PeteC:

Thanks for the info.
I am most interested in having the coolant cut off to the core when the A/C is directed at the vents. I think that, for me, either will work as long as I tap the RED vacuum line. That being said, a trip to AuotZone is much faster than ordering something online and that will be the way to go.

I thought you had problems with the AutoZone part number working for you?
Does your 99 have different sized heater hoses than my 2K?

Thanks for the help.
I appreciate all the free help available here and hope to be able to help others out at some point...

Craig

 

sorry for double post...

 

How hard was the install? I may need to order one before the summer gets here.

Steve

 

I don't know about the 2000's or any other year. I don't know why Ford used different size heater hoses.

I will see what I can find out at the Ford dealer next week.

 

I tried to get a heater control valve at the Ford dealer this week. The parts guy told me there was a heater control valve on the 99 Superduties. I told him I did not think that was so. First he pulled out a valve that was the same as the one I had from Advance Auto, with 5/8" lines. I told him I had 3/4" lines on my 99.

Then he found another valve, but it was a simple on-off valve (not the flow rerouting type) and it too was for 5/8" lines.

He looked up a part # for the 03 but he could not find it anywhere in the area. He could order it for $40 but it was nonreturnable. Not knowing whether it would work I passed.

So I am out of luck for now.

If anyone has been able to find a flow rerouting valve for the 99s with 3/4" lines I would appreciate knowing where to get one.

 

I looked under the hood of an Excursion w/5.4L (2000) belonging to a friend, and it has a heater core shutoff valve that is a simple cutoff type. So, I conclude that a flow re-routing type is not needed. I ordered one for an excursion for my f-250, but I have not installed it yet. The hose connections are both 5/8"
The vacuum line controlling the valve on my buddy's Excursion is gray in color and I'm curious if anyone knows where it comes from.
mike

 

I have read through this thread and others a few times and have still have a question or two. Is there a heater core shutoff / bypass for the V10 that still allows some movement of coolant through the heater core? I don't even really want to tie it in with the hvac controls, a simple lever on the device itself would be fine. Thanks for any advice.

 

Installed heater hose bypass yesterday afternoon. Tapped into red vacuum line. NO heat whatsoever anytime "vents" are selected. Easy, very worthwhile mod.

Note to PeteC: When I got my bypass valve from Advance Auto, same part number as Auto Zone part (Factory Air PN 74809) I thought the valve would not fit my heater hoses either because I measured the ID of the connector by the coolant pump at the front of the engine which is either 5/8" or 3/4" (hot coolant spewing slightly) but after committing to install, the heater hoses do fit MY 2000 SD perfectly as they do most everyone else. The openings on the valve itself were only just over 1/2" ID. I think the hose may be slightly tapered open to accommodate the connection on the front of the engine. Double check things and you may find you had a working part the whole time. Best of luck!!

Sorry for the long post but this mod offers lots of bang for the buck and SD owners who live in places where the A/C gets a workout in the summer should definitely consider this upgrade.

Tight lines!!

 

Can someone pplease post the full instructions for this or a link. Thanks.

 

craigwilliamson

You may be on to something here. I did pull the hose at the engine and was going to connect to the valve and add a new piece of hose to go to the engine. Perhaps Ford stretched the hose at the engine.

Now that I think about it, I did put a Prestone bypass fitting in the truck a while ago and I used the 3/4" T-fitting. I hate to cut the hose and find that things don't fit. I will have to take another look at it.

Thanks

 

cwb

Check my earlier (and others) earlier posts for a link. You may have to piece things together from the links as there were a few different ways that people installed the valve. Perhaps craigwilliamson will ltell us what he did.

 

i bought the valve but am confused as to which hose is the "heater hose" that i am suppose to tap into???

there looks to be two that could be it...... one that is closer to the right side fender that goes to the engine block and another that is closer to teh center of the truck that connects to the manifold.... any one know which i should cut into??

would it be the red arrow or the yellow one????

 

The short answer is "yellow"...
The 'diesel site' valve is just an on/off valve. You can tap the white vacuum line to shut off coolant flow when using 'max A/C' only. If you tap the red vacuum line, you cut off coolant flow whenever 'vent' is selected on the HVAC controls from inside the cab.

The AutoZone and Advance part number 74809 actually reroutes the coolant flow from the heater core back to the block when the vacuum actuates the valve.

To answer prior questions concerning the install of the AutoZone/Advance valve, I installed the valve about where the heater hoses make their 90 degree bend, just about 10-12 inches forward of the firewall. This is where both of the hoses are in close proximity to each other and makes for ease of install. Do one line at a time. Valve orientation does not matter for the install. It works either way! Complete one line at a time. It is kind of tight back towards the firewall but everything fits fine.

Another note on running the vacuum line. If you lift the front passenger floor mat, you will find a rubber grommet 'knockout' in the metal firewall. You can put a hole in the grommet and created a passageway to the opposite site of the firewall without drilling. Doing things this way also does not allow air to get into the cabin on cold days as the rubber grommet forms a nice seal around the vacuum line without pinching it.

It is raining like heck in Va. today or I would go grab some pictures....

Thanks to everyone's help on this forum. Let me know if I can be of any further assistance to anyone.

Craig

 

So, is the heater hose on my 99 V10 5/8" or 3/4"? Yes, it is both. The heater inlet hose is 3/4" at the attachment to the engine, but then necks down to 5/8". I had originally pulled the hose off the engine to check the hose size, which had led to my confusion.

I cut the hoses where they turn parallel to the firewall and installed the 74809 valve. Be careful where you cut the hoses. I should have cut the heater inlet hose a little further from the engine as my cut had just barely made it to the 5/8" section of the hose.

I have the vacuum line attached directly to the spare port on the vacuum resorvoir in the engine compartment. I plan to put a vacuum switch in the cab so I can maually turn the heater core on and off. I want to be able to have heat out the vents in the winter.

The AC works great now. Vent temperature was down to 44 degrees. Previously, 52 degrees was the best I ever got.

 

Way to go, PeteC....

I thought you might jump on in and give it a try.



Craig