freaky radiator thing

Belgian1979vette

Belgian1979vette

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New engine started, after setting idle mixture and rpm, ignition, checking for leaks...started the engine again a couple of days later to fully warm it over and when quirks in the vacuum system were done with to get the heater valve to open to allow the heater system to get the air out. When opening the heater, shortly after the upper hose got a little harder than became softer again. Figured this was the air being pushed out to the rad. No air bubbles in the overflow tank. Engine was run for 5 minutes after warm up, varying rpm.

After shut down I noticed a leak on the exit tank of the radiator. Oh well, something else to fix. Took the rad out after engine was cooled down and took it to a radiator shop. Verdict : radiator tank was swollen...wtf.

Now, this radiator was run with the original engine in the car, the previous engine that defaulted. Not sure where that happened.

Showed no signs of obstruction before mounting it in the car.

Thermostat tested (which is the Stewart type with 3 holes in it to allow coolant to pass so no obstruction to air there). No problem opens fine.

Lower radiator hose warmed up together with the upper when run, so coolant was flowing.

A little in panic I performed the following test : put the lower hose in vertical position. Filled up the engine with coolant to the manifold neck at the thermostat housing. Put my air hold plug in each cyl and put 3 bar on it. No bubbles, no spilling over water, no nothing.

Would this test be ok to confirm head gasket integrity ? If so, the swollen radiator is to be blamed on the previous engine.
 
You will not see bubbles out the lower hose, the upper..you might but you also might not. I don't think you can diagnose a failed head gasket this way. Does the upper hose get rock hard? It shouldn't in any circumstance. Do you have access to a Co2 tester for coolant?

This:

VS0061.jpg


It's a tester that has a detection fluid that discolors when i contact w/ CO2 escapng from the coolant, the luid level must be about 5cm lower than full and then you put this on the open radiator and run the engine. If the stuff turns greenish or yellow you have a problem.
 
I have to convert 3 bar to psi (43.511).... but no, unless the gasket is really blown you wouldn't see an issue. Also, your radiator car would relieve the pressure before the tank would swell.... did you ever fill the radiator with just water to run the motor? Is is possible it froze?

IIRC the cylinder pressure on firing is in the neighborhood of 160-180 psi (11 bar).

and even if you did pressurize it to that level, you'd have a devil's time getting enough pressure to overcome what is blowing by to actually check the pressure.

and (cringing cause of last time I agreed with TT I almost got banned) - TT is right, you'd see bubbles from the upper hose not the lower
 
arojnd 175psi is just from compression, when the mixture burns the cilinder pressure actually is much higher. Typically anywhere between oh let's say 350psi or so on light load and WOT anywhere between 1000 and 1500 psi depending on engine specs. You will never dupliscate that with pressurized air.

SBG, WTF on the last sentence??
 
With my 68 the highest point in the cooling system is the thermostat housing. It's aluminum made by Billet Specialties. I drilled the top of it for a 1/4 inch pipe plug. This is to bleed all the air out of the system. I have a Be Cool radiator. I modified the Be Cool radiator cap to remove the pressure relief function of the cap, so that the stock 68 overflow tank/expansion tank cap works as stock.

Cooling system heating problem can be very pervasive. In building my 68 cooling system I was lucky to discover two potential problems that would have cooling problems that I might not have ever discovered.
1) I ordered a GM Performance Parts Serpentine belt system that included all the accessory parts. It was poorly packed. The box was full of plastic foam "peanuts" for packing material. The cast iron water pump had broken out of it's box and was full of the plastic foam "peanuts." I took the water pump out shook to get rid of the "peanuts" inside it, soaked it in water to float out remaining peanut parts. Finally, a little suspicious, I removed the steel backing plate off of the pump......and WOW! there was another peanut in the impeller. If I had not have removed the backing plate, installed the pump on the engine, and started the engine, this peanut would have lodged in the cylinder head and blocked water flow. I would have had a serious aluminum cylinder head heating problem that would have left me clueless as to the cause.
2) The Billet Specialties aluminum thermostat housing. The aluminum casting (not billet!!!) inlet channel had a tremendous restriction. Although the inlet channel was about 2 inches in diameter (?), there was an approximate 3/4 inch opening above the thermostat housing. I used a die grinder and greatly opened the flow path. If I had not noticed this, I'm sure..once again...I would have had a heating problem with no clue as to the cause.

My response here does not unfortunately answer the Belgian1979vett's original question. I just wanted to point out that there can be cooling system problems that can be very obscure and very difficult to identify!!!!
..............................

Background: To neatly drill the 1/4 inch hole in the thermostat housing, I went out and bought a drill press. I didn't want to do a 1/2 ass job with a hand drill. Also, for cooling my ZZ4 Small Block engine, I bought a Be Cool radiator for a Big Block (electric fan). Also, I actually didn't use the cast iron pump included with the Serpentine system. I instead used a reverse rotation Edelbrock aluminum pump. I don't have any water in the cooling system of my 68. It has had no water in the cooling system since about 1973. The engine coolant is 100% ethylene glycol. It runs colder than a witches tit. About 180 degrees F. Its never overheated. BTW. I have 100% ethylene glycol coolant in both my 97 Thunderbird DD and my wife's 95 Cadillac Seville. My 08 Corvette still has the factory recommended water/Dexol solution.
 
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No, I don't have that testerkit.

Water was not frozen that I know of.

The radiatorcap was tested in the mean time by the guys that looked over the radiator. It worked fine they told me. So pressure relief valve is working.
Thermostat has 3 holes in it to bypass towards the rad, so in any case if pressure would have built up, it would have pressurized the cap and it would have opened an I would have had to see the bubbles in the overflow tank I would think. I didn't see that.

To add to my previous post : I didn't watch for bubble coming from the lower hose. The lower hose was put upward to fill up the engine. Coolant was filled to the surface where the thermostat normally sits in the manifold. I watched for bubbles appearing there. My reasoning is that if the gasket deformed because of warped heads/overheating or whatever, it wouldn't even keep the pressure at 3 bar I would think.
They test cylinderhead gasket integrity with a leakage tester don't they. I cannot assume they would do that with 11 bar on it, as they would be able to hold the piston on TDC to do that.
Besides the plugs were in the other cyls, so they were compressing the air as well.
 
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they test cylinder seal with a leak down tester. A cyl that leaks down isn't necessarily a blown headgasket, can be rings too. 2 cyls next to each other leaking dow, now there it might just be a head gasket.

Buy the tester kit, it's cheap.
 
I think if it was me I would try and borrow a cooling system pressure tester, pump it up, let it sit and watch the gauge...
 
Did the same test again at 6,5 bar. Hard to keep the crank from moving. Anyway, same results.

TT, anywhere they sell the color type kit to test ? Price ?

Got the rad back as well. Cap was working just fine. Opens at 1,2 bar (about 17 psi). Cannot imagine this would have caused this type of damage. So I'm assuming it was already there.

Rad had been worked on. According to the radiatorshop the core was exchanged for a heavy duty one. 3 rows, closer together and with more finns on them. The fixed the leaks and tested it for € 60 which is not that bad.

If I have to replace this HD item, I will be looking at a BB rad.

The car came with some strange things, like LT1 pistons, forged crank, M22 trans, 292 turbo heads (unfortunatly cracked between the seats) and now I find out it had a HD radiator core installed.
 
redvetracr said:
I think if it was me I would try and borrow a cooling system pressure tester, pump it up, let it sit and watch the gauge...
Click to expand...

Being a cheep bastard, I mad my own....simple device, spliced into the heater core line, with a T made from 1/2" copper plumbing fitting and soldered up to a R12 type fitting....on the T.......so to cold or heat test engine for pressure, just hook up the HVAC gauge set on the lo pressure side, to the rad, I have another fitting to use the air compressor into the freon can side.....so to pressure the entire system, and so blow the cap at 16 lbs, let it stop bleeding, and then come back a couple hours later to see what if any pressure drop you have.....

actually, if you have any leak at all, that will drop like a rock and you know from that, you have a problem SOMEWHERE.....so to fill it to the gills and do the same test.....see water? wellllllll DUHHHH.....

IF you get unlucky you maybe have to remove plugs and spin engine over....:eek::surrender:
 
At a light angle, the fluid in the rad has to be about 5cm or so below full, the tester should NOT! suck up fluid, only vapors that's what you suck up and if there's CO2 present the indicator will turn.
 
An easier way to test for coolant system pressure is just to run the engine with a coolant pressure tester installed. Reset the gauge once the coolant has heated and expanded and see if it climbs too high.

Tank damage probably from before, it can happen over time.
 
Belgian1979vette said:
Water was not frozen that I know of.

.
Click to expand...

You're killing me - you did have just water in the system?

I'm having a hard time believing that it's a blown/leaking head gasket - if it's blown (and I've had lots of them), it overheats and blows antifreeze out of the cap/overflow. Further, the cap would have relieved the pressure before it would have blown the tank - unless there is a huge amount of pressure in the system AND it goes through the bottom hose (and through the impeller)

still, I've not see it all - so I'm certainly interested in what the true cause is.
 
For initial start up (+ for the first 20 minutes of running) of the previous engine I did just use water. Was left in there a couple of weeks and then drained, because had to do other work to the car. Didn't freeze as far as I know during that periode when the water was in there + chassis with engine was stored inside.

Radiator is old. Had nothing to compare it too, so could be like this since the beginning. Previous owners had the core replaced with a better one. (BTU rating just below that of a high hp big block) according to the repairshop. Lots of things changed on the original engine as well, among which the installation of turbo heads (292's). Could have been an overheating issue.

Anyway. Rad was repaired for a small amount so that I could do some tests.

Put coolant back in the engine yesterday. Used the improvised method with a bycicle pump to pressurize to 0,5 bar (approx. 7 psi). Slowly lost pressure over half an hour. Some leaks at the heater hoses. Fixed, pumped up pressure again and found out that cap was leaking around the axle in the middle of it (which holds the valve). Pressure didn't drop immediatly. Will have to find a new cap before going further with the test.
Air seemed to pass the radiator cap with not a lot of problems to the overflow, which necessitated me to close of the tube to the tank. Don't know if that's supposed to do this, but it means that any pressure build up would have not been possible without blowing air into the overflow tank.

Not 100% but I'm very confident that the engine is going to be fine.
 
I'm sticking with my assessment - there's only a slight chance your motor has a blown head gasket (like infinitesimally small).

Just as a matter of course - I have a 327 in my shop where the guy rebuilt the motor and broke it in with just water in it (I also have a 350 Buick with the same story). He pulled the lower hose to drain the motor..... the temperature froze between that start and him putting it in his car. It cracked the block because he didn't pull the plugs to drain the block....
 
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.
 
Belgian1979vette said:
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.
Click to expand...

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.
 
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What's krazy is that over the years, I have never owned/messed with any BBC....none of them....the one in my '72 here is a '89 roller engine, I installed back in '97.....many a head job.....but never a blow by.....

:clap::clap: at any rate, all of my olde tyme hotrodding big blocks were olde tyme PONTIAC.....400+ ci...... built for 550 ft lbs at idle.....

I sort of look at something the size of a 455 Poncho and think of it in my '72 vette, and I feel sorry for the rear end, and that is awful close to my wallet....:suicide:
 
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