What is the OEM thermostat temperature from the factory?

TWEBB101

MEMBER
1984 CHEVROLET TRUCK
7.4L
V8
2WD
AUTOMATIC
171,000 MILES

I know there are a multitude of opinions on what temperature the thermostat should be. Do you know what the OEM temperature was from the factory? I’m running a 160 in there now, but I’m seeing a lot of internet chatter about 180 or 195. When looking on gmparts. Com, those are the two temperature options that are available. Do I need to replace mine? Thoughts? For reference, I live in northern Utah, temperatures range from 20’s-100.

7 Replies

STEVE W.

MECHANIC
13,577 POSTS

The factory temperature for the 454 that year is 195 degrees. The higher temperature allows for better economy. The low temperature units were developed to mask a cooling issue, the thinking being that if the thermostat opened earlier, it let the engine run longer, under heavy load, without heating up.

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Sunday, June 30th, 2024 AT 1:51 AM

TWEBB101

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178 POSTS

Great, thank you. Would you recommend putting a 195 in? Or a 180?

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Sunday, June 30th, 2024 AT 7:29 AM

STEVE W.

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For most driving I'd run the 195. The engine will run cleaner, and you should get a bit more MPG (for a 454 it isn't going to be a lot, but every little bit helps with those) especially in the winter as I like heat.

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Sunday, June 30th, 2024 AT 11:11 AM

TWEBB101

MEMBER
178 POSTS

I put a GM 195 in, and it seems to be working, just wanted to verify. I have the temp sensor installed in the water neck/thermostat housing, and the gauge on the dash stays dead on at 210. Does that sound about right, to have the 15 degree variation?

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Tuesday, July 9th, 2024 AT 7:47 PM

STEVE W.

MECHANIC
13,577 POSTS

With GM gauges of that era 15 degrees off is somewhat normal. They didn't get closer to true temperatures until the late 90's when they became more computerized.