Losing coolant

[Cezar]

I just came back from a 1200 mile trip. Before I left I made sure the radiator was full.

When I got back I had to add 2-3 quarts of coolant to get it back full. Trying to discern if its a head gasket or a leak. I'm going to add dye to the coolant, but what else should I check?

Hoses are new, thermostat is new, radiator is new, heater core is new. Water pump has around seven years on it.

No other symptoms.

 

[AuSeeker]

I just came back from a 1200 mile trip. Before I left I made sure the radiator was full.

When I got back I had to add 2-3 quarts of coolant to get it back full. Trying to discern if its a head gasket or a leak. I'm going to add dye to the coolant, but what else should I check?

Hoses are new, thermostat is new, radiator is new, heater core is new. Water pump has around seven years on it.

No other symptoms.

V6?, what year?

Without knowing the above, I would first look to see if the water pump is leaking out the weep hole on the bottom of the shaft area if it's a V6, if it's a V8 it's going to be hard to see the water pump because it's buried in with the timing belt but you could possibly see if any coolant is coming out at the bottom of the timing cover, also it's possible since you've recently replaced all that you've mentioned that there was some air trapped in the system and it worked itself out during your trip, I would watch it over the next week or two to see if you're still losing coolant

 

[Voltan73]

Use a block test kit to check for exhaust gases in the cooling system. That will be the easiest way to determine if it's a head gasket. I hope that it's not!

 

[Cezar]

V6?, what year?

Without knowing the above, I would first look to see if the water pump is leaking out the weep hole on the bottom of the shaft area if it's a V6, if it's a V8 it's going to be hard to see the water pump because it's buried in with the timing belt but you could possibly see if any coolant is coming out at the bottom of the timing cover, also it's possible since you've recently replaced all that you've mentioned that there was some air trapped in the system and it worked itself out during your trip, I would watch it over the next week or two to see if you're still losing coolant

V6. I feel like V8s are rare enough that the 4.0 should be assumed and the special snowflake V8 owners should have to be the ones to clarify

Sounds like, in order of likeliness:

- Air bubble worked itself out on long trip. When I opened the rad cap I hear a kind of suction noise and a bunch of water shifted *downwards* into the system, so I actually feel like this is likely

- Water pump bad. Dye will reveal this

- HG

I'll monitor over the next couple weeks. If #1 and #2 are no-go I'll get one of those bubblers.

 

[SocalSam]

Carefully smell exhaust. If sweet sickly smell, coolant is getting into cylinder(s). Pull plugs and boroscope. Look for coolant cleaning.

 

[Parks Junkie]

When I got back I had to add 2-3 quarts of coolant to get it back full. Trying to discern if its a head gasket or a leak. I'm going to add dye to the coolant, but what else should I check?

2 or 3 quarts? That's a lot. You should be able to find it. Again, that's a lot, but water pumps can be tricky, leak, but never hit the ground. Also any hose on the back of the engine can cause seemingly invisible leaks. On a BMW decades ago I had to pressurize the system to find a tiny leak at the back of the head. Pressurize it if needed, but don't go over 15 PSI or so, you don't want to blow the radiator or the heater core.

 

[Three dogs]

Use a block test kit to check for exhaust gases in the cooling system. That will be the easiest way to determine if it's a head gasket. I hope that it's not!

This^^^^

My son was fighting gremlins on a ford I said head gasket, he worked on it for a couple of weeks. I bought the kit, he did the test and confimed it in a couple of minutes.

 

[daprotege5]

alot of people forget to change the clutch fan, mine was loosing a little bit and changed the fan, resolved the issue.

 

[Cezar]

I ran most of a tank through and re-checked the rad and it was completely fully. Must have had an air pocket. What's interesting is I had heat cycled the truck multiple times and topped off before my trip, and yet it needed a 1200 mile drive to fully burp itself. Guess I need one of those pressure filling doodads.

Also burnt out the exhaust between the pipe and muffler and had to get a welder to fix it while on vacation, so it definitely got HOT on that trip. Running great though.

 

[Cezar]

Okay. I am losing like half an ounce per week.

I have dye in the system, its circulated. I checked in a pitch black garage with a powerful uv light and found zero traces of leakage.

Is there ANYTHING this could be, other than a very slightly damaged headgasket?

 

[AuSeeker]

Okay. I am losing like half an ounce per week.

I have dye in the system, its circulated. I checked in a pitch black garage with a powerful uv light and found zero traces of leakage.

Is there ANYTHING this could be, other than a very slightly damaged headgasket?

It could be a leaking heater core, check the AC condensation drain hose that comes out of the firewall above the frame on the passenger's side.

But a half ounce a week is not a lot so it would be very hard to find such a small leak, it could be a head gasket leak, you can check each cylinder with a bore scope in the morning after sitting all night to see if any coolant is on top of the pistons.

 

[Cezar]

It could be a leaking heater core, check the AC condensation drain hose that comes out of the firewall above the frame on the passenger's side.

But a half ounce a week is not a lot so it would be very hard to find such a small leak, it could be a head gasket leak, you can check each cylinder with a bore scope in the morning after sitting all night to see if any coolant is on top of the pistons.

It's not a heater core leak I have a brand new denso unit in there and I'm pretty sure this has been going on before I did that. Previous heater core was in great shape, and in fact the only reason I swapped it was for PM.

Absent any other clues I think I have to chalk this up to headgasket. That said I wouldn't be shocked if I get another ten years out of it as is.

 

[ArthurKotb]

How's the oil level? I've seen head gasket leaks send coolant into the oil. Just a thought.

 

[Buckaroo]

you can check each cylinder with a bore scope in the morning after sitting all night to see if any coolant is on top of the pistons.

If coolant is not observed, you can look for a piston top that appears to be "cleaner" than the other 5. Can also pressurize your coolant system overnight and then check for visible coolant in the morning.

 

[Cezar]

How's the oil level? I've seen head gasket leaks send coolant into the oil. Just a thought.

Losing a normal amount for a car with 250k miles on it lol

 

[zguy1]

Rent yourself a cooling system pressure tester from Autozone. Pressurize the cooling system and then take a borescope and start inspecting each cylinder starting with #6, then #4.

A lot of the times the 1GR-FE will pass a combustion tester when the head gasket leak is small. I had mysterious coolant loss with no running issues or codes. Only when I pressurized the cooling system could I observe a single drop trickling down the cylinder wall from the head gasket every minute or so.

https://i.imgur.com/7tDjQIU.mp4

 

[Cezar]

Rent yourself a cooling system pressure tester from Autozone. Pressurize the cooling system and then take a borescope and start inspecting each cylinder starting with #6, then #4.

A lot of the times the 1GR-FE will pass a combustion tester when the head gasket leak is small. I had mysterious coolant loss with no running issues or codes. Only when I pressurized the cooling system could I observe a single drop trickling down the cylinder wall from the head gasket every minute or so.

https://i.imgur.com/7tDjQIU.mp4

That seems like a lot of work; pulling plugs and getting a borescope running, driving to autozone and back.

Is there any reason to assume I should bother, vs just letting the engine do its thing until symptoms become pronounced?

 

[Buckaroo]

That seems like a lot of work; pulling plugs and getting a borescope running, driving to autozone and back.

Is there any reason to assume I should bother, vs just letting the engine do its thing until symptoms become pronounced?

Nope - keep the engine coolant filled up and wait for the miss or the crank no start.

 

[Buckaroo]

You may foul the oxygen sensors but that would probably be the least of your worries.

 

[zguy1]

That seems like a lot of work; pulling plugs and getting a borescope running, driving to autozone and back.

Is there any reason to assume I should bother, vs just letting the engine do its thing until symptoms become pronounced?

Okay lol. Just figured I would offer some help.