Ok, here ya go...

I have been on here before along with others complaining of the no-heat, little-heat problem for years. It has stumped me. Front & rear AC/ Heat setup. Good water pump, good heater cores, good thermostat, good blend door actuating servos, good servo potentiometers, good blend door spindles, good fans, etc. Still no heat or just a smidget on low. Turn up the fan and no heat. Sometimes, more heat than other times, but usually very little.

185,000 miles on the clock.

I *know* some of you have this same problem. Sometimes it is a blend door or actuator or control. Sometimes it is other things, but this time it was something completely new to me and the first time I'd ever seen anything like it.

The problem is that on the supply heater hose (stock hose in my 99 and still good) coming from a tube at the rear of the block (on the passenger side), there is a FLOW RESTRICTOR in the hose. You can feel it inside the hose if you run your hand over it. I thought it was some type of check valve, but it is just a small device with a plate and hole in the middle.

For whatever purpose this is in there for, as the vehicle ages, it is possible for some small flecks of cast iron to come off in the cooling system. The ID on the heater hose is 1/2". The opening inside the restrictor is 1/4". It is *very* easy for that orifice to get clogged or to be partially blocked, resulting in little or no flow.

When you consider that (in my vehicle), the plumbing travel is about 36' in total, then I'd think you really want and need as much flow as possible.

My son and I clamped the hose on either side of the restrictor and cut it out. We then reconnected the hose with a piece of 1/2" copper pipe and double-clamped each side.

Viola! Works like new. As a matter of fact, it works so well that I had to make the statement that I hadn't made in years; "It's too hot in here, let's turn down the heat."

So, if you have your family wrapped in blankets in your vehicle like I did, this could well be the problem. I am just really, really disappointed that it took me years to find it when it was really something pretty simple.

I hope your final solution is as easy as this was! If it was, please add it to this thread and maybe it will get a sticky.

 

(posted in 2007+ in case they have the same restrictor)

 

Youmay want to replace the restrictor. The increased flow may cause the heater core to leak, and replacing the heater core is a beeyatch.