1991 cfi 454 runs at 210,

[charlesg]

is this normal? also the truck has an electric fan, does this just come on with the ac? or is it temp regulated?

thanks

 

[Taylorb27]

210 may be just a little spicy, not too hot by any means but I'd think you could be more around 200° especially with an electric fan. I'm not aware of factory electric fans on a truck setup so it's probably aftermarket and SHOULD come on mostly by temp. I think some harnesses may turn them in with AC too which isnt a bad idea especially if you're worried about temps. You'll have to check which setup you have unless you installed it, then you'd know lol

 

[bucket]

There were some 3/4 and 1 ton trucks with an auxiliary pusher fan. Iirc, there's a temp switch in the passenger side head that turns it on.

 

[Vbb199]

210 with AC? I wouldn't be upset with a 454.

 

[Craig 85]

I've had 5 square bodies with 454's and A/C and 2 90's Suburbans with 454's and A/C. 210 is pretty normal with the A/C on. My current truck did not have the fan and I'm in the process of hooking it up. The OEM temp switch on the pass side of the block is a ground to turn on the relay. I had to get one for a 91-95 model truck which has a different plug.

GM 10096147 or ACDelco 15-4457. Temp off/on: 211/234 Degrees. I think the OEM one was a few degrees lower for turn on. Either way, when the electric is designed to turn off at 211, I would guess 210 is fine.

Before I started the install process, I thought the fan was controlled by the A/C. It is not. It gets power when the ignition is in the ON position. Once the block sensor gets to temp, it grounds and turns on the relay for the fan.

You must be registered for see images attach

 

[charlesg]

Thanks!

 

[SirRobyn0]

I think part of this is going to be climate, driving style, loads ect. However 210 is safe. Think about this. If your talking about an electric only fan, most cars and trucks come out of the factory with the fan kicking on between 210 and 220. Most fan clutches will engage to keep the engine under 210. I've seen 210 in my truck in Washington, mostly when it's hot out pulling hills at lower speeds. However if your seeing 210 a lot, or notice it creeping higher occasionally, or it's never made it to 210 in the past I'd want to double check the fan clutch is working, but I would say hitting 210 at times is pretty normal.

 

[bucket]

The gauge could easily be reading 10 or more degrees too high as well.

 

[Mark Jones]

is this normal? also the truck has an electric fan, does this just come on with the ac? or is it temp regulate
thanks

I don't like to run my 454s this hot, but it could be normal. I run @ 177 or under, but that carburated.

 

[AuroraGirl]

The gauge could easily be reading 10 or more degrees too high as well.

I'd definitely check against it for sure. Gauges be spitten rotten things sometimes.

 

[SirRobyn0]

The gauge could easily be reading 10 or more degrees too high as well.

That's a really good point, these trucks are kind of know for gauging issues.

 

[Craig Nedrow]

Swapped a 454 from a 350, 170 degree thermostat, same radiator, and runs around 180-200, higher temp on hot days pulling a trailer. I have 50% antifreeze/water, and a 13 lb cap.

 

[SirRobyn0]

Another thing to think about is that for example with a 170F thermostat that temp is suppose to be the temp the thermostat starts to open at. So in that example it's probably fully open somewhere around 185F, that is some what speculation and some what just from what I've seen, as far as I know no thermostat manufacture publishes fully open temps. So if your running a 195F thermostat it's ruffly fully open at 210F, which is just another reason why I'd say 210 is ok, or at least okish. I've also seen where aftermarket thermostats are not as consistent as original equipment. Some engines, and I'm currently thinking of the Toyota 20R, 22R & 22RE react very badly to aftermarket thermostats, with temps swings all over the map. Back when those were common engines in the shop we always put Toyota thermostats in them. My truck currently has an A/C delco thermostat in it, because I feel I can trust it better than standard aftermarket thermostats like stant. I think I mentioned this before but even with a lower than factory temp thermostat your still going to build heat at times when there isn't enough natural air flow, it will build until the fan clutch locks the fan in which is usually around 210F. Fan clutches can be modified to kick in at a lower or higher temp, and it's not hard at all to do. If someone wants I'll do a write up on how I've done it.

 

[AuroraGirl]

Swapped a 454 from a 350, 170 degree thermostat, same radiator, and runs around 180-200, higher temp on hot days pulling a trailer. I have 50% antifreeze/water, and a 13 lb cap.

is 13lb what they normally run? seems like a low pressure, but old engines didnt use 16+ psi a lot of newer systems do either

 

[Ricko1966]

I would bet your truck came factory with a 195 degree thermostat. Aftermarket thermostats are going to range from 160-205 degrees depending on which last person changing it picked. 210 on a factory 195 Tstat I would consider pretty normal. Your truck shouldn't boil until about 250.