• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

Order of operations: coolant temp issues


spmls

New Member
Joined
Feb 10, 2021
Messages
9
Reaction score
1
Points
3
Location
California
Vehicle Year
1998
Make / Model
Ford Ranger
Transmission
Manual
@Dirtman, the new t-stat does apparently have a jiggle valve, it's a Motorad 2000195 for anyone looking at this for reference. It isn't located on the flange like the old one though, it's under the frame closer to the piston.
 


Rock Auto 5% Discount Code: 7FA902352B4C01: April 5th, 2021

spmls

New Member
Joined
Feb 10, 2021
Messages
9
Reaction score
1
Points
3
Location
California
Vehicle Year
1998
Make / Model
Ford Ranger
Transmission
Manual
Glad to hear that your problem seems to be solved now! Of course, some road-test results would be even more interesting (hint, hint:)).It's been a few years since I last replaced a stuck-open thermostat, but I don't recall any signs that the old thermostat had been stuck open upon visual inspection after I'd replaced it. But the replacement solved the problem ever since then. And the graph of ECT with the new thermostat shows a drop when it opens, whereas the old thermostat didn't.

Thanks for the update!
I finally got around to refilling the coolant this afternoon, let it warm up and took it for a drive. Now the ECT graph gets up to about 82° C, and then kicks down a couple degrees. The temp, gauge indicates just below halfway, perfect. @RonD was spot on with their prediction. I think that the old 165° t-stat was actually working fine, now that I know that the ECT temps are typically lower than the t-stat ratings...But hopefully running it a little warmer is better for MPG's and emissions in the long run.

Thanks all for your suggestions. Now on to the blend door
 
Last edited:

RonD

Well-Known Member
Joined
Jun 2, 2012
Messages
18,517
Reaction score
2,993
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
@Dirtman, the new t-stat does apparently have a jiggle valve, it's a Motorad 2000195 for anyone looking at this for reference. It isn't located on the flange like the old one though, it's under the frame closer to the piston.
That would defeat the purpose of a "jiggle valve", it needs to be on the flange, closer to the edge the better, and then when installed its put at the 12:00 position
Jiggle valve is there to let AIR out from behind thermostat when its closed

When you refill the system take one heater hose off at the firewall, that will let air out when there is no jiggle valve
 

spmls

New Member
Joined
Feb 10, 2021
Messages
9
Reaction score
1
Points
3
Location
California
Vehicle Year
1998
Make / Model
Ford Ranger
Transmission
Manual
I guess I'm a bit confused as to which part is the jiggle valve. Is this actually the bypass valve?
56016
 

RonD

Well-Known Member
Joined
Jun 2, 2012
Messages
18,517
Reaction score
2,993
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
That's a jiggle valve
But for a thermostat that would sit facing down, like in a 4.0l SOHC, not good for sideways mounting

The distance from the jiggle valve(mounted at 12:00) to the top of intakes water passage is the amount of air that can be trapped behind the thermostat when its closed
So you could have 1.5"-2" of air trapped behind thermostat

The above jiggle valve wouldn't be any better that waiting for the thermostat to open, lol, BUT........it would let out enough air to at least keep thermostat covered with warm coolant so it COULD open and let more air out

Just giving you a hard time :)
But jiggle valves do belong at the edge of thermostat plate when its mounted sideways, or anytime really, not sure of the thinking of MotoRad on that one
 
Last edited:

Dirtman

Former Middleweight Moss Fighting Champion
Supporting Member
Joined
May 28, 2018
Messages
16,206
Reaction score
9,897
Points
113
Location
41N 75W
Vehicle Year
2009
Engine Type
2.3 (4 Cylinder)
Transmission
Automatic
2WD / 4WD
2WD
Total Lift
It's up there.
Total Drop
It's down there.
Tire Size
Round.
Jiggle Jiggle!
 

RonD

Well-Known Member
Joined
Jun 2, 2012
Messages
18,517
Reaction score
2,993
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
Hooters

I love owls :)
 

MikeG

Well-Known Member
Joined
Jul 15, 2020
Messages
1,358
Reaction score
738
Points
113
Location
central Texas
Vehicle Year
1997
Make / Model
B4000
Engine Type
4.0 V6
Transmission
Automatic
2WD / 4WD
2WD
Total Lift
2"
Tire Size
235/75r15
Would it hurt anything to drill an itty-bitty hole on the flange that would sit at 12 o'clock? Say less than 1/16" or so. Should serve the same purpose, right?
 

RonD

Well-Known Member
Joined
Jun 2, 2012
Messages
18,517
Reaction score
2,993
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
Yes, that's fine, I do an 1/8th inch hole when I get one that doesn't have the jiggle valve
 


Top