Author Topic: What is the normal operating temp?  (Read 674 times)

TA6.6Liter

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What is the normal operating temp?
« on: June 11, 2017, 10:06:06 AM »
I just purchased my first 301 and it is a 1980 Indy Pace Car with turbo.  It seems to be getting hot really fast.  After maybe 1 mile at 30-40 slow acceleration, flat road, the gauge is stating 220.  Open the hood and it is crackling and definitely hot. My only hint that this might be okay is that 220 is in the middle of the gauge and 280 is at the top.

Is 220 a normal operating temperature and is it typical after such a short, easy drive?

 

ta9590

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Re: What is the normal operating temp?
« Reply #1 on: June 12, 2017, 06:31:23 AM »
I found this document below and I think, if I'm reading it correctly, the thermostat opens at 195.

http://transam403.free.fr/PDFS/Firebird%201980%20MVMA-web.pdf
Steve
1980 Trans Am, 400, TH400 auto

TA6.6Liter

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Re: What is the normal operating temp?
« Reply #2 on: June 13, 2017, 05:46:54 PM »
I found this document below and I think, if I'm reading it correctly, the thermostat opens at 195.

Yes, I found the same information; OE opens at 195.  Since it is a summer car and figuring the thermostat was an easy potential fix, I pulled the OE and put in a 180 thermostat.  I also put in a new fan clutch.  It was a comedy of errors being my first time working on a car in a long time, but I got it back together and it started with no leaks  :grin: 

Took it out for a very short drive from cold engine and again the gauge spiked to 260 in less than one block at 25-30mph.  Then it suddenly dropped to 190.  Now, I'm thinking an electrical issue or the temperature sending unit is bad.  At the moment, I am lead to believe that the temperature showing on the gauge is not accurate.  Still want to chase down this gremlin to ensure I can trust the gauge in event something does go wrong.

On another thread the idea of a gunked up engine was suggested.  The car did set for about 11 years and only had 1300 miles in that time, so that is very possible.  Not sure it would spike the temperature in less than a block, though.

TA6.6Liter

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Re: What is the normal operating temp?
« Reply #3 on: June 16, 2017, 07:40:41 PM »
At suggestion of a fellow car enthusiast, I pulled the connector off the temperature sending unit.  Started the engine and the gauge read zero.  Grounded the connector and the gauge pegged past the 260 mark. Break the circuit and the needle drops to zero again.  Repeat a few times, same result.  Now, I know it is the sending unit that is wonky.  Got another one tonight and will install during the engine flush process.

TA6.6Liter

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Re: What is the normal operating temp?
« Reply #4 on: June 16, 2017, 07:43:35 PM »
Started the engine and the gauge read zero.  Grounded the connector and the gauge pegged past the 260 mark.

Of note is this will not work unless the engine is running. Won't work with the key in accessory or the unlock position.

Re: What is the normal operating temp?
« Reply #4 on: June 16, 2017, 07:43:35 PM »

ta9590

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Re: What is the normal operating temp?
« Reply #5 on: June 17, 2017, 07:48:47 AM »
Good to know.  Let us know how it works out after replacing the sending unit.
Steve
1980 Trans Am, 400, TH400 auto

TA6.6Liter

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Re: What is the normal operating temp?
« Reply #6 on: June 18, 2017, 07:53:21 PM »
Well, drained the coolant.  Pulled the old temperature sending unit and installed the new one.  The connector is burned, but I was not able to find one locally, so attached the original back.  Added the flush fluid and filled with water.  Started it up and after about 15-20 minutes it still registered upwards of 260.  Not sure if that is okay, but seems too hot.  My wife took it around the block and it did drop to 230.  Then, decided to take it out on the road.  When the car was at highway speeds the temp dropped to 190, which seems better.  Not really sure what to make of this, though the only other thing that seems off is the belt to the water pump/air pump does not seem to be not as tight as it should.  I also noted that when the engine is hot, the fan clutch spins more freely than when it is cold.  I presume that is correct.  Lastly, I looked closely at the old temperature sending unit and the engine end was covered with a thick black deposit.  Maybe the engine flush is what it needs to remove all the deposits and let the coolant do its job.  Guess I'll now in a few days.

stros

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Re: What is the normal operating temp?
« Reply #7 on: June 20, 2017, 07:06:27 PM »
I know nothing about the 301 but have you checked your timing and your AFR (Air/Fuel ratios)?  I remember my temps rushing towards 250 when my Idle AFR wasn't rich enough.  To me it sounds like your cooling system is ok as you seem to be cooling down when cruising.  From my experience bad timing and AFRs can overwhelm the best of cooling systems.

Darryl

'77 black TA Hardtop L78
Build thread:
http://transamcountry.com/community/index.php?topic=61066

TA6.6Liter

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Re: What is the normal operating temp?
« Reply #8 on: June 23, 2017, 05:39:36 PM »
After the last time driving the car, the next day is would not start, so that delayed the flush process.  In another thread, I explain the reason for the non-starting: http://transamcountry.com/community/index.php?topic=77212.msg725610#msg725610.  Anyway, the car was started by our local Firestone and ran for about 30 minutes.  There was no overheating, so the assumption is that there is not issue with the temperature.  On the drive home, my wife said it never spiked to peg the gauge and was steady at 220.  Maybe the new sensor and flush have done the job.  Tomorrow will start it up and see if it is consistent.  It seems that maybe the car is settling in and will be okay for now.

Brown79TA

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Re: What is the normal operating temp?
« Reply #9 on: June 27, 2017, 01:19:59 PM »
How old is your heater core? I had a similar issue and turned out the heater core was shot.
1970 Firebird - Sold for parts
1976 Sunbird - Wrecked
1987 Fiero - Traded
1988 Fiero - In the garage - below
1979 Trans Am - In the garage - above
1980 Turbo Trans Am - In the garage - above, in front

TA6.6Liter

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Re: What is the normal operating temp?
« Reply #10 on: June 27, 2017, 01:49:53 PM »
How old is your heater core? I had a similar issue and turned out the heater core was shot.

I suppose it could be 37 years old, but I don't know.  It is putting out heat, no antifreeze smell in the car and no evidence of leaking on the passenger side floor.  Since I did the flush and changed the thermostat and temperature sending unit, the car has stayed between 190 and 220.  It is not spiking passed the 260 mark from a cold start in only a couple of blocks driving at low speeds, so I'm going to say that some or all of what I've done has solved the problem.

tiggershark

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Re: What is the normal operating temp?
« Reply #11 on: August 29, 2017, 08:23:52 AM »
My 79 301 non turbo ran hot for a couple of years. 215 to 220 everywhere. The radiator started leaking so out it came. 2 core rad and the car has A/C. I bought a new Modine 3 core and the car never went higher than 190 from that day forward, even with a high performance 406 chevy under the hood now. ran it once w/o the shroud and that was a mistake, got warm going slow but cooled down at highway speeds. those shrouds make a huge difference.

Re: What is the normal operating temp?
« Reply #11 on: August 29, 2017, 08:23:52 AM »
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