Thermostat Housing and Water Pump???

[mikeinri]

Hey guys,

I just became a victim of the lower thermostat housing failure problem. No small leak, this thing just erupted like a geyser! Fortunately, this happened literally in front of my house, so I didn't get stuck with it and need to be towed.

This happened in the dark last night, and all I saw was billowing steam. Doing some searching this morning, I came upon the lower housing issue. I checked the oil, no signs of water (whew)...

I don't have a pressure test kit available, so I just started the engine today to see if I could find the problem. At first, nothing happened, then the water pump started screeching. I shut it down, added water to the coolant tank, and started it back up. Sure enough, water was shooting out of the rear of the lower housing at about Mach 10...

So, I'm about to replace this part. I found a Dorman kit (contains "everything needed") locally at Advance Auto Parts for about $85. I could wait and get it from Rock Auto for about half that price, but I want to be able to install this ASAP (tonight or tomorrow).

Hopefully, I didn't kill the water pump during my "diagnostic testing"???

BTW, 2004 Explorer, 4.0L, 170,000 miles.

Mike

 

[Exproblems]

Hey guys,


I don't have a pressure test kit available, so I just started the engine today to see if I could find the problem. At first, nothing happened, then the water pump started screeching. I shut it down, added water to the coolant tank, and started it back up. Sure enough, water was shooting out of the rear of the lower housing at about Mach 10...

So, I'm about to replace this part. I found a Dorman kit (contains "everything needed") locally at Advance Auto Parts for about $85. I could wait and get it from Rock Auto for about half that price, but I want to be able to install this ASAP (tonight or tomorrow).

Hopefully, I didn't kill the water pump during my "diagnostic testing"???

BTW, 2004 Explorer, 4.0L, 170,000 miles.

Mike

As long as your cooling system didn't lose too much coolant prior to you finding the leak from the T-stat housing, your water pump should be okay. The screeching you heard was probably from the leaking coolant getting on your serpentine belt, meaning the wet belt is making the noise you hear.

At the end of May this year, I replaced the whole t-stat assembly as you are about to do, with the same Dorman part from Advance Auto Parts. Here is the part numbers for the t-stat assembly and a new temp sensor if you feel like changing that while you are at it. Dorman Upper and Lower Thermostat Housing Kit #902-860, new BWD Temp Sensor #WT5067. My Explorer is a 2005 4.0L, so double check the part numbers at Advance Auto Parts while you are there for your vehicle. The Dorman housing comes with a new t-stat, 3 housing bolts and o-ring pre-installed, 2 sensor ports and 1 plug with o-ring and 1 sensor clip. It also has a pre-installed o-ring at the mounting base where it meets the manifold, where those 3 mounting tabs hang down. My Explorer only has 1 sensor, so I had to use the plug with o-ring and clip they give you to plug up the extra sensor port. The new temp sensor I bought came with a new o-ring for that, but no locking clip, so you will need to re-use your old sensor clip from your current temp sensor to hold the new temp sensor in place. Don't forget to lubricate ALL of the O-rings with coolant prior to seating things in place. When I first looked at the new t-stat housing out of the box, I noticed the extra sensor port plug they give you was mounted in the left or center port of the housing. This is where my new temp sensor needed to go. So I had to pull out the plug, and move it to the right hand port. My old temp sensor was mounted in the left or center port, so I kept things the same. You need to use a little force when seating the new temp sensor or plug in place. Just be careful not to damage the new temp sensor electrical connector when pressing down on the sensor while you try to seat it. It's a tight fit, but it will go into place. I seated the new temp sensor and plug into place on the assembly prior to mounting the assembly to the manifold, it was easier that way. I also had to remove the new t-stat housing cover and t-stat, to wiggle the new assembly into place because I had a wiring harness in the way coming from behind the spark plug wire coil pack running over the top of the t-stat area going behind the alternator area. Removing the t-stat cover gave me the room I needed to get it seated properly.
The t-stat housing bolt torque is 89 inch lbs (use a torque wrench, don't over tighten bolts), that includes the 3 bolts that mount to the manifold at the base of t-stat assembly. Don't damage those 3 tabs at the base of the assembly that stick downward and go into the mounting hole on the manifold. When you remove the old assembly, same thing, don't damage or break off those tabs when removing the old one. They could fall into the manifold hole if they break off. Don't forget to clean up the mating surface of the manifold prior to seating the new assembly into place. You can use a Scotch Brite pad to clean it up, but don't gouge or scratch that mating surface. Long handled needle nose pliers come in handy removing the short by-pass hose clamps off and on at the water pump and assembly.
When ordering your parts from Advance, use an online coupon from www.couponcabin.com I think they have a $40 off coupon on an order of $110 or more. The new assembly, temp sensor and 2 gallons of full strength coolant will come to over $110, so the $40 off coupon would be good to use there. You need to order the parts online at the Advance web site, apply the coupon code during checkout, and select the store you want to pick up the parts at. Use 2 gallons of Distilled water to mix up the full strength anti-freeze into a 50/50 mix. Buy 2 gallons of full strength anti-freeze if you plan on changing over all the coolant. You only need to drain roughly 2 gallons of coolant from the system to do this repair. If you have any questions on this repair, just ask me. Not a hard job to do. BTW, Dorman claims they have corrected the cracking and splitting flaws of the Ford housing, so this is why I went with the Dorman product. I've had no leaks or problems with anything since I did this repair.

 

[mikeinri]

Wow, what can you say but, just, WOW!!! THANKS for the great reply!

I found this while searching: http://bengrosser.com/howto/fordthermostat/ Very helpful, but this looks way more complicated than my setup. I see no reason to remove the throttle body, radiator shroud, fan, etc. as I've seen on several posts. This one "looks" pretty straightforward (famous last words).

How long did this job take you? I honestly think I could get it done in 2 hours (which probably means 3-4), but there really isn't much in the way, from what I can see on my 2004.

Thanks for the tip on the coupon, that will make a huge difference! I'm like you, I'd much rather mix my own than overpay for the premixed antifreeze. I always use distilled water for the mix. I did add tap water today just to test it out, but I plan to replace all of the coolant anyway.

I would normally replace all of the hoses when doing such a repair, but I don't want to cross that bridge yet until I'm sure the water pump is still OK. No sense in dealing with those hoses twice.

As for the Dorman part, I thought the kit came with the T-stat and temp sensor? Either way, I'll make sure to buy all of that. Again, don't want to be doing this twice if I can avoid it.

My 2004 also only has the one sensor, so I'll need to plug the second hole. Not thrilled about that idea (one more place for a potential leak), but hopefully it will be OK.

Anyway, I'll check back after I get this done. Thanks again!!!

Mike

PS: Mods, this appears to be such a common problem, and there are several good threads here about this repair; why is none a Sticky?

 

[Exproblems]

Wow, what can you say but, just, WOW!!! THANKS for the great reply!

I found this while searching: http://bengrosser.com/howto/fordthermostat/

How long did this job take you? I honestly think I could get it done in 2 hours (which probably means 3-4), but there really isn't much in the way, from what I can see on my 2004.

Thanks for the tip on the coupon, that will make a huge difference! I'm like you, I'd much rather mix my own than overpay for the premixed antifreeze.

I would normally replace all of the hoses when doing such a repair,
As for the Dorman part, I thought the kit came with the T-stat and temp sensor? Either way, I'll make sure to buy all of that. Again, don't want to be doing this twice if I can avoid it.

My 2004 also only has the one sensor, so I'll need to plug the second hole.

Anyway, I'll check back after I get this done. Thanks again!!!

?

No Problem, your welcome.

Those Bengrosser instructions are handy, but outdated for our Explorers. I think his instructions were for a 1998 4.0L engine, which has a different throttle body setup and you need to remove more parts from the engine to get at the T-stat assembly. You should be able to look straight down at your t-stat assembly as I could, without having to remove anything to see it. You'll just have to remove the 3 base mounting bolts and some clamps, hoses and 1 wiring harness plug from the temp sensor to remove the whole assembly. Tip, if you see an electrical harness running across the top area of the t-stat assembly going from behind the coil pack over to the back of the alternator area, carefully unplug the plastic clip that holds the harness in place where it meets up with the mounting plate for the coil pack, it's on the back side of the mounting plate. Doing this will give you a little extra play in the harness wire so you can wiggle out and in the old and new t-stat assembly. Kind of a tight fit in there. Removing the t-stat and it's cover plate helps also during removal and installation. Mount the new t-stat and cover plate to the assembly after you have torqued down the 3 base mounting bolts to the manifold.

The job took me roughly 2 1/2 - 3 hours, counting the clean up and putting away my tools. I don't move as fast as I use to and wasn't in a big hurry either. Messing with the short bypass hose and clamps during installation was a PITA at times.

Yes, those Advance Auto Parts coupons come in handy.

I wanted to change the coolant hoses as well during this repair, but there is a bunch of them and wasn't sure I could reach all of them myself. I skipped doing them for now, they all still look in good condition.
The Dorman assembly does come with a new t-stat, o-ring and cover plate with new bolts for the cover plate, but no new temp sensor. I had to buy that separately, cost me like $16.00. BTW, you will need to re-use the 3 old, manifold mounting bolts with your new Dorman assembly, doesn't come with them.
Just remember to lubricate those O-rings with some coolant prior to torqueing down the bolts or pushing the temp sensor and plug into place. Don't forget to use the locking clips for them either. The manifold o-ring on the bottom of the new assembly is hard to see because it is slid up inside a slot on the bottom of the assembly. Run your finger across the slot with some coolant on it to lubricate it.

Good luck with the repair!

 

[mikeinri]

Sounds good, thanks.

Mike

 

[mikeinri]

BTW, good catch on the temp sensor. I looked too quickly at that picture and thought it was in there, it does look like just a plug. Pretty deceiving when they say the kit "Includes all hardware necessary for a complete repair."

A nice disclaimer that "all hardware" doesn't include 3 bolts, a sensor and a clip would help...

That coupon didn't register the full $40. It saw the kit as $85 and gave me $25 off, but didn't recognize the rest of the order totaling over $110. Better than nothing!

Of course, they don't have a store that carries both the kit AND the sensor near me, either...

Mike

 

[Exproblems]

BTW, good catch on the temp sensor.

A nice disclaimer that "all hardware" doesn't include 3 bolts, a sensor and a clip would help...

That coupon didn't register the full $40. It saw the kit as $85 and gave me $25 off, but didn't recognize the rest of the order totaling over $110. Better than nothing!

Of course, they don't have a store that carries both the kit AND the sensor near me, either...

Mike

Yeah, I was surprised the new t-stat assembly didn't come with 2 new sensor clips, 1 instead when there are two open sensor ports. My old Ford assembly, the one that cracked, had 2 sensor ports built into it, just that the right hand side port was never drilled out from the factory.

The 3 new t-stat housing bolts that come with that new assembly are a larger head size than the factory ones.

I'm surprised that coupon didn't register the full $40 off, it did when I ordered my parts. During the checkout process, the coupon value gets discounted from each item purchased in different amounts $$$, depending on how much that certain part costs. Maybe check you store receipt to see if they deducted a smaller percentage from the coolant and sensor prices. You should have qualified for the full $40 off if your initial order was over $110. I know Advance doesn't allow you to use online coupons when ordering oil change stuff, they said it is because they have oil and filter combo sales all of the time. Maybe they changed their policy to include buying anti-freeze online.

Nice thing about the Advance web site, is it tells you if the part is "in stock" at a particular store. I had to drive a few extra miles to get to the store that had the t-stat assembly in stock and they had the new temp sensor as well. 2 stores closer to me didn't have it.

Let us know how you make out with the install and if you have any problems bleeding air/getting cabin heat from the cooling system after you re-fill it.

 

[mikeinri]

OK, got the new part in, a few minor issues (below) and one potentially major one.

The upper hose is full of air. I've filled the tank (didn't take 3 full gallons, let alone 4), and let it run while squeezing the upper hose. Something is screeching, I think it's the water pump but can't be sure.

It heated up to normal temperature (on the gauge), and gives plenty of heat, but the coolant level in the tank isn't dropping, and the upper hose is definitely empty, and isn't getting hot.

What am I doing wrong???

Mike


PS:The minor problems:

The plug in the Dorman part was installed on the wrong side (no big deal).

There would have been no way to remove the housing without unclipping that wire from the back of the coil pack (thanks for that heads-up).

I managed to break two of the tabs on the bottom of the old housing while trying to remove the lower hose. I found one piece (got it out with a long gripper), have no idea where the other one went, but I don't think it's in the engine.

I had trouble getting the engine side of the port clean, but hit it with a Scotch Brite pad and got rid of the bulk of the mess.

 

[mikeinri]

OK, I may be on the way to fixing this. Did some searching, and can't find a great purging technique, other than just driving it.

So, I took it for a drive on the highway, did some rabbit starts on the side roads. Temperature gauge is rock solid, in the middle of the range. Stopped and checked the hose, it's definitely hot now. Not sure that there isn't any air left, but I'm feeling better about this.

No obvious leaks. The screeching has mainly stopped now. There is still coolant in all sorts of nooks and crannies on the top of everything under the hood. I don't see any way to get rid of it all, aside from having the engine steam- cleaned.

When I drained the radiator, the typical 1.5 gallons came out. So far (I've only filled it once), it has taken 2.5 gallons back in.

Hopefully, this is the end of this problem. The truck has plenty of others...

Mike

 

[Exproblems]

Disregard!

 

[Exproblems]

PS:The minor problems:

The plug in the Dorman part was installed on the wrong side (no big deal).

.

What sensor port was the Dorman assembly "plug" installed into when you bought the part, the left or the right port hole? On mine right out of the box, the plug was already pushed into the left sensor hole, with the right hole open. At the inside, bottom part of the right sensor hole (looking into the hole) on the Dorman assembly, there was a short plastic post sticking upwards from the base of the assembly in the middle of the hole. The left hand hole did not have a post sticking upwards in it. I don't know why there was a plastic post inside the right hand port hole. On my old Ford factory t-stat assembly, the left hole had my old temp sensor installed into it and the right hole was never drilled out at the factory or closed up. So to keep things set up like Ford had it, I then removed the plug from the left hole on the Dorman assembly and moved it to the right hole, then installing my new temp sensor into the left port hole. Both the Dorman and Ford t-stat assemblies looked very similar in size and shape. Glad you got the air out of the system and it is working correctly now.

 

[TucsonDon]

My wife has a 06 w/the 4.0l (106,000 miles) and it to was leaking from the t-stat housing so last weekend I removed the housing and replaced both seals and reassembled it. Night before last I went out after she got home from work just to check on the repair and found some coolant pooled on the top of the block between the heads (around a freeze plug).

Just some history on the repair, once I had completed the repair I took my electric pw (only 1300 psi) and washed all the residual coolant from the leak off. Now what I found the other night was not a liquid but more of a jell.

Of course my main concern is that it has a blown head gasket or is leaking from the freeze plug.

any thoughts or comments would be appreciated.

 

[Exproblems]

My wife has a 06 w/the 4.0l (106,000 miles) and it to was leaking from the t-stat housing so last weekend I removed the housing and replaced both seals and reassembled it. Night before last I went out after she got home from work just to check on the repair and found some coolant pooled on the top of the block between the heads (around a freeze plug).

Just some history on the repair, once I had completed the repair I took my electric pw (only 1300 psi) and washed all the residual coolant from the leak off. Now what I found the other night was not a liquid but more of a jell.

Of course my main concern is that it has a blown head gasket or is leaking from the freeze plug.

any thoughts or comments would be appreciated.

Don't know if you have a bad freeze plug or a head gasket leak or not, but the t-stat housings have a tendency to crack or split at their seam lines and it is very hard to see the housing leak at first, till it splits apart further over time. Starts off as a very slow leak that and gets worse over time. My problem wasn't an o-ring leak, the housing was split. It took several months before the leak got bad enough to hit the ground under the truck. The leaking coolant was pooling on top of the intake manifold in back of the t-stat housing and was drying up as the engine ran. The coolant looked like greenish crud at first when the leak was slow and stayed liquid once the leak was really noticeably worse to where I could see it spilling out of the crack in the t-stat housing. The jell you see, maybe the same greenish crud I am describing which I attest to is dried up coolant. You have an 06 Explorer, which would be a 4th generation Explorer and mine is a 3rd gen Explorer, so I don't know if you have the same type of t-stat assembly as I do. You may want to change out the whole t-stat assembly if you have the same type as the 3rd gen Explorers, since they are known to split and leak. Start here and go from there.

 

[TucsonDon]

Thanks for your help

 

[swshawaii]

Ditto lower thermostat housing. Only fail safe repair is replacement. Four parts needed for basic repair are the RH148 lower housing, DY1004 ECT sensor, and both rubber seals. Sensor requires replacement because the old o-ring is usually compressed and won't seal tightly in the new housing. Size is 2.5mm thick x 9mm I.D. if you can find automotive type.

http://www.explorerforum.com/forums/showthread.php?t=259795&highlight=lower+thermostat+housing

 

[TucsonDon]

Hey guys
Just to follow up with this issue I did some investigating this weekend and found that the seal on the temp sender is leaking and I'm going to replace it.

 

[mikeinri]

What sensor port was the Dorman assembly "plug" installed into when you bought the part, the left or the right port hole? On mine right out of the box, the plug was already pushed into the left sensor hole, with the right hole open. At the inside, bottom part of the right sensor hole (looking into the hole) on the Dorman assembly, there was a short plastic post sticking upwards from the base of the assembly in the middle of the hole. The left hand hole did not have a post sticking upwards in it. I don't know why there was a plastic post inside the right hand port hole. On my old Ford factory t-stat assembly, the left hole had my old temp sensor installed into it and the right hole was never drilled out at the factory or closed up. So to keep things set up like Ford had it, I then removed the plug from the left hole on the Dorman assembly and moved it to the right hole, then installing my new temp sensor into the left port hole. Both the Dorman and Ford t-stat assemblies looked very similar in size and shape. Glad you got the air out of the system and it is working correctly now.

My plug/hole situation was exactly the same as yours.

It still seems to have quite a bit of air in the upper hose (although I haven't driven it since the night I fixed it last week).

Mike

 

[Exproblems]

It still seems to have quite a bit of air in the upper hose (although I haven't driven it since the night I fixed it last week).

Mike

Driving the vehicle will help purge any remaining air from the cooling system if there still is any. You said you are getting good heat through the heater core and the coolant level hasn't been dropping and the temp range is fine, so I wouldn't think there is much air left in the system. If you weren't getting good heat, then I'd suspect air still in the system.

 

[mikeinri]

OK, thanks.

Mike

 

[TN_53_F100]

I had the same problem about a year and a half ago. I didn't buy the kit. . .I wish I would have. I replaced the lower housing and the thermostat. I reused the sensors [my x has 2 . . one for the gauge (brown) and one for the computer (grey)], and the upper housing or water outlet as it is also called. This weekend I replaced the stuff I didn't replace in the first place (upper housing and both sensors). But. . .It's still leaking. I have new o-rings, new upper and lower housings. I even put a bead of Permatex on the upper housing. That slowed it down significaltly, but it's still leaking. I've got all new parts and it shouldn't be leaking. Everything looked really good. No foreign objects. No grooves or imperfections in the plastic parts. It's seeping out between the upper and lower housings in the back. . .near the two sensors.