It is likely that I do have a bad control valve, though I've read some claims that the heater core can contribute to higher temps in the footwell area even with a properly functioning valve.DieselSpider wrote:So you had a bad control valve or one that was poorly adjusted so it was not shutting off completely.KevAndAndi wrote:I realize that the premise of the original question has been withdrawn, but FWIW, bypassing the heater core in my case did virtually eliminate unwanted cabin heat. It made a noticeable difference.
You might get away with that up North however in the Deep South you can have problems on hot humid days when roadway temps are sizzling at close to 120 degrees.
Today it was so hot out I could not go over 55 mph without the temperature gauge passing 205 with the bypassed heater hose noticeably hotter than either of the radiator hoses. I really need to put a full shut off on that bypass to make it work as designed at the factory or possibly connect a universal heater core to it up front by the radiator to provide additional engine cooling for the Turbo Diesel.
I know that I have a severely corroded heater tube through the firewall. The heater core is of unknown condition. The insulation and carpeting is fairly new, and I cannot tolerate the risk of a coolant mess in the interior, not to mention the risk of hot liquid on the passenger's legs. Therefore, the bypass seemed like a prudent temporary option for me, though for some it is a permanent one.
The plan is to eventually replace the tubes (with stainless steel) and the valve; possibly, the heater core, as well. In the meantime, I have not experienced any overheating problems with the bypass. The temperature doesn't go over about 193. There's a brand new aluminum rad up front that seems to keep things slightly cooler than the stock rad did.