Help with splitting thermostat housing

[HAWAIIZR-1]

Hello all,

Finally getting around to maintenance on the ZR-1 to prepare for shipping to Hawaii. Since I was changing coolant and upgrading fans, I decided to install the Randy Woods 160 stat I had for a few years now.

All the bolts are off and bracket, etc. but it won't come apart without force. I see the place where I can pry it and I did put a pry bar to it with light pressure and no deal. I'm afraid to put torque into it and snap or crack something. I know looking for a replacement housing is like finding a Unicorn and I don't have any children to sell if I screw up and buy a new one.

Has anyone else had to pry to split the thermostat housing and that is just what has to be done? I have that hose loose and the radiator/fan assy, etc. are all loose to so when it splits should be no issue to change the thermostat.

Thanks for your thoughts and advice in advance.:handshak:

[Dynomite]

Lets see what the others say who have had a Thermostat Housing stuck together like yours (all my thermostat housings came apart rather easy). It was getting the NEW Thermostat set in place correctly with its rubber seal correctly in place that was the issue for me when putting the two halves of the thermostat housing back together (Marc Haibeck has a solution for that) Thermostat rubber seal install TIPS (http://www.zr1.net/forum/showthread.php?p=139426)

I am not so sure about the 160 deg thermostat as I have tried that also and just too cool. Other Tips....see below Jerry's photo of thermostat housing.

Thermostat Housing by Jerry
http://jerrysgaskets.com/store2/root/images/14104599-N.jpg

I am skeered to offer advice on things that are stuck or even glued ;)

But.....rather than pry with bar against parts of the Thermostat Housing.....I actually take a very sharp (at least 3/8 inch wide...not narrow) flat head screw driver (take the screw driver to a grinder to sharpen the blade like sharpening a knife) and tap it between the seams of the Thermostat Housing halves. You will bugger maybe just a bit the edges but the main coolant seal on the Thermostat is a rubber gasket around the Thermostat itself so no harm to the sealing surfaces near the rubber gasket. I use Permatex on the mating surfaces of the Thermostat Housing when putting the two halves back together.

Tapping on the Thermostat Housing Halves in a way to separate might also help but I hesitate to tap with a hammer on that aluminum thermostat housing.

I use Marc Haibecks 180 deg Thermostat.....I am not so sure but the 160 deg Thermostat might be too cool.

Getting the Air Out Simplified TIPS (http://www.zr1.net/forum/showthread.php?p=189150)
LT5 Air Locked Water Pump Simplified (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584756847)
Thermostat Housing TIPS (http://www.zr1.net/forum/showthread.php?p=186630)
Thermostat rubber seal install TIPS (http://www.zr1.net/forum/showthread.php?p=139426)

[QB93Z]

I have always been able to separate the housing halves with a light hammer tap. I would try threading in the bolt that connects the two halves and back it out 1 turn (so that it is mostly engaged with the threads on the "back" half, and there is some space from the bolt head to the front half. ) Then tap on the bolt head lightly to separate the halves.

Good luck, Jim

[WVZR-1]

I have always been able to separate the housing halves with a light hammer tap. I would try threading in the bolt that connects the two halves and back it out 1 turn (so that it is mostly engaged with the threads on the "back" half, and there is some space from the bolt head to the front half. ) Then tap on the bolt head lightly to separate the halves.

Good luck, Jim

Or use a longer bolts and let it "bottom" in the female threads. When I saw this post early this morning my first inclination was to suggest "a wait until" I had gotten back to HI but then I figured he was in beyond maybe the "turning back" point and just didn't respond.

Jim I like your idea - I've a friend of many years ago that would have likely done it that way. A very good friend now usually has a surprise for me when something unusual surfaces and I sometimes walk away with the "I should have known" something as simple as the solution he offered.

[scottfab]

Craig,
Here is my method. I've managed to do this without cracking the housing or garffing up the outside.

1. get both bolts out first. (use WD40 in the thread sides and bolt head sides if they don't come out) If the threads get damaged you can always use an a longer bolt with a nut on the end to reassemble. As you back out the bolt keep spraying with WD40 and go out with the bolt a 1/2 turn then back in 1/4 turn. This is to try and preserver the threads on the cheep cast metal. Don't proceed to step #2 until both bolts are out because you don't want to fight both the bolts AND the housing halves at the same time.

2. Once the bolts are out liberally spray WD40 on the inside of the pipe openings (both the inlet and outlet side) Then spray the outside seam of where the two halves come together. Then spray the inside of each bolt
hole. The key is to NOT be in a hurry. Let it soak in. Then repeat a few times. Take 30min or so to do all this.

3. Next using a plastic mallet whack at the seam all the way around. Keep whacking all the way around for a time. Now grab both sides of the housing and pull and twist. If you can have someone else whack it as you apply the twist and pull.

Once apart drill the one bolt hole all the way through so that next time you can apply WD40 easier. Use anti-seize on the bolt threads when re-assembling. Use anti-seize on both halves of the housing at the contact surface. The next time you get in there it will be a breeze.

[WVZR-1]

Once apart drill the one bolt hole all the way through so that next time you can apply WD40 easier. Use anti-seize on the bolt threads when re-assembling. Use anti-seize on both halves of the housing at the contact surface. The next time you get in there it will be a breeze.

Why would you suggest "drilling all the way through" a threaded hole that is already threaded the entire depth and already is a pass through if you use a threaded fastener of the appropriate length. His issue isn't the female threads and your "idea" would mean "demolishing" the one fastening system in it's entirety. One housing threaded bore can't be drilled through and the other is already piloted "all the way through" and with the proper length fastener would protrude but I don't know for what good reason "UNLESS" the threads were ruined in some fashion in the housing. There would be I believe no reason to drill unless a larger diameter fastener was required for some foolish reason.

[HAWAIIZR-1]

All,

Thanks for the responses and tips. I slept on it waiting for some ideas and will look at it with new insight this morning. I was not going to mess with the thermostat and wait until return to Hawaii in case something like this did happen, but it was a while I'm in there thing and maybe I will just leave it alone. It seemed too easy from the research I did and instructions in FSM and on various sites, but did not seem mention of having to force the halves apart. The threads and bolts are all in good shape (no corrosion or anything like that too) and don't want to mess that up with no issues to remove.

I think I'll go with Jim's idea (Thanks!) with a combo of Scott's WD-40 soak it while I have some breakfast and coffee. If it does not give without minor tapping, etc. I'll leave it alone for now and readdress it later. Thanks for the thoughts about the 160 degree and all the other info too that will help with reassembly if I am successful. This paranoia made me just purchase a spare TS housing even though I probably will never need it (maybe it is a better investment than even facebook stocks...ha, ha). Thanks again guys and I really appreciate the quick responses; especially with the time zone difference from here it is a big help and relief. We can always count on this brotherhood to help out. :cheers:

[bradley]

graig, just to let you know I pulled my 160 out of my white car after I went to the strip and found the car went 2 tenths slower . I put in my 180 and went back the next week and I got my 2 tenths back .jmho

[scottfab]

Why would you suggest "drilling all the way through" a threaded hole that is already threaded the entire depth and already is a pass through if you use a threaded fastener of the appropriate length. His issue isn't the female threads and your "idea" would mean "demolishing" the one fastening system in it's entirety. One housing threaded bore can't be drilled through and the other is already piloted "all the way through" and with the proper length fastener would protrude but I don't know for what good reason "UNLESS" the threads were ruined in some fashion in the housing. There would be I believe no reason to drill unless a larger diameter fastener was required for some foolish reason.

Here is why I would suggest drilling all the way through.
My 90 thermostat has three bolts. On mine the threads on the short bolt (the one that is one of two that hold the bracket on) were galled up and were virtually gone. I went to a nut on the other side.
On the opposite side of this there is another bolt that is a bit longer (or maybe the same size can't remember).
Originally it did not go all the way through the back side of the housing. Now it does.
It was similarly stuck but the treads survived. On this one as memory serves I used a slightly small diameter bit so as to not damage the treads and went all the way through. This so that I could use a tap to clean out the threads and use a longer fastener to now go all the way through.
So, again I drilled through but did not drill out the threads.

BTW The longest bolt of the three had no issue. Came right out.

As far as "his" issue not being the female threads? Well I can't speak to that since I can't presume to know from what was written that he does or does not have an issue with the female treads. Also, I'm only speaking (as I said) to how I approached getting the housing apart.
What you sure don't want to do is damage that housing. And of course if the bolts come out just fine, no sense in drilling anything ;)

[Schrade]

Why the 160' thermostat?

That means it will take longer to go CL (IF 160' CT is ultimate criteria that ECM says go CL, besides 600' exhaust temp).

Biggest myth with 'stats is they keep motors running @ the temp rating of the 'stat.

Fans on radiator govern max temps. Maybe get Marc H to write ECM code for fans to keep op temps @ 160', if that's what you're looking for...

[Franke]

"Computerized engine systems require a operating temperature of about 195 degrees. The emission controls as well fuel and spark systems are all calibrated to work within a given temperature range. The wrong one for the application can cause driveability, economy, emissions, and performance problems."

[HAWAIIZR-1]

Thanks to all. I appreciate all the comments and tips. All went well, but the tapping and WD-40 did not help me out in this case. What I found when I finally did pry it open was there was a sealant causing the halves to appear stuck. I also found I had a 165 degree thermostat and not a 160. It was good to do that I as learned more about the car and all the other work I did at the same time. I can see how well designed the seal is with the housing and the cover so just cleaned it all up and put it back together with anti-seize on the bolts. So much easier to do this with the SAMCO hoses than the stock stuff.

[WVZR-1]

After seeing "Schrades" deadly "signature" I was going to suggest a small pocket "knife blade" or a putty knife and a couple "taps/raps" to separate them. I assumed from your original post that there were no issues with the threads in the housing. It's good to see it behind you.

When is the ship?

[HAWAIIZR-1]

After seeing "Schrades" deadly "signature" I was going to suggest a small pocket "knife blade" or a putty knife and a couple "taps/raps" to separate them. I assumed from your original post that there were no issues with the threads in the housing. It's good to see it behind you.

When is the ship?

Thanks and good tips. Sort of like what Cliff suggested I wanted to find something thin but strong to try to separate. I did find a good knife blade that can be used for the future, but really limited with some of my normal resources here since most tools are in long term storage until I meet up with them it again. I spent more time looking for a bolt to the frame that dropped for the accumulator. I can't think how much time I've wasted over the years trying to find things that drop in this engine compartment. My new digital inspection camera is being charged so I can find the bolt and start the car to check for leaks, etc.

I'm trying to delay shipping the car with one last chance of a job to allow me to extend here in Japan for 2 more years. By the 3rd week of Feb I'll have to ship it since household goods pick up and no where to store it. Thanks for your thoughts!! :cheers:

[Schrade]

Thanks and good tips. Sort of like what Cliff suggested I wanted to find something thin but strong to try to separate. I did find a good knife blade that can be used for the future, but really limited with some of my normal resources here since most tools are in long term storage until I meet up with them it again. I spent more time looking for a bolt to the frame that dropped for the accumulator. I can't think how much time I've wasted over the years trying to find things that drop in this engine compartment. My new digital inspection camera is being charged so I can find the bolt and start the car to check for leaks, etc.

I'm trying to delay shipping the car with one last chance of a job to allow me to extend here in Japan for 2 more years. By the 3rd week of Feb I'll have to ship it since household goods pick up and no where to store it. Thanks for your thoughts!! :cheers:

You CAN'T huh? I SURE can think how much time I HAVE looked for dropped stuff!!!

I even got one I found with the seein' eye cam, and don't know where it is!

[HAWAIIZR-1]

You CAN'T huh? I SURE can think how much time I HAVE looked for dropped stuff!!!

I even got one I found with the seein' eye cam, and don't know where it is!

I think it was part of the design to make things hard to find if dropped. I was able to find that darn bolt in less than 10 seconds with the new digital inspection camera. Definitely the best tool that I have ever invested in and can't believe I waited so long to get one. It was under the front part of the motor below the damper a bit of a ways in. :cheers: