Which CSF Radiator for Renix conversion is best

[Ecomike]

The heater blend door is cable operated and easily adjusted from under the passenger side dash. 3 minute job.

True for renix, but I am told that changed in later years, FWIW. My problem was often a bad vacuum line and once the Vacuum valve was bad on the outside fresh air door.

 

[Ecomike]

I was just looking on the CSF site...in their catalog. They have the "economical" aluminum 1 row with plastic tanks, with filler neck, and what looks to be the bung for the temp. sensor. Their part number is #3251. Has anyone used this radiator before? I know it has the plastic tanks, but my other one lasted many years. I'm waiting for a CSF tech to call me back to confirm.

I tried 3 of them in recent years, junked them all, gave them away. They worked good the first 2-3 years. I only use the 3 row brass-copper all metal now.

One clogged up, and two developed plastic tank problems.

 

[Ecomike]

Mike...My plastic tank radiator has been in my XJ for some 14 years now...ever since I put the new Jasper engine in. I haven't had the first bit of trouble with it...nor any sign of reduced flow....until my surge tank cap started failing. The radiator itself is clean, as is the block. I know you get "some" buildup over time, but all-in-all it has been a great setup. SO...if it takes 14 years for this new radiator to show signs of clogging...it'll be time for another one all over again. I'm thinking to myself...get the '88 CSF, use the inline filler cap, run it for 10 or so years and change the hoses along the way and I should be good. Sound like a plan??

BTW... I'm thinking of starting a new thread and calling it Renix Rejuvenation...or something. I'm taking pics of everything as I tear it down...from hoses, vacuum lines, rocker arms...you name it. I'm replacing every sensor in sequence, and checking all my wiring as I go. Once I start the thread, I'll be posting more questions when I hit a wall on something. I'll be starting with the mechanics, and moving on to suspension, and then an interior refresh. It should be fun...slow, but fun! My plans are to outfit the "new" Renix XJ as an Expedition rig for my family to enjoy. I have plenty of pics too, we all love pics!

Here's what I'm starting with...all over again...

Two doors, and green, both very RARE!!!

You got very lucky. In 38 years I only had one vehicle radiator give me minimal trouble, and 5-8 years was the limit IIRC. If you go with the inline filler neck on the upper hose, I would stay with the closed Renix system and use a Renix bottle. There are two defects on the current Renix bottles (made in China), the bottom nipple is too soft, and the cap is crap (it spreads and looses the thread grip, and is too tall, hits the hood crushing the bottle). Use a volvo bottle cap, they work like a champ, and see my old renix bottle thread for details on installing a 3/8" NPT brass pipe nipple liner in the bottom 1/2" plastic tube to solve the other problem. Both are a simple cheap $10 net cost fix!!!

Now that I think about it, that also slows the bypass flow through the bottle I think I mentioned below.

On the build up issue, it varies (build up rate) with coolant formula, metals used (head, radiator, heater core, Aluminum versus Iron and copper-brass), open versus closed system and head gasket leak rate. Combustion CO2 and open system CO2 react with water to make H2CO3, carbonic acid, it reacts with metals, and coolant additives to form boiler scale, metal carbonates and metal silicates, on the cooling tube walls...add in multi metal electrolysis and the fun and joy are off to the races!!!

 

[imajeepnut]

I talked with CSF today and wrapped it up. I think I'm going with the 3-row all metal for the '88...and it does have the bung for the temp sensor. I'm going to try the filler add-on and try it as an open system first. If it doesn't work as it should, I'll get Mac's aluminum tank with a standard radiator cap and go back to a closed system. I can go either way with the '88 unit.

I have to fess' up Mike...it was a black 2-door originally...and I painted it Land Rover green I love green...especially when it's running right!

 

[8Mud]

Just talking a little sideways on the subject, but the heater/bypass from the thermostat housing to the the water pump, either through the heater core or through the heater valve or "T" (whatever is applicable) bypasses the thermostat and helps make the thermostat more responsive.

Picture at start up, you have cold coolant next to the thermostat, little flow and hotter coolant piling up behind that, as the engine warms up (without the bypass). Or the thermostat opens some and eventually cooler coolant flows to the thermostat, it closes and hotter coolant backs up behind that (without the bypass). Fluids of different temperatures mix slowly and often don't pass much heat, they homogenize slowly, if at all,. depending on how much they are agitated.

You put the wrong gasket behind the thermostat and cover up the bypass and you are going to get some wild swings in your temperature gauge. Ask me how I know this .

Back in the day when we built hot rods, we disconnected the heater and plugged the bypass/heater hoses, we learned quick you had better take out the thermostat and throw it away (or run a loop in place of the heater core) or you were going to overheat. The hot coolant was going to back up, in high horsepower motors, behind the thermostat and the motor would usually overheat before the thermostat opened.

Somebody mentioned the heater valve becoming plugged with deposits, this can also cause some pretty wild swings in the temperature gauge for the reasons mentioned above.

I don't have much of an overheating problem here, but have thought if I lived in a hotter climate, I'd pull all of the rubber heater/bypass tubing out and replace it with soft copper tubing. Just rubber on the ends to make hooking it up easier and to give it a little flex. Copper is a conductor, rubber in an insulator, you could likely radiator a couple of hundred watts through the copper lines. Every little bit helps.