I noticed this morning that my lower radiator hose is contacting the power steering belt, so that pretty much makes my decision for me. The rad is coming out and going back to champion. I'm going to do what I should have done in the first place and order a fan shroud for the super cooling radiator I've got...

 

There are differant radiator core support openings. First measure the core, just the core, then the opening. I have the super heavy duty cooling and if just going by web sites I may have ordered the wrong one. Dennis carpenter has a lot more shrouds then anyone else and it was a simple direct fit.
Here is the thread
https://www.ford-trucks.com/forums/1...or-shroud.html

 

My core support isn't the problem, a super cooling radiator fits just fine, I already tried it once to make sure it would fit. I just got a radiator that quality control obviously missed because everything was wrong.

 

So, I put a new lower radiator hose on and decided to run the radiator just to see if it cooled any better. Despite the fact that it seems much larger and holds an additional gallon of coolant that my old one didn't, it runs exactly the same as my original 39 year old radiator. I'm now wondering if perhaps my thermostat isn't opening up all the way.... Any other ideas?

 

I kinda have similar situation, my new 460 acts the same way. I had a intake here that I used along with the Robert Shaw 195 t stat in it. I have no idea how old it is but I did check it on the stove and though it appeared to open like it should.

The other day when it hit low 40's here I went down a decent hill and it dropped to 160 and normally hangs 195-210. I'm kinda wondering if it actually is opening too soon and may stay closer to 195 vs the 210. The rapid cool off like that tells me it's not as good as I thought.

I'll have a new one in by the end of the week.

 

Well back to this then...
From what I remember, most 400's should never be bored that far. Did your shop (or wherever the engine was rebuilt) do a sonic-check of the block first, to make sure the cylinder walls were thick enough to handle such an overbore?
If not, you could be dealing with something that's really never going to get better no matter how much cooling capacity you throw at it.

Then again, you could get lucky and it's not the problem at all. Time will tell perhaps.
Then again, again, you may not even have a problem, considering the temps only rose 5° at idle and no more than 20° at it's max. Hardly an emergency in V8 motor temps.
Nobody likes things to change of course, without at least checking to see if anything can be done to get back to how things were before, but your engine change was pretty radical in my opinion. Even without a big cam.

First, did you also change the sending unit? If you did, is your old one still sitting around somewhere that you can swap it back in to see if the temps go back to what they were before?
Second, 215 is not worrisome if it does not climb. Obviously you'd like less because you live in a hot area and this gives you less headroom for extreme conditions. But back to the overbore, you may never be able to get it back down if that's the underlying reason.
Nothing wrong with you wanting to check other things of course (like the thermostat you mentioned) but I would not do anything further until you first verify that the gauge and sending unit are giving you good info.
Since you changed the engine you might have buggered the wire somehow, or a new sending unit is messing with you.
We can hope anyway...

I'd say that's a great sign. Says to me that your coolant flow and air flow are not a big issue here. At least on the surface.

That's a big possibility, and very common. Under other circumstances you could also be looking at the lower capacity of the smaller radiator running out of steam (so to speak) at the higher temperature producing speeds. But since you already checked with the larger radiator, and you're not really driving in any extreme conditions externally, I doubt it's a capacity issue. Even with the smaller radiator.
If you were diagnosing this from scratch, that could be an air flow issue, but since it worked with the old engine. I'd say not.
Did you put your restrictor plate into the cooling chamber under the thermostat? Hmm, sorry, that's only with Clevelands isn't it? Not the 400? Nevermind...

Sorry, but I'd have tried that first. I know you thought about it, and maybe avoided it to avoid buying a new shroud first, but since you paid to have this one reconditioned I would have used it.
I'm in the same boat though, with the desire to use a wazoo aluminum thingy up front like that. But have put it out of my head for the moment since I have a brand new in the box super-cooler waiting to go it. So no aluminum for me at the moment.

Sorry you had such a bad experience with the new aluminum unit. I've seen that problem before on other vehicles (Early Bronco radiators are notoriously ill fitting unless you go with a factory reproduction) and every aluminum radiator I've ever worked with (even the high-zoot Ron Davis ones we sell) seem to need more than just a wrench to make them work.
Yours did sound like they put the wrong one in the box though, from what was said.

Sounds like this is with the new super-cooling unit. A new hose should not suck down unless there's some extenuating circumstances causing it. Even a halfway worn out water pump can crush a lower hose if the flow out of the engine is not balanced. But a new hose is much harder to do.
Anyone know what the exact dynamic at work actually is, when a lower hose collapses? Is it just old hoses, or is there some problem internal to the coolant system that actually causes it?
I thought I knew but sitting here writing I'm thinking I don't really know.
Love to learn though!

At some point you'd just have to sit there and watch it (or GoPro it) to see if you have that problem.

You said you have a Robertshaw high-flow (sorry, "balanced flow") t-stat? And didn't I read you tested it? Sorry I didn't re-read but I seem to remember that mentioned unless that was someone else.
It's possible that it's not working right. Only a replacement would tell you that I think. If you watch it in boiling water, can you actually see that type open up all the way? It's not quite as visible a working item as the standard type of stat, so not sure.
But if you can see it, then I would at least test it again to rule it out.

If it was another engine I'd say to run it without a stat temporarily to see what changes you see. These engines are much better with the water restricted though, so not sure you'd get a good test without one installed.
But at least you could use it as a check.

Anyway, I'm back to verifying your gauge readings first, then moving on to the next thing.
A high-flow water pump is actually supposed to support better cooling by raising the "water pressure" (as opposed to ambient pressures) to better force coolant around all the water jacket's curves and uneven surfaces, and reduce the instance of steam pockets being created at hot spots where the cylinder walls are to thin from the overbore.
Just not sure I can recommend one until you determine the temps. I always use them myself, but I've never actually had a cooling problem in any engine that could not be tuned out.
Except for my 400 of course, which always runs hot.

Just not hot enough to cause me to worry about it, since even the high temps I saw were well within the normal "safe" range. As are yours.
If that is an accurate 215 reading, you're still in the sweet spot of engine temps. At the high end, to be sure, but still not overheating by any stretch.

Good luck. Sorry for the novel just to tell you to check your temps (which you may already have verified anyway) but that was the first thing I thought of after re-reading that you'd gone .060 over on the cylinders.

Paul

 

When overheating problems are encountered, the thermostat should be one of the first things to be considered. They deteriorate with age. Sometime they "stick" in a partially open condition. Sometime they don't open when they should. Sometime they don't open at all. A thermostat's performance should be verified before making any costly expenditures. Don't assume that a new one will perform correctly. ALWAYS VERIFY COMPONENT PERFORMANCE WHENEVER POSSIBLE. Put your thermostat in a pot of water on a stove with a known good thermometer. Heat the water from room temperature to boiling while watching the temperature and action of the thermostat simultaneously. If the opening action of the thermostat doesn't agree with its rating replace it. Then test the replacement the same way. I'm not sure about your engine, but thermostats for my 460 are available in various ratings from 160F & up.

 

The block checked out fine, I do realize that's a lot of overbore on a 400. I reused all sending units from the old engine for consistency's sake, I also reused the thermostat because it was relatively new, and fairly expensive. I went to the parts store and bought a cheap thermostat to compare to mine. I threw them both in a pot of water on the stove and the new one opened up right at 190. The old one out of the truck just barely opened and was still only partially open when the water was actually boiling. I put the new thermostat back in and took the truck for a spin.
Temps are now where they should be.
I'm going to swap my original rad back in next chance I have and see what effect that has.

 

A good result! Funny how the thermostat decided to just take this moment that you were working on things to fail. Figures it would do that just to mess with you.

Paul

 

Good to have at least a chance at fixing it, and sorry to hear about the radiator - I have a Champion in a farm pickup (at least I think it is, was a FleaBay special, for the application it was worth the gamble at half the price of a "good" one), and it bolted in perfect..... But the old one was a "narrow", offset to the passenger side, the aluminum one was a "wide", centered one, so the shroud was 4" too narrow.... However, the holes are symmetrical top/bottom, and the offset put all the passenger side holes correct, so it centered up on the fan perfectly - just needed a little 4" extension on the driver's side (again, not a show-winner, just a user farm pickup - the extension is a piece of road sign ). Surprised they could mess that up. As far as the hose - the old one came up a little short, but it looked trimmed by the last installer. The wider radiator had the neck a little farther to the driver's side as well, and the local parts store only showed 1 hose option....... but it was slightly longer, and worked fine, although it's still a little closer than I'd like to the PS belt, I think they all were.

 

95 is hot. Try 115-122 southwest ambient sitting in traffic where the pavement is much hotter than that. That gap will make a difference. Oem design is a minimal gap. You are probably fine with mild 95 degree summer temps. My recommendation is for everyone else reading to not trust that a set up with any kind of gap is fine in every case.

The goal is to suck as much air through the cores as possible. Not have it bypass.

If anyone needs one of the original radiators re-cored in the Las Vegas area, talk to Quick's Radiator.