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Help identifying coolant leak

ODY80

New-ish
Joined
Aug 7, 2019
Messages
16
Howdy all was seeing if anyone has suggestions on the following. I have a 97 lx450 1FZE with 305k Just went through and updated the cooling system.

Issue - I noticed dripping what i thought was AC water under the passenger front side of the vehicle. I think its actually coolant based off the red tinge when inspecting it closer. Right between the cats and transmission is where i saw the leak coming from. I also noticed coolant dripping from the firewall (the soft black material on the firewall towards the bottom is wet in the attached image)View attachment 81665 onto the headers.

When going for a test drive 50 ish miles it stayed around 185-187F round trip with the highest temp reached being 190. AC was being ran and it was running nice and cold. when parking and turning off the vehicle.
I tried my best to look into the tight spots but having a hard time identifying source of leak and figuring where to start to tear into things. The hoses and connections seem to be dry as well as the interior floor on passenger side.

Some online searching bring up the more likely front or possibly rear heater cores. Or possibly the lines supplying those units. Any suggestions would be appreciated. As im not sure where to start taking things apart to find the source of the leak.

Recently performed maintenance -

flushed cooling system till clear w/ distilled water
New Radiator
New thermostat (toyota)
New Fan clutch (aisin)
New Water pump (aisin)
New belts (toyota)
New radiator hoses (gates)
New PHH (gates)
New heater control valve and hoses
 

ODY80

New-ish
Joined
Aug 7, 2019
Messages
16
Hard to see but at the bottom of the soft material on the firewall is soaked through.
lea_LI.jpg
 

nuclearlemon

Hard Core 4+
Joined
Aug 23, 2005
Messages
8,298
Location
windy wyo
i stopped reading at between cats and tranny,....the rear heater hard lines are notorious for failing (rear heater is under your passenger seat). check the well. a lot of people just eliminate the rear heater completely. those lines have been known to take out complete engines
 

SteveH

Hard Core 4+
Joined
Aug 10, 2006
Messages
2,907
Location
Colo Springs
I would dry off the entire area (blot out the insulation until no more red stuff is on your rag) and see if it comes back. You've done/checked all the right stuff at this point. Perhaps at some point, you could get a cooling system pressure tester and pump up the system and see how badly it leaks at 15 psi or so, and study that area while the system is under pressure and look for drips/leaks.
 

ODY80

New-ish
Joined
Aug 7, 2019
Messages
16
I would dry off the entire area (blot out the insulation until no more red stuff is on your rag) and see if it comes back. You've done/checked all the right stuff at this point. Perhaps at some point, you could get a cooling system pressure tester and pump up the system and see how badly it leaks at 15 psi or so, and study that area while the system is under pressure and look for drips/leaks.

Appreciate that good advice!! Turns out simplest things get overlooked first in my case. One of the heater core clamps wasnt fully on the fitting and when full pressure hit fluid would cause the leak. made adjustments and took for a test drive to check. Just took went downtown and back not a drop so far! May consider bypass for long run loss prevention.
 
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