The supply hose (from cylinder head to firewall via heater control valve) is 1/2" on vehicles starting in '70, to reduce waterflow noises emitted from the heater and to reduce coolant exit velocity from the heater core, which under some circumstances improves heater performance. Pre-'70 cars had dual 5/8" hoses. Fix is very easy: Note that the heater hose nipple on the cylinder head is threaded. Unscrew it and install a 1/2" nipple instead. Hose from there to heater valve, heater valve to heater core inlet, then 5/8" hose from heater core outlet to return nipple integrally cast into water pump.

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Too many people who were born on third base actually believe they've hit a triple.

Great answer Dan! I'd always wondered about that 1/2" hose.

I remember that my '82 Dodge Aries w/ 2.2L AT, wo AC used a heater hose that had a different size at each end - dealer only - and I seem to remember it was 1/2" and 5/8" (it's been awhile), but the dealer maybe can get one.

Is it possible that sometime in the past the firewall outlet and inlet got reversed? The inlet (according to the FSM) is on the right and is 5/8, and the outlet on the left is 1/2.

two other problems getting this engine ready to run.

1) I have three pulleys on the crank, two on the water pump, and one on the alternator. When I line up the main fan belt on all the inside tracks, the belts slightly touches the head (this won't do). When I put the belt on the 2nd track on the crank and the water pump, it doesn't rub, but looks maybe slightly crooked on the alternator (potential bearing problems later?). The belt that runs the power steering pump fits fine on the third track out on the crank and on the single pulley on the p/s pump.

2) Finding a lower radiator hose that fits was not successful. I tried the Goodyear 60664, fits but doesn't have that subtle bend around the bolck so the fan belt doesn't rub on it. Tried a Kelly-Springfield s-105, not really close. I went through all the hoses at Kragen, nothing close enough to trim to fit. My old hose is OK, and I will use it for awhile, but if you have any suggestions on what brand/model number will fit would be great.

Not really...the inlet and outlet pipes are integral parts of the heater core; they cannot be swapped.
Doesn't make a whole lot of sense, since the heater valve is generally placed upstream of the core, not downstream of it. That said, it makes no operational difference which direction water flows through the heater core. And, for that matter, it makes relatively little difference whether the heater valve is upstream or downstream of the core—if the valve is placed downstream (in the outlet line), the heater outlet air will be slower to cool down and won't cool quite as far down when you move the temp slider to "cool" after it's been on "Hot". If you are looking at the right diagram in the FSM (Labelled "L" or "V, L" or "Dart" or "Dart, Valiant"), it could be a simple mpsinrit!
Fan-Alternator belt goes on the middle crank pulley groove, the front fan pulley groove, and the one and only alternator groove.

Power Steering belt goes on the frontmost crank pulley groove and the P/S pump.

Air conditioning belt goes on the rearmost crank pulley groove, the rear fan pulley groove, the A/C compressor and the A/C idler pulley.
19" or 22" wide radiator core in your '73?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks Dan! You saved me some head scratching! The radiator is the heavy duty for AC, but since I am at work I will have to measure it when I get home.

Howdy,

I appreciate the quest. re radiator width and recognize its relevance. However, I have neither size having used one from a 88 truck, but a Carquest RBR 20229 fit perfect and is an exact match for my old hose and radiator too.. Pricey though..my net was $19.38. I saved my old one. Those kind of charms ward off evil spirits.

rock
'64d100

[quote="SlantSixDan"][quote="RDJ"]
Doesn't make a whole lot of sense, since the heater valve is generally placed upstream of the core, not downstream of it. That said, it makes no operational difference which direction water flows through the heater core. And, for that matter, it makes relatively little difference whether the heater valve is upstream or downstream of the core—if the valve is placed downstream (in the outlet line), the heater outlet air will be slower to cool down and won't cool quite as far down when you move the temp slider to "cool" after it's been on "Hot". If you are looking at the right diagram in the FSM (Labelled "L" or "V, L" or "Dart" or "Dart, Valiant"), it could be a simple mpsinrit!

quote]

I found this on Page 24-3 fig 4. heater hose routing (Dart)

OK, that means 22". Try a Dayco 70792 or a Gates 20949. Both of these come "extra long" so will require a little shortening in most cars, but both of them should have the right bends.

20949 looks like this:


70792 looks like this:

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

the Napa 7674 (lower rad hose) came up with the numbers you provided and fit like a glove, no trimming required, thanks!

I actually fired up the engine last night, and it fired right up! It is the first time this car has had a running engine in at least a couple of years. It runs pretty rough and won't idle more than about 15 seconds without dying, but at least I don't have to trouble shoot the whole ignition system.

I will try to dial it in this weekend, and I need to figure out the vaccum hose mess. I capped off most of it so far. I need to figure out what I can eliminate since thhis car is old enough to not require smog testing. The FSM shows more hoses and connections than my car has. I already bypassed the OSAC valve by connecting the distributor directly to the carb.

I am running a BBS for the moment, but my BBD will be back from the rebuilder in a few days. I would like to get it running smooth before I do the 2 bbl transformation.

Thanks for all your help!

I purchased two (upper and lower) of the 'long' ones in the dead of winter, for nearly $50! I was more than a little peeved having to cut nearly 4 inches off between both ends and try to fit and refit time and time again for it to clear the block in sub zero temperatures. One slip up or cut too short and you'd have to buy another.