In the classic car world, we use citric acid to clean up a heavily gunked and rusted cooling system. I don't know if citric acid would be safe for an XJ cooling system with plastic radiator tanks and an aluminum core. If it is safe, citric acid would be a good ide for that cooling system. I don't think anything less will touch the rust and gunk.

*Now that I think about it, I know Mercedes Benz uses citric acid to clean cooling systems and I'm pretty sure those cars have aluminum radiators.

 

Correct and Be-Cool offers the really high dollar one.


I have a Griffin in my 1978 Malibu Wagon and also had a Be-Cool in the "56" Chevy with a Blown BBC street/strip/show we had for about 7 yrs. till the wife was hit broadside by a guy who ran a red light. She cried for a month over that car we built it for her and she drove it a lot.

 

IMHO a wise decision and the right time to do it for sure.

 

I would flush the system with the old radiator still in it to get rid of some if the gunk. This way you won't have to flush the gunk through your new radiator!!

 

Anyone who has redone the cooling system before have any other tips before I get started this weekend?

 

- When you drain the radiator, it's easier to just remove the lower radiator hose connection rather than trying to use the drain plug at the other end. Either way, you'll get coolant spewing everywhere and pulling the hose is a LOT faster

- I recently used the Blue Devil radiator flush and it appeared to work pretty well at removing all the Stop Leak the previous owner had added to the cooling system

- If you use the Blue Devil stuff, drain the coolant and flush it as best you can with plain water. Then add the Blue Devil and top it off with water.

- Drive it as long as you can with the Blue Devil and water mixture. The directions suggest driving the vehicle like that for several days. If you're in an area where the temps are getting below freezing, you obviously can't let it sit overnight without antifreeze. Since you're in Florida, you would probably be OK doing this.

- Flush it again with plain water.

- THEN replace the radiator, thermostat, water pump and heater core. Unfortunately, the condition of your cooling system warrants replacing all these components to avoid future problems. Be sure to get good quality parts rather than whatever is cheapest. Be especially careful with low quality thermostats. They're unreliable. Cheap parts are not a good deal.

- Check the radiator hoses and heater hoses. If anything is suspect, replace it

- Use a good quality antifreeze with a bottle of Redline Super Cool Water Wetter. That stuff really works to help the radiator and heater work better.

 

Snap some pics with your cell phone just to reference how the rad support goes back in and where fasteners go. Remove the old rad 1st and install the new rad last. With the rad out of the way, removal/reinstall of stat, pump and fan clutch is a walk in the park. Removing the air filter box allows easier access to the bottom rad hose at the pump. After all the old stuff is off, flush the heater core both ways thru the hoses multiple times then flush the head/block multiple times thru the t-stat hole in the head. Not necessary, but easy to do......jack/raise the rear end, doing so will allow for a little extra drainage out of the block.

Re-fill the cooling system very, very, very slowly........pour in a little at a time. This assures minimal air in the system. Let the motor idle with the rad cap off keeping the rad full. When the stat opens, close it up with a new rad cap. Check coolant level in both the radiator and bottle, motor COLD, for several days and several heat/cool cycles. Add coolant as needed. Radiator should always be full to the top, motor COLD.

 

Here's the "bad boy" XJ rad (when money is no object).......it will require a little messaging to fit. It has two 1.25" wide rows, the OE style has one 1.25" wide row.

http://www.summitracing.com/parts/GRI-8-70168

Griffin does make a one row 1.5" wide drop-in fit rad but the price is the same so why not go with 2rows.

http://www.summitracing.com/parts/gri-5-70095

 

Thanks for the tips.

I wasn't going to replace the heater core at this time due to the difficulty of getting to it. How necessary is it?

 

Not necessary at all unless it is totally solid plugged AND u absolutely want a heater and/or it is leaking.

 

It would be wet on my passenger floorboard if it was leaking, right? It might be solid plugged though. I ordered a heater backflush tool like this one...

http://www.carid.com/lisle/heater-co...FQsxaQodez8Atw

If that doesn't flush it, I might have to replace the heater core. I tried using a funnel and garden hose and it just overflowed.

 

Yes.

Cool tool......I want one of those.

 

I haven't noticed any wet areas, so I'm good in that department.

 

Let's quit discussing the heater core................bad luck.

 

Please

I'm already feeling a little overwhelmed without having that go bad too.