Topics

Thermostat housing removal on COBRA radiator

Andy Drake
 

As some of you know from the National meet, I've been having problems with my Roundside running hot. Since then, I've been going through it to figure out what's what.

I have a spare radiator with the thermostat housing at top tank and it's generally in good condition -- fins look pretty good, it flows well and flushes out very clean after running a couple of gallons of vinegar through it. That said, I'm pretty sure I can feel the bottom end of an old thermostat hiding in the aluminum housing where it bolts to the upper tank. I figured I'd take it out to be safe. The retaining nuts came off with no drama and I got a a very thin putty knife inbetween the housing and the spacer to deal with the old gasket, but no dice. The housing will not come off. The whole thing is currently sitting outside in the sun soaking with some PB Blaster to see if that will dissolve whatever goo is holding the studs to the housing.

Anybody done this before? I am about ready to take a small torch and heat just the area around the studs to see if that will melt it out. On a side note, I wonder just how many cars that originally had COBRA motors are out there running two thermostats because the mechanic didn't want to bother when doing the CIBA conversion. At least a few! 

Andy

crosleyshortsport
 

Andy, there is no reason the housing should not come away from the tank once you have removed the nuts. Keep wiggling it and pry carefully. When you put it back, be sure ALL old gasket material is cleaned off and then take your new gasket and hang it up with some wire. Now use the blue Permatex and smooth it on both sides of the new gasket, now leave it hung up for 24 hours. Now use your leakproof gasket and tighten down the housing. I have done three of them like that, and they do not leak. Neal Daglow taught me that trick.
Jeffrey

On Sun, Aug 11, 2019, 4:47 PM Andy Drake <drakeap@...> wrote:
As some of you know from the National meet, I've been having problems with my Roundside running hot. Since then, I've been going through it to figure out what's what.

I have a spare radiator with the thermostat housing at top tank and it's generally in good condition -- fins look pretty good, it flows well and flushes out very clean after running a couple of gallons of vinegar through it. That said, I'm pretty sure I can feel the bottom end of an old thermostat hiding in the aluminum housing where it bolts to the upper tank. I figured I'd take it out to be safe. The retaining nuts came off with no drama and I got a a very thin putty knife inbetween the housing and the spacer to deal with the old gasket, but no dice. The housing will not come off. The whole thing is currently sitting outside in the sun soaking with some PB Blaster to see if that will dissolve whatever goo is holding the studs to the housing.

Anybody done this before? I am about ready to take a small torch and heat just the area around the studs to see if that will melt it out. On a side note, I wonder just how many cars that originally had COBRA motors are out there running two thermostats because the mechanic didn't want to bother when doing the CIBA conversion. At least a few! 

Andy

Spock Arnold
 

Andy, I have a suspicion. Can you take a picture of your problem and send it to me?  
Dave Anspach 

On Aug 11, 2019 6:26 PM, crosleyshortsport <crosleyshortsport@...> wrote:
Andy, there is no reason the housing should not come away from the tank once you have removed the nuts. Keep wiggling it and pry carefully. When you put it back, be sure ALL old gasket material is cleaned off and then take your new gasket and hang it up with some wire. Now use the blue Permatex and smooth it on both sides of the new gasket, now leave it hung up for 24 hours. Now use your leakproof gasket and tighten down the housing. I have done three of them like that, and they do not leak. Neal Daglow taught me that trick.
Jeffrey

On Sun, Aug 11, 2019, 4:47 PM Andy Drake <drakeap@...> wrote:
As some of you know from the National meet, I've been having problems with my Roundside running hot. Since then, I've been going through it to figure out what's what.

I have a spare radiator with the thermostat housing at top tank and it's generally in good condition -- fins look pretty good, it flows well and flushes out very clean after running a couple of gallons of vinegar through it. That said, I'm pretty sure I can feel the bottom end of an old thermostat hiding in the aluminum housing where it bolts to the upper tank. I figured I'd take it out to be safe. The retaining nuts came off with no drama and I got a a very thin putty knife inbetween the housing and the spacer to deal with the old gasket, but no dice. The housing will not come off. The whole thing is currently sitting outside in the sun soaking with some PB Blaster to see if that will dissolve whatever goo is holding the studs to the housing.

Anybody done this before? I am about ready to take a small torch and heat just the area around the studs to see if that will melt it out. On a side note, I wonder just how many cars that originally had COBRA motors are out there running two thermostats because the mechanic didn't want to bother when doing the CIBA conversion. At least a few! 

Andy

Butch
 

Andy,

Those can be real stinkers, to remove. Gentle heat, on the aluminum will help expand the stud holes some and help the oil to penetrate.

Be careful with heat. The studs, are actually brass bolts, soldered in, on the upper tank. Use some wet rags, as a heat sink, to prevent the un-soldering of them.

Butch

On 8/11/2019 4:47 PM, Andy Drake wrote:
As some of you know from the National meet, I've been having problems with my Roundside running hot. Since then, I've been going through it to figure out what's what.

I have a spare radiator with the thermostat housing at top tank and it's generally in good condition -- fins look pretty good, it flows well and flushes out very clean after running a couple of gallons of vinegar through it. That said, I'm pretty sure I can feel the bottom end of an old thermostat hiding in the aluminum housing where it bolts to the upper tank. I figured I'd take it out to be safe. The retaining nuts came off with no drama and I got a a very thin putty knife inbetween the housing and the spacer to deal with the old gasket, but no dice. The housing will not come off. The whole thing is currently sitting outside in the sun soaking with some PB Blaster to see if that will dissolve whatever goo is holding the studs to the housing.

Anybody done this before? I am about ready to take a small torch and heat just the area around the studs to see if that will melt it out. On a side note, I wonder just how many cars that originally had COBRA motors are out there running two thermostats because the mechanic didn't want to bother when doing the CIBA conversion. At least a few!

Andy

Tim Hamblen
 

My experience is like Butch's. You have brass studs in an aluminum housing. You have electrolytic action going on there. The studs will be corroded into the housing. It's not the gasket, it's the studs. I've wondered if some CRL might break it loose.

Ron D.
 

I sprayed mine with PB blaster, and let it sit. Then I took a thin but stiff putty knife, that was sharpened, and just kept tapping it all the way around the housing. I wasn't sure if it was the right way to go about it, but after a while, it finally broke free without ruining anything. Good luck.