I have a 93 DA and have a temp question for you fellas. Let me paint the picture first. My car usually runs right at about the 11 oclock on the temp gauge. Mind you my cooling fan is on a toggle switch and i can let this bad boy idle FOREVER w/o turn the fan on and it wont climb over the same mark…at any ambient temp. The issue is that if i turn the selector from the hot setting to cold the temp will climb to about the 1 oclock mark. Now i can beat this thing all day long and with no blower or fan on the gauge stays steady. Turn the knob and blammo…temp gauges rises. Cant say how far it will climb can im not into melting down my motor for the sake of diagnosis. Have a few ideas but want to gather some more before i dive into it!!! Any ideas?
with the heater on, coolant flows through the heater core. it’s a heat transfer. like a mini radiator. with the knob turned to cold, the heater valve closes and bypasses the core.
why do you have a manual switch for the fan? human error becomes a factor this way
I know how a cooling and HVAC systems work in cars no doubt but thanks anyway…the fan is on a switch cuz that’s how I bought it 2 years ago. Never been a problem and in that span I have put less than 5000 miles on the car. Just wondering what could be the causes of such a great temp swing with the settings from cold to hot
[QUOTE=DAGeetee74;2239423]I know how a cooling and HVAC systems work in cars no doubt but thanks anyway…the fan is on a switch cuz that’s how I bought it 2 years ago. Never been a problem and in that span I have put less than 5000 miles on the car. Just wondering what could be the causes of such a great temp swing with the settings from cold to hot[/QUOTE]Bleed the coolant system, you may have air in it. 94
FCM to the muthfckin rescue!!! LOL!!! I already bled it once after i changed my upper radiator hose about 3 weeks ago. Think i should do it again? i mean that is the easiest and cheapest way to start
Maybe turning the dial from hot to cold is something that would warrant the fan (in an unaltered system) to come on for a minute to cool it down.
If the cooling system or wiring have been tampered with, that’s the first place i’d look. See what’s been bypassed/disconnected etc.
If the previous owner bypassed a relay or something, could there be an issue there?
Basically I’m just rambling… if fcm is on the job, I’ll just sit back and learn 
does the heater blow hot?
OH YEAH!!! like the breath of hell…i think im just gonna have to return everything back to original state before a proper diagnosis can be performed. looks like i just earned myself a winter project…
i’d try and bleed it thoroughly again first, like fcm said. because of the placement in the system, the heater core is a common spot for air to be trapped. did this just start occurring after you changed the upper hose?
no its been goin on for a while (i think…dont drive it much so i cant say that ive noticed) im gonna bleed it again today. ill let ya know what happens!!!