Aluminum radiator leaking at different spots, a common thing?

paul

paul

XjunkieNL
Curious if others have seen the same leakage from the radiator.
I have the first BobG aluminum radiator installed.
It started leaking last year, only small amounts.
Maybe the leaking started earlier as I've been fighting air in the cooling system.

Last month I got it out to be repaired.
To my surprise the repair man says it has several leaks.
All leaks where at the top left and top right.
He thinks it has something to the way it's mounted.

Did anyone take special measures to mount it?
Do I maybe need to make a frame around it, so it can't flex?

Here are some photos of the repair.
Top right side:
20200517_125053.jpg
Top left side:
20200517_125103.jpg
 
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The radiator should be able to flex , within the mounts. If it is rigidly mounted, then the rad end tanks can flex relative to the core, which is a problem. Does yours have all the stock rubber isolators in place?

I don't know if your issue is design flaw or mounting issue - hopefully others using that rad will report. I do recall some recent thread on leaking aluminum rad's - you may want to search the forum for that also to see if it's relevant to your situation.
 
Thanks for the link to the thread, Jim.
I did a search on "radiator leakage", it didn't pop up.

That sounds exactly as what's happening to mine.
Too bad there isn't a real solution.
Seems mine will start leaking again in the future.
 
paul said:
He thinks it has something to the way it's mounted.
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I tend to doubt it has to do with the mounting. To answer your question, as you see in the thread that Jim linked these rads are very prone to leaking. And the location of your leaks is the same as I've found. It is where the end plates are attached to the core, inside of the end tanks (not the tank seams). All along that connection on both sides and both ends. That would indicate an internal design/quality issue, not necessarily related to the tanks or overall size or mounting, etc. Those end plates are assembled to the core before the tanks and frame are added to the unit when it is being manufactured. So it would appear to be more about the manufacturing than the application.

To address the mounting question. On mine one of the mounting studs on the bottom broke off. All of the studs on them (fans and main rad mounts) are aluminum so they are not very strong. It really isn't practical to attach a new stud without completely disassembling the rad. And even if that were done there is still a chance of the other stud breaking or similar issues. So I made new mounts that do not use those studs. I formed a pair of metal "cups" or "stirrups" with rubber cushions in the same manner as many rads are mounted on other makes of cars. They saddle the bottom of the rad to secure it from the bottom. The top mount is the original one. I haven't completed the car's build so cannot report any experience with that yet. They look something like this:
351-8466-1_800__02559.1584024994.jpg
 
I used the stock mounting spots. Not sure if the stock mounting points at the extreme ends originally had rubber grommets, but I made sure it had them when I replaced the original rad with the aluminum unit. Don't over tighten, it can negate the reason behing having the rubber mounts. BTW, my rad had several "voids" in the tig welds right from the manufacturer. These were fixed with no small effort, at considerable cost in both cash and time (as I had mounted, filled and bled it prior to finding the problems). These aftermarket rads are clearly not as robust as our orginal parts. 45 years with the original, with several engine changes, and my original is still servicable. I seriously doubt the aftermarket rads will be as tough half a century from now. So it goes with our hobby. Good luck.
 
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tigeravg said:
Not sure if the stock mounting points at the extreme ends originally had rubber grommets
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I'm not certain if I understand your comment. Mounts at the extreme ends? Perhaps the 1300's had different mounts (I've never owned a 1300)? But all of my 1500's only have three mounts (on the original rads and any aftermarket units); a single post at the top center, and a pair of threaded studs on the bottom roughly 1/3 inward from each end. Does your stock rad have something different from that?
 
paul said:
Thanks for the link to the thread, Jim.
I did a search on "radiator leakage", it didn't pop up.

That sounds exactly as what's happening to mine.
Too bad there isn't a real solution.
Seems mine will start leaking again in the future.
Click to expand...

Sorry you are having issues Paul,

I am going to check out my BobG "initial production run" rad in the 85X the next nice day. I think it has been in the car for about 6 years. I have never seen a leak, but I do smell antifreeze occasionally. Maybe it is the rad, I have been thinking it was the overflow, but never really looked. I have the full list of things Matt mentions as potential issues: performance 1500, coil overs, 300lb springs at all 4 corners, front sway bar, kinda short sidewall tires at 185/60/13. I will check the car over looking for signs of a leak focusing on the rad.

Come to think of it, when I acquired the car in 2013, the elbow hose from the water pump pipe to the t-stat housing had a drip and the clamp was loose. I will check that hose connection again too.

I have a second BobG rad on the shelf from the initial production run. My 86 could use some better cooling, so I might as well start the road test on that 2nd unit. 🚗 :)
 
Yup. '74 has two big honk'n posts at the extreme ends of the bottom support bracket, as well as a couple small studded flanges along the bottom line of the nose valance. Plus the rubber-ringed tab on top of the rad to sit in the locating hole at the top edge of the rad and rad "box".
 
Dr.Jeff said:
And the location of your leaks is the same as I've found. It is where the end plates are attached to the core, inside of the end tanks (not the tank seams). All along that connection on both sides and both ends. That would indicate an internal design/quality issue, not necessarily related to the tanks or overall size or mounting, etc. Those end plates are assembled to the core before the tanks and frame are added to the unit when it is being manufactured. So it would appear to be more about the manufacturing than the application.
Click to expand...

Not good, but good to know yours was leaking at the same position.
Probably independent of the mounting it would leak.
The current three point mounting seems to be engineered to give it some flex.
 
JimD said:
I have never seen a leak, but I do smell antifreeze occasionally. Maybe it is the rad, I have been thinking it was the overflow, but never really looked.
Click to expand...

Mine also never really had a puddle under the car.
When parked it didn't seem to leak, maybe a little drip now and again.
My main problem I was getting air in the system.
Had to fill up every now and again, but like you I thought it was overflow.
 
tigeravg said:
Don't over tighten, it can negate the reason behing having the rubber mounts. BTW, my rad had several "voids" in the tig welds right from the manufacturer. These were fixed with no small effort, at considerable cost in both cash and time (as I had mounted, filled and bled it prior to finding the problems). These aftermarket rads are clearly not as robust as our orginal parts. 45 years with the original, with several engine changes, and my original is still servicable.
Click to expand...

This sound all too familiar.
Not sure when mine started leaking, as it doesn't overheat with the leaks.
Original parts or refurbished ones seem the way to go.
Will make sure I don't overtighten things when mounting.
 
tigeravg said:
'74 has two big honk'n posts at the extreme ends of the bottom support bracket, as well as a couple small studded flanges along the bottom line of the nose valance.
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I didn't realize there was a different arrangement on the early cars (as I said, I've never had one). By chance anyone have pics of it?

This has me thinking about the mounting locations in general. Is it better to support the rad at the end tanks or along the lower frame? Some rads incorporate mounts on the end tanks only. Some OEM designs have mounts along the lower frame. As @paul says, the mounting or flexing may be one aspect of the leaks (although I still think there is a bigger quality issue at play here). I've noticed the frames on the aluminum X rads are a bit flimsy. So could the location of the lower supports help or hinder one way or the other?

The lower mounts I made are positioned just inboard from the stock mount locations. I could not put them directly over (under) the original mounts without interfering with the stud bosses, and my AC condenser mounts prevented me from locating them outboard of the stock locations. So I either had to go all the way over and put them under the tanks or go inboard. The decision to go inboard was somewhat due to the fact that brackets under the tanks could interfere with things like the drain plug, lower hose neck, etc.

Here are random examples of aluminum rads with tank vs frame mounts:
TotalZParts_Koyo-High.jpg
166-mc370.jpg
32-1139002M_withtext_large@2x.jpg
al_rad_9.jpg


However it seems that most OEM mounting arrangements from back then are on the frame, not directly on the tanks. But then again, they were not aluminum rads either. The later rads with plastic tanks and aluminum cores were often mounted by the tanks.
 
By the way I should mention that the aluminum radiator that I'm referring to in my prior posts is not one of the BobG originals, nor one of the latest revised versions from MWB. It was purchased a few years ago from a different Fiat vendor. So there may(?) be differences depending on what you have? But I'm inclined to think the majority of them come from the same factory, not sure. However I find it interesting that these same issues do not seem common on other aftermarket aluminum radiators from similar overseas factories for other makes of vehicles. So there may be something to the overall shape of it - being wide (long) and short with the tanks on the short ends?
 
I have to plug the Howe Racing product. They have an expansion joint where the top & bottom plate meet the tanks. None of the issues I've heard of with the other manufacturers. Their first versions quite some years back (9-10 years ago) did not have that, and in my Volvo install, I had seepage in similar places to the OP. The revised design (8-9 years ago), the only install change, resolved all that. I have had this rad in my X1/9 for about 7 years now.

IMG-2634.jpg
 
lookforjoe said:
They have an expansion joint where the top & bottom plate meet the tanks.
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The "cheap" aluminum rad I have also has similar expansion joints. I'm sure the difference between the leaking ones and yours is mostly due to quality of construction.

Those joints are where I notice the most flex along the frames. I realize that is by design, that's what they are supposed to do, but it is also why I'm wondering if mounting the unit from the frame is a good idea or not...it may be allowing too much movement and therefore stressing the welded joints at the ends of the core?
 
Dr.Jeff said:
The "cheap" aluminum rad I have also has similar expansion joints. I'm sure the difference between the leaking ones and yours is mostly due to quality of construction.

Those joints are where I notice the most flex along the frames. I realize that is by design, that's what they are supposed to do, but it is also why I'm wondering if mounting the unit from the frame is a good idea or not...it may be allowing too much movement and therefore stressing the welded joints at the ends of the core?
Click to expand...

Could well be. Mine sits on rubber blocks set under the end tanks, so the 'frame' sees no load in that regard.
 
lookforjoe said:
under the end tanks
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That's exactly what I'm debating. As mentioned I made custom mounts for mine. I had to, one of the mounting studs on the alum rad broke off. Therefore I could locate the new mounts anywhere I feel is best. Currently they are under the lower frame similar to the stock location. But now I'm wondering if it would be better to move them under the tanks. That isn't as ideal a location in terms of fabrication though. The support member that the rad sits on narrows at the ends before reaching the tanks, so it is a more difficult spot to attach my custom mounts to. And the rad has less open room for mounts to clear at the tanks; the drain plug on one tank and the lower hose neck on the other tank are pretty much in the way. I'll see if I can get a couple pics later today to illustrate this better.
 
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