New thermostat = New coolant leak

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Confirmed, Toyota still has new parts available as of 9/2018.
 
Yes, just the O-Ring and not the pipe.

Also, make sure you change out your radiator cap. That coolant mix builds sludge and can prevent movement. My radiator cap was built up with sludge and didn't move and relieve, and caused my radiator to explode.

Flush that thing with plenty of distilled wter. I did a hose in every orifice for 30 minutes, then (6) fill and drive with distilled, then final fill with Toyota red. I will switch to green next time due to availability and cost. (I will do massive flushes first!)
 
What is the part number of the gasket for position 1 in the original post. Mine Is definitely leaking from there.
 
What is the part number of the gasket for position 1 in the original post. Mine Is definitely leaking from there.


No gasket there just O rings

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I replaced all of those orings. I’ll attach a pic to show what I’m talking about. Maybe it’s rtv? It looks like rtv in the original post.
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This little pipe always full of coolant? I need to replace those o-rings too, lazy to drain all coolant again
 
This little pipe always full of coolant? I need to replace those o-rings too, lazy to drain all coolant again
Yes because there is not supposed to be any air in the system. Will have to drain to that level.
 
I replaced all of those orings. I’ll attach a pic to show what I’m talking about. Maybe it’s rtv? It looks like rtv in the original post.View attachment 2340461
This is exactly where my tstat housing is leaking. Does this require RTV? I don't see a gasket listed in the FSM or Toyodiy.
 
This is exactly where my tstat housing is leaking. Does this require RTV? I don't see a gasket listed in the FSM or Toyodiy.
I just fixed this same leak about 30 minutes ago. There are three O rings in the thermostat bypass. there is the little tube inside the riser that requires 2 O rings, and the riser that bolts to the head. The riser uses an O ring as a gasket/sealant. When I put in all new components this fall, the O rings on the little tube got messed up some how. This time around, I used a very light coating of vegetable oil to help the O rings seat correctly in the thermostat housing and in the riser. Problem solved.
 
This time around, I used a very light coating of vegetable oil to help the O rings seat correctly in the thermostat housing and in the riser. Problem solved.
Your cruiser is a carnivore. You need to use tallow. :nailbiting:
 
Your cruiser is a carnivore. You need to use tallow. :nailbiting:
Better to use just plain antifreeze.

Don't contaminate your cooling system with oils of any sort.

The only lube I would even remotely consider is KY Jelly because it is water soluble. (And.....you know........sodomy.)
 
I had the same leak, I replaced the water bypass pipe with a new one. I did all 3 o-rings for good measure.

It's a short aluminum pipe with 2 o-rings on it that will probably be mangled on removal. Half of it sticks in the housing and the other half protrudes for the larger pipe to fit over.

It was a b*tch to get out. I used 2 flat head screw drivers.

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How was the reinstall? Did you use any lubricants to place back. I removed mine late last night and have to pick up another pipe. I wasn’t expecting that aluminum pipe to be as stubborn.
 
How was the reinstall? Did you use any lubricants to place back. I removed mine late last night and have to pick up another pipe. I wasn’t expecting that aluminum pipe to be as stubborn.
The metal tube inside was a bitch to get out. I ended up using a pipe wrench and having to buy a new one. On the reinstall, I used a little (just a very light coating, a drop or two) of kroil on the o rings. It also helped that I was doing the reinstall/reseating in warmer temps.
 
How was the reinstall? Did you use any lubricants to place back. I removed mine late last night and have to pick up another pipe. I wasn’t expecting that aluminum pipe to be as stubborn.
I just did this this past week.

Take your time with a 3M Scotch Brite pad and clean up the interior sealing surface of all connections. I think the PO on my truck replaced them at 145k and I'm now at 327k and they were starting to leak when cold.

I cleaned up all mating surfaces, wiped them with a coating of Toyota red antifreeze and slipped them together like a drunken prom date! I did install a new short pipe as well. It took me longer to clean up the parts than it did to take apart and reassemble.

Torque the two bolts to 15 lb-ft. Same as the t-stat housing.
 

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