Howe Radiator Overflow?

[ba123]

Who has a Howe Radiator with their 22-24lb cap and messed with an overflow?

I'm just curious...with that high of a pressure cap, is there really a point in having an overflow?

Has someone installed one with this rad and seen coolant flow both ways?

Truly asking.

Thanks!

 

[duffymahoney]

I don't think mine has ever had any fluid in it.

 

[ba123]

Thanks! I'll try it without one and see then...if anything ever comes out, I'll put one.

 

[DirtDonk]

Isn’t it a specific design cap, rather than a pressure rating thing?
I think that though all modern vehicles use recovery tanks, many of those systems are using higher pressure than the old days.

Then there are those that are full flow systems that have external tanks that are part of the flow. Not just overflow.
Would love to know more about the design pluses and negatives for the different versions.

I think any cap, no matter how high the pressure rating, is going to puke fluid at some point.
Whether just from running hot, or more likely when it’s turned off and temporarily heat soaks.

 

[ba123]

Regular cap, but just a higher pressure rating and the rad designed to hold a higher pressure as well. Hopefully everything else I have can hold that pressure…

It’s my understanding that most caps, even now days, go so like 16-20 and pretty sure our systems aren’t going to put out more than 20, but that’s my guess. This cap would need around 24 to let anything go out of the overflow and then I have no idea how much suction it would need to suck some back in. I’ve never thought that much about a cooling system in that regards.

I really have no definite idea…just thoughts which is why I was hoping someone who had this one could offer some experience. 24 lbs is a lot of pressure.

To be clear, the overflow of this cooling system is above the sealing surface of a cap. Pressure has to be enough to push the seal beyond what the cap can handle and then exit the hole. And that is also different than a modern cooling system. In a modern system, the overflow is pressurized and there is no radiator cap (expansion cap holds the pressure). Very different. And neither of my other vehicles use this high of a pressure…Porsche is 18lbs and Raptor is 21.

I always overthink things.

 

[ba123]

Just a quick update to this thread that I ultimately decided to add an overflow.

Might even make mores sense to have a lower lb cap and allow more fluid by filling the overflow some and no air at all in the system.

Is my train of thought correct or unnecessary?

 

[ba123]

A couple pics, looks nice:

 

[nvrstuk]

I have never run a cap that high. Don't have a Howe so no experience there.

If it's never burped then the cap pressure is so high that it isn't needed.

Why the additional reservoir then? Just trying to add capacity?

More capacity is always good- at least if you're having overheating issues.

Lower pressure cap will allow fluid past it when hot and then you'll need the reservoir tank.

 

[ba123]

Yeah, was thinking it would add capacity instead of the bit of air at the top of the radiator.

Engine isn't overheating, but just want to do all I can to make sure it stays that way. Not even sure what I'm thinking is correct...not really sure how much cc sccum it would need to pull through the cap, anyone tested that?

It would need to be able to push the air out, and then pull the fluid back.

 

[Yeller]

Howe knows their stuff and does things in ways that no one else in the biz does. Long term is where I see the issue with the 22#+ caps. It’s hard on radiator tubes, over 20psi and they can swell causing fatigue leading to failures of the tubs, according to the cooling engineers I’ve had discussions with and one of them used to work for them. I’ve also found them hard on hoses, been doused with 250* coolant when a hose let go. Only thing that saved time at the burn unit was that I fell in a 4’ deep water hole trying to get away from it. Give me a plain ol 13 pounder and I’m happy.

 

[Speedrdr]

Following. Interesting stuff here to digest!

Randy

 

[ba123]

yes, was thinking the same thing...just because the radiator can handle it, doesn't mean everything else can, and what's gonna fail first?

I'm going to change it to a 16lb cap and see how it goes. I think 13 is too low for my system. That's proper for stock, but I want it higher before releasing pressure.

And I found this while searching, so it looks like I was thinking the right way as far as how it should work in an ideal world for me:



Also reading that I need a vented cap in order for this to work this way (if I understand correctly) and I prob have a non-vented cap that would never suck coolant back in any scenario.

 

[nvrstuk]

Especially with an alum core with a 20+ lb cap.

Wasn't thinking of that when I responded but I have not purchased any cap higher than 13 because of it!

if you have any weak seam or weld on brass or alum a 24 lb cap is 200% more pressure than what most std radiators that we are dealing with are built for. No safety margin left.

What are you gaining with 3more psi? A fee more degrees before potential boil over?

Size the radiator, great shroud/fan setup and you'll never need those 3 extra psi.

Gotta remember why less expensive radiators are less expensive. Less alum is used in their builds. I have called them, Griffin, RD, and asked tube dia, wall thickness, tank thickness etc before I bought mine.

Just a thought.

 

[ba123]

That's the cap that Howe gives with their radiator that is all weld and no glue, so I'm not worried about the radiator giving out, but what about everything else?

The other day, I actually did notice my lower hose leaking and I tightened it and has been fine ever since. I don't like overtightening things, but yeah, 22lbs is a lot!

I just ordered a cap...I kinda wanted one with the sacrificial anode anyway to be extra sure the radiator is ok. I did ground the rad, but that's an expensive part to fail. Stupid Graveyard sells the How Radiator and displays a sacrificial anode on the sales page that goes into the drain hole and wouldn't you know that it doesn't fit! (I did not have the best of luck with that place and their customer service left much to be desired). Ordered the cap from WH.

 

[nvrstuk]

I use a cap with an anode also.... good insurance. Kinda sad the Graveyard one doesnt fit. lol

 

[Soylent]

Are the anode caps just for aluminum radiators?

 

[ba123]

Are the anode caps just for aluminum radiators?

Yes, the anode keeps the electrolysis away that corrodes aluminum. The anode corrodes over time instead.

 

[Yeller]

yes, was thinking the same thing...just because the radiator can handle it, doesn't mean everything else can, and what's gonna fail first?

I'm going to change it to a 16lb cap and see how it goes. I think 13 is too low for my system. That's proper for stock, but I want it higher before releasing pressure.

And I found this while searching, so it looks like I was thinking the right way as far as how it should work in an ideal world for me:

View attachment 920359

Also reading that I need a vented cap in order for this to work this way (if I understand correctly) and I prob have a non-vented cap that would never suck coolant back in any scenario.

This is correct. One thing that I have discovered is many of the aftermarket overflow/purge tanks are not large enough. I chased random, unexplained overheating for a long time, only my engine wasn't overly hot. Turns out my purge/overflow was too small. through temp cycles the purge tank would overflow when hot, then when it would cool it would run dry. as the heat continued to cycle through use it would get a little low, about normal low for an old school radiator without an overflow tank, just so happens that's about where the water level reaches the top of the head, my radiator is lower than stock and my motor is higher than stock. With the water level near the top of the head it would steam and proceed to push water out of the radiator like it was boiling over, chased that for a long time. Made a 3 quart tank and have not had a problem since.

 

[Soylent]

Yes, the anode keeps the electrolysis away that corrodes aluminum. The anode corrodes over time instead.

Any need to use one for aluminum heads?

 

[ba123]

Any need to use one for aluminum heads?

I've never thought about it, but it certainly couldn't hurt and might be a good idea. I really only got mine in order to just be sure.

And I LOVE it when WH gets things out that quickly. I ordered yesterday and already got it today!

So, I put it in and then put a bit of coolant in my overflow. I'll try to look after a bit to see if any got sucked out.