Radiator Leak

[legend42]

After 1500 miles on my Mark IV, I have 2 small(pin hole) radiator leaks, one on each top outside edge on the engine side. I tried a bottle of Bar T aluminum liquid radiator repair, which helped for a few days, but the leaks have started again. Any suggestions on what might fix this, or should I just replace with a new radiator? Is it possible to replace the radiator without pulling the painted body off?

Thanks
Rob M.

[FFR 3099]

Put a ground wire from the radiator to the chassis.

[NAZ]

Photos?

[egchewy79]

Put a ground wire from the radiator to the chassis.

are all the bolts holding the rad to the frame not enough to ground it? I'm using Breeze's upper and lower radiator mounts.

[rich grsc]

Put a ground wire from the radiator to the chassis.
:rolleyes: the bolts through the radiator into the frame are grounding it. That wouldn't prevent cracks anyway

[J R Jones]

legend, Tanks can be TIG welded, core welding is just about impossible.
Believe it or not some radiators have cores bonded to tanks, always when plastic tanks are used.
If you want a shortcut and have access to the leaks for cleaning and drying, you could try epoxy patches. Loctite EA 9460 works well.
jim

[Papa]

After 1500 miles on my Mark IV, I have 2 small(pin hole) radiator leaks, one on each top outside edge on the engine side. I tried a bottle of Bar T aluminum liquid radiator repair, which helped for a few days, but the leaks have started again. Any suggestions on what might fix this, or should I just replace with a new radiator? Is it possible to replace the radiator without pulling the painted body off?

Thanks
Rob M.

If you can get the car far enough off the ground, it can be replaced from the bottom side of the car without removing the body. I just had to do a replacement a couple of weeks ago. Thank goodness for the Bendpak!

https://thefactoryfiveforum.com/showthread.php?24916-Papa-s-MKIV-Roadster-Build-9115-(Graduated)-Fuel-Injection-Upgrade-Coming&p=478810&viewfull=1#post478810

If you don't already have the Breeze top mount, consider adding it. The top mount transfers the weight of the radiator, shroud, and fan to the hinge and frame. I have not found anyone in my area that will repair the old radiator yet.

Dave

[legend42]

If you can get the car far enough off the ground, it can be replaced from the bottom side of the car without removing the body. I just had to do a replacement a couple of weeks ago. Thank goodness for the Bendpak!

https://thefactoryfiveforum.com/showthread.php?24916-Papa-s-MKIV-Roadster-Build-9115-(Graduated)-Fuel-Injection-Upgrade-Coming&p=478810&viewfull=1#post478810

If you don't already have the Breeze top mount, consider adding it. The top mount transfers the weight of the radiator, shroud, and fan to the hinge and frame. I have not found anyone in my area that will repair the old radiator yet.

Dave

Thanks Dave. I do have the Breeze top mount and use a Quick Jack 5000, which I think will go high enough, although I will be on my back:) I pretty much thought replacement was the way to go, thanks for confirming it can be done from underneath.

Rob

[egchewy79]

:rolleyes: the bolts through the radiator into the frame are grounding it. That wouldn't prevent cracks anyway

couldn't electrolysis be the cause of the pinholes?
are you using distilled or tap water?

[legend42]

couldn't electrolysis be the cause of the pinholes?
are you using distilled or tap water?

I used Peak prediluted orange 50/50 and added no water.
160347

[rich grsc]

couldn't electrolysis be the cause of the pinholes?
are you using distilled or tap water?
As I said the radiator is bolted to the frame, it's ground. I'd say no, maybe if the system was on a 10 year old vehicle it might happen. Most like cause is insecure mounting, or putting the radiator in a bind or twist. If you are using the correct coolant it should never fail due to electrolysis

[Papa]

As I said the radiator is bolted to the frame, it's ground. I'd say no, maybe if the system was on a 10 year old vehicle it might happen. Most like cause is insecure mounting, or putting the radiator in a bind or twist. If you are using the correct coolant it should never fail due to electrolysis

^^^^^ This!

I attribute my leak to stress on the radiator when my top mounts failed. I use pre-mixed coolant (switched to DexCool) and hope the new radiator is good for many years to come.

I also added protection against rocks and other debris this round.

[mike223]

As I said the radiator is bolted to the frame, it's ground. I'd say no, maybe if the system was on a 10 year old vehicle it might happen. Most like cause is insecure mounting, or putting the radiator in a bind or twist. If you are using the correct coolant it should never fail due to electrolysis


The question was wrong.

It's not about grounding the radiator - it's about stray (starter) current finding a way to ground through the antifreeze / coolant / aluminum radiator.

This is the classic cause of pinhole leaks in aluminum radiators.


Make certain the engine + starter are well grounded.

https://www.mechanic.com.au/news/electrolytic-corrosion-in-radiators-demystified1/



And maybe add an anode for good measure (which any stray current will dissolve before it dissolves your radiator).

https://www.summitracing.com/parts/flx-32060

[egchewy79]

The question was wrong.

It's not about grounding the radiator - it's about stray (starter) current finding a way to ground through the antifreeze / coolant / aluminum radiator.

This is the classic cause of pinhole leaks in aluminum radiators.


Make certain the engine + starter are well grounded.

https://www.mechanic.com.au/news/electrolytic-corrosion-in-radiators-demystified1/



And maybe add an anode for good measure (which any stray current will dissolve before it dissolves your radiator).

https://www.summitracing.com/parts/flx-32060

interesting. the article talks about NOT grounding the radiator to prevent electrolysis. You learn something new everyday:

Do NOT ground the radiator

If a stray current is present in the engine and chassis, these stray currents are offered an excellent entry point into the cooling system if the radiator and/or heater core is grounded to the chassis.

Bear in mind that the rubber mounts of a radiator are not only intended to reduce the effects of vibration on the radiator; they are also intended to insulate the radiator from any stray currents that might develop, which means that grounding the radiator and/or heater core effectively defeats this insulating mechanism.

[NAZ]

Thanks Dave. I do have the Breeze top mount and use a Quick Jack 5000, which I think will go high enough, although I will be on my back:) I pretty much thought replacement was the way to go, thanks for confirming it can be done from underneath.

Rob

Rob, you should really troubleshoot the issue and find the root cause of the leaks. Unless you know the root cause and mitigate it you may be replacing the radiator again. And have you really determined the radiator is not repairable? If the pin holes are from corrosion then likely replacement is the best choice but if pin holes are a manufacturing defect (like pinholes in a weld) they may be repairable. Welding aluminum radiator tanks and fittings is not that difficult. Welding tubes and fins are. That's why I suggested you include photos, some of us have dealt with these issues and know how to make the repairs.

[legend42]

Rob, you should really troubleshoot the issue and find the root cause of the leaks. Unless you know the root cause and mitigate it you may be replacing the radiator again. And have you really determined the radiator is not repairable? If the pin holes are from corrosion then likely replacement is the best choice but if pin holes are a manufacturing defect (like pinholes in a weld) they may be repairable. Welding aluminum radiator tanks and fittings is not that difficult. Welding tubes and fins are. That's why I suggested you include photos, some of us have dealt with these issues and know how to make the repairs.

Thanks NAZ, good advice. My plan is to remove the radiator and take it to a repair shop to see if they can fix it and/or give me any answers on what caused it. I have ordered a zinc anode to install in the new radiator I ordered from FF5. My plan is the same as Dave's, if it can be repaired I will keep it as a spare. I have attached a picture that shows were the leak is. Curious its on the same band, both sides of the radiator.
160476160477

[egchewy79]

Do these pics change anyone’s opinion about stress fracture vs electrolysis?

[NAZ]

Do these pics change anyone’s opinion about stress fracture vs electrolysis?

I can't say it changed my opinion between stress fractures and electrolysis as without photos or personally examining the defect I couldn't even guess. But looking at the photos it appears these are manufacturing defects not stress fractures from mounting the radiator wrong or electrolysis. The first photo shows cold fractures at the bend from cold working the metal, a common defect when bending aluminum with the grain. The second photo shows some very sloppy weld and causing the heat affected zone to reach the tubes. And it appears that there is porosity in the weld and I suspect some hot cracking in the toe of the weld but the camera angle doesn't show down at the intersection of tube well enough to be sure.

You may get away with welding the striations in the 1st photo but the general rule of thumb is you can weld repair a crack in the weld but welding cracks in the base metal is considered a temporary repair as the metal is already fatigued. But the sloppy weld near the tubes is a lost cause.

IMO, the root cause of the leaks is manufacturing defects not a problem with the electrical system or the way the radiator is mounted. If it was mine I'd R&R the radiator and scrap the leaking one. I'm an expert at welding aluminum and I wouldn't waste my time on this one.