Replacing Thermostat Housing Gasket in a Ford 289 or 302

I had a coolant leak near the Thermostat housing, figure it was a leaky gasket!
Thermostat Gasket = Fel-Pro #35067 amzn.to/3PUQjAc
Thermostat = 180 degree, MCS #3358
Temperature Sensor = IDI #17-1226
Check out me new website for parts and merch that I am selling - krusebuilt.com/
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The car is a 1966 Mustang Fastback with a factory V8 and C4 transmission.
Shot with GoPro Hero 8 with the Media Mod, edited on Davinci Resolve 17.
Credit for the music in the video:
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Epidemic Sound
Try it today! www.epidemicso...
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#Mustang
#1966
#Fastback

[@dcheetham8603]

Hey man! I just found your channel and wanted to say Thank you!!!!! you're helping me a ton with my 63' falcon w/260 v8. Appreciate you!

[@AndyKruseChannel]

Awesome, welcome aboard!

[@kiddgrower9860]

Thank god I’m not the only one who had to turn that bottom thermostat housing bolt one half turn at a time.

[@AndyKruseChannel]

Yup, it's a super poor design. :)

[@engihere5434]

I'm having this same issue with my 85 f150 with the 302 small block, it's such a headache why engineers whyyyyy

[@andrewschmidt3974]

@@AndyKruseChannel the worst :|

[@derbymankg]

I just did that on my '78 Thunderbird I hope Karma paid back the person that designed it!

[@keepingupwiththejones2933]

Third 66 Mustang. Such a cool thing to be able to say.

[@AndyKruseChannel]

Haha, depends on how you look at it. :)

[@nwesterbeckmaster]

Your videos have been a big help for me. It's funny that you seem to run into at least a couple of issues during each job, which i like because it's frustrating when other people show a smooth process. It's almost never actually easy. With regard to the thermostat, you expressed some disappointment with getting a 180, but most resources ive seen online have said that 180 is the correct thermostat to use. Have you kept he 180 in your car?

[@AndyKruseChannel]

I currently have the 180 in the car, no issues. But I've upgraded quite a bit of the cooling system since this video, so I don't know if that has played a role. :)

[@BrianKeithPREPPER]

It's NOT just the mustang man, My Ford F150 '94, has a current leak also right now, I gotta fix ASAP, Just got the parts today for it from O'reilys. My motor is the same .302 5.0L V8 motor, Same Thermostat body design. Must be a designer flaw!

[@AndyKruseChannel]

I agree, I think this could have been designed better. But I haven't had a leak there since I replaced the gasket, that that's good. :)

[@JoseGarcia_xo3e]

I have an aluminum intake manifold on my mustang. Learned my lesson on tightening a carb stud. Righty tighty became righty loosy. Thankfully a helicoil kit fixed it. Now I torque wrench everything I can just in case.

[@AndyKruseChannel]

This is good advice. :)

[@davidlis6709]

Nice video. I have a 1965 GT and there is no grove in the thermostat housing. In all my years working on cars, I have never seen one without a groove. I tried the installing with 1 gasket but it leaked, so I am going to try it again with 2 gaskets, 1 on each side.

[@AndyKruseChannel]

I don't recommend two gaskets, it almost never works. Maybe try purchasing a new thermostat housing and trying the install method I did in this video. I did this same gasket replacement on my latest engine upgrade and I do not have any leaks. Everything has been great. :)

[@etmccaus]

Thanks for this vid - I'm probably gonna have to do this on ours. I thought Dad replaced it a couple years back but sure enough, I'm getting coolant in that V-notch above the water pump... 😞

[@AndyKruseChannel]

Awesome, I'm glad this helps. :)

[@dennissecor8092]

Nice job😊

[@AndyKruseChannel]

Thanks. 😊

[@drewsky1967]

my aluminum intake gave me the hardest time on my old 67, i ruined the threads maybe 2-3 times trying to fix the leak on this thermo housing. seems to be common on the ford engines.

[@AndyKruseChannel]

Unfortunately I have struggled with that housing on all three of my Classic Mustangs. It's a poor design, but I'd like to believe I've figured out how to deal with it now. :)

[@UnapologeticAmerican1776]

I did this same job. And it leaked worse after the job than before the job. I'm guessing I over tightened it

[@AndyKruseChannel]

There's a handful of reasons why it could be leaking, it's too bad Ford had to design this in such a way that we have to almost be NASA Rocket Scientists to get it to not leak. :)

[@UnapologeticAmerican1776]

@AndyKruseChannel you got that right. Everything is new. I was amazed it was leaking. Not to mention, it is a show car. So, now I got a week worth of cleaning and touch ups to do.

[@williamsimmons152]

Trick on that bottom bolt…..hacksaw a slot in the bolt head and a screw driver will easily get it going.

[@AndyKruseChannel]

Sometimes I wish I could post the video before I finished the project, because there's usually helpful tips in the comments afterwards. :)

[@ChipperskisTahoeChipper]

Oh brother! Thank you! I'm going to go get my hack-saw right now and do this. It's been a struggle on that darn bolt.

[@domfer2540]

Should go to a restaurant supply store and buy a bus boy pan, this is very useful for retrieving fluids from under the car.

[@AndyKruseChannel]

Where's the fun in that? Clean up the mess is part of the learning process. If it was easy, I'd continue to do it the hard way. :)

[@forddriver8827]

Surely you will flush the motor & radiator then put fresh coolant in it?

[@AndyKruseChannel]

That wouldn't hurt, but no.

[@jimbob1332]

You are correct not question about it.

[@gurkiratsingh2506]

Hey man, thnx fir the video. Can i know gow many litres coolant do we need to fillup once we replcaed everything.

[@AndyKruseChannel]

Depending on your radiator size and if you have your heater core installed, anywhere from 2 gallons (7.5L) up to about 3 gallons (11L). In this video I was just around the 2 gal mark for coolant. :)

[@williamschristopher12]

Omg! Brother! I have the same leak! 302 in my 64 Mercury Comet Caliente…I was gonna replace the water pump…geez I saved me some time and money!!

[@AndyKruseChannel]

Nice!

[@williamschristopher12]

If same leak is there, after doing the thermostat replacement, is it because gasket is seated wrong?

[@AndyKruseChannel]

@@williamschristopher12 Possibly, but it might be a few other things. Check the tightness of those two bolts holding on the thermostat housing. If they're loose it can leak, but if you over tighten them, it can leak too. Also, check the hose clamp on that radiator hose, it might be leaking subtly there. The third thing it could be is the intake manifold gasket right there on that end of the intake manifold. If the bolt is loose or the gasket is bad, it can leak right there into that pocket.

[@blippacg]

That gasket is completely in tact. I just pulled the thermostat on my '67 and it's fuzed to the housing. Using a grinding wheel to remove it fully. And my old thermostat didn't have any holes in it for bleeding, nor does the new unit, so I'm choosing to leave it alone.

[@AndyKruseChannel]

You are more than welcome to not put a hole in the thermostat, but it will be more difficult to get the air our of the system. :)

[@blippacg]

@@AndyKruseChannel And I need that spray adhesive. Muttered some choice words this morning with the thermostat constantly falling out.

[@rickyr2942]

Hey Andy can you do alittle brake down of the 289 engine harness and all the sensors around the block just to give the viewers a little view of what the 289/302 has on it. No one has a video brake down on this. And knowing you had 3 mustangs u most have a good view point on it. Thanks for the videos I'm always following . 👍 Building a 65 with 302sbf ...on its way😎

[@AndyKruseChannel]

That's a good idea, you're probably right about people finding value in a video like that. I'll see what I can do. :)

[@rickyr2942]

@@AndyKruseChannel thanks im sure you'll do great. Ricky.r

[@rickyr2942]

@Andy thanks ..im sure you'll do great. Ricky.r

[@jjdavis1209]

Andy, in this video, why does your top hose at 7:29 connect back into your water pump? That one goes into my heater core, is this some type of bypass? Thanks!

[@AndyKruseChannel]

At this time in my build, I was bypassing the heater core, so looping the hose from the manifold to the water pump allows me to do that without any issues. I don't drive my Mustang in the winter, so there's not much need for a heater in my car. :)

[@MrTW89]

Rookie question but why didn’t you pressure test it to verify that was the leak source? I have a similar leak and am about to try and trace it down. Thanks

[@AndyKruseChannel]

This is the most common location for a coolant leak on these motor. I had dealt with it on my two previous Mustangs, and this one had the same issue. The cause of this leak is usually installation error, in which case it doesn't take long to get another leak in that same spot. The rest of the time it's just age that gets to these gaskets and they need replacing. :)

[@MrTW89]

@@AndyKruseChannel thanks. Big fan of your channel by the way. Hugely helpful!

[@AndyKruseChannel]

@@MrTW89 No problem, happy to help!! :)

[@jeffunderdahl8605]

Hi Andy. I have this same issue on my 68. I noticed you didn’t put the rtv silicone between the housing and gasket…only between gasket and intake. Has that worked well for you? I would think it should be on both sides, no?

[@AndyKruseChannel]

This has worked great, I've done it on all three of my Classic Mustangs, never an issue. :)

[@jeffunderdahl8605]

@@AndyKruseChannel And since you can't get a torque wrench in there, and manual says 15 ft lbs, I assume you're just going hand tight? Also, did you use the same gasket method for the water pump and backing plate, and the water water to timing cover?

[@AndyKruseChannel]

Nope, different method on the water pump gaskets and timing cover. I cover it in the video I made where I replaced both the water pump and timing cover. Check it out! :)

[@trig5010]

Do I have to use a new gasket ? And also, how do I bleed the system,you spoke about ?

[@AndyKruseChannel]

Yes, because the gasket gets "glued" in place, you'll need a new one. Because of the hole drilled in the top of the thermostat, most of the air will get pushed through when refilling the coolant. Next, you can leave the cap off, fire up the motor, and let it run for about a minute, then put the cap back on before you shut the motor off. There shouldn't be any air trapped in the system by that point. :)

[@yoyokid6661]

Great video, thank you 👍🏻

[@AndyKruseChannel]

No problem 👍 Just a heads up, you can overtighten those bolts that secure the thermostat housing to the manifold. Just saying...... :)

[@rogerwatson5995]

They make a 13mm socket wobble head that fits the inside bolt for the thermostats with a 6 inch extension thats Quarter drive only that works Great for this project as the 13mm wobble socket needs to be Quarter drive as three eights socket won't work

[@AndyKruseChannel]

This is good to know. 😁

[@kevincady5613]

Like your videos…that’s called a sending unit

[@AndyKruseChannel]

Yeah, I mess up on that stuff all the time. :)

[@MP-mz1vu]

How long did you give the gasket sealant to set?

[@AndyKruseChannel]

Some mechanics will tell you an hour is plenty of time (this is from the days when a car would come in for service and head back out when it was completed) and some people say give it several hours or even a day. Because I wasn't in a hurry, this sat for a day before I fired it back up. :)

[@MP-mz1vu]

@@AndyKruseChannel thanks for the reply. Got a 67 Cougar over here. Got it done. Waited a couple hours and it worked. You have directly made my life easier with this video so thank you. Subscribed

[@Adrian.foringa]

Can this cause white smoke ?

[@AndyKruseChannel]

No, a leak here would not cause white smoke. If you're seeing white smoke, it is likely the manifold gasket or head gasket leaking and the coolant is getting into the combustion chamber.

[@salvatorebarnao3815]

Def a poor design on Fords part… I have a 69 fastback and have struggled with this as well. Good video.

[@AndyKruseChannel]

Thanks for watching!

[@mjj6870]

whats next on the car

[@AndyKruseChannel]

Can't say, it's super secret.

[@WillKlaver]

.. i used a Mr Gasket housing to fix mine, but used a Fel Pro gasket instead of the Rubber deal they come with because they always Pinch & Leak .. also Contact Cement the Thermostat to the Housing, because Every One wants to Fall Out & they stick between Block & Housing & you Wind Up doing Everything Over .. 👨‍🔧🧰💦

[@AndyKruseChannel]

Yeah, this thermostat housing is not the best design. :)

[@WillKlaver]

@@AndyKruseChannel .. no, it's way too Thin & Flexible ..