small puff of steam when I turned the engine off

[thegipper]

So something crazy happened after I got home today.

I already had the hood open because I was checking some other stuff out, engine was running.

When I went to turn the engine off, I saw/heard steam by the firewall. Not a lot but enough to notice it. I've never heard or seen this before, coolant levels are all spot on.

I could hear coolant sizzling on the crossover pipe or whatever exhaust piece that is by the firewall, I grabbed a flash light and saw the base of the two coolant hoses "wet" looking.

https://photos.app.goo.gl/dvCltisXAEod29ci1

It looked like the hose on the right in the picture was dripping, but it had stopped and never got a solid confirmation of it. the hose on the left in the picture also looks wet near the base of the hose.

I'm assuming these are some kind of heater hoses? It looks like one of them goes to the rear heater which I have disabled because the lines are damaged (sawzall wrecked them when someone stole my cat) several years ago.

when I started it back up, no more coolant came out. It's almost like pressure built up and coolant leaked past the clamps. I drove it around the block and turned it off again, no more steam/coolant leaking.

thoughts? Fluke?

I was thinking of replacing both hoses and clamps. the problem is, how the hell do you get them off? There is like zero room in there.

Anyone have part numbers on those hoses/clamps?

Coolant was flushed and replaced with Toyota coolant last spring. I'm thinking of replacing the lower radiator hose (looks old), thermostat and thermostat gasket for good measure.

 

[ltsr]

how's your heater control valve? this is my wild guess.

http://www.toyota-4runner.org/3rd-g...s-had-replace-their-heater-control-valve.html

 

[thegipper]

I'm not sure, but I'll certainly check that. I still think its the hoses/clamps.

 

[thegipper]

Heater control valve is not leaking and seems to be fine.

 

[phattyduck]

Once the engine is turned off, coolant can boil near the cylinder walls. Maybe there was a momentary spike in cooling system pressure (while the radiator cap was releasing some amount) and that caused a small drip.

You might be able to sneak some worm drive clamps down there, though new constant tension clamps (like those factory parts) are technically better...

-Charlie

 

[LittleCaesar]

The hoses are old. I try and replace all coolant hoses after a car/truck hits 17 years if I plan to keep it for some time in the future.

I don't have rear heat but the two or three hoses by the heater control valve were about $70 from the dealer.

 

[thegipper]

I'm assuming there is no rupture or it would be leaking all the time. I believe the radiator cap I have is an aftermarket one, I can snag an OEM one from the parts vehicle I bought.

I'm not sure if this is related or not, but for the first time, I tried turning on the rear heat (Hi/low) yesterday even though I know it doesn't work. I don't know how that would cause any issues with pressure but it seems suspicious. I was contemplating swapping the rear heater lines from the parts vehicle so I could use my rear heat again. I wanted to make sure the fan still worked on mine before messing with it.

Before I blindly order parts (even though I cannot find those hose part numbers to save my life), maybe I'll just see if it happens again.

Maybe I'll check this weekend which position my jiggle valve is at on the thermostat just for shits and giggles.

 

[thegipper]

Rock auto has a ton of hoses to choose from, but I don't know which exact ones they are. One is "S"shaped and the other is pretty straight.

Even if I replaced the hoses and clamps, it looks like it would be a nightmare to get them off.

 

[4Reak Show]

Yeah those are heater hoses. Looks like clamps are starting to give. I would suggest all hoses and thermostat while its drained ( jiggle valve at 6 o'clock)

If you go to Toyota with your vin they should be able to get exact hoses and they normally come with brand new clamps already.

To remove clamps, this is the tool. These and long needle nose pliers and a razor blade to cut old hoses. A twist normally breaks the hoses loose as well

https://www.amazon.com/OTC-4525-Cable-Type-Flexible-Pliers/dp/B000F5JM0O

Good luck

 

[thegipper]

Anyone have the diagram or can link it, to the these heater hoses? I've checked on several Toyota parts sites and cannot find them to save my life. Rock auto has a bunch of heater hoses but I'm not sure which one.

Thanks

 

[giovannie23]

Anyone have the diagram or can link it, to the these heater hoses? I've checked on several Toyota parts sites and cannot find them to save my life. Rock auto has a bunch of heater hoses but I'm not sure which one.

Thanks

I just changed out mine there a pain in the ass you have to take off the top hoses for sure. I suggest just changing all of them since they all have to come off
here a diagram for you

 

[badattitude]

The rad cap on your parts truck is only a few years old, from 2014 IIRC. Good idea to give a visual inspection to make all rubber seals are there, they should be.

Also, the parts truck had the rear heater lines deleted. There is a coolant hose behind the throttle body that was used to circumvent the old rear heater lines. Its the one that touches the hood insulation right there behind the TB and at the top of the firewall. It's kinda half-circled shaped and connects the old rear heat out line to the old rear heat in line. All the hard lines were removed due to rust caused leaking.

 

[thegipper]

The rad cap on your parts truck is only a few years old, from 2014 IIRC. Good idea to give a visual inspection to make all rubber seals are there, they should be.

Also, the parts truck had the rear heater lines deleted. There is a coolant hose behind the throttle body that was used to circumvent the old rear heater lines. Its the one that touches the hood insulation right there behind the TB and at the top of the firewall. It's kinda half-circled shaped and connects the old rear heat out line to the old rear heat in line. All the hard lines were removed due to rust caused leaking.

Thanks for the info Rob!

Mine is also already bypassed. I think the heater hoses themselves on mine may be fine (the two I suspect are leaking) but the clamps may not be tight enough anymore to hold back coolant under extreme temps.

Now that I got the part numbers, I'll replace the hoses and clamps.

 

[T4R2014]

Buy new OEM hoses and clamps. I don't like to play with cooling on these. The general 4Runner issue is that once these things overheat it's going to chase your ass because the engine will usually suffer something permanent.

 

[badattitude]

I concur about the hoses, those are hard to get to but if you can change them its a good idea.

I had what I thought was a leaking radiator but it was the hoses that had stretched and were leaking. I put on new upper and lower rad hoses in 2014; still using the old clamps and the leak stopped. I knew as soon as I put on the new hoses that was the issue, the new hoses fit much tighter than the 15 year old hoses. I'd guess that leak you have is from the old hose more than the old clamp.

 

[JayRolla]

I recommend to get OEM hoses. I went cheap on hoses in the past and when they are near hot exhaust the cheapos fail. I had a heater core rupture due to heat fatigue that I had just replaced. It was on a 400whp turbo car making 32+psi so it has a very hot engine bay. Might be okay going cheap but I would not risk it.

I have had better luck pulling OEM hoses at a junk yard then using aftermarket.

 

[thegipper]

I recommend to get OEM hoses. I went cheap on hoses in the past and when they are near hot exhaust the cheapos fail. I had a heater core rupture due to heat fatigue that I had just replaced. It was on a 400whp turbo car making 32+psi so it has a very hot engine bay. Might be okay going cheap but I would not risk it.

I have had better luck pulling OEM hoses at a junk yard then using aftermarket.

It just so happens that I have a parts vehicle to snag stuff from, maybe I'll just do that.

 

[thegipper]

Ok, first off, this repair is a TOTAL pain in the ass. Easily as miserable as removing the starter, in fact, worse.

There is no room if you have hands larger than a 10 year old. I gave up trying to remove the hose clamps with regular pliers. I went to the parts store and bought one of those hose clamp tools, that made it somewhat easier.

It is a total nightmare to get the bottom two hose clamps off (where it was leaking). Even when you get the damn clamps off, removing 20 year old glued on heater hoses, with zero room, sucks the big one.

My plan was to remove my hoses/clamps than take the hoses off my parts vehicle. After 2.5 hours just trying to get my heater hoses off, I said screw doing it all over again. Once I got my hoses off, I just went and bought some 5/8" heater hose and used that.

I think the problem wasn't the hoses themselves, or at least they weren't the main cause. The clamps had very little tension anymore. I think it was a combination of old/stretched hoses and weak clamps.

I used the heater hose I bought and stainless steel regular hose clamps (the screw down style). I hooked everything back up and drove it for a good 25 minutes and no more leaks.

Let it be known, this repair is a PITA! You have to undo essentially every heater hose to get to the bottom clamps. I had to remove the heater control valve (or whatever that thing is) also, including the cable that attaches to it. My hands/arms are all scratched up since Toyota figured no human being over the age of 10 will ever have to put there arms/hands in there......ever.

Glad its done!

 

[LittleCaesar]

Even being only 5'7" it was a PITA for me until I wised up and removed the upper manifold. Then it was a piece of cake.

When repairing cars/trucks and something can't be reached, remove more stuff to access it.

 

[thegipper]

I'm 6'4 280lb...

I was getting very close to removing the upper intake but managed to work around it.

This repair should be added to the "things I hate about 3rd gen's".....