ECU to dump more fuel thru the injectors in an attempt to compensate for the cool temp. Hopefully someone finds this post useful.

What this means... Ultimately, either my old thermostat or temperature sender was bad. I don't know which. But for $75 in parts and my own labor (free) I'm not that worried about it ;) This was a simple task that ended up being way more work than it should of been. I've never run into a parts fitment issue like this before.
 
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