Hounddog

3rd Gens have no vacuum to heat/ac.

LawnDart

Hence my approch.....

LawnDart

Sorry it's a 4 port but will work just the same.. Four Seasons part #74809

The valve is an "H" pattern that has two "in's" and two "out's" normaly and when Vac is applied the heater core is bypassed..

AggieJustin

Good to know. I haven't looked too close at the 3rd gens. I'll keep that in mind for future mods.

Thanks! Four port is even better. Otherwise I was going to run 2 3-port valves to completely isolate the core when they are closed.

LawnDart

I'm going to "T" the #6 head port into the heater core return after the "H" valve, I'll post a pic. when finnished.. I own a light truck and auto repair shop so parts wont be much of a problem...

Oh BTW the valve is about $25.00!!!
It's plastic but they last about 80,000 mi. in fleet duty..
Ford products operate at about 220 deg. radiator temp with a 16 psi rad cap so pressure wont be a problem on our CTD's..

One other thing a CTD runs a 16 psi cap also, so my thinking on the core plug at the back of the motor is more of a heat cycle, metal expansion, plug pop out thing, not pressure related..

XLR8R

CTD coolant pumps generate 75psi at rated RPM - pressure causes the plugs to eject... be a good idea to ascertain that the plastic valve can withstand PSI@*F.

LawnDart

Well taking into consideration a CTD W/P is possibly capable of 75PSI and a high volume to-boot, add a 5/8 orifice and two feet + of 5/8-3/4 hose, the water will go the path of least Resistance to the t-stat. I would think the only reason a truck would see that pressure at the heater core or "valve" is if you have a very restricted Radiator, but that being said if the rad is restricted you wont have the flow or supply to the pump in order to generate the pressure in the first place. Hmm.

BTW?? If a CTD produces this pressure consistently why didn't Daimler Chrysler/ Cummins use rack/pinion type hose clamps instead of the torsion/spring type??
I don't think pressure will be an issue with these mods or valve, I've seen several blown head gaskets on many vehicles when cylinder compression "150 psi" is entering the cooling system without popping core plugs out of the block,breaking plastic rad tanks or bursting good condition hoses..


Note: These are my opinions based on my experiences of thirty years in the automotive light truck repair industry and in no way mean a **** thing on this message board.. LOL

XLR8R

... since a "restricted radiator" isn't necessary for a 75psi head, there's not much to think about - just make sure everything in the circuit can handle PSI@*F

"rack/pinion"?
- you mean worm screw?
Only shielded clamps are better than the OEM spring clamps.

jcismo1

I did the mod. today. I did the bypass with one valve. I used (1) #53356 5/8 nipple with 1/2 NPT after pulling the plug at #6 cylinder, (1) #36387 5/8 tee, about 1 foot of 5/8" heater hose. Initially I used the valve pictured in MikeyB's posts, but that piece of junk leaked. I even tightened the stem nut to no avail. Went to Home Depot and got a #22462 3/4" Pex Ball Valve, In my opinion this is a much better valve to use. I don't think you really need to use two valves. I did a little test after the job. I let it get to operating temperature, then put the dial on full heat. I couldn't hardly detect any heat coming out of the registers and the A/C was off. Now my A/C works like a champ! A very worthwhile mod.

MikeyB

Sorry you bad luck with that valve. So far mine hasn't leaked yet, fingers crossed.

MikeyB

EverydayDiesel

holy cow, 29 pages

i read a few but couldnt get a straight answer on a part number that works good. Which one has had the most luck?

LawnDart

XLR8R, I have viewed your posts in other threads and your knowledge is vast with the CTD's.
In comparison 75PSI is huge compared to the rest of the automotive/truck industry. That suprised me and is good to know.

Yes I meant shielded clamps. lol

I can not find specs on this valve but being designed for cooling systems running in the -20 to +240 deg. range under normal conditions I'll use it as it keeps this mod simple as well as the others posted, I'll let you know how it is working in a year. LOL

AggieJustin

My main concern with that valve was how well it was going to handle the external temperatures, especially since it is going to be sitting right over the exhaust manifold/exhaust housing on the turbo. I think we're covered on water temperatures, but the mounting location on the other vehicles is in a much cooler location.

jtamulonis

The pressure in the cooling system will NEVER be higher than the pressure of the radiator cap.

SpeedyWS6

Yes it will... Has been proven time and time again. Pressure in the radiator may stay at ~16psi but pressure in the cylinder head can get pretty high.