I was able to find many posts about this same issue. But still wonder what size of hose to use or whether to cut the metal line or not etc etc.

Ok, it is 97 4R SR5 Auto with Rear heater.
the coolant line to the rear heater (running under passenger size from front to rear) is pretty corroded although it seems holding up quite ok now. But I better replace it now at my place than somewhere someone's parking lot later. I identified part number but shipping and handling could be quite difficult. It is about 90bucks for part only. So I decided to go with rubber cooler hose. then, I have several questions,

1. what size of hose (ID or OD) is suitable for this case?
2. Should I cut the metal line only where it is severely corroded or should I entirely remove that metal line to completely replace with rubber hose?

Any advice will be highly appreciated.
Thank you.

 

I had to replace my last because of it breaking from rust, the new lines run all the way to the top of the engine. If you go with the rubber hoses be cautious of the heat from the exhaust melting them or dry rotting them.

 

so just wondering if anyone else has noticed this but on my '01 4runner my rear heater lines are all stainless steel and was jus wondering if any others have these same lines

 

I think some of those 'other' threads you mentioned had the size in them. Check the heater lines under the hood that run to the rear heater and see if they have a size on them - they should go from rubber to metal to rubber en route to the rear heater.

I would replace them now. IF you do not, just remember that if you get a leak, you can just bypass the rear heater under the hood by connecting the out to the in...

 

I used some universal brake lines from the Autoparts place to replace that section of pipe as mine was leaking. I think its 3/8" or 5/16"

 

Ah ha! Brake line! did you use metal brake line? aluminum or stainless steel? how did you prepare the end of metal line? do you have flaring tool etc? or just clamp it with rubber hose? (Am I throwing too many questions or what?...

 

It was just standard coated steel. You can use the flared end on one end and flare the other end or just use it cut straight and sand the burrs off, just slide the hose over 1-2" and use two hose clamps. You do have to cut one end as you need to remove the nuts that are on the pipe. SS will work too. I wouldnt do Aluminum. I ave been running thos for two years now with no problems or leaks.

 

mine just sprung a leak today in the driveway. got under there and there is a 2-3 foot section along the frame rail that's corroded and flaking like crazy, the rest of the line is pristine. i used some 5/16" bolts in the ends of the hoses in the engine bay secured by small hose clamps for a temp solution. i may just bypass the whole thing and call it good since i rarely use the rear heater. but, i'm going to price the brake line option too in case it's cheap so i can keep the rear heat. rust sucks!

 

The brake line was under $10.

 

Ok!. I just placed an order for a few different size coated brake lines.
One 25ft roll of coated steel brake line (3/8") was 25bucks. I will need to do a little bit of custom bending and flaring. Also, ordered smaller diameter brake lines (3/16 and 5/16) at much less $$ to take care of rusted fuel line and real brake line. It will be fun for a while....

By the way, that 3/8" line will be used for external tranny cooler. It will be really cool to get rid of those thick ugly hoses for external tranny cooler... oh it will be fun ....

Thank you.

 

FYI - I priced new OEM rear heater lines, part # 87248-35061 at $97.03. Thankfully I have a "friend" at the dealership that passes on the discount to me so I went OEM. It wasn't as cheap as the $10 break lines, but I was comfortable with the price, should be bolt/clamp on ease of install, and I wanted to keep it 100% Toyota.

One additional question... since these lines seemed to corrode on the frame rail where they get most exposure to moisture/salt, would there be any adverse affects of coating the lines with some asphalt undercoating to protect them from the elements and keep them intact longer?

 

All you need to do is run rubber lines - it is really that simple. And the bypass is as simple as disconnecting the hoses under the hood from the steel lines and then connecting them together. PIECE of CAKE.

I just ran the rubber and zip tied it to the corroded steel lines so they do not flop around and rub....