My radiator sprung a leak, so I guess I get to replace it. Looking in the service manual it appears to be fairly straighforward but I have a few questions about it.

The service manual claims that the xmission does not have connections to the radiator on a 1500, which we know to be false. Do these lines carry coolant to the xmission, or xmission fluid to the radiator? When I disconnect them will transmission fluid just keep on coming out, or will I lose just a little bit? If it just keeps coming out I'll need to figure out a way to plug the lines.

Finally, how much coolant can I expect to lose just draining the radiator? I know the capacity is 20 qts (5 gallons) but I would expect a fair amount to stay in the block, heads, and heater core. Will 3 gallons be enough?

Thanks!

 

The lines from the transmission carry ATF to/from the radiator.

There are two ways to disconnect them, either at the flare fittings or at the quick disconnects. I chose the flare fittings because I didn't have a big enough QD release tool at the time. I seem to remember you will loose about a cup of ATF from the lines and cooler. There's not that much in there. Plug the fittings at the radiator and hard lines to keep dirt out. Tin foil works well for this.

When you drain the rad, coolant in the heater core, heads, water pump and some of the block will drain, so yeah, expect at least about 3 gallons. If it's the better quality Dexcool (orange stuff) and uncontaminated, then just poor it back in when you get your new rad installed.

 

It's transmission fluid in those lines.
You'll lose a lot. You'll be draining the radiator, that hose, and everything that sits higher than the bottom radiator hose. Mmm, pretty much everything. It'll hold some in the block, heater core, and heater hoses but not as much as you're thinking.

 

Thanks for the info.

I may end up flushing the whole system anyway. When I saw the leak I panicked, and, against my better judgement, I poured a half can of JB stop leak in there. My heat still works fine, but it didn't stop the leak.

It has the green stuff in there. I'll probably just mix up 5 gallons in a clean 5 gallon gas can (I have 6 of them that have only had water in them-- just moved my reef aquarium and had to have a bunch of reverse osmosis water to mix up the saltwater). This way I'll be covered.

Do you think the Prestone flush will take out the JB stop leak? Ugh, putting that in there was dumb. I know better, too.

 

I think so. The way that stop leak stuff works is by finding and plugging the little pin hole leaks. If there are none, then most of it should stay suspended in your coolant until it gets flushed out.

 

I've never had stop leak work. The only one I've used previously is Bars Leaks, though. That one really sludges $hit up.

One last question-- the A/C condensor is mounted seperately so I won't have to deal w/ it while removing the radiator, right?

Thanks!
Chris

 

It does not come into play at all.

 

OK, sounds good. Thanks!

 

i got a dodge ram 1500 4.7...my temp is up 3/4...not at the middle..my mechanic replaced the thermostat last year..and now i found a small leak in my radiator..! help

 

Your radiator needs to be replaced. You are losing coolant and pressure. Check ebay if you want the lowest price or you local parts store if you want a warranty and are willing to pay more.