My deer-crash saga continues...

[Highsider]

I swear I usually am a very lucky guy. But not this month.
Some of you have read my other thread about last Sunday when the 240-pound, fatso, suicidal doe rammed my truck so hard, I felt my recent alignment was knocked out of the park. So, before I could drive a 60-mile round trip to see a body (any body shop) in to the shop it goes.

So, the alignment guy says my battery was dead and he had to jump it. No way.

He then left the truck running while he was waiting for his spot in the shop and the truck overheats and POW! The top of my stock, 1957 truck radiator explodes!

I popped the hood and the radiator cap is facing me and the top of the radiator is like a tent. That is not right.


The hose outlet is supposed to be level.


It turns out one of the wires for the fan got unplugged during the wreck and the fan never comes on.

- Why doesn’t the 16-pound radiator cap not protect the radiator?
- None of the hoses are new, actually all are at least over 20-years old, so why didn’t one of them burst?

Can't wait to see what is next.

[lowrodderchev]

Man I'm sorry to hear that good thing u love her enough she'll be back on the road in no time

[71swb4x4]

Dang man. It's a sad day when a radiator only lasts 56 years Just ribbin.
Like you said that's crazy that it would pop like that without the hose splitting or cap releasing pressure.

[LEEVON]

Sorry about your luck, not sure about the cap, but 16psi can be alot on an irregular shaped container. I've seen 5 psi break ductile iron pipe. Chances are the radiator had a weak spot and popped before the cap had a chance.

[parkwood]

Mommy said there would be bad days but she didn't say they would come like banana's in bunches ....

[1project2many]

That sucks.

- Why doesn’t the 16-pound radiator cap not protect the radiator?

Did you ask the radiator if it was safe at 16 psi? Really. The stock radiator ran at about 1/2 that pressure. I know plenty of people run them higher (I do) but at least in my case I pressure tested it to 20 before applying the cap.

Next issue, the vent tube at the radiator neck is 3/8" ID max. As the engine gets hotter and hotter the coolant boils in more and more places within the block and may reach a point where most of the coolant is trying to turn to steam instantly. There's little chance a 3/8" vent tube could continue to safely relieve enough steam from an unattended running vehicle for an indefinite period.

Next, steam carries a *lot* of heat energy. While water temp won't get above its boiling point, steam temp can be higher. Pure lead solder melts at about 370 degrees, not too far from the boiling point of coolant at 16 psi, 265 deg F. It's possible for steam temp in an unattended overheating vehicle to rise high enough to soften the solder, further increasing the chance for radiator failure.

The radiator cap is not meant to protect the radiator, but to maintain a pressure in the cooling system. Old systems which had no recovery tank would often vent large amounts of steam because there was no gasket at the top of the cap to keep it in. Converting to a recovery tank system with a sealed cap eliminates this vent path.

It would have been nice if a hose blew but they can often handle high pressure and temp better than the old technology radiator they're attached to. But consider this: If the cap did relieve all steam and pressure then the coolant level in the block would have gotten lower and lower while the engine got hotter and hotter. There's a small, Chernobyl-like reaction waiting to happen in your engine in that scenario.

[L_Brown]

See, this lady is right.....lol

http://youtu.be/jgGSLybhFOc

[Highsider]

project: thanks for the detailed information. Felt like I was reading a science textbook.

I took the radiator to the guy who soldered my overflow tube and he seemed to think it is salvageable.
I may have the body shop look into a "modern" unit.
This one is neat and if I can keep it I would like to.
It has the built in trans cooler at the bottom.

In the first photo you can see some of the id numbers. The manufacturer's name is on it there somewhere.

[mr48chev]

Originally Posted by Highsider

- Why doesn’t the 16-pound radiator cap not protect the radiator?
- None of the hoses are new, actually all are at least over 20-years old, so why didn’t one of them burst?

Can't wait to see what is next.

I'd have to check but Orrie or Ogre will probably come up with the answer. I believe that those trucks originally came out with a six or eight pound cap. The 16 lb cap is way too much pressure for a stock 56 radiator.

According to my O'Reilly's cheat sheet it should have a 7 lb cap with a stock 56 radiator. http://www.oreillyauto.com/site/c/se...make=Chevrolet

[Highsider]

No kidding?
Well, thanks for finding that for me.

In my modern thinking, 16 didn't seem all that high.
I see now it may be.

EDIT:
Maybe I should mention it is hooked up to a 350 out of a '75 C20.
Does that call for a compromise on cap poundage?

[OrrieG]

yes early vented systems are max 8 pounds. when I worked in a service station in the 70's we used to see a lot of miss matched caps to cooling systems. Usually the hose blows first, your rad must have been weakening over time.

[1project2many]

IF the radiator will handle it, higher pressure will allow you to run with higher thermostat temps, which can help the engine run cleaner. Generally, low engine temp promotes carbon and sludge buildup and increases tailpipe emissions. I'm running 16 psi and 195 T-stat with a cooling fan that turns on at 216 degrees.

But... plenty of people run cooler thermostats without any significant problems.

Your radiator guy can check your radiator and give you an idea about its structural integrity. A good, experienced guy is invaluable for this stuff. If he says "No go" then you should probably look around for something else. 350 likes to have a good cooling system so don't skimp on this one.

[Highsider]

project- that is how I roll...195 stat and (up til now) a 16# cap.
Can old caps stick and not let out fluid?

This one may have been on Mary's burro.

[mr48chev]

It wouldn't be high with a modern radiator but with the made in 1956 radiator made with 1956 Technology 16 lbs is twice too high.

One thing to always remember a chain is only as strong as it's weakest link or in this case a cooling system is only as strong as it's weakest link. When you put two weak links together = an electric fan that depends on all electrical connections being perfect along with depending on a thermal switch that works and a radiator that is 57 years old problems can develop if one or the other fails.