Shopsmith Forums

I have been reading and searching to find out if my 1997 Chevy Silverado 1500 Z-71 truck has a water valve in the coolant lines (heater hoses). I found one site where a Chevy mechanic said that there was one and that it was under the hood near the firewall.
The next guy said that there was not one and it was all controlled by the temperature blend door in the heater. Other sites had similar answers.
My truck does NOT have one under the hood. The lines are fully visible from the block to the heater tubes at the firewall and back to the water pump. No valve there anywhere...
My question is: is there a coolant valve in the cab inside of the "heater box"?
BTW, one source says to allow 7 to 8 hours of labor to remove the "heater box, make repairs and re-install it. It says that the whole dash must come out...
If there is no water valve involved to check my next step is to replace the suction side heater hose as its liner may be collapsing cutting off the flow.
One of the first things you check is the hose temps and when the heater stops working the block side is hot and the water pump side is cold. I do not believe that the heater core is blocked since when it does work (and it does work now and then) it will literally drive you out of the truck right away. The mode doors and their control are working perfectly. I can't be sure about the temp blend door except that a blend door not working would not cause a cold return heater hose. That has to be a blockage or a coolant valve. If there is no coolant valve it has to be a blockage...
I can find no reference in the Haynes manual to a heater valve at all... Yet I do see valves listed as a part in parts catalogs for that year truck but not sure which engines they are for. My truck has what ever engine size ID number they now use for a 350 CID (I forget at the moment ).

My god I loved the heater in my old 1961 IHC Scout... You could pull the heater core in 30 seconds using one tool... You could pull the blower motor in about a minute using one tool... The heater unit sat up just behind the grill on the driver's side on top of the inner fender. You could take it all apart in seconds while sipping ice tea with one hand.
This is progress?


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Frances;
I am not a Chevy guy but I did have an older Ford SW that had a similar problem that was caused by a bad vacuum controlled heater valve. Mine was on the fire wall but others may be part of the heater control system. Mine resembled a vacuum advance diaphragm on the side of a distributor. You may want to look for one of those critters.
Bill V

Too bad you are not here in Florida where you can simply disconnect the heater

Ed in Tampa wrote:Too bad you are not here in Florida where you can simply disconnect the heater

I had a good friend (and later, employer) who came to Indiana from Fort Myers FL driving a newish Ford Maverick that he had bought new without a heater in it. He drove it through most of the first year and about froze to death. Worse than the cold was the window frost etc. He drove most of the winter peeping out of a little scraped hole.


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robinson46176 wrote: You could take it all apart in seconds while sipping ice tea with one hand.
This is progress?
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They have made it hell on us shade tree mechanics.

robinson46176 wrote:
My god I loved the heater in my old 1961 IHC Scout... You could pull the heater core in 30 seconds using one tool... You could pull the blower motor in about a minute using one tool... The heater unit sat up just behind the grill on the driver's side on top of the inner fender. You could take it all apart in seconds while sipping ice tea with one hand.
This is progress?


.

I fortunately never had to replace the old Scout heaters (neither of Scouts I owned had heater issues). But I loved how warm they kept us. My only Chev however did require a heater repair. I tried to do it myself. What a disaster. Come to think of it that heater is why I never owned another Chev. Jim

My how things have changed. My Sprinter van based RV has a heater that will continue to blow until all the heat has been removed from the coolant after the engine is shut down. There is a pump that continues to circulate the coolant through the heater for up to 30 minutes or until the heat has all been removed. Also, there is a fuel fed heater that pre-heats the coolant right after startup to bring it up to operating temperture in a matter of minutes so the heater will work in sub-zero weather as well as warming up the diesel engine much faster. My fingers are crossed as none of this fancy stuff is covered any longer.

We SS owners find it difficult to believe that there could be other forums out there that might support other enthusiasts or owners looking for how to do something. Try this one:

http://chevroletforum.com/forum/

If that doesn't do it then Google Chevy Users Groups or go to Lincolnsonline.com. That's for Lincoln owners but is the best auto info users' group I've found and there WILL be someone there who can either give you the answer or tell you where to go to get it.

I do not remember any valve on them but the one I did was a 1996. Yes you need to drop steering column and take dash out we lift them and pivot them on to passenger seat and leave driver side close wiring won't let it come all the way out. Then you take the heater a/c case out then take it apart to get to heater core. Oh you also have to discharge a/c. I did work on a gmc suburban that the blend or temp door motor or actuator was bad. Sorry don't remember which one

No valve under the hood on any chevys I've owned. the 93 z71 I drive now does not have one. My 97 suburban I will check in the daylight but I don't believe so. I have heard heater cores are not wonderful to repair and/or replace. Thats one of the FEW things I don't think I've ever done.