So the issue is, she gets warm, about 210-220 climbing grades, ac on or off, doesn’t matter. Throttle position and gear doesn’t matter. Then, on the down hill, back to 190, level ground about 210. Idling, standing still she sits at 220. I’m thinking fan clutch, I can hear the fan sometimes, when it’s on it cools right off, but sometimes if it gets to 210-220, it doesn’t engage. Any thoughts?
Anywho, it doesn’t increase under load, or decrease when load reduces. If I accelerate, it will drop. Sometimes it gets hot at cruise, sometimes it doesn’t. Sometimes the fan kicks on at 210, sometimes it’s at 230, sometimes not at all.
See first quote. You're saying that the temperature increases when going up a grade (heavy load) then decreases when you come down the grade (no load) Then increases some on level ground (light load)
Your own description is saying the temperature is load-related. And that's perfectly normal, except the cooling system should have enough capacity to maintain closer control over temperature. I can easily believe that the temperature would increase SOME going up the grade, but not that much.
What disturbs me is that it's running 220 at idle; which indicates you do have some low-load issues if the RPM or speed is low enough.
I got a fan clutch anyway, as far as I’m concerned, it’s an old part.
I'd prefer testing it, but since you already have it, great.
Thermostat not yet, what I have in there, does not match what they are selling at vatozone.
It's approximately the most-common automotive thermostat on Earth. It CANNOT be hard to find a replacement. If you've got some kind of goofy thermostat--maybe someone else put the WRONG ONE in. In that case, installing the correct kind would maybe fix all the problems.
These are the two most-common designs:
You must be registered for see images
The photo was taken with both of them in near-boiling water.
Radiator was replaced by po shortly before I got it, gave me the receipt and it still looks new.
"New" does not mean "good". Is the AC condenser OK? Packed full of bugs, half the fins folded over?
210 is about normal for most chevys.. it's fine.
Absolutely NOT TRUE unless there's electric fans involved, which typically aren't set to run unless the coolant is at 210 or so. My '88 never sees 210 unless I'm towing a heavy trailer uphill. For awhile I had a 205 thermostat in the thing to get more heater output, and it never went over 215. The "heater problem" turned out to be a cold-air leak at the ducting for the blower motor, so I removed the 205 thermostat for a 190.
Wasn’t sure if you could read CTS temperature with a scanner on an OBD1.
As far as I know you can’t. I loooooove my tactrix cable and laptop.
Can't check CTS on an OBD I system? OF COURSE you can, along with fuel trims, knock sensor activity, time since engine started, O2 voltage and cross-counts, lock-up converter activity, and plenty of stuff I'm too lazy to type. What's available is dependent on the system design, pre-86 had less info available and slower update times, but you could get the basics including CTS all the way back to '80 1/2 on most GM computers. No promises on the MIN-T system (Chevette).