Hi again, everyone! I believe this whole project is wrapped up and resolved, and I wanted to share a few of my reflections and lessons learned. I also have a question to pose later....
First, I mentioned earlier that I had recently purchased a new thermostat housing, tstat, seals (tstat & lower housing), and temp sensor from Ford. These were Motocraft parts in the original bag. Now, I have seen plenty of videos and comments about the benefits of using Ford parts -- but I have to say, that is a load of crap. First, it turned out that my housing wasn't the cause of my air leak -- and the seal I thought that I was missing actually was not missing, the seal comes in all of the aftermarket housing kits I've seen. I spent $185 for all of the Motorcraft pieces that essentially come in the $70 aftermarket housing kits. Last Thursday I went to put on the thermostat housing using the Ford parts. It looked like there was some space and potential for a leak, but I figured it was Motorcraft and I installed it anyway -- in about 25 minutes. I filled the system up with coolant and was getting ready to bleed the air out when to my amazement there was coolant streaming out of the Ford parts. It was coming from the lower housing -- not where the upper housing meats the lower housing, but in between the layers of the lower housing. I was very irritated. I had torqued the bolts properly, and as you all know the torque is a very low specification (84-89 inch lbs). Because of the holiday, I had to rush and get the housing off and go back to Ford. I rinsed it out and showed the parts guy where the leak was, and explained to him that my mistake was putting it on -- I should have returned it as soon as I saw the space on the housing itself. He was kind enough to swap out the housing for me, but when he brought yet another new one out of the bag -- it was even worse! I could not believe it. Here I was spending twice as much for OEM parts and all of the housings they had in stock were clearly poorly sealed. I exchanged it anyway -- but I didn't feel comfortable installing it. So on the way home I got another aftermarket kit for $70 and just visibly comparing them it was clear that the aftermarket housing was sealed WAYYY better than the Motorcraft housing. I ended up installing the aftermarket kit instead. I am using the Motorcraft temperature sensor, but nothing else.
One thing to note regarding the temperature sensor is that it sits pretty loose. I was concerned it wouldn't seal well, but it's holding up quite well with no leaks -- and I must say it's nice that it installs effortlessly.
Once I got a good housing installed, I was able to fill up my system again. Tech by Trade's tip about filling the block with antifreeze was a great idea, though I didn't fill it before I put the housing in. What I did was install the housing and then fill it after that. The aftermarket thermostat housings have the space for two sensors, and the second space has a plug in it. I just took that plug out and then filled the housing with coolant through the heater core hose inlet on the left side of it. Once you see the coolant come out of the extra sensor hole -- then you can put the plug back in (that way the air will come out of the block).
Since I was tired of installing and uninstalling parts, and draining and refilling the coolant, I decided once I had it all apart that I would flush the heater core. I went to the hardware store and bought a basic hose fitting -- I guess it's a quick connect fitting. But, I screwed it on to my hose and it fit perfectly into the hoses for the heater core. One tip here -- the heater hoses do not come off the metal fittings well. One of the hoses connects to some sort of plastic switch -- I'm assuming it's the switch to open the flow when the heat is on. That plastic piece is much easier to remove the hoses from --- so if you hold on to the plastic switch (underneath the tensioner pulley on my '06 4.0 V6), you should be able to pull the hose off easily once you remove the clamp. For the other hose (IB -- I believe), it came off easiest at the housing, so I just used those two locations for flushing my hoses. If you attached a small hose (I used my carpet vacuum hose) to them you can use them as an outlet hose and direct the water away from the engine towards the ground. Then I just went back and forth and flushed water through them. I'm not sure that my heater core was blocked up -- but I had everything apart and didn't want to find out that the core was blocked up later.
I recommend changing all of the Ford spring-type hose clamps when you are doing anything related to the cooling system. I think I had 2 that failed to provide proper seal: the lower radiator hose and the heater hose between the water pump and the plastic heater switch I mentioned above (it's about 6 inches, an elbow type hose).
I did have a small leak, and that ended up being the 6 inch elbow-type hose I just mentioned. It is the hose that connects from the lower left side of the water pump and goes to the plastic temp-switch for the heater. You can get Dayco part #A71877 to replace it, but it is about 1/4" short. You are probably better of getting heater hose and just curving it slightly (don't allow it to pinch -- a strong, flexible heater hose will not pinch and will work perfectly). Once I swapped that hose out and put new hose clamps on, I was able to fill up the system with coolant once again and bleed the air out. If you've never bled the air from your cooling system -- it's easy. I used the Lisle 24610 Spill-Free Funnel, it was like $40. Basically you fill up the entire system with coolant and then, with the funnel connected to your radiator, you over fill it -- let the funnel get to about 1/4 of the way full. Then run the car for 15-20 minutes with the heat on to allow the heater core to open up (that plastic switch I mentioned). If you give it a little gas from time to time you'll see air bubbles come out as the coolant makes its way through the system. Worst case scenario you can jack up the front end a bit to ensure the radiator is the highest point in the cooling system, though that really doesn't seem necessary. If you have to do that, you probably have an air leak like I did.
So, all in all this project was major pain in the ass. But, once I got all of the parts installed and found the leaking hose everything came together well. I will say that I got lifetime warranties on everything I bought, so that's somewhat of a positive aspect. And for far less than the price of paying a mechanic, I got a lot of new tools (pressure tester, fill funnel), lifetime warranties on everything, and a lot of new experience. I ended up replacing the tensioner and the idler pulley since I had them off for access.
So that's my two cents for anyone who's facing similar problems. Don't discount the heater hoses!!! And definitely replace the hose clamps as you're doing the job or you'll be doing it later anyway.
Here's my question though.... I've been monitoring my coolant temp a lot more closely with my GoPoint BT1 on my iPhone since this project, and I'm starting to think that I'm focusing on it too much. Anyway, my temperature rises slowly now but will eventually get up to 205-208 degrees. Around 207 or 208 it tends to jump down to 196 and works its way back up. Obviously my thermostat is opening and letting coolant flow through, but that seemed a bit high to me. That is, until I read on a forum that the Haynes manual states that the V6 thermostat is 194-210. I'm not exactly sure what that means, because I thought at 194 it would just open up and let coolant flow through the radiator. Is that not the case? What does the 210 have to do with this? Is it opening up by 210 and closing back at 194? If that's the case, I'm right within those ranges. My truck is between 196 and 208 -- so two degrees off of the recommended 194 to 210. I will be keeping an eye on it for the next week or so, but I should add the my gauge on my dashboard remains at dead center of "Normal" now -- it's exactly where I'm used to seeing it. So, clearly the Bluetooth BT1 is more accurate than my gauge on my dashboard...but is 208 considered normal? Can anyone explain what the range 194-210 really means?
Thanks everyone!
Alex
