VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 38 Master Sport Heater Hoses?

I have amnesia from my former 38 Master Deluxe, but do not remember the heater hose running over the tope of the valve cover. Is this an odd setup, I don't like it and swore my Master Deluxe wasnt setup like this.

It looks like it's connected to the port for the temperature gauge sending unit. This is not correct. Both hoses run along the passenger side of the engine.

Do a quick google of "1938 chevrolet engine pictures" as there are lots showing the hoses and it's easier than posting a bunch...

Tim is correct. The normal heater hose connections are both at the front right side of the engine. On hose is connected to a hose nipple that is in the thermostat housing. The other nipple is in the water pump housing.

If you look on your engine I expect that you will see a pipe plug in one of those ports.

Here's where they connect.

The earlier engines used the setup pictured by solafide with hot water outlet on same place as thermostat bulb. Don't know when they changed.

I don’t like it, looks messy and I wonder how they secured the hose? Prior owner secured hose to horn, eek.

There is one advantage by connecting to the temperature sensor outlet. The heater circuit should start getting hot water a little earlier in the warm-up cycle.

The water flows from the water pump to the back of the block and then up into the head at the rear. The last place to get hot water is the front of the head where the thermostat housing is attached.

You can read this temperature difference during the warm-up cycle with an infrared temperature gun. The head temperature on my car will read 180 at the temperature gauge sender and on the gauge. The temperature at the thermostat housing will be 10 to 15 degrees cooler at that time. Within a couple of minutes the thermostat will open and that housing will read 180.

I wonder why Chevrolet abandoned the setup and I guess 37 and earlier used that setup? I wonder how they routed and secured hose

When I got my ”˜37 the heater hoses were routed to the front of the engine.

Makes me wonder if my 38 has the heater shutoff valve, original buyer might have saved .50 without valve.

the hosees were black. Chevrolet never used red.

Welcome back Gene!! I was going to mention that. I don't have a photo with the correct hoses (on the car now) but that one shows the location.

Thanks gents

The other point is that in very cold weather and at road speed the front of the engine does not get hot enough to heat the passenger compartment. About 1/3 of the heat in the fuel goes into engine power. 1/3 is dissipated by exhaust and air flowing past the block and 1/3 from the radiator. In colder weather the radiator might not do much cooling at all particularly with a passenger compartment heater. Chevrolet opted for function not looks.

I agree with Chipper about engine heat in cold weather. The heater core alone often has the capacity to handle the heat load especially if the heater fan is moving a lot of air across it.

When I was in college I had a car that the engine temperature would drop below the thermostat setting when going down Afton Mountain in Virginia. This would happen in the winter because it was a convertible so you had the heater on full air flow and there was no load on the engine. As soon as you reached the bottom of the grade and the engine started to have load on it things went back to normal.

That is why Chevrolet offered a wnter front to cover the grille in cold weather.

The lowest the temp gets around my area is low 40s with an extremely rare dip below 30. I will say that my 38 Master Sport sedan temp stays cool no matter how long I let her idle while my old Master Deluxe ran hot all of the time. I really want to see how Chevrolet routed and secured the hose that currently runs over the top of the valve cover

Did you look at the photo I posted? The outlet is on the thermostat housing and the inlet on the water pump. Here's another view. The outlet has the shut off valve and the inlet is about 6" below that in the photo.

Funny, all the hoses are orange. The picture is nice but shows no connections except to the firewall unless your referring to the earlier picture. Does anyone have a sample of the hose being connected to the temp sending unit? Is my setup better or worse than the standard setup?

1934 was the last year for the hose being connected to the sending unit. After that there was a pipe plug in the water pump and a hose nipple replaced the plug when a heater was installed.
With this newer connection location Chevrolet says the water passing through the heater core is about 10 degrees hotter.
GM NEVER USED ANYTHING BUT BLACK HOSES.

The hoses were replaced with black after this picture was taken. Look at the front of the engine. The shut-off valve connected to the thermostat housing is where one hose connects and the port just below that is where the other hose connects. It shows the connection points better than the first I posted. I can make arrows pointing to the ports if this doesn't help. The shut off valve is just an accessory and probably not on your car.

I do not know where the instruction for the '37/'38 heater showed to put the shut off valve. Tiny said to put it on the thermostat housing. Shown in his picture. I also don't know if it really matters? But, the instruction with the '46-'48 and maybe '42 shows and tells to install the shut off valve on the water pump. Click on file.

Your shut off valve is clearly visible in your first post.

I don't know that it really makes a difference but I put it on the push side of the system so when it's off it's not pressurizing the heater core.

It belongs in the water pump.In 1938 it did not have the winged shut-off valve but rather a larget bolt head to turn with a lock nut.

I agree with Tiny’s thinking.

Plus this position will prevent heat transferring to the heater core through conduction in the coolant.