Radiator Leak Repair - Anyone Done It?

[billybaloneey]

I recently noticed the "Low Coolant" light coming on. Looking under the car after it has been parked, I discovered a small puddle of coolant. Because of the design of the lower radiator shroud it only drips out on the radiator drain plug side (lower right), so there was no easy way, short of taking off the upper shroud, to try and determine where the leak might be coming from.

The 5 main horizontal mounting screws...one 10mm and one 13mm on the left side and one 10mm and two 13mm on the right side...that secure the upper shroud were easy enough. But the six 7mm vertical mounting screws...3 on the lower right side and 3 on the lower left side, were a pain. I'm not looking forward to putting those bad boys back. Once all the screws were removed it took some lifting, twisting and turning of the shroud from the driver side...after the coolant overflow hose and the dual oil cooler lines were disconnected and swung out of the way...to get the shroud off. The same goes for the upper shroud, I'm not looking forward to putting it back in place...all the hoses and lines located on the top right side of the radiator assembly...will make for some Olympic caliber shroud acrobatics later.

If your shroud is anything like mine you’ll note exposed fiberglass fibers in various locations. Anyone needing to remove their shroud should work with gloves and a long sleeve shirt, to protect your self from the loose/exposed fibers. If you’ve ever worked with fiberglass you know what I’m talking about. The fibers work their way into your skin, and it can be very painful and only time will heal the pain.

I put a radiator pressure tester on the coolant fill tank, and at about 4 psi...the fill tank radiator cap is marked/rated for 15 psi...I saw several small streams of coolant coming out of the front right side...located at the 8th, 9th & 10th ribs down from the top, where the side tank meets the front side cooling fins. I was lucky with respect to the location of the leak. If it had been anywhere else I might have had to do much more disassembly to see and get to it.

Initially I planned on removing the whole radiator for a better look, and to eventually have the leak professionally repaired at a radiator shop. The top radiator hose was easy to remove. The lower right hose is a different story. I stopped trying to remove the hose…located between the bottom right side of the radiator and the thermostat housing side…for fear of damaging the hose. I have a set of the SAMCO hoses, but I just can’t bring myself to replace the black ones, with the gaudy bright blue hoses…I only bought them for emergencies.

(My youngest brother works at AutoZone. One day I plan on giving him the set of SAMCO hoses and have him to go through all of the “black” hoses they have in stock and find exact matches with respect to diameters and bends…some if not all will require cutting and trimming. I think he will be able to find a match for every hose. They won’t be OEM, but they’ll be “black”. This is another post for another day).

Now back to my original post. The leaks are accessible for repair without out having to remove the radiator. I did a Google search on aluminum radiator repair. There seems to be three basic types of do-it-yourself repairs…JB Weld, solder and several products designed specifically for exterior radiator repair…one mentioned several times was called Stic-Tite. I’m not going to consider any of the liquid treatments designed to seal the leak internally. Many people have had good experience with the JB Weld product.

With three leaks at one time, I’m sure it’s a coincidence or signs of more/bigger problems, (leaks), to come.

1) Does anyone have any first hand experience in repairing a small aluminum radiator leaks?

2) Is there an easy way to get the lower radiator hose off without damaging it? I think it would be easy to find a suitable replacement for this hose. It’s only about 4-5 inches long and straight. If I have to, I’ll use my SAMCO replacement hose after I paint it black or wrap it in electrical tape.

My engine bay is a pig pen...that's the way it was when I got it. I'm slowly but surly cleaning it up when time permits. Working in and around the radiator has kicked things off for me.

Pressure test:


3 leaks:


Exposed fiberglass on my upper radiator shroud:



3 side mounted screws: (FYI that wire appears to be attached to the outside temp sensor...with it disconnected...the instrument panel said it was 50 F...it was actually in the mid 80's F...so it apparently defaults to 50 F when there is no input from the sensor. This is just an observation on my part, I could be wrong on all accounts)



Fins need cleaning and some need straighting...all kinds of things can be found hiding and in need of addressing under a radiator shroud. A/C condenser on the left, oil cooler in the middle and radiator on the right.

[GOLDCYLON]

1) Does anyone have any first hand experience in repairing a small aluminum radiator leaks?

Answer yes, However you would be smarter to replace the radiator now as the effort expended as you well know it not worth the effort on the repair. The radiator is the same as any other MY 90-96 C4. And holly crap it already has three holes to mend????? A new direct replacement radiator can be had for $150

2a) Is there an easy way to get the lower radiator hose off without damaging it?

Simple answer no especially if you have the orginal Corban style ring clamps. Its a nightmare to get in there to try and pull the clamps off due to tight space and even harder if you dont have a Corban style Ring clamp puller


2b) I think it would be easy to find a suitable replacement for this hose.

Possible but difficult and whiles its a straight hose the angle of attack is essentially an hi to low elbow. When you get under at look at the extreme you will understand

2c)
It’s only about 4-5 inches long and straight. If I have to, I’ll use my SAMCO replacement hose after I paint it black or wrap it in electrical tape.

When you try to return the hose remove the thermostat housing cover. Its the only way to get that damn hose back on because of the extreme elbow from high to low.

[FU]

I have a radiator that was in my white car for 28K miles 100.00 plus shipping if your interested.

[tomtom72]

I would just throw this out for you to mull over Clint. The side tanks are plastic on the OE rads and are held on by a combo of adhesive + cinch clamps. According to the 90 FSM in theory it is possible to r&r the side tanks to correct leaks from the tank/core flange area.

I have not done the r&r on the tanks as I had no leaks when I did my rad r&r for cleaning & new hose kit install. I did a backyard/ redneck re-tighten of the clamps with a small channel lock and alot of gentel force applied over many trips.

JMHO on the replacement rads out there: most reasonably priced ones are dual use, auto and/or manual trans application....the OEM ones were trans app specific. The next level up in quality and price are the aftermarket, but you do get an all aluminium unit w/alum tanks...but the prices are no joke. I'm saving up for a Ron Davis unit.

On the lower rad hose, the best way is to "split" the T-stat housing ( I actually removed my housing for ease of working room) so you can get enough twist on the hose to break it loose from the rad pipe. Having the special clamp tool with the cable extension option is the way to go and most parts stores have them....they are worth every dollar! Heck you might as well do the T-stat & O-ring while you're there. Oh, save all the spring clamps as they work much better on our motors than the ideal type clamps.

Oh yea one more thing, if you are gonna actually drive your Z, I would suggest doing the intake screen mod from the "How To" section over at the netregistry site.....trust me it's a game saver! It's easy & cheap.
http://www.zr1netregistry.com/ZR1_radiatorscreen.htm


Tom

[White Bullet]

I would second a replacement radiator. Repair will only patch the problem and may lead to bigger problems down the road. The cost for the part is reasonable and you have most of the work done now. Yes the hardest part maybe the lower radiator hose but it can be done. With a new radiator you will have a better piece of mind. Really do not want to experience overheating the LT5 that may cost you thousands.