See my previous post here http://forums.corvetteforum.com/zerothread?id=797255

I did a little investigating. I dug down to the heater core and was able to pour water right through it, didn't seem to be much restriction. I got to looking at the part below, it's in the lower heater hose. I took the hose off of each end of it, it appears to be some kind of restrictor. I thought it might be a check valve or something. Who knows, it's got some trash in it. Since I don't know exactly what it is I'm not sure what it's supposed to look like inside. I replaced the lower radiator hose with one that doesn't have said piece and put it all back together. After checking for leaks I took the car for a drive and the heater works great. In fact when the coolant temp was only 90 degrees I was already getting more heat out of it than I did on the way home today.

So what is this piece, and do I really need it? I don't want to blow up my heater core or something by running without it.

 

Maybe some kind of filter?? To keep junk out of the heater core??
That's my guess. :seeya

 

Nathan, GM calls that a VALVE, HTR WAT FLOW CONT GM # for just that part is 10157988, AC-DELCO # 15-5423. If your get the hose from a dealer it should come with the valve. The part number for that inlet hose is 10213634. The outlet hose is 10135697. If you go ahead a get those, you might as well get the J shape hose to the surge tank # 10257254. :steering:

 

Ok, great. What exactly does it do? I've looked in the service manual and can't find any mention of said part. :cheers:

 

:crazy: Don't know.

 

my guess? it controls coolant flow through the heater core.

 

I had one break in half on my Trans Am. It is like a spring loaded restrictor. There is a hole in the middle of the spring loaded piece inside. Not to sure what it does past that. :nonod:

 

Did you replace it or run without it?

 

I've got a theory about this thing. It almost looks like some kind of restrictor. Is it possible that it's there to regulate the pressure going into the heater core, maybe to restrict it at high RPM's.

If this is the case it's possible that I might not even need it since I'm running an electric water pump which flows at a constant rate and pressure all the time.

Any thoughts?

 

makes as much sence as anything...

doesn't the electric WP speed up??? how odd.

 

Looks like a surge protestor for the heater core...so you don't blow out the seams of the core when you stomp on the motor and have a hugh rush of water slamming into the heater core :yesnod:

 

If that's the case then I really probably don't need it. Like I said the electric WP turns at a constant speed all the time. The only pressure difference in the cooling system should be from temperature, which is a gradual change as the engine heats up.

I called one of the local auto parts stores, they can get the part and it's $12. He tried to look at the description though and he couldn't really tell me what the part was for. I'll probably have them order it just in case, but in the mean time I'm not gonna worry about it too much.

 

:iagree: Yup!

 

It's a flow restrictor. You really do need it. Water is like electricity, it will flow wherever the resistance is the least. If you don't have it more water will flow through the heater core and less through the radiator. End result is hotter running temperatures (unless you are willing to run with the heater going full blast all the time even then then heater core is a relatively inefficient radiator when compared to the real radiator).

The only way to get the part from GM is to buy the complete hose assembly!

At least that's how the mechanic at the shop explained it to me.

 

When my ta blew it up I just replaced it. It was real cheap from dealership. If it protects your heater core I definetly would put it back in. Good way to ruin your passenger carpet.


[Modified by BAM92, 1:58 AM 4/14/2004]

 

Everyone is correct, it is a restrictor. The reverse flow cooling design needed a higher output water pump. Its there to restricy flow to the heater core, so it lasts longer and doesn't leak.

 

Alright, thanks for the info. I replaced the hose so all I really need is the part. I can get it for $12 from a local parts store, but they'll have to order it. It'll be alright for a day or two until I can get the replacement. :cheers:

 

Ok, I was talking to my dad about this stupid thing and curiosity finally got the best of us. Obviously it was part of my heater problem, so I'll be putting a new one in it. This means that there's no reason not to hack the old one up, out comes the Dremel tool and hacksaw.

I carefully sliced this baby open to see exactly what it did.





Sure enough it's just a simple flow restrictor of sorts. When the spring is in it's relaxed position coolant is allowed to flow around the restrictor as well as through the center hole. As the pressure increases on the input side the spring compresses and the restrictor is pressed up against the housing, allowing coolant to only flow through the smaller hole. This piece did have a little bit of trash in it, and as you can see it's kinda crappy looking inside. It may have been stuck closed or the trash was keeping it from flowing fully. The spring is also VERY weak. I don't know how strong it is supposed to be, but I'm sure after 12 years and a lot of heat it's lost a little bit of it's strength.

I'm still not convinced 100% that I even need this with my electric water pump. The car doesn't run any cooler or warmer without it. I know, it was 30 degrees yesterday and 70 degrees today! Don't you just love KY weather. Although I'm not 100% convinced I need it, I'm going to replace it anyway. $12 is certainly cheap enough insurance to not have to replace the heater core! :cheers: