Weigh in on puzzling engine temp issue---UPDATE

wolfe10 wrote:
Let's get back to the basic question-- do you have an auto bleed line from thermostat housing to reservoir or other higher point in the system? Nope I do not have an auto bleed line.

I now our old 3116 did not, but the coolant line to the air compressor came off the thermostat housing and was an easy place to crack open the connection and bleed until bubble free coolant came out. We opened the pressurized cap on the surge tank and ran it while parked. With cruise at about 1500 rpm's it takes about 15 minutes to come up to temp and open stat. Stat opened at about 190 and I let it run for about another 15 minutes and it stayed at 190. When we first serviced up with fresh coolant we did crack the stat housing and ran till bubble free coolant came out but I am guessing all the air wasn't out. New stat & coolant now runs at (barely detectable) about four degrees higher than old. 194 comes from silverleaf 190 is what both needle guages show. I am pleased it is not "loping" any longer.
Thanks Brett.

Once you have proved that there is no air bubble, and problem persists, I would pull the thermostats and check them in a pan of water on the stove with a candy thermometer. Make sure the thermostats are properly seated and installed right side up!

If those prove OK, suspect a gauge issue.

ShapeShifter wrote:

JimM68 wrote:
If I'd just paid someone to do some routine maintenance and now my temp gauge was bouncing all over hell and creation, I'd be freeking out, and back in thier lot, and unmoving until they corrected the problem.

Based on his most recent response, it looks like he did the work himself. So there isn't any lot to go back to while waiting for them to correct the problem.

Thank goodness, this will never happen to me. I do all my own maintenance. If something goes screwy, I know exactly who to blame.

I'm guessing that's what he's doing right about now - blaming himself and looking for help on how to fix it. Everybody makes mistakes, there's no shame in that. But you can tell a lot about a person's character about how they handle their mistakes, and asking for help is a good move.

I tend to agree with the majority here, it's more likely to be air than the thermostat. Anybody have experience with his engine, someone who knows the best way to properly bleed all of the air?

JimM68 wrote:
If I'd just paid someone to do some routine maintenance and now my temp gauge was bouncing all over hell and creation, I'd be freeking out, and back in thier lot, and unmoving until they corrected the problem.

Thank goodness, this will never happen to me. I do all my own maintenance. If something goes screwy, I know exactly who to blame.

Two Jayhawks wrote:
My coach always operated under almost any driving conditions at about 190 and a hard pull might push it to 200 for a short time. This is based on the needle gage on the dash. I recently had the coolant drained, flushed, and replaced with CAT ELC. Replaced the stat also. Now instead of running at a constant 190 the needle lopes from 180 to 210 continuously. It takes about 15 seconds to climb then the same to drop. Basically it never stops & rests at one temp like before. BTW the radiator & cac are cleaned regularly and are spotless. Also the engine temp gage in the engine service bay is behaving the same so I doubt both gages are malfunctioning. Ideas?

ScottG wrote:
Honestly I wouldn't worry about it then. Your temps are perfectly good.

Born To Travel wrote:
I would ask them to put in a new thermostat... You may have a faulty one... As for an air bubble, it does not take long to work the air out of the system... also maybe replace the pressure cap on your radiator..

dougrainer wrote:
The tell here is the 15 second spike time. THAT points to an air bubble in the system. It also indicates that the temp sensor is an IMMERSION type sensor. That means it needs CONSTANT immersion in liquid. My Lincoln will do the same thing. You HAVE to follow the exact bleed procedure on my Lincoln to bleed the system. I had the same temp spike after I changed the Lincoln tstat and did NOT follow the correct procedure (I was in a hurry). Once I followed the procedure and bled the air out the proper bleed plug, the system stayed fully charged with liquid. I would make sure you have followed the correct bleed procedure. There is NO WAY the actual temp of the coolant can change in 15 seconds back and forth. Doug