Rod S
Member
Posts: 25
Loc: Decatur IL
Reg: 02-08-06
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07-12-12 08:53 PM - Post#2247628
I replaced the thermostat with a "failsafe", 180 degree in my '90 GMC C1500. When the thermostat opened the water level went down. My temp gauge read about 240 or so. My pocket thermometer I had in the radiator neck read about 180. After I added water the dash gauge read about 180 also. Are these gauges typically off some? I'm going to let it warm up tomorrow and check it again. Thanks in advance, Rod
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454cid
Contributor
Posts: 297
Age: 40
Reg: 02-18-12
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07-13-12 03:48 AM - Post#2247682
In response to Rod S
I replaced the thermostat with a "failsafe", 180 degree in my '90 GMC C1500. When the thermostat opened the water level went down. My temp gauge read about 240 or so. My pocket thermometer I had in the radiator neck read about 180. After I added water the dash gauge read about 180 also. Are these gauges typically off some? I'm going to let it warm up tomorrow and check it again. Thanks in advance, Rod
180 at the neck seems a bit hot to me, as that side should be cooler since it's just passed through the radiator.
My sending unit for the gauge and temp sensor for the computer can be about 10 degrees different, and the gauge changes faster.
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Allan In NE
Contributor
Posts: 906
Reg: 12-27-11
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07-13-12 05:12 AM - Post#2247695
In response to Rod S
Normal,
Before you topped it off, the sender was reading steam.....way, way higher temp.
Then, when the liquid finally hit it, (you're filling) the sender then correctly read the actual water temp.
Allan
| Lifelong GM automatic transmission specialist |
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Allan In NE
Contributor
Posts: 906
Reg: 12-27-11
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07-13-12 05:15 AM - Post#2247698
In response to 454cid
I replaced the thermostat with a "failsafe", 180 degree in my '90 GMC C1500. When the thermostat opened the water level went down. My temp gauge read about 240 or so. My pocket thermometer I had in the radiator neck read about 180. After I added water the dash gauge read about 180 also. Are these gauges typically off some? I'm going to let it warm up tomorrow and check it again. Thanks in advance, Rod
180 at the neck seems a bit hot to me, as that side should be cooler since it's just passed through the radiator.
My sending unit for the gauge and temp sensor for the computer can be about 10 degrees different, and the gauge changes faster.
Comon now, the water at the neck has NOT "just been thru the radiator".
Allan
| Lifelong GM automatic transmission specialist |
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 someotherguy
Moderator
Posts: 23397
Age: 43
Loc: Texas
Reg: 08-01-03
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07-13-12 06:00 AM - Post#2247713
In response to Allan In NE
If it were my truck I'd go back and put the correct 195F thermostat in it. That's what the tune in the computer is expecting, and it has the best chance of running properly with the correct thermostat.
Richard
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Rod S
Member
Posts: 25
Loc: Decatur IL
Reg: 02-08-06
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07-13-12 08:51 PM - Post#2247997
In response to Rod S
Thanks guys, for the info. someotherguy, I had considered the 195 degree thing. If it doesn't work out, I'll go back to the 195. Thanks again, Rod
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someotherguy
Moderator
Posts: 23397
Age: 43
Loc: Texas
Reg: 08-01-03
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07-15-12 10:23 PM - Post#2248603
In response to Rod S
There's never-ending debate about thermostats but fact remains that 195F is what the truck came with from factory and what they wrote the tuning around. If you install a 180 or 160 it doesn't necessarily mean that's what temp your truck will run at, because so many other variables come into play it's impossible to predict what it's going to do until you run it. It's my opinion though that it's best to go with the original spec thermostat so there's less guessing involved trying to solve problems.
Richard
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 CowboyTrukr
"2nd Year" Silver Supporting Member
Posts: 701
Loc: Salt Lake City
Reg: 06-20-09
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07-16-12 07:29 PM - Post#2248915
In response to Rod S
Rod, don't sweat your dash gauge being off. As long as the water neck temp is running pretty close to the thermostat temp, you're OK. That's not to take away anything from the previous discussion about operating temp and engine performance. I'll side with Richard as I've experienced problems using something cooler than a 195.
My gauge is nearly 40 degrees off. Still works enough to tell me my stat's ok. I check the neck with an infrared about every oil change.
Greg
'94 Silverado K2500 4X4 5.7 5spd Xcab LB
RV cam, Pace Setter Headers, TBI spacer, Flow Tech air cleaner adapter, Hypertech street chip
"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke |
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