Engine question!!!

What?

I have 2019 with hot water valves on them, they are ball valves and factory as factory can get.

 

I’m sure it’s in the spec of each truck. My 2001 ISX had gate valves on it. I replaced them a couple years ago with 1/4 turn ball valves.

I’d guess the gate valves were original?

Our company T680’s 2013 with ISX didn’t have them and the NEW paccar engines we just got don’t have them. I’m sure it’s the way they are ordered.

Trucks today have better HVAC controls than back in the day so they are not as useful as they used to be. Plus the BTU’s of modern AC is huge compared to old.

 

Its probably not so much engine specific as it is truck manufacturer specific.

 

I don’t know hat they ever QUIT putting them on moreover making them optional. I can’t think of any reason you couldn’t put one on. All it would take is an in-line “T” fitting, and a ball valve. Well actually two of each, you would have to run one supply, and one return line.

 

Dang I thought those were for instant coffee...

 

I think it’s all in the way the truck was ordered. I’ve driven Macks, Cats, & Cummins that were all hit or miss on whether or not the specific truck would have them.

 

Kinda like whatever the manufacturer had on hand at the time.

 

Some are plumbed in line with the def tank heat coil, they don't get shutoff valves because that would also stop the circulation through the def tank.

If that is the case on your truck then you must separate the def tank lines from the heater core lines and install the ball valves after the split, you cannot just install them in the block port like the pre emission engines had.

I put them on my PACCAR but I first replumbed it so the heater core was independent of the def tank plumbing so it would not throw a code related to the def temperature

 

It’s already been answered obviously that it’s truck manufacturer and who ever orders dependent. Trucks with a modern HVAC with blend doors don’t really need the shut offs. A truck like my Western Star that still uses a HVAC system that always blows through both the heater core and the a/c evaporator still need them.