Antifreeze Leak near Cat/Rocker

[toyman317]

This is on a 1994. The other day I noticed my overflow reservoir was low on antifreeze. The radiator was full. I filled up the reservoir to where it should be and ever since that time I have noticed antifreeze leaking along the rocker pinch weld near the cat in small drips. The interesting thing is that I haven't ran the truck since I filled the reservoir. About an hour ago I went out and started the truck and let it warm up. The leak didn't change.

What is up in there that could be leaking antifreeze? Would it be rear heater lines? If so, how the hell do I replace them. Has anyone else had this issue. I don't recall any leaks when the reservoir was empty. Not a drop. All help would be appreciated.

 

[80t0ylc]

This is on a 1994. The other day I noticed my overflow reservoir was low on antifreeze. The radiator was full. I filled up the reservoir to where it should be and ever since that time I have noticed antifreeze leaking along the rocker pinch weld near the cat in small drips. The interesting thing is that I haven't ran the truck since I filled the reservoir. About an hour ago I went out and started the truck and let it warm up. The leak didn't change.

What is up in there that could be leaking antifreeze? Would it be rear heater lines? If so, how the hell do I replace them. Has anyone else had this issue. I don't recall any leaks when the reservoir was empty. Not a drop. All help would be appreciated.

You guessed it! It's your rear heater lines. There's a series of hard and rubber lines back to the rear heater core and the lines directly over the cats are hard lines. If it's the hard line rusted through, you have 3 choices:
1. Bypass rear heater lines near firewall in engine compartment. Then your rear heater will be inop. (Easiest & cheapest to do.)
2. Replace hard lines. To do this you have to buy all the rear lines at one time - it's like a kit. (most Expensive and difficult)
3. Run by pass rubber lines back to heater core. There's various levels of this, depending on where you want to start the bypass.

There's considerable info already on this subject in threads on this site, so I won't duplicate all of that. Just search on rear heater, or rear heater lines, or coolant leak by cats - something like that.

Personally, I did the bypass in the engine compartment, partially to avoid what you're experiencing and also to simplify the cooling system which helps to make it more reliable and give less headaches.

 

[NorCalDoug]

there's a coolant line that runs toward the rear heater. It could be that one that's busted somewhere along the way there. I took a look at mine a while back and while mine was dinged up a bit, it wasn't busted at all.

there must be a way to either reroute or simply cap off the line, depending on whether or not you want to be able to use the rear heater.

 

[audaciousduo]

I cut mine where they were rusted and connected them with good quality heater hose. Not to bad of a job but messy.

 

[80t0ylc]

I cut mine where they were rusted and connected them with good quality heater hose. Not to bad of a job but messy.

If you replace the hard line with rubber heater hose near or above the cats, you might experience very short life in those hoses due to heat.

This website is chalk-full of good info. there's even a good diagram that shows all heater hoses including rear hard lines and hose. I down loaded it and printed it and stuck in in my FSM because a lot of that info is not in it. Brian is a great guy and wealth of info!

ExpeditionLCMajorcoolingoverhaul

 

[toyman317]

I am assuming that in order to replace the lines (I have some from a parts rig), I would need to remove the cats to get to them. Is that correct? I will check some of the other threads. Thanks for the info so far.

 

[pharmerdan]

This winter I was on a tight work schedule when the factory line rusted through. I used rubber heater hose as replacement. It's been several months since then, and so far so good.

 

[80t0ylc]

I am assuming that in order to replace the lines (I have some from a parts rig), I would need to remove the cats to get to them. Is that correct? I will check some of the other threads. Thanks for the info so far.

IIRC, it's mostly heat shields that need to be removed for access. But, there's several and if your hard line has rusted through, I can imagine the nuts & bolts on your heat shields are going to be a challenge. Check the threads, though. That's cool you're not having to buy the whole kit just for the parts that you need! Good luck and keep us posted on your progress.

 

[canman]

Same thing happened to me last fall. The rear steel lines rust around the clamps that are used to support them to the floor. I got the heat shield off with no problems after soaking the nuts with some Seafoam Deep Creep. I purchased the OE steel lines and installed them with some new hose and SS clamps. The problem really was that the pair of steel lines that run up to the firewall were starting to rust pretty badly where they went over the frame. Now these would be a *itch to replace. I ended up pulling/ pushing them so that I could get access and with a lot of hand/ dremel tool sanding I got most of the rust off. I then coated with some Eastman rust enamal.