Overheating and blown radiator tanks.

[Ecomike]

I'm 99% sure this is a pressure problem. Today it was hot. There is about a five mile 5-6% grade to pull to get to my house. I had my trailer on and I noticed the temp get a little warmer and warmer as we got home. Pulled into the driveway and shut it off (giving it a min or two to cool down) about 15 sec after I shut it off the tank blew out. I'm not talking started leaking around the tubes. I'm talking a 2 inch by ten inch gash in the outward wall of the tank.

Which tank blew? If it was the side where the transmission cooler is located inside the tank, and coolant flow to that area was poor, I could see how the transmission could have locally overheated the plastic in the side tank, and started the failure process, if was a plastic tank, which It sounds like it was?

I have given up on plastic tanks!

The head gasket leak tester kits that they rent for free (you buy the test fluid) work great for detecting head gasket exhaust leaks into the coolant. Amazon has it for $30

http://www.amazon.com/dp/B0007ZDRUI...nd=8899678761435584503&hvpone=&hvptwo=&hvqmt=

 

[DrMoab]

It was the opposite side of the trans cooler.

 

[Ecomike]

If you read my first post I said I had an all aluminum champion radiator in there. It failed too.

I missed that too! But did it just leak, or blow out a tank wall too. I have heard that a lot of the all aluminum radiators are failing due to structural design issues combined with vibration stresses, or some such story, after just a year. I think they told me even Champion was having stress-failure leak issues. That is why I went back all brass-copper rads.

Thought, if only one cylinder is leaking, and it is not firing (but the spark plug should be a good clue there), it would not have CO2 in the exhaust. The exhaust leak in coolant test, tests for CO2 in the coolant!!!!! The CO2 forms carbonic acid, and reacts with the test fluid, and a pH color change indicates the leak. Nice thing about that test, is you can rev the engine up to 3500 rpm and run it for 30 minutes, and be really sure there is no leak. To rev it up, you need to remove a little coolant first.

I was chasing what seemed to be a headgasket issue for years in my diesel, (2003-2006) it leaked air (and blew out coolant) out the overflow that was coming from somewhere. But it passed the CO2 test. And only pushed out air at peak high way speeds and loads. It turned out I had a water pump gasket leak on the suction side of the water pump, and a slow flowing radiator, so at at high rpms, the water pumped sucked in air!!! But it never leaked coolant under pressure because I had the fiber head gasket leak sealer, bars leaks, in the coolant.

That was one I did not even think was possible!!!!

 

[Ecomike]

It was the opposite side of the trans cooler.

OK, so just to be clear, same side on all the failed radiators? By the way, that is same spot that failed on my daughters aluminum-plastic tank radiator last winter! Just blew a hole out the same place, right at a plastic weld seam. In that case it looked like some AC tubing brazing work got a little too close to that area the year before.

The part that bothers me the most, is that yours blew after the engine stopped running.

 

[Ecomike]

FWIW, the one that failed here on new years morning this year, was the same exact vertical line on the left side of that picture!!!!!! I believe that is an ultrasonic weld seam, and is a weak spot on that style radiator!!!!

The hole

 

[Ecomike]

Haven't pulled them yet. Waiting for my new radiator to get here.

It's kind of hard to pressure test a coolant system with a fist sized hole on the radiator

Just shove a Rag in the hole, LOL!!!:cheers:

 

[Ecomike]

All three radiators that failed have had new caps.

Is it possible there is a leak that forms on engine shut down, where coolant suddenly sees overheated steel (thinking exhaust head areas), superheats to steam and suddenly pressurizes the coolant with more pressure than the cap can release? A leak that is mostly sealed during daily driving?

If it was my vehicle I would try adding bars leaks medium duty head gasket sealer to the coolant with the new radiator. But I know a lot of people don't like the stuff.

 

[DrMoab]

OK, so just to be clear, same side on all the failed radiators?

No. The first radiator didn't blow out (stock one) it started leaking where the rods are pressed into the tanks. IIRC it was on the pass side.

The champion leaked from the same spot....where the rods are pressed into the tanks but on both sides.

 

[DrMoab]

The part that bothers me the most, is that yours blew after the engine stopped running.

Less than ten seconds after. Shut the key off, opened the door and bang.

 

[n5xl]

Doc, this sounds like an overpressure situation from a head gasket. Somewhere back in a few of the posts, it was mentioned to use a coolant system pressure gauge. Use it to pump up the system to 16psi and then look for the coolant system pressure to hold for a long time. If it doesnt hold pressure, pull plugs and look for coolant in the cylinders. If that doesnt reveal the problem, release pressure on the system but leave the gauge hooked up. Start it up with the pressure tester still attached to the radiator and watch the pressure build up over time. If it reaches 16 psi pressure before the temperature reaches 210, you've got a cracked head or head gasket problem. You should be able to find the problem one of these two ways.

There should be a white tag on the top of the radiator with a part number that starts with 520. If you still have the busted rad, could you pass along the number that is on the top? Just curious if this was the standard radiator or if this is the heavy duty cooling version.

 

[Ecomike]

If it reaches 16 psi pressure before the temperature reaches 210, you've got a cracked head or head gasket problem.

This would be true on a closed system, like Renix, but if the cap pressure is rated for 16 lbs, I think an open system will hit 16 lbs and bleed some coolant from a cold start up before it hits 210 F. If the coolant is already hot, and there is some air in the radiator already, then you may be alright.

 

[Ecomike]

Perhaps an air/steam bubble in the block supperheats in a hot spot, when the coolant stops flowing?

I do know that many of my vehicles over the years would get hotter, and the upper radiator hose would get harder (pressure) the first few minutes after shutting off the engine. That is also, when I when I learned to look for early signs of leaks, from peak pressure!

 

[85xjwoody]

A long shot here, but could a lower radiator hose without the spring inside cause this to happen? Just tossing that out there to check.

 

[garr]

A long shot here, but could a lower radiator hose without the spring inside cause this to happen? Just tossing that out there to check.

That’s what I was thinking!

+ I would think that the upper hose should fail before the tank blows apart?

Another long shot, assuming you are using a 16PSI cap, Is the overflow hose blocked preventing proper expansion?

 

[Ecomike]

A long shot here, but could a lower radiator hose without the spring inside cause this to happen? Just tossing that out there to check.

In my opinion a lower hose would never collapse unless the radiator flow was restricted, causing high pressure on one side of the pump, and low pressure on the other. At 16 psi, there is no way a lower hose could collapse, unless it was starved as I suggested above. One other way it could be starved, is a stuck T-stat, and we have heard all sorts of complaints about bad T-stats lately.

DrMoab, have you tested the T-stats after the leak-blown tank failures to see if they failed?