I can smell rad fluid in the truck from the interior heater. Gets a little humid in there when the fan comes on. When its cool and you turn the heater on the first blast of air from the fan seems to fog the window a bit temporarily.

I am assuming this is the heater core. Does anyone have any experience with this?

Is there anything else that it could be under the dash causing this. I know the connecting hoses might, but if it was a hose I would expect more coolant loss. Or fluid on the floor inside the cab.

I guess my question is, I am about to order a new heater core. As I live in a remote area getting parts in the middle of a job just does not happen. Things end up apart for a few days waiting for other parts.

It is definitely a coolant smell. IMHO it can only be the pin hole in the heater core?

Thoughts?

 

Heater core, valve, hoses, everything need to be checked.

Depending on age, if you are going in there, might as well do all new.

I would do all the vacuum hoses I can reach at the same time.

 

I had the same smell and suspected a bad heater core. Called a dealer I trust and he said I could replace the heater core but the cause was probably the egr cooler allowing too much pressure in to the system. I had them replace the cooler.

 

Pressure test the core w/ an air compressor. It is not that hard to access the coolant lines going to it.

 

Pressure test need to be done with these conditions:


A) Temp selected to hot (wide open)

B) The shut off valve (if equipped) wide open


A closed, B open

A and B both closed

Needed to isolate it to heater core, temp valve, and verify shut off valve working properly (should not leak into cab, but who knows where it is on your model)

 

It can be pressured up from the heater core return hose - regardless of whether it has a valve or not.

 

Sure, but what if the leak is ahead of the valve when you pressure up from the return hose?

Closed valve would mean that would not show.

I would disconnect both hoses, and pressure in the direction of coolant flow rather than reverse --- to as close as possible simulate actual operating conditions.

 

There is only one valve. The shutoff valve, which is in the engine compartment. And some trucks don't even have that.

Pressure testing should be as easy as disconnecting both hoses in the engine compartment, plugging one of tightly and putting pressure on the other and then watching to see if that pressure is maintained.

 

I stand corrected.

There is either no valve or a shut off valve on that model --- the temp is moderated by opening and closing the doors with vac.

I do maintain that pressure need to be applied in the direction of normal flow and not the other way --- as faults do not always turn up going the other direction.

Oh.,.. applying pressure.. be careful... you can blow stuff if you use too much.

 

Sorry, I am a bit confused. You can smell coolant in the cab and they replaced the EGR cooler? I understand that a leaking EGR cooler can add pressure to your coolant system, bubbling, burping or puking at the degas bottle, etc. but I don't understand how the fluid smell is getting into the cab and fogging my windows. Does there still not need to be a hole somewhere for the fluid to get out in to the cab, or are they saying that the build up of pressure in the coolant system is to much for the heater core connections and is burping at the connections within the cab? and further to that, once the EGR cooler is replaced everything will re-seal?

I just replaced my EGR cooler last week. I have been suspecting a leaking heater core for a bit now, but could really smell it after the EGR cooler was replaced, when I was driving the bag off of the truck trying to purge the air from the system. I could see a light fog on the window. But as it blows for a bit the smell is gone and the fog goes away. It only does it when I start up the fan blower. So I have been thinking it is a slow pin hole leak that dries up with the fan blowing. When off the leak builds up and bang when the fan turns off it blows that build up of moisture up onto the windows. The rest of the time the fan can stay ahead of the moisture building up no causing fog on the window or smell in the cab. IMHO it must be a really small pin hole.

I guess I need to open it all up and see if I can see fluid staining on anything. Or residue build up from the leak. That might tell me if its burping from a hose or clamp or valve. Or the heater core itself.

I don't have a pressure gauge, but maybe its time to take a trip to the store. Seems they are pretty useful with these motors. Just priced one out locally that does inch vacuum and pressure. My vacuum gauge quite a while back so I guess its time for a new one. Only $26.

I have a 2005 F350 6.0L Lariat Powerstroke. It doesn't look to hard to take out the heater core. Looks like it can be all accessed through the glove box location without taking the dash off. Is that correct?

It might be best just to pull it and bench test it in the sink. If it has been the hoses burping at the connections it should be taken apart and give the connections all a cleaning and put back together with a clean seal.

Looks like this weekend's project.

 

Don't waste time... you have narrowed it down to the HVAC subsystem.

Take it out, that is the only way to thoroughly inspect it.

You can test it with the leak staring at you in the face.

Can be... joints... hole that seals with heat expansion.. or negative pressure when the system cools..

Unless you want to be an aspiring engineer... just take it out and fix it.