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Radiator changed - Drastic temp change
Thread Starter
Intermediate
Joined: Sep 2007
Posts: 37
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From: Britton Michigan
Radiator changed - Drastic temp change
I replaced the Radiator in my '92 LT1 after it developed a bad leak. Before the change, my vehicle would run at about a normal temp while moving/driving(180 deg. as indicated by the factory gauge) and heat up quick in stop & go driving to 230 deg. or so and the fan would kick on then off as it got cooled off.
Now, after the new radiator, fresh coolant, burping the system, a 165 deg Powerstat and a coolant by-pass kit, the temp stays about 145-150 deg on the gauge while driving and will heat up after an extended idle and then go right back down to 145-150 degrees while driving.
Is this normal or possible, or is it likely my gauge isn't working properly? I've always worried about how hot these LT1's run, now I'm wondering if mine is now running too cool.
Pit Bull 49229
Now, after the new radiator, fresh coolant, burping the system, a 165 deg Powerstat and a coolant by-pass kit, the temp stays about 145-150 deg on the gauge while driving and will heat up after an extended idle and then go right back down to 145-150 degrees while driving.
Is this normal or possible, or is it likely my gauge isn't working properly? I've always worried about how hot these LT1's run, now I'm wondering if mine is now running too cool.
Pit Bull 49229
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From: Merritt Ils Fl
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Le Mans Master
Joined: Apr 2000
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From: Manassas VA
or your guage is incorrect. Keep in mind the water tempature should be opening to let water in the motor at 160 and not letting it out of the motor like a standard smallblock. Thats the reason it came factory with a 180 and not a 195.
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
Your OE radiator likely had a lot of debris jammed into it and its heat transferring ability was greatly diminished and that is why you saw the high coolant temps, it wasn't because you had the factory 180 F thermostat. Myself and several others in 160 stat threads always say that the summer temps won't be any different with a 160 stat (ok 165 for you) but in the winter the radiator's ability to get rid of heat is much greater and your coolant will be running not only lower, but too low for proper engine operation. You just proved it. Year around you should have the OE 180 thermostat installed.
Melting Slicks
Joined: Mar 2008
Posts: 2,141
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From: Santa Maria, CA
I had a similar experience when I replaced my radiator with a Dewitts. I installed a 180 thermostat that had three small holes drilled in it. The flow through those holes combined with the high capacity radiator was getting me temps in that range in cool weather.
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Thread Starter
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Joined: Sep 2007
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From: Britton Michigan
Thanks for all of the feedback - I believe that I'll have to change back to the 180 deg thermostat. It is in the mid 30's at night here in Michigan and low to mid 50's during the day and I believe that jbf hit it on the head - There was a lot of crud in the fins of the radiator I replaced and in conjunction with the 165 T-stat, was too much.
I believe that the gauge is close to being accurate because watching it go up while the car is at an idle I see it go up to about 230 before the fan kicks in.
Guess I'll keep the 165 deg around for those 90 + deg days.. next summer.
Pit Bull 49229
I believe that the gauge is close to being accurate because watching it go up while the car is at an idle I see it go up to about 230 before the fan kicks in.
Guess I'll keep the 165 deg around for those 90 + deg days.. next summer.
Pit Bull 49229
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From: Cincinnati, Oh USA
Guess I'll keep the 165 deg around for those 90 + deg days.. next summer.
The coolant temp stabilizes where the radiator gets rid of heat as fast as the engine makes it, it doesn't pay a bit of attention to the opening temperature of the thermostat! In warm weather your coolant temperature will NOT be 165 F, it will be higher and the 165 stat will be wide open all the time. Leave the OE stat in place!
The coolant temp stabilizes where the radiator gets rid of heat as fast as the engine makes it, it doesn't pay a bit of attention to the opening temperature of the thermostat! In warm weather your coolant temperature will NOT be 165 F, it will be higher and the 165 stat will be wide open all the time. Leave the OE stat in place!
Le Mans Master
Joined: Jan 2006
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From: Orlando FL
The southern guys are always messing around with different thermostats because its hot down here, as in other places also. Last week still over 90 and that bottom feeder effect is closer 95+. You can get away with the lower stats in the hotter climates cause the stat just stays open and the air is warm keeping engine temp higher. It’s the wrong approach but sloppy do-able.
We have had out 2 days of cool weather here, 50 on the drive in today. Engine stays at 193 with any forward motion, no fans and 180 stat as it should be. The heat mode was a nice change to for today as I will probably be back to A/C in 2 days in the morning.
I have never had this vett out of Florida. I can only imagine how nice it runs with that cool air in the northern climates.
The 180 stat works fine with a clean radiator. Of course here in summer I run the secondary fan when necessary but you Michigan guys wouldn’t know anything about that.
Thread Starter
Intermediate
Joined: Sep 2007
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From: Britton Michigan
Update
Was thinking about my situation and read over the replies to my post and it dawned on me the post by aminnich about watching both gauges. I finally put on the temp setting on my dash and it was showing what I can assume are more accurate readings - 176 to 182 deg coolant temps during driving, while the temp gauge that's under the oil temp read 145 to 155 deg.... at an outside temp of 55 degrees. It hadn't read like that before the radiator change... they seemed to run more closely to one another.
Although those numbers are more like normal, I'm still going to replace the 165 T-Stat with the 180 as is recommended.
Pit Bull 49229
Although those numbers are more like normal, I'm still going to replace the 165 T-Stat with the 180 as is recommended.
Pit Bull 49229
