chevy 350 tbi operating temperature

jeep350chevy · 04-25-2009, 08:24 PM

I have a small block 350 tbi in my yj, and it has a Chevy nova radiator
with a fixed flex fan on the engine, and a electric fan on the outside of the radiator, this is on a switch not used all the time

I wanted to see what the operating temp should be. it has been 210-220 . and i changed the thermostat last year to a 160, and it still runs hot, I also changed my temp sensor on the head, could my headers be throwing off the temp sensor?

any help would be great, just trying to figure out what my next step should be

I can also get some picks up tomorow

93jeepyj · 04-25-2009, 08:48 PM

I have another car I put a truck 350 in and it ran 180 all day long with a 180 thermostat and a flex fan. I put some underdrive pullies on with a taurus fan to try to pick up a few ponies and it ran just over 200 after that and would get hot in traffic, i'll probably donate the taurus fan to the yj and get something more subtancial for the car. How old is that radiator and water pump ? those are pretty much the heart of the cooling system. I replaced both when we put the motor in the car ( had a 6 cyl before ) The other issue could be the radiator shroud, that really affects how well the fan pull air through the rad. without it you would be fine when moving but when stopped or going slow when wheeling etc that will cause temps to rise.

jeep350chevy · 04-25-2009, 08:51 PM

that's one thing it does not have is a radiator shroud

even when the jeep is doing 50 it stays around 210

could i run no thermostat?

Krochus · 04-25-2009, 09:45 PM

Quote:

Originally Posted by jeep350chevy

that's one thing it does not have is a radiator shroud

even when the jeep is doing 50 it stays around 210

could i run no thermostat?

It would probably run even hotter then because the trermostat also acts as a restriction slowing down the coolant fow enough to allow the radiator to work.

Quote:

and it has a Chevy nova radiator

Buy yourself a modern aluminum cored radiator OE style or aftermarket and I'll wager you'll be able to throw the electric fan away. Also as another poster mentioned a shroud is critical to cooling system performance

Quote:

I wanted to see what the operating temp should be. it has been 210-220 . and i changed the thermostat last year to a 160, and it still runs hot, I also changed my temp sensor on the head, could my headers be throwing off the temp sensor?

OE temp gauges are notoriously inaccurate. You may wnat to hook up a scanner and see what the coolant temp sensor for the ECU thinks the temp is. This should be a much much more accurate measurement.

jeep350chevy · 04-26-2009, 07:24 AM

will it hurt anything with the engine running that hot? should i wrap the headers?

jeep350chevy · 04-26-2009, 08:00 AM

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jeep350chevy · 04-26-2009, 08:02 AM

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here are a few pictures

Krochus · 04-26-2009, 08:39 AM

I think you should remove the electric fan, Electric fans aren't nearly as good at pushing air as they are pulling and with your installation I believe it's only serving as a restriction to your mechanical fan.

Again a shroud is CRITICAL. There likely isn't a thing we can do to help you till you get one

I also would eb skeptical of any temp readings that sender setup gives, it's too close to the header and is too far removed from the cooling passage it should be probing directly into, you should move this sensor. Check the coolant temp with a scanner to find what your temp really is.

yjcrawlr · 04-26-2009, 08:51 AM

It needs the shroud and the electric will spin even when it is off.

jeep350chevy · 04-26-2009, 08:51 AM

ok thanks for the info, how would i go about getting a shroud? any ideas what shroud would work?

I wrapped the header just now, going to see if it changes anything

Krochus · 04-26-2009, 08:54 AM

Quote:

Originally Posted by yjcrawlr

the electric will spin even when it is off.

even free spinning it's still slowing down your airflow.

No hotrod I've ever owned with cooling problems was ever helped by adding more fans. If your radiator is big enough and in good working order. You have a good belt driven fan and a shroud you shouldn't need a fan in front of your fan

yjcrawlr · 04-26-2009, 08:57 AM

I have the electric in front of mechanical with the shroud and a big winch in the way and still don't overheat not running the electric. I guess I'm lucky.

**TxJeepGuy** · 04-26-2009, 08:59 AM

I don't think wrapping the headers will help as much as it could hurt - a local shop, that has built alot of racing/serious offroad rigs, suggested that I use a plate made to replace the thermostat and play with the size hole drilled in the middle. They suggested to just use a hole saw with approx. a 3/8" drill to start - then just drill the hole out if increased flow was needed. I checked this out with a friend that races on dirt tracks and he indicated that is what he is running. don't know if this will help, but maybe worth a try. I agree with the puller fan comment above.

jeep350chevy · 04-26-2009, 09:00 AM

the problem is, i don't know what shroud to use

Krochus · 04-26-2009, 09:05 AM

Quote:

Originally Posted by jeep350chevy

the problem is, i don't know what shroud to use

you could start with a jeep one.