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Old 09-19-2010, 04:37 PM
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strange overheating issue...

Ok sitting in line at a car show while idling i noticed the nova running hot. 220 230 area. Normal is 190. Shut the car off and the temp dropped rapidly to 180 area and leveled off. started the car back up and it maintained 190 during stop and go conditions. Had the same problem on the way home... i have never had a problem like this.

The day before the show I did remove the heater hoses and cap the ports on the intake and WP. Could this be the issue? ive read that you can either cap them or run a loop. Any help?

Its a 71 nova with a sbc 350...

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Old 09-19-2010, 04:43 PM
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19duce71,

I think when you disconnected the heater you caught an air bubble in the system. Once you shut it down the bubble went to the highest point in the system and then when you started it up again it was gone. Kind of like a "burp"

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Old 09-19-2010, 04:50 PM
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Sounds like a loop would be a good idea, that flow will ensure that the stat see's the engine temp at all times. I had this happen when I put a valve in my heater loop because my c10 only has a damper inside to stop flow of air and the heater was adding heat. My temp sensor was in the head it would get to 220+ every time on start up. After the stat finally opened the temp would level out +5-10 deg above the stat rating so I just crack the valve open a bit to keep the flow and it never gets hot.

2 more of my cents
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Old 09-19-2010, 04:57 PM
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yea my sensor is in the head. should a bubble work its self out? it did the same thing twice.
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Old 09-19-2010, 08:43 PM
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You probably need to change to a high flow stat. They open differently than a regular one. When you remove the heater from the circuit you cause a little more physical pressure from flow against the stat. This will cause delayed opening and wild temperature swings.
The high flow stats are not susceptible to this extra pressure.
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Old 09-20-2010, 11:13 AM
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Quote:
Originally Posted by 19deuce71
Ok sitting in line at a car show while idling i noticed the nova running hot. 220 230 area. Normal is 190. Shut the car off and the temp dropped rapidly to 180 area and leveled off. started the car back up and it maintained 190 during stop and go conditions. Had the same problem on the way home... i have never had a problem like this.

The day before the show I did remove the heater hoses and cap the ports on the intake and WP. Could this be the issue? ive read that you can either cap them or run a loop. Any help?

Its a 71 nova with a sbc 350...
Probably, the SB Chevy really likes a functioning thermostat bypass. After all these years I'm still not sure why, but more than any-other engine I've seen, the SBC gets temperamental without that bypass operating.

Bogie
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Old 09-20-2010, 04:48 PM
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Quote:
Originally Posted by T-bucket23
You probably need to change to a high flow stat. They open differently than a regular one. When you remove the heater from the circuit you cause a little more physical pressure from flow against the stat. This will cause delayed opening and wild temperature swings.
The high flow stats are not susceptible to this extra pressure.
I"ll have to try this. Can you get them at summit? I guess thats a stupid question... Until then i guess I'll just run the ugly old bypass. I took the hoses off just to clean it up. Oh well gotta keep it cool going to the track this weekend. Gonna get a time to work upon.
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Old 09-20-2010, 05:57 PM
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Sure you can summit/jegs and i am sure a few more places as well.


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Old 09-21-2010, 06:00 AM
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In the mean time you could drill a couple small hole in the stat to allow a little flow when the stat is not open
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