freaky radiator thing

True, but that's not all of it.The 400 block has siamesed bores, which lets water stay on top of the bores even if you take the drain plugs out. I found this out too late as it caused a lot of rust in the cooling jacket as well. Not sure if block cooling jacket was well cleaned as the machine shop double crossed me on this one.
I'm pretty sure that that block overheated and might have caused the radiator to swell. If the cap bleeds at 7 psi, it virtually impossible to have this type of damage.

The block wasn't reused again as it had other issues as well, among which the biggest offender were the bores not being plate honed as requested with the consequent rings not being able to seal the cyl at TDC. Block was already at 4.165 so maximum overbore. It's sitting in my shop in a corner somewhere now.

I didn't realize that - now you have me curious, I'll have to go look at mine

I'm not in love with the 400s - I think they have too many problems for hot rodding (siamese bore issues). For torque, they're good - thus decent truck motors, however I've yet to see an application where a BBC wouldn't fit that where a 400 would.

For your information I didn't build a 400. I stayed at the 350 ci capacity but did so with a large bore, short stroke combo. I know...some say I'm not a general concensus typ guy :drink:
 
Damn, I think I yahoo'd to soon. This morning when going back in the garage I found some water in front of the passenger seat. No interior yet. Pulled the radiator and did a compressed air test on the heater core when put under water and it's leaking on one of welds were the pipe enters the tank. Had to put on a new hose strap after one of had the bolt shearing off when tightening yesterday during the pressure test. Was not so easy to pull the hose of the pipe. Guess that the weld broke at that point. Not a very big leak so I don't think it lowered the pressure enough to notice in the hour I left it on.

What would be the best option, have it repaired ? New core ? How is the quality of the replacements ?
 
Damn, I think I yahoo'd to soon. This morning when going back in the garage I found some water in front of the passenger seat. No interior yet. Pulled the radiator and did a compressed air test on the heater core when put under water and it's leaking on one of welds were the pipe enters the tank. Had to put on a new hose strap after one of had the bolt shearing off when tightening yesterday during the pressure test. Was not so easy to pull the hose of the pipe. Guess that the weld broke at that point. Not a very big leak so I don't think it lowered the pressure enough to notice in the hour I left it on.

What would be the best option, have it repaired ? New core ? How is the quality of the replacements ?

have it soldered, how much pressure are you applying to your cooling system?
 
Or swap to non aqeous coolant, no pressure no corrosion due to demixing of water ant anti freeze when standing

Sent from my GT-I9000 using Tapatalk
 
What would be the best option, have it repaired ? New core ? How is the quality of the replacements ?

I don't know about Corvette ones - but I just replaced the core in my 83 pickup and struggled to find a brass-core radiator...

Old trucks just live forever, eh?? my '85 Dodge 6 door 3/4 ton window work van has about 300k on the clock, still driven by my stepson.....

When pressure testing the vette some years ago, I just left the rad cap on, and hooked up air pressure to my heater hose, controlled by HVAC gauge set, put in enough air to blow off the cap a bit, then turn off valve, and watch the blue gauge.....:clobbered:
 
Damn, I think I yahoo'd to soon. This morning when going back in the garage I found some water in front of the passenger seat. No interior yet. Pulled the radiator and did a compressed air test on the heater core when put under water and it's leaking on one of welds were the pipe enters the tank. Had to put on a new hose strap after one of had the bolt shearing off when tightening yesterday during the pressure test. Was not so easy to pull the hose of the pipe. Guess that the weld broke at that point. Not a very big leak so I don't think it lowered the pressure enough to notice in the hour I left it on.

What would be the best option, have it repaired ? New core ? How is the quality of the replacements ?

have it soldered, how much pressure are you applying to your cooling system?

10 psi
 
What would be the best option, have it repaired ? New core ? How is the quality of the replacements ?

I don't know about Corvette ones - but I just replaced the core in my 83 pickup and struggled to find a brass-core radiator...

Old trucks just live forever, eh?? my '85 Dodge 6 door 3/4 ton window work van has about 300k on the clock, still driven by my stepson.....

When pressure testing the vette some years ago, I just left the rad cap on, and hooked up air pressure to my heater hose, controlled by HVAC gauge set, put in enough air to blow off the cap a bit, then turn off valve, and watch the blue gauge.....:clobbered:

Gene, it was your idea that put me on the way to conduct this test. However, I put a barb fitting in the thermostat housing, used a bicycle pump with a pressure gauge on it an put 10 psi on it and watched if it lost pressure.
 
What would be the best option, have it repaired ? New core ? How is the quality of the replacements ?

I don't know about Corvette ones - but I just replaced the core in my 83 pickup and struggled to find a brass-core radiator...

Old trucks just live forever, eh?? my '85 Dodge 6 door 3/4 ton window work van has about 300k on the clock, still driven by my stepson.....

When pressure testing the vette some years ago, I just left the rad cap on, and hooked up air pressure to my heater hose, controlled by HVAC gauge set, put in enough air to blow off the cap a bit, then turn off valve, and watch the blue gauge.....:clobbered:

Gene, it was your idea that put me on the way to conduct this test. However, I put a barb fitting in the thermostat housing, used a bicycle pump with a pressure gauge on it an put 10 psi on it and watched if it lost pressure.

Years ago, I made an adapter from two brass fittings, to allow the air hose at ~125 psi to run into any HVAC system, and I have stayed with the R12 fittings, for my old shit, the camper and the vette....I backwards adapt to the newer Miata and now Focus....pressure is pressures.....

so having a method of charging air into a HVAC system, I push it to 125, turn off the blue valve, and wait.....during the afternoons in the Florida sun, I have had them gain about 20 lbs over several hours....

I figger it's good enough, so I evac pump the system down to ~28 vac and wait for a couple hours, then hit it with freon....

so I used the exact same thing to pressure the cooling system and the rad caps are all 16 psi here....so just so it holds full coolent/water, and I pump to 16 psi, let it settle down from rad cap blowoff, and watch the gauge for a couple hours....I know, I"m cheep and lazy.....

:clobbered::club::hissyfit:
 
What would be the best option, have it repaired ? New core ? How is the quality of the replacements ?

I don't know about Corvette ones - but I just replaced the core in my 83 pickup and struggled to find a brass-core radiator...

Old trucks just live forever, eh?? my '85 Dodge 6 door 3/4 ton window work van has about 300k on the clock, still driven by my stepson.....

When pressure testing the vette some years ago, I just left the rad cap on, and hooked up air pressure to my heater hose, controlled by HVAC gauge set, put in enough air to blow off the cap a bit, then turn off valve, and watch the blue gauge.....:clobbered:

83 3/4 ton diesel, 6.2l Gale Banks turbo, lockers, a/c, loaded truck... this on a SAR practice mission
PB250005_zpseb84da5b.jpg
and I still beat the living snot out of it - and it loves it :)
 
Brought the core in for repair. It's probably going to cost me as much as a new one. They said that to correctly solder the tubes and clean up the core, they had to desolder the tank. (pipes are very close to the core, so in some place I assume the cannot properly weld it). 60-70€
 
As a Gene-esque aside, The radiator in my 73 was always oozing smegma from various solder joints so while I had the engine out this year I took it to the only radiator repair shop left in the entire Front Range of Colorado, which happens to be in the city where I work.
Dirty, cluttered, dark, sloppy, messy little place run by two guys just like that too. I was very not impressed but they are the only place left who rebuilds radiators & heater cores rather than just sending out for aftermarket replacements which don't usually fit. And they have a very good longstanding reputation for knowing their shit. (I've done safety inspections there and could write them up on so much stuff they'd be out of business tomorrow, but sometimes I try to look at a bigger picture, so I overlook a lot and only ask them to fix a couple things at a time. And I will do the same again next time and next time.)
So I took my OEM radiator in for them to repair, and when I went back to get it they showed me the parts, explained that it was too far worn to repair, the side tanks eroded too thin to use again. Then he pointed to a tag soldered on the side tank and said, "We repaired this very radiator in 1978. That's the tag we put on every one we work on. It lasted a good long time, don't you think?"
I had to smile and agree and ask "Well, what now? can you help me?" He said "Yeah, but all we can do is order you a new one which probably won't be exactly the same but you should be able to make it fit." (He knew the problems associated with fitment of aftermarket 'Vette parts, we had talked about it on my inspections....) He didn't charge me anything since he couldn't fix mine, even though he had time into cleaning & disassembling & inspecting it.
So I told him,"OK, I'll trust you to know best. Order me a new radiator. A good copper core equivalent one."
When it came in a week later, the bill was $400. I noticed a shipping sticker which was to the local Chevy dealer. So a couple days later I stopped in there and asked them what a replacement OEM radiator went for and the parts man looked a while and then told me, "Well, it'll take us a while to locate one, the last one any of the regional warehouses had got shipped out last week. It'll run around $600 or so."
I told him my story and he chuckled and said, "You got a deal, our cost is about $375. Yep, looks like it came through us and we charged them no mark-up." (I've done inspections at the Chevy dealer too, and BS'd about old 'vettes, so the parts man recognized me and was at ease telling me what the real scoop was.)
No, it didn't fit quite exactly like the original, the side tanks were larger which put a pinch on the lower trans cooler line to the frame, but I got that fixed with a grinder to the frame horn and a $20 bill to a local hose & fitting shop to tweek the bend on the metal line.
That same Chevy dealer--OK, plug for them, Ghent Chevrolet, Greeley, CO--also found me an OEM GM heater core a few years ago. I specifically asked for OEM not aftermarket. Took them around two months to find one, he said it was the last one out of a Canadian warehouse, and it fit.
 
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I understand what you're talking about. These guys were about the same, but they still have lots of work. And they do a good job and are not expensive.

I have to agree on the aftermarket parts. I used to judge most of them by the price. If it was to good to believe, it usually was, but lately even the low quality parts seem to cost high enough not to cause alarm....
 
As a Gene-esque aside, The radiator in my 73 was always oozing smegma from various solder joints so while I had the engine out this year I took it to the only radiator repair shop left in the entire Front Range of Colorado, which happens to be in the city where I work.
Dirty, cluttered, dark, sloppy, messy little place run by two guys just like that too. I was very not impressed but they are the only place left who rebuilds radiators & heater cores rather than just sending out for aftermarket replacements which don't usually fit. And they have a very good longstanding reputation for knowing their shit. (I've done safety inspections there and could write them up on so much stuff they'd be out of business tomorrow, but sometimes I try to look at a bigger picture, so I overlook a lot and only ask them to fix a couple things at a time. And I will do the same again next time and next time.)
So I took my OEM radiator in for them to repair, and when I went back to get it they showed me the parts, explained that it was too far worn to repair, the side tanks eroded too thin to use again. Then he pointed to a tag soldered on the side tank and said, "We repaired this very radiator in 1978. That's the tag we put on every one we work on. It lasted a good long time, don't you think?"
I had to smile and agree and ask "Well, what now? can you help me?" He said "Yeah, but all we can do is order you a new one which probably won't be exactly the same but you should be able to make it fit." (He knew the problems associated with fitment of aftermarket 'Vette parts, we had talked about it on my inspections....) He didn't charge me anything since he couldn't fix mine, even though he had time into cleaning & disassembling & inspecting it.
So I told him,"OK, I'll trust you to know best. Order me a new radiator. A good copper core equivalent one."
When it came in a week later, the bill was $400. I noticed a shipping sticker which was to the local Chevy dealer. So a couple days later I stopped in there and asked them what a replacement OEM radiator went for and the parts man looked a while and then told me, "Well, it'll take us a while to locate one, the last one any of the regional warehouses had got shipped out last week. It'll run around $600 or so."
I told him my story and he chuckled and said, "You got a deal, our cost is about $375. Yep, looks like it came through us and we charged them no mark-up." (I've done inspections at the Chevy dealer too, and BS'd about old 'vettes, so the parts man recognized me and was at ease telling me what the real scoop was.)
No, it didn't fit quite exactly like the original, the side tanks were larger which put a pinch on the lower trans cooler line to the frame, but I got that fixed with a grinder to the frame horn and a $20 bill to a local hose & fitting shop to tweek the bend on the metal line.
That same Chevy dealer--OK, plug for them, Ghent Chevrolet, Greeley, CO--also found me an OEM GM heater core a few years ago. I specifically asked for OEM not aftermarket. Took them around two months to find one, he said it was the last one out of a Canadian warehouse, and it fit.

:flash:

Sounds like a flashback story of my automotive life over some 50+ years

:mobeer::friends:
 
Well it continues. I had it up and running again. This time no leaks. Was trying to get her up to temp (which is 180°). Now it's freezing here + snow, but after one hour I gave up. There was no driving btw. I had it running in my garage with the doors open. The temp gauge showed barely 150.

I suppose the Stewart pump + it's dedicated thermostat (with bypass holes) flow too much water to the rad to get properly warmed up in winter.

Anyone have the same thing happening ?
 
Where are you measuring the temp? the head or somewhere else? eletrical gauge or mechanical?
 
I dunno man, some times it took a forever and a day run to get my car up to blowing hot air into the cabin.....

I have bypass holes in my remote thermostat, and so in this colder ~35f weather, the gauge says barely 150 or so on the freeway.....

computer sensor and mechanical cap tube are both into the heads.....


I have computer electric fans....so can idle forever to reach temp, but they WILL turn on eventually.....

:crutches:
 

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