Radiator Woes

[ggunter]

The radiator on my MKIV has given up for the second time. I had it repaired once, and it lasted about a year. It is at the repair shop now being repaired again. It seems it always springs a leak at the bottom of the core where it meets the tank on the left side. I have it mounted with a piano hinge at the top and the Breeze mount at the bottom. This seems to be the generally accepted way of mounting. Not sure of why this is reoccurring, weather this is a mounting issue or a radiator quality issue. Curious as to other radiator failures and remedies to fix this problem. I am going to mount the piano hinge with a strip of 1/4 x2" rubber at the top this time in attempts to reduce vibration. Any thoughts are appreciated.

[CraigS]

At the rubber strips use a bolt, a couple of fender washers, and a Nylock nut. Tighten the nut so there is just barely pressure on the rubber. Also if there is a way to have maybe a 3/8" hole in the steel and use a 1/4" bolt, that will keep all steel to steel contact from happening. You might also be able to find something like this;
https://www.zoro.com/midwest-fastener-316-x-58-x-02-rubber-bushings-10pk-72646/i/G902526247/

[egchewy79]

How do you have it mounted at the bottom? Any vibration dampeners there?

edit: I do see now that you mentioned the breeze lower support as well.

[AA-ron]

My radiator failed in that exact same spot after about a year on the road. I just replaced it and did all the upgrades to the mounting (top hinge, rubber bottom mounts). I’m hoping for the best!

[ggunter]

The bottom Breeze mount consists of a square tube with rubber hose the length of it with a tab on each end that mounts to the cars 3/4" square tube. the radiator frame lays on the rubber hose supported by the square tube that runs cross ways.

[ggunter]

Those little rubber bushings may be a good idea.

[PNWTim]

There are isolation nuts and bolts that can be used to mount radiators as well. Essentially they are rubber covered and expand as you tighten them to provide a vibration reduced mounting method.

[ggunter]

I have used those isolation nuts before, and I think they would be the ticket for the upper mount. Never gave them a thought, Thanks.

[BrewCityCobra]

A bit of a different idea. If it is on the driver side, could it be that your lower radiator tube is exerting too much pressure on the radiator itself? If the alignment is off a bit the tube could be torquing on the connection point, which in turn causes the reservoir to separate in that same corner.

Just a theory.

[ggunter]

I would agree with that if the hose was short. I think its plenty long enough to absorb any flexing or twist.

[J R Jones]

I know where this mounting design comes from, but that does not mean it is good or even adequate. A review of OEM raditor mounts are not the like that. They use rubber isolation exclusively.
Assuming chassis flex is not enough to stress the radiator, the more likely dynamic is vibration fatigue and air flow through the core. Vibration and displacement force is isolated by rubber but not by a metal mount. Indeed the rubber results in some movement and a bending moment near the solid mount.
jim

[ggunter]

I agree that rubber isolation is the way to go. Still waiting on the radiator shop to get done. Not like them to be this long, going on three weeks. When I go back this time, I will enlarge the lower piece of rubber hose the bottom of the radiator sits on to increase the surface area contact of the hose, and use rubber well nuts in the top mount on the piano hinge. AND.... hope for the best.

[ggunter]

Finally got my radiator back from the shop yesterday and will install it this weekend. I purchased a new radiator from FFR about a year ago when it failed the first time just to keep as a spare. I was going to install it this time when mine went to the shop and took it out of the box and noticed the lower pipe (engine inlet) was angled pretty steeply as opposed to the stock rad, where the pipe comes straight out of the tank. Just wondering if it is a better set up hose wise to go with the new rad or will that be another engineering feat to change over the hoses. I have Boig pipes. Any thoughts.

[Jeff Kleiner]

If you were starting from zero I'd say to use the one with the angled pipe since it can result in a cleaner and straighter hose routing but since you're already set up for the straight one that won't require you to rework your hose you might as well stick with it.

Jeff

[ggunter]

Thanks Jeff

[kevin j sullivan]

Hopefully there's no "greenish" color around the leak. If so, you have an "electrolysis" issue. Which means there's too much of a charge going through your radiator, which creates a weak spot hence a leak. TEST: Digital volt meter, lowest setting on DC side, black to ground, red probe in the coolant. Power on, engine off, aux. stuff on, lghts, fan, radio. Reading should be 00. - 0.3. Anything above, add a ground wire. (Had to replace my custom AFCO radiator after 1 year!) added a ground - 6 years and no leaks!)

[Rebostar]

After reading a few posts about leaking radiators and seeing the Breeze mounts I decided to not use the piano hinge upper mount. I cut off the FFR mount blocks and welded on a 1.5" strip if 1/8" steel full length of the upper radiator 3/4" square tube. To this installed five 3/4 x 3/4 isolation mounts from Mcmaster Carr. (https://www.mcmaster.com/products/isolation-mounts/vibration-damping-mounts~/general-purpose-vibration-damping-sandwich-mounts-with-studs-6/) On the Breeze style lower mount I welded on the attach brackets after setting the angle of the radiator I wanted. I used 1/2" square tube with a 3/8" piece of threads-all to hold it in the welded on brackets. I used 3" sections of 5/8" heater hose, over these I slid 3" sections of 3/4" heater hose. This doubles the thickness of the lower "cusions". Before setting the radiator angle and welding on the lower tabs I put a bottle jack under the radiator to put upward pressure on the 5 isolation mounts to account for the "sagging" of the isolation mounts down the road. So I have five 3/4" rubber mounts on the top and six double thickness heater hose sections supporting the radiator. No metal to metal contact.

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[Kbl7td]

My new radiator is leaking on my coupe. Honestly I think these are just poor quality. My leak is near the middle where a runner meets the side tanks.

[ggunter]

Kevin, electrolysis is something no one thinks about, and yes, it is a concern. The radiator should be grounded, and most are grounded with the piano hinge mount method. But if your radiator is all in rubber, I would add a ground strap to it. Anyone who deals in boats knows the power and the damage of electrolysis.

[bartock]

I ended up damaging my FFR supplied radiator and they were out of stock for a replacement. I ended up using one from a fox body mustang and it was pretty close to the dimensions of the FFR one. Only problem was it came with a radiator cap of its own so I had to put a 30psi cap on that one, so the remote filler cap would vent before that one. Seemed pretty good quality otherwise and was not as expensive. The hoses as is fit fine.

[Rebostar]

Kevin, electrolysis is something no one thinks about, and yes, it is a concern. The radiator should be grounded, and most are grounded with the piano hinge mount method. But if your radiator is all in rubber, I would add a ground strap to it. Anyone who deals in boats knows the power and the damage of electrolysis.

Great point. Completely spaced that. Should have known better. 20 years in Alaska' always owning a boat and changing the zinks every year!
Thanks
Allyn