Is the filter filling full of rusty gunk?If filter is dirty, clean it and run it, and keep cleaning it. If filter is not full of gunk, then I would u run it w/o filter and only water until it happens again. I had this happen on my 68. My filter was clogged. I cleaned it, and it was full of gunk a week later. It took several more times of cleaning to finally catch all the big rust chunks. How new is radiator?
I have never tightened clamps when hot. I usually do it cold, then re-torque when hot. You can get a pressure tester to see if u have all water connections tight and leak free. I have one, but I think auto parts stores rent them.

 

Is the filter filling full of rusty gunk?

I eliminated the filter and thermostat as possible causes because the hose came off at the upper radiator. This makes me think there is high pressure downstream of the filter. (I'd be with you if the hose came off at the t-stat housing.)



Sounds to me like an issue at the connection: hose ID too large, radiator inlet OD too small, and/or clamp torque too low. Similarly, high pressure in the radiator shouldn't happen unless the radiator has diminished flow or there's reduced flow in the block, which technically would make it a block block. :grin:

Then again, I don't have any first hand experience with this problem. "Been there, done that" trumps some guy sitting in his living room chair.

 

Maybe the cap is bad.

 

Obviously too much pressure in the system....Sounds like you have a blockage in the block or radiator... Check both and flush both out...

)

Tony K.

 

After you burp it and get all the air out of the system, I would check for bubbles(with the cap off) after your thermostat opens. Possibly you have a bad head gasket.

 

The whole system, radiator included, is brand new. I think i'll pull the filter and start there. Since it pops off on the lower side of the filter, I wonder if either the filter is clogged or if it's being restricted. I couldnt find any reviews on the Summit filter which makes me wonder if it's suspect.

I'll then top it up and burp it. Let it idle and get good and warm and go run the p1ss out of it. If I cant get it to blow, then I think that might be the culprit.

Thank you for the responses guys. This has been pretty frustrating.

 

If there are bubbles with the cap off, is that good or bad? I've been keeping an eye on the oil and water which are both clean.

The engine is a brand new build with less than 150 miles on it. Not that it means anything.

 

FWIW, I think water is cycling through the engine ok. I've been in traffic a couple times and i see the temp go up and down safely. Like tonight, I was in stop and go in 90 degree heat and it fluctuated between 190 and 200. The downward side of the coolant flow (exiting the block) was 220 so it was sweeping heat away). That would prove out a bad head gasket right?

The more I type this out, the more I'm getting REALLY suspicious of that filter...

 

Just a shot in the dark, Is the hose connecting to a chrome plated thermostat housing ? Those are notorious for slipping hoses.

Z

 

No sir. Its a CVR machined housing. It first threw the hose at the inlet of the filter itself. All signs are pointing to this filter.

 

I am not familiar with that filter. Mine was a SD/Gano filter. It broke. Since I had already cut the hose, I had to use what I had. I ended up using the kitchen sink strainer stuffed into the Gano clear tube. I had screen stuffed into the clear tube and wrapped around the outside of the tube. I had to slide radiator hose completely over tube so it blocked the “visibility “ of the clear tube. It caught a lot of crud, blocked flow and blew the hose off. Luckily it happened on my street and I coasted to my driveway. Clogged in a short period of time. Maybe a week?

 

My suspicion grows deeper...So it looks like the inlet / outlet of this filter is significantly smaller than the hoses themselves. I measured the radiator neck and the housing and they are both 1.40 inches inner diameter. This filter is 1.10" inner diameter. So that's over a quarter inch difference in inner diameter. That would tell me that the filter is creating a pretty significant restriction in the coolant flow.

I'm going to remove it and see where we're at.

 

Oh and the 1.1" is the inlet diameter. It necks down even further inside the filter!

Basically...from what I can tell, the inside of this filter necks a 1.4" hose down to about 3/4 of an inch or so. Now, i dont know how much force is going through this hose but, with a high flow water pump, even with a cap normalizing to 13 psi, there would be a boost in pressure coming directly out of the pump right? If that pressure is being restricted almost 3/4 of an inch, that could induce a hose pop.
Or am i performing some wishful thinking...

 

Yeah plumbing principles say constant flow in a larger tube suddenly going into a smaller tube suddenly and significantly increases pressure. Get a different kind of filter, I think.

 

If there was silicone sealer used at one point, and the seal was broken, the dried out sealer will be slick as snot and allow the hose to pop off.

 

Slightly off topic here, but is that a picture of your upper radiator hose that's slipping off? If so, why do you have a spring in it?

 

Thats how the hoses came. They're bendable / universal. The spring starts about 2" or so inside the mating surface of the hose.

 

I had a lower hose that kept blowing off. It turned out I had the right head gasket on backwards blocking a water port.

 

Well, if the hoses are the proper size I.D., meaning they fit the radiator and filter necks snugly and are clamped down tightly then my assumption would be that the amount of pressure built in the cooling system exceeds the pressure caps ability to vent, meaning possible head gasket leak from combustion chamber into cooling system. Grab a combustion gases test kit from the auto parts store.

Also, FWIW, I never liked "universal" hoses as they typically exert sideways pressure on the radiator necks which can break the soldered/welded joint(s) and also like to slip off water pumps and thermostat housing necks.

 

Is a combustion gases test kit the same as a pressure tester? I have one of those coming to test the cooling system.

 

No, it's a chemical test that will detect the presence of combustion gases in the cooling system. Another check which may or may not be useful, depending on whether the leak only occurs when the engine is hot, is to remove the spark plugs and, using a compression tester adapter, put compressed air in each cylinder and look for bubbles in the radiator.

The combustion gases test is pretty conclusive. Most large auto parts stores with "Loan-a-Tool" programs have these for free rental...you just pay for the "detector".

 

good posts re the possibility of head gasket on backwards, etc. Barring those type of causes, I think we keep coming back to the issues with the filter design.

If I were in your shoes, the 1st thing I would do would be to ditch the universal hose (thanks Woodchuck) and and also ditch the existing filter.

The Tefba radiator filter has been used by hundreds of VFM members, and I don't recall a single instance of hose blowing off problems.

you can get it in the original plastic, which I've used for over 15 years with zero problems, or an aluminum version. Either one should be trouble free.

original:
https://www.tefbafilters.com/

aluminum:
https://www.aeroflowperformance.com/af64-2043

Z

 

FWIW, I was never sold on cutting the upper hose to add a fancy filter when a piece of old panty hose over the end of the hose at the thermostat housing works pretty well....and it's CHEAP! Just hold over the end of the hose when you push it on the thermostat neck, letting it slide between the hose and the neck, clamp and trim the excess.

 

Some of us guys don't have panty hose lying around though, Woodchuck! Sounds like your life may be more exciting than my own!


I'm not judging here, or anything...

 

That's true, If you have a head Gasket on backwards as Tom991 mentioned, That will cause a good amount of extra pressure in the coolant system...I forgot that one.., but wait, You have a Coolant filter???!?? Why?? It's not needed....It's probably a big cause of your problems... Ditch it...!!!

Also, You should not have a spring in the upper hose.... It's only needed on the lower hose...

It sounds like you have a lot of "overkill" stopping up the works..

)

Tony K.

 

I ditched the filter last night. I ran it awhile this morning to get it topped up and burped. Temperature was better than before staying right at 185 (vs 195). I 'think' my issue was that damn filter but, i'm going to perform all the tests you guys have mentioned. I have a combustion tester as well as a pressure tester on their way. I'm sure I'll need them in the future on the other cars so I just bought them...they arent that expensive anyhow.
I'll report back when I get the tests ran.

Forgive my ignorance here but, why would having a spring in the upper radiator hose be detrimental? The reason i have the universal hose is because there is virtually nothing original about the car, including the radiator (much bigger), and finding a hose the proper length with the right bend(s) was proving difficult.

 

I ditched the filter last night. I ran it awhile this morning to get it topped up and burped. Temperature was better than before staying right at 185 (vs 195). I 'think' my issue was that damn filter but, i'm going to perform all the tests you guys have mentioned. I have a combustion tester as well as a pressure tester on their way. I'm sure I'll need them in the future on the other cars so I just bought them...they arent that expensive anyhow.
I'll report back when I get the tests ran.

Forgive my ignorance here but, why would having a spring in the upper radiator hose be detrimental? The reason i have the universal hose is because there is virtually nothing original about the car, including the radiator (much bigger), and finding a hose the proper length with the right bend(s) was proving difficult.

The springs are to keep the hose from collapsing. Since the upper hose is under pressure (the pump fills it as it sends water to the radiator) it generally doesn't do that. Only the lower hose typically has problems. Technically there's nothing 'wrong' with having one in the upper hose, but it's rather pointless.


The generic hoses are always more flexible than the fitted ones, which means they're ready, willing, and eager to make friends with fans, pulleys, etc. - and because they're thinner, they don't usually last as long. That being said, there's a flexible 'generic' hose on my dad's old truck that's been there for 30 years now, and that poor thing has not been treated kindly. So, it may not matter at all. =)

 

I chased a puking problem on my 331 for several years, which also kept pressure in system after cool down. After troubleshooting the entire cooling system, turns out the person I bought the long block from used the wrong head gaskets. Frig! Good Luck, hopefully you solved it.

 

I ran both a radiator pressure test and a combustion leak test. Both came back negative so the head gasket is fine.

After removing that stupid filter, the hose seems to be behaving. I ran it about 50 miles or so Friday, thrashing it pretty hard, and everything stayed in tact. For the most part, it's also running COOLER!

The next issue is that I get a seemingly random spike in temperature. Revving the car a moment clears the spike. I 'THINK' this is probably due to an air bubble in the cooling system so I'm going to pull out the thermostat, drill a hole in it, and reset the system since I dont think the thermostat has a relief hole. Yes i know I can burp it without doing this but, since it's down, I figure it's worth doing.

 

:shrug:Why would you want to run a filter on new motor and radiator? Don't get the filter thing and never even heard of it until this forum. I'd heard of guys using pantyhose temporarily when flushing the system though.

 

Shrug. Doesnt much matter now since it's gone and in the trash.