Pouring coolant in radiator; Going straight to muffler while engine is off? Help!

[matix440]

Working on a 1999 LX470, can’t quite figure out this issue! Help me out, I’m a bit stumped but not totally ruling out a blow head gasket. Here’s what I’m trying to figure out:

Currently the muffler has a small rust hole in it, soon to be replaced. When filling my radiator with coolant, moments later that coolant starts to slowly trickle out of the rust hole in the muffler(parked on a slight incline); engine is off while this is happening. What could this be exactly? (Coolant expansion tank level has stayed exactly the same even after running engine.)

There are no visible leaks in the engine bay, no steam, no dripping underneath the engine bay area(skid plates are currently removed), and no signs of running leakage anywhere along the block, underbody, etc.

Currently waiting for new ignition coils and plugs to come in the mail, my scanner is pulling a few misfire codes(3, 5, 7, sometimes 6) but that’s all that pops up. Engine starts and is fairly quiet as it should be(minus the rough idle due to the ignition coils). When running the engine and eyeing the temp gauge, temp doesn’t rise quick at all, just at a normal pace. Eventually after 30 minutes or so it may go slightly above normal running temp. Dipstick shows a slight color of chocolate milkshake/clear oil color.

 

[matix440]

Working on a 1999 LX470, can’t quite figure out this issue! Help me out, I’m a bit stumped but not totally ruling out a blow head gasket. Here’s what I’m trying to figure out:

Currently the muffler has a small rust hole in it, soon to be replaced. When filling my radiator with coolant, moments later that coolant starts to slowly trickle out of the rust hole in the muffler(parked on a slight incline); engine is off while this is happening. What could this be exactly? (Coolant expansion tank level has stayed exactly the same even after running engine.)

There are no visible leaks in the engine bay, no steam, no dripping underneath the engine bay area(skid plates are currently removed), and no signs of running leakage anywhere along the block, underbody, etc.

Currently waiting for new ignition coils and plugs to come in the mail, my scanner is pulling a few misfire codes(3, 5, 7, sometimes 6) but that’s all that pops up. Engine starts and is fairly quiet as it should be(minus the rough idle due to the ignition coils). When running the engine and eyeing the temp gauge, temp doesn’t rise quick at all, just at a normal pace. Eventually after 30 minutes or so it may go slightly above normal running temp. Dipstick shows a slight color of chocolate milkshake/clear oil color.

Also

Working on a 1999 LX470, can’t quite figure out this issue! Help me out, I’m a bit stumped but not totally ruling out a blow head gasket. Here’s what I’m trying to figure out:

Currently the muffler has a small rust hole in it, soon to be replaced. When filling my radiator with coolant, moments later that coolant starts to slowly trickle out of the rust hole in the muffler(parked on a slight incline); engine is off while this is happening. What could this be exactly? (Coolant expansion tank level has stayed exactly the same even after running engine.)

There are no visible leaks in the engine bay, no steam, no dripping underneath the engine bay area(skid plates are currently removed), and no signs of running leakage anywhere along the block, underbody, etc.

Currently waiting for new ignition coils and plugs to come in the mail, my scanner is pulling a few misfire codes(3, 5, 7, sometimes 6) but that’s all that pops up. Engine starts and is fairly quiet as it should be(minus the rough idle due to the ignition coils). When running the engine and eyeing the temp gauge, temp doesn’t rise quick at all, just at a normal pace. Eventually after 30 minutes or so it may go slightly above normal running temp. Dipstick shows a slight color of chocolate milkshake/clear oil color

Working on a 1999 LX470, can’t quite figure out this issue! Help me out, I’m a bit stumped but not totally ruling out a blow head gasket. Here’s what I’m trying to figure out:

Currently the muffler has a small rust hole in it, soon to be replaced. When filling my radiator with coolant, moments later that coolant starts to slowly trickle out of the rust hole in the muffler(parked on a slight incline); engine is off while this is happening. What could this be exactly? (Coolant expansion tank level has stayed exactly the same even after running engine.)

There are no visible leaks in the engine bay, no steam, no dripping underneath the engine bay area(skid plates are currently removed), and no signs of running leakage anywhere along the block, underbody, etc.

Currently waiting for new ignition coils and plugs to come in the mail, my scanner is pulling a few misfire codes(3, 5, 7, sometimes 6) but that’s all that pops up. Engine starts and is fairly quiet as it should be(minus the rough idle due to the ignition coils). When running the engine and eyeing the temp gauge, temp doesn’t rise quick at all, just at a normal pace. Eventually after 30 minutes or so it may go slightly above normal running temp. Dipstick shows a slight color of chocolate milkshake/clear oil color.

Also forgot to point out— While engine is running, after turning on the heater to high temp/full blast, it’s “somewhat warm” but not as warm/hot as it should be.

 

[Bisho]

The only way for coolant to flow out the exhaust is a blown head gasket or cracked head. I would also expect a plume of white smoke when it’s running.

 

[matix440]

Thanks, any other opinions or potential possibilities please post! The LX is in the shop now, awaiting to hear back from the mechanic to see what the exact issue is. It’s been about a week now and they haven’t started working on it, so I’m getting anxious. Can’t wait to get it back!