Coolant leaking when turning heater or A/C on?

Hi,

The first thing we need to determine is where the leak is coming from. Can you actually see it drip? Also, when you turn the A/C or defroster on, do you hear any noise from the compressor? I ask because nothing should change by turning the AC on or the fan to circulate air. Check to see if you can find an approximate location for me. For example, is it at the front of the engine, the rear, is the radiator wet at the bottom, or is anything wet you can, see?

Let me know. Also, take a look through this link and let me know if it helps.

https://www.2carpros.com/articles/car-is-leaking-coolant

Take care,

Joe

The A/C stopped working a while ago and I think it is the compressor because it made a lot of noise before going out, so no A/C.

Usually when I turn the Fan on, the steam will start coming out almost instantly but by then it is so steamy and makes it impossible to pin point the leak, and I usually stop the fan and everything goes back to normal, no leaks, the weird thing is that this will happen every time I turn the fan on, (there are no noticeable leaks before or after using the fan).

In an unrelated (or maybe related) incident, yesterday I had my truck towed from the road because I started seeing steam coming out of the hood (again). Let me say I have had every possible coolant hose bursting at least once with this truck.

Today I pressure tested the coolant system with my hand pump and I detected a leak coming out of the manifold. I will be ordering and replacing it when possible. But the question still remains. Why can't I use the heater on this truck?

Hi,

That is confusing and really doesn't make sense. The blower motor has nothing to do with the coolant flowing through the heater core or the blend door cable.

By any chance, has someone installed a heater control valve on one of the heater core hoses? Also, I want you to try something. Select heat but leave the temperature on cool and see if you still get steam.

Let me know what happens.

Take care,

Joe

Thanks for the reply, I will do as you advice as soon as I get my hands on the repair I mentioned before, which brings me to another question, When I did the hand pump pressure test, I saw coolant dripping from a small crack under the exhaust manifold, this means I have a bad head gasket right? I should not have coolant in there.

Hi,

The head gasket is there, but are you referring to a crack in the head or the seam between the head and cylinder block? That makes a big difference.

Is it possible for you to get a couple of pics where you see the leak and upload them for me to see?

Joe

Let me try to clarify, the part that was leaking when I did the pressure test was the exhaust manifold itself, right before it attaches to the beginning of the muffler pipe, then after this I noticed that the coolant was leaking with my truck just parked there and no pressure whatsoever. See pic I took from under the engine. Thanks

Hi,

That is an interesting one. We know it shouldn't have coolant from the exhaust, so either it is coming from a head gasket issue or there is a cracked head.

Just for curiosity, what is the hose behind the exhaust that I see in your picture? I circled it below. Is that going to the heater core? Could that be leaking and dripping on to the exhaust?

Let me know.

Joe

See pic below.

Thanks for following up with my questions, yes so coolant should not be leaking out of there, so how do I find what is the issue here? (Cracked head or head gasket) before I spend any money,
And to answer your question, that one is the heater hose.
I attached it.

First, make sure the heater hose isn't causing the issue. It could be spraying and making it look like an engine issue.

If the hose doesn't leak, the next thing to do is remove the exhaust manifold and confirm exactly where the leak is coming from.

Let me know what you find.

Joe

You were right! The heater hose was cracked, (the hose you saw in the pic) there was a burned spot on it. This was causing the leak that made it look like it was coming out of the exhaust manifold.


I also replaced the heater control valve since it has leaked in the past and it's been a while since the last time it broke (like 3 years)

I will keep an eye on it next time I try to use the defroster, maybe I can pinpoint the leak.

Thanks a lot for your suggestions.

Hi,

That is good news. I'm glad you found the issue. I had a feeling that was the cause, but like everything else, anything is possible.

Regardless, let me know what you find with the steam/defroster issue. I have a feeling it won't happen anymore.

Take care and I hope you have a great Thanksgiving.

Joe

Sure thing I will let you know. Thank you, have a nice thanksgiving as well!