Radiator Replacement On Cj5

Hello,

I'm preparing to replace a leaking radiator on my '59 CJ5. I understand this is a fairly straightforward job, but my car experience has been limited to fluid changes, spark plugs, etc.

Sounds like it's drain, unbolt, detach hoses, then reassemble with the new unit.

Anything particular to watch out for? Anything else I should service at the same time?

I found this replacement: https://www.ebay.com/itm/204601171410

What is the appropriate coolant to refill? Any special notes when filling the new unit for the first time?

Thank you! I really appreciate the guidance.

 

Get new hoses while the radiator out.
Leave the cap off while you run the engine to burp any air from the system.

 

You may possibly need to warm it up several cycles to burp any trapped air in the heater core, and such.

Always leave about an inch of air-space in the header tank, for expansion.

I use 50/50 mix of conventional glycol anti-freeze. (But I don't use any steenkin' aluminum.)

 

If you're going through the trouble of draining and pulling the radiator, pop open the drain on the side of the block as well to get the remainder of the coolant out of the engine and flush the crap out using a garden hose. Once it runs clear, do a final rinse with distilled water. That way, you're not running old floaters and rusty coolant through your new rad. Might be good to give the new radiator a rinse with the hose as well incase there are any assembly crumbs etc lurking in it.

Take a look inside your thermostat housing while the hoses are off to confirm there's actually a thermostat in there. Mine was missing LOL.

If you have a heater assembly, Now is also a good time to check that for leaks and replace the heater hoses.

As for the coolant, catch it in a bucket and take it to a disposal facility. Not good to run it down the drain and illegal in most places anyway.

 

But don't leave it where animals can reach it. Sweet tasting but very toxic.

 

Oh and might as well replace the radiator cap. I think they're 7lbs?

 

On this note... save your coolant jugs and pour the old coolant into em for storage/transport.

 

I would like to see the install after you get it in. Seems very reasonable on the price.

 

Since draining antifreeze is a rare occurrence, it is usually a good time to:
Replace the thermostat.
Replace any old hoses (don't forget the heater).
New cap. If you replace the cap, get a double sealed one that will take a catch tank, which would be a good addition.
Check the water pump.

 

Its a good idea to reuse your original fan shroud, but you might have to fabricate some brackets. The aftermarket radiators usually don’t have provisions for the shroud.
-Donny

 

Thank you! Good to know about the expansion space.

Would something like this work: https://shop.advanceautoparts.com/p...e-conventional-green-1-gallon-f101/12447460-P

Cut 50/50 with distilled water?

 

Thank you so much! Appreciate the response. Sorry if this is a silly question, but where would I run the hose in to flush the block? I see the drain on the side near the distributor, but not sure where I should run into to flush.

I will look into the thermostat as well!

 

a) I don't usually pay more than about twelve bucks a gallon. Maybe ten on sale.

b) I've never troubled about using distilled water. But you may have different minerals in your local water.

c) You should verify that whatever you use will protect your aluminum radiator. I'm not certain about the product you show.

 

Thank you!

The replacement says it comes with a "CNC cap." Should I look for a better one?

What should I look for with the water pump?

Appreciate the help!

 

Thank you! The shroud is pretty bent up, but I could try to refashion it. I've read conflicting things about needing the shroud. Would it be okay to leave it out?

 

Got it, thanks for taking a look. I'll read some more on the aluminum compatibility.

 

All good advice but no need to overthink this. It's not rocket surgery.

 

Hello. All sound advice given here. Have you considered having the current radiator repaired instead of replacing? Are there any local radiator repair shops near you? Depending on how bad and location of the leak(s), repairing the radiator might be an option.

For me, using the shroud aids in the ability of the cooling system to function as designed. For consideration on using the fan shroud or not, here's a couple of articles:
Prevent Overheating With A Custom Built Fan Shroud (motortrend.com).
Analytical Investigation of Fan Shroud on a Thermal Heat Exchanger for Automotive Applications (sae.org) - click the "Preview Article" button if you would like to read the whole technical document.

 

The replacement says it comes with a "CNC cap." Should I look for a better one?
- CNC Cap only means it was machined. Should work as long as it is PSI rate for your system (Usually 7 PSI, as mentioned previously). When it comes to radiator caps there are two types - Vented and Non-Vented. Vented are used when you have an expansion/recovery tank as part of the engine cooling system.

What should I look for with the water pump?
- weeping of water from the weep hole, weep hole is usually on the underside of the water pump. Here's a short video on the weep hole - Water Pump Weep Holes - YouTube
- Any signs of leaking around the area where the pump attaches to the engine block.

 

Early cap, much like the one that came stock on your ECJ. Note the brass bevel spring at the top. When pressure builds, the lower seal will unseat from the radiator neck and coolant will flow out the overflow tube onto the ground. As the system cools, it contracts,pulling air back into the system. This forms that inch or so air pocket at the top of the radiator tank.

Sealed cap. Same basic design and function, but instead of a beveled brass spring at the top, there is a rubber gasket. This forms a second seal at the top of the radiator. As the coolant cools, the system contracts. Instead of pulling air back in, the upper seal allows the vacuum to pull the coolant from the overflow bottle back into the system.

Start by wiggling the fan. If there any movement in the water pump shaft, it is starting to go.
As stated:
coolant moisture at the weep hole.
Leakage around the perimeter of the pump means the gasket may be leaking. That being said, replacing the gasket means removing the pump, which may warrant replacement anyway.