When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Are there any good ones available? I replaced what I guess to be the original ,preventatively, a long time ago. Ever since, the new made in Mexico and China valves don't tend to last more than 6 months to a year.
Most recently I bought an AC Delco valve thinking it would be better but it is just a rebranded valve of some sort. It didn't last 10 miles.
What happens is the lower hose connection caves in and sometimes even develops an opening, as if it has melted. That prevents the clamp from being able to clamp. There have been no instances of overheating and coolant level is always good so it's not like I'm running it hot or with inadequate coolant.
Or, is it something I could be doing during install that is causing these failures?
Last edited by charliemccraney; Apr 6, 2017 at 08:45 AM.
When mine failed, the new one didn't last long before cracking .I couldn't seem to get the thing to seal well until I realized the hoses had swollen enough so they couldn't be tightened enough to stop leaking. New hoses that fit more snugly was the solution for me.
I'm interested in a better valve as well. These valves have become a yearly maintenance item for me. I've thought about trying to reinforce the plastic with some metal inserts, but not tried anything like that yet.
When you say the GM ones are much sturdier, would that be a different valve than the AC Delco Product?
Unless this AC Delco valve I just put on is a fluke, they are worse than the cheaper ones I get at the parts store.
ACDelco more than likely isn't stocking the OEM parts for these cars (for most things) anymore. Which means they're rebranded reproduction ones which as we've both found, are pretty garbage. I don't know if it's the type of plastic they use or the heat of the our cooling systems but they seem to mush up pretty quickly.
I haven't actually gotten one from a GM dealer for over 10 years or so, so I don't really know if they have gotten cheaper or not. When mine first cracked I got a replacement one from Kragens or somewhere and crushed it trying to tighten the clamp enough to stop it from leaking. The OEM ones at the time and what I collect at the JY are much sturdier material. New hoses helped a lot in reducing the amount of force needed for a tight seal
It's parts like this where I wish I had a lathe. Wouldn't be hard at all for someone experienced with one to create some metal inserts for the tube connections that have a slight press fit (very slight obviously due to plastic). Keep a small lip on it to make sure it doesn't go flying down the tube or into the valve .
Is there any difference between an 88 305 TBI and an 86 305 4bbl. heater control valve? Mine is original and still going strong. Maybe never using heat (winter storage) has something to do with it??
Not using heat may help. It also sounds like the OEM valves are made of a sturdier plastic than the aftermarket. The failure mode for the aftermarket valves is that the area the hoses clamp on to gets mushy and starts caving in, causing a loss of clamping pressure and either a leak or the hose coming all the way off. When my first one failed I just happened to be at the emissions center and the valve plastic came clean off with the hose, pouring coolant all over the floor.
Yeah, The ones I got from the Chevy dealer 10 years ago and the ones I collected in JYs are made of a solid material that is not flexible and would not be cave in , but would have to be shattered by extreme force. Well, my failed one actually cracked from heat and old age I guess?
It looks like my problem was a clamp and / or hose problem. The leak was occurring right at the screw portion of the clamp. I positioned the clamp 180 degrees from where it was and the leak stopped. Haven't replaced the hose yet.
The AC Delco valve was already showing signs of distortion. I've never examined a valve after so few miles, so I don't know if that is the norm or not. So I did go ahead and replace it. I looked at my records, and the last one lasted about 2 years, so I got the same one, Everco 5929 (or 74805).
It looks like only the upper nipple, of the two pointing in the same direction, opens and closes. So it might be pretty easy to rig something up with some fittings and some high quality shut off valve.
This is how mine always fail. Sometimes the caved in portion will actually be a hole. I don't think using the heater or not will have an effect as coolant is always flowing through that lower nipple.
Last edited by charliemccraney; Apr 19, 2017 at 06:57 PM.
I think the "Murray" Brand might be as good as it gets at a parts store.
4 Seasons I believe is made by "Standard Motor Products" and that should also be decent.
Unfortunately Murray has the problem as well. I believe it's the one I put on as my original replacement from O'Reilly's. Haven't tried any from any of the other major stores.
. 
