Coolant leak at thermostat

[captainhero]

Hi
07 ranger xlt 4x4 auto trans 4.0 v6

I have a coolant leak by the thermostat, looks like it's leaking by the horizontal seam in the middle of the plastic housing.
What do you think is the right fix for this, do I need to change the whole housing?
Or is it just an O-ring kind of problem?

I think changing just the thermostat only needs the air duct to be removed, is there more disassembly work required to change the housing too ?


Finally what coolant should I put back, I believe oem spec is yellow but will universal work just as well?

Thanks

 

[sgtsandman]

By in the middle of the plastic housing, do you mean where the gooseneck bolts to the lower housing or underneath where the housing meets the block?

Either point has a seal that can be replaced. If you mean elsewhere, the housing will have to be replaced.

As far as coolant, I’ve been using universal 50/50 coolant with no issues.

 

[captainhero]

Yes I think it's the seam between the gooseneck and the lower part. Not the engine block.
So that part should be fine then?

https://www.napaonline.com/en/p/NDP6052523?partTypeName=Engine+Thermostat+Housing&keywordInput=thermostat

 

[acsnowrider]

I replaced the entire housing, on my 4.0 at about 130000 miles--you can buy the entire assy, in some cases, even has the sensors, for a very reasonable amount--Wasn't worth trying to reseal the "plastic" housings!! It's a bit tight in there, just to remove the housing--I pulled my throttle body off, ect, made it a lot easier.

 

[sunnyboy]

New lower housing. I know, because it just happened to me last month. The lower housing is molded in two parts, which are then radio-frequency (RF) welded together. If the weld lets go, you can't fix it.

The part is not that expensive, and although it's a huge pain to replace (mostly tight spaces for the wrench/socket) it's easily doable in a day or less.

 

[sheep herder]

You can buy an aluminum replacement housing for it.


https://www.ebay.com/itm/Upgraded-A...Lv5PairwiseWeb&_trksid=p2047675.c100005.m1851

 

[sgtsandman]

Yes I think it's the seam between the gooseneck and the lower part. Not the engine block.
So that part should be fine then?

https://www.napaonline.com/en/p/NDP6052523?partTypeName=Engine+Thermostat+Housing&keywordInput=thermostat

It should work, however, it could just be that the seal is bad and needs replaced.

The above link is a good replacement for the plastic housing and not having to worry about problems with the plastic getting brittle or seam leaks. It's also the best price I've seen. From what seem, most places want $135 for the same item.

It will be up to you if you just want to replace the seal, the goose neck as you have linked, or go for the whole housing.

 

[captainhero]

Yeah I’ve seen the aluminium replacement a couple of threads below mine. But I'm not planning on keeping the truck so I'll try the part I linked above, hopefully replacing the O ring will do. I don't want to spend too much $$$ and time on it right now but I don't want to make a shady repair either like adding a coolant leak additive or something like that.

 

[G8orFord]

Lower:
https://parts.autonationfordwhitebe...yYW5nZXImeT0yMDA3JnQ9eGx0JmU9NC0wbC12Ni1nYXM=

Upper:
https://parts.autonationfordwhitebe...yYW5nZXImeT0yMDA3JnQ9eGx0JmU9NC0wbC12Ni1nYXM=

ANFWBL's website kinda sucks for pics and info, but their prices can rarely be beat on OEM parts. If you want to verify the part numbers with pics, Tasca parts is pretty good. Also give the guys at ANFWBL your VIN when you order and they'll verify fitment.

 

[acsnowrider]

New lower housing. I know, because it just happened to me last month.

The part is not that expensive, and although it's a huge pain to replace (mostly tight spaces for the wrench/socket) it's easily doable in a day or less.

It is abit tight--Was glad when it was done, and by replacing the entire housing, repair was solid--no redo's!! time to celebrate--
Especially with beer!!!

 

[G8orFord]

It is abit tight--Was glad when it was done, and by replacing the entire housing, repair was solid--no redo's!! time to celebrate--
Especially with beer!!!

If you loosen the intake manifold and disconnect the EGR pipe, it's not really that bad. I replaced the unit itself without doing that, but when I had to go back and replace the sensors, it was much easier and quicker to just loosen the manifold. You do have to be careful not to let anything get down in the ports, so it needs to be pretty clean to start with.

 

[acsnowrider]

If you loosen the intake manifold and disconnect the EGR pipe, it's not really that bad. I replaced the unit itself without doing that, but when I had to go back and replace the sensors, it was much easier and quicker to just loosen the manifold. You do have to be careful not to let anything get down in the ports, so it needs to be pretty clean to start with.

With my luck, on a engine with 130000 + miles, I'd have a new vacuum leak, and "mil" lamp on!!!!

 

[cbxer55]

You can buy an aluminum replacement housing for it.


https://www.ebay.com/itm/Upgraded-Aluminum-Thermostat-Housing-Kit-For-02-11-Ford-4-0L-Sohc/223214850362?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=225654&meid=21cfd7666df4440aa9b46f8521df806b&pid=100005&rk=1&rkt=12&mehot=pf&sd=182767928621&itm=223214850362&pmt=1&noa=0&pg=2047675&algv=SimplAMLv5PairwiseWeb&_trksid=p2047675.c100005.m1851

I'm assuming the 4.0 in the Mustang and the one in the Ranger are nearly identical? They use the same bolt-on thermostat housing that also has that stupid plastic pipe the heater hose attaches to? When I bought my Mustang, I didn't realize this was plastic. It has a seep at the heater hose. All the hoses had been replaced by the previous owner, along with the water pump and thermostat using worm gear clamps. So naturally, I just tried tightening that clamp. OOPS, damaged the plastic pipe. Damn it! Stupid plastic parts.

So anyway, I simply got a piece of brass tubing with an OD the same as the ID of the plastic pipe. Coated it with coolant proof RTV and lightly tapped it down into the plastic pipe with a hammer. Then reinstalled the heater hose and clamp. Now I can fully tighten it since it has a metal backing. No more leak. YAY!!

I was also finding little seeps around the thermostat itself. I didn't feel like replacing it right now, in the winter. So, I had already drained a gallon out through the overflow bottle. I took two acid brushes, little cheap brushes with a metal handle that can be bent to get in tight places. Used one dipped in alcohol to thoroughly clean the entire area. Then used another and some black RTV to brush the RTV all over the entire top surface of the stupid thermostat housing, covering up every single place it could leak. This includes all around the perimeter of the thermostat itself. Let it dry 24 hours, put the gallon back in. No more pesky little leaks. And it's black RTV, so it doesn't show.

I'm the master of "bodge" fixes. LMAO!!

Now that I know there is a metal part, I may replace it if it ever leaks again. But as long as what I did above works, I'll leave it be.

 

[sgtsandman]

I’m not sure. Probably. Check your current housing to make sure if it has one sensor or two. Apparently, there are two different housings out there.

 

[cbxer55]

I’m not sure. Probably. Check your current housing to make sure if it has one sensor or two. Apparently, there are two different housings out there.

Only has one sensor. I've looked at it enough to know that one for sure. One sensor and a plug in another opening, next to the sensor, likely for another sensor?