[donate12]

What have you all done about not blowing heater core hoses and/or heater cores off from spirited driving pressures? I’ve finally ordered the Ford flow restrictor (and new hoses…again…) but, am curious if there are any other options or ideas.?. Is the Ford flow restrictor effective enough? Being in Florida, I want to keep the heater for the brutal winters here

 

[irvin]

whats the part # and which hose is it installed in ?
this the same one the fox body mustangs use?

 

[donate12]

XR3Z-18599-AA On the inlet (larger) hose. I think it came stock on 1996-2004 Mustangs.

Here is the carnage. This inlet hose (Dayco) is about 6 or 7 yrs old and was replaced when I replaced the last leaking heater core. I'd be curious to know the psi at this point when it blew!

 

[Zep5.0]

Stock cooling system with enough pressure to blow a hose? I'd think the radiator cap would blow before a hose burst like that.

Does your cap work correctly? Overflow tank?

 

[donate12]

Only upgrade on the cooling system is the upgraded water pump design. And well, maybe the FRRP PI intake. No radiator cap but overflow tank works fine.

After researching this further, this is not really an uncommon or unknown problem. I feel dumb for not discovering this 20yrs ago but, Ford knew quite well about the issue. Not so much with blowing the hose (probably my saving grace) as in prematurely destroying the heater core. There are two flow restrictors available. XR3Z18599AA came stock on 96-04 Mustangs, 2003 Cobra, and all police cars Ford made. The other appears to be discontinued from Ford but re-created and available from a few vendors (E7VY-18358). Both fit into the heater core inlet (3/4"), restrict the flow down to 1/4", and fit 1979-2004 Mustangs. Quite a decrease in size! However...the E7VY-18358 is basically just plastic, while the other is plastic with a rubber washer inside that acts as the main restrictor. Looks like a smaller version of the rubber washer you put on garden hoses. I imagine there was a reason they altered the design to be a bit more dynamic with this rubber section...

I haven't installed it the restrictor yet but, I am happy to think this might keep me from replacing another heater core. #3 or #4 in 20yrs. Geez...

Still interested in hearing if anyone has done any other mods/tweaks to thwart the pressures in that section. Or have installed one of the restrictors with results.

 

[donate12]

A quick follow up on this: I got the restrictor installed into the upper portion of the heater intake hose (where the hose leaves the intake and does a 180 down behind the intake). I stuck with using the XR3Z18599AA version after some debate and number crunching. The earlier versions of these restrictors had a problem with being noisy and Ford tried to skirt around the real issue but stating it needed to be moved close to the intake (didn't help, they had ignored fluid dynamics to save cash).

The short story is: the newer design actively handles the variations in pressure between idle to load. Thereby, helping to remove the noises they can create at low pressures.

So far, the new version is silent. Heater temps don't seem to be affected. And I haven't blown a hose off or apart ... yet