Coolant system leaks. (1 Viewer)

[g-man]

If you go to the length of pulling the heater core and you can't obviously tell it has a leak..ie greenish white stains and corrosion. Then there is a way to test it for leaks. Cut a bicycle inner tube across the tube and opposite from the valve. slide the tube where you cut it over the heater core inlet. and the other side of the tube over the outlet. Clamp in place with hose clamps. Submerge the heater core in a bucket of water and inflate the bicycle tube ..just about 5 to 10 lbs ...as the inner tube will start to expand. Any leaks should show in the way of air bubbles coming from the unit. I did this on a heater core in my 70 Torino. There was coolant all in the floor under the carpet. Turned out the heater core was good and had already replaced by the P.O/or mechanic. but whoever did the work didn't bother pulling the carpet and cleaning up the coolant.

 

[fjgdk]

@OSS @CaptClose One of these two should know. Also, from my understanding the brass pipes are not actually connected directly to the heater core, rather pressed in with rubber o-rings. When those o-rings fail all kinds of fun happens. This may also be your issue if you are getting water inside the cab.

I did some work on the heater core when I first got the truck, with the purpose of cleaning out mice nests from the po. Your post is bringing back the aweful memories of that job, in particular that the pipes arent a direct connection to the heater core.

Knowing what I just did over the past two days, I think I have to pull it to fix a leak most likely at the secondary pipes. Here is why:


1) First troubleshooting shows leakage at the hose/pipe connections at the firewall. Pipes are found to be ovular.

2) In trying to pull and replace hoses, I think I pulled on one quite hard and actually destroyed the connection of the pipe inside the dash at the heater core.

3) My trying to fix one problem caused another.

 

[CaptClose]

@OSS @CaptClose One of these two should know. Also, from my understanding the brass pipes are not actually connected directly to the heater core, rather pressed in with rubber o-rings. When those o-rings fail all kinds of fun happens. This may also be your issue if you are getting water inside the cab.

Just divide the circumference by Pi (3.14159) to get the diameter...

I actually don’t know, but it’s not rocket science. I’ve used any round tool that was handy to reform those brass pipes. You just gotta get it close and let the rubber hose and clamps do the rest.

Edit: remember that these trucks were built for the second and third world too. Toyota intended for these to be repaired in the field with minimal tools and precision. A big hammer, a few wrenches and some duct tape is all you ever really need

 

[fjgdk]

Just divide the circumference by Pi (3.14159) to get the diameter...

I actually don’t know, but it’s not rocket science. I’ve used any round tool that was handy to reform those brass pipes. You just gotta get it close and let the rubber hose and clamps do the rest.

Edit: remember that these trucks were built for the second and third world too. Toyota intended for these to be repaired in the field with minimal tools and precision. A big hammer, a few wrenches and some duct tape is all you ever really need

To get to those pipes that connect to the heater core, do I have to evacuate the AC and remove the evaporator ?

 

[micruz60]

Thanks for the documentation, I'm going to have to do this 'maintenance' sometime in the future. No leaks yet. Just lukewarm air in dash.

 

[fjgdk]

It's leaking because it's distilled water now and before it was goopy coolant. But it still shouldn't leak with distilled water - though the cooling system shouldn't be filled with 100% distilled water either, even for troubleshooting. Distilled water is a solvent devoid of buffers and it's ph is too low. It's not doing the cast iron any favors that's for sure.

What may be happening (a guess) when the heater valve gets opened and then a leak develops, is 200° water now is flowing through the valve and the metal/rubber changes dimensions with the temperature change. When the valve is off, it's relatively cool. Just guessing.

Be very careful tightening the heater valve hose clamps. It's pipe nipples are soft brass and it's super easy too over tighten the hose clamps & crush the nipple.

To temporarily get my rig running (so I can drive it to get the AC evactuated to start the heater core job), can I simply bypass the heater by having a hose go from the bottom of the heater valve to the pipe on the side of the engine that comes from the bottom of the radiator ? Of course I will keep the heater selector switch to cold (valve closed).

 

[gregnash]

Don't have to evacuate the AC for the heater core, they are not linked. There is a post floating around with pics on bypassing the heater core. But basically if you plug the upper pipe that goes to the valve the heater core is not fed by another system so it will not get anything.

 

[OSS]

The best way to completely bypass the heater core is to remove the inlet and outlet hose from the water valve and plug them.

 

[fjgdk]

Be very careful tightening the heater valve hose clamps. It's pipe nipples are soft brass and it's super easy too over tighten the hose clamps & crush the nipple.

Just hit me over the head ... alot. I deserve it. I really screwed up. See the brass pipe below coming from the wall. This is the cuprit. Yes, it is split.

 

[OSS]

When you get around to fixing it, only use the Toyota dual hoop clamp that is designated for that location. It won't won't crush the pipe. Standard worm screw hose clamps (found everywhere) damage the hose - and as you witnessed, and can crush soft pipes.

96112-10250 - Genuine Toyota CLAMP, HOSE

 

[gregnash]

Ouch that sucks!

 

[morganism]

If you wrap those pipe ends in teflon tape, they won't rot bond onto the pipes as bad, and will seal small irregularities, so you dont have to crank it down so tight. Works even better on the aluminum nibs, like the thermostat housing.

 

[fjgdk]

When you get around to fixing it, only use the Toyota dual hoop clamp that is designated for that location. It won't won't crush the pipe. Standard worm screw hose clamps (found everywhere) damage the hose - and as you witnessed, and can crush soft pipes.

96112-10250 - Genuine Toyota CLAMP, HOSE

View attachment 1595705

Fortunately I still have the OEM clamps. I went with the worm drive because they were easier to install, except for thr fact I completely screwed up the pipes.


Here is my bypass solution, derived from another thread:
1)
Here is a bolt w clamp on a cut off part of the old hose coming from the hot coolant split valve from the engine driver side.

2. Here I removed the cool coolant output side of the heaters to only feed from the rear heater. I removed the metal pipe tee and assembled some contraption with a 5/8 to 5/8 tee and and 1/2 to 5/8 coupler.

 

[g-man]

what about the heater clampwith the cotter pin in it...90460-24039? Are they reusable? How to install? Or can you just use 96112-10250 the double banded clamps in there place?

 

[fjgdk]

what about the heater clampwith the cotter pin in it...90460-24039? Are they reusable? How to install? Or can you just use 96112-10250 the double banded clamps in there place?

Well I must admit I couldn't figure out how to get the clamp with the cotter pin off without destroying it. This was the one that clamped thereat heater output (cool side) pipe to the joint pipe with the main heater cool side output, correct ? I made it un-usable via taking it out. It was a beast.

Right now I have all non-oem hose clamps on the hoses I've messed with. I find them easier to use and will need to take hoses on and off to chase down leaks. Once I figure everything out, I will go back and do it as OEM as I can with the clamps.

With the heater bypassed, I am getting another leak at a location yet to be determined. There is a large puddle of coolant directly under the timing gear housing/oil pan gasket area at the front of the engine. I didn't think coolant went into the timing gear area. I think that the smaller oil cooler to water pump hose (on the bottom side of the water pump) is the culprit. I have to start taking things off to know for sure.

 

[fjgdk]

When you get around to fixing it, only use the Toyota dual hoop clamp that is designated for that location. It won't won't crush the pipe. Standard worm screw hose clamps (found everywhere) damage the hose - and as you witnessed, and can crush soft pipes.

96112-10250 - Genuine Toyota CLAMP, HOSE

View attachment 1595705

Is there any FSM that has any info on the engine oil cooler or is the parts diagram pretty much the only picture of the system ?

 

[OSS]

The only info about the oil cooler is that there is a copper washer behind each of the big banjo bolts and a rubber O-ring on the other side placed in the groove. The two big banjo bolts should be torqued to 47 ft-lbs.

 

[mwebfj60]

....

With the heater bypassed, I am getting another leak at a location yet to be determined. There is a large puddle of coolant directly under the timing gear housing/oil pan gasket area at the front of the engine. I didn't think coolant went into the timing gear area. I think that the smaller oil cooler to water pump hose (on the bottom side of the water pump) is the culprit. I have to start taking things off to know for sure.

Take a close look at the weep hole while you're checking the hose.

 

[fjgdk]

The only info about the oil cooler is that there is a copper washer behind each of the big banjo bolts and a rubber O-ring on the other side placed in the groove. The two big banjo bolts should be torqued to 47 ft-lbs.

View attachment 1598243

Out of curiousity, where does the 47 ft-lbs spec come from ?

 

[OSS]

I have it marked in my manual. I don't recall where I initially found that spec, but it's correct. If you want to verify, start snooping around and sifting through manuals. I already did that 3 years ago to find the spec. It's very time consuming.