Thermostat? Yes or No?

[savatreatabvr]

I just put a new thermostat in my 1973 c20 454 pick up and come to find out there wasn't one in it in the first place! When I test drove it the temp went way up way fast, it was reading around 210 degrees according to the factory gauge. It rarely got over 170 degrees before I put a new one in it according to the factory gauge. I've heard running a BBC over 200 degrees over time can be bad so I'm thinking about ditching the new thermostat and going commando again! Good idea or bad idea?

[BMERDOC]

I dont like going without one. The heat isnt adequatly removed from the rear of the block which could cause the rear cylinders to overheat.

[INSIDIOUS '86]

Originally Posted by BMERDOC

I dont like going without one. The heat isnt adequatly removed from the rear of the block which could cause the rear cylinders to overheat.

I'm curious how this comes about.


If you put a 190 thermostat in then that would explain why the temp is so high. Use a high flow 165* balanced thermostat
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[Firebirdjones]

I use a 160 stat in my 79 454 pickup. I like to keep it as cool as possible for towing purposes (and lots of hills around here )

I also drill a pair of 3/16" holes in my thermostats (in all the cars).

[thesickc10]

Originally Posted by Firebirdjones

I use a 160 stat in my 79 454 pickup. I like to keep it as cool as possible for towing purposes (and lots of hills around here )

I also drill a pair of 3/16" holes in my thermostats (in all the cars).

x2

[motornut]

Originally Posted by Firebirdjones

I use a 160 stat in my 79 454 pickup. I like to keep it as cool as possible for towing purposes (and lots of hills around here )

I also drill a pair of 3/16" holes in my thermostats (in all the cars).

interesting had not heard of "holes" to fix air locks
have run with no stat tho,leaky rad to get home
winter up here doubt the choke would ever turn off with no stat

[bilfman]

A stat is a must, a vehicle will be more prone to overheating without one. Coolant requires time in the rad to really drop in temperature. The start/stop of the tstat lets the rad do a much better job of dropping the temp of the coolant. The free flow with no tstat does not slow the flow enough for the rad to work as intended.

The no stat may work, but under circumstances where you are really creating heat, such as, hot day, slow traffic, grinding a trail, pulling a load etc running without a t stat is not a good idea.

[BMERDOC]

Originally Posted by INSIDIOUS '86

I'm curious how this comes about.

The thermostat is a temp regulator and a restrictor. Without the thermostat there to slow down the flow, the heat at the back of the motor isn't absorbed and can cause overheating of those cylinders. Premature ring failure is an example of what can happen from this overheating. You'd notice oil foulded plugs and low compression towards the end. There is a temp difference between the back and the front of the motor anyway but running coolant unregulated or restricted only makes the situation worse.

[kelsfine69]

Originally Posted by BMERDOC

The thermostat is a temp regulator and a restrictor. Without the thermostat there to slow down the flow, the heat at the back of the motor isn't absorbed and can cause overheating of those cylinders. Premature ring failure is an example of what can happen from this overheating. You'd notice oil foulded plugs and low compression towards the end. There is a temp difference between the back and the front of the motor anyway but running coolant unregulated or restricted only makes the situation worse.

Yes and you can always run a cooler Stat but if it still runs hot then the Fan or Rad(or Both) are not doing there job. Also check with a good temporary temp gage to make sure you actually have a heat proble and not a gage problem.

[bakerboys]

I put a 180 in my k20 and have an electric fan never gets above 180

[notyo_cheez]

Originally Posted by savatreatabvr

I just put a new thermostat in my 1973 c20 454 pick up and come to find out there wasn't one in it in the first place! When I test drove it the temp went way up way fast, it was reading around 210 degrees according to the factory gauge. It rarely got over 170 degrees before I put a new one in it according to the factory gauge. I've heard running a BBC over 200 degrees over time can be bad so I'm thinking about ditching the new thermostat and going commando again! Good idea or bad idea?

There's no such thing as unimportant parts. Before replacing the t-stat with one with the correct temperature rating perform a leakdown test to insure you don't have a leak somewhere. There had to be a reason why the previous owner never replaced it...

[old Rusty C10]

I would pull the cap on the radiator and make sure that the radiator is nice and clean in there.. make sure there is no crap blocking the fins and they are free of dirt and anything else that could cause the radiator to block up.. I fully agree with the statements above about not running a thermostat as well as the wrong temperature one. IIRC the book calls for a 165 thermostat in these trucks.. id replace the one you have with that and see how it goes after doing my first suggestion.. also if you have a port to install one, you may want to install an aftermarket coolant temp guage sometimes the electrical ones have a bad sensor or read bad

[csb#356]

It probably came up to temperature fast because it now has a thermostat and it is doing its job. Its supposed to stay closed and warm the engine up and then open, Running the engine too cold can cause problems with efficiency and fuel to not burn correctly. 210 doesn't sound terrible if it doesn't go above that, but if it makes you feel better put in 180 degree thermostat. I've been told that without a thermostat restricting flow you won't actually dissipate heat into the coolant like its supposed to because it will move too fast, and it will also not dissipate heat into the atmosphere becuase it moves too fast through the radiator. But the guage will read cooler because its measuring the temperature of the water itself, not the engine parts. I don't know for sure though because i've never ran without a thermostat, just passing on the info.

[hopped up]

where do you guys drill the 3/16 holes?
Posted via Mobile Device

[Firebirdjones]

I drill 2 holes on the flat surface of the stat. This keeps the air pockets from forming, and also helps coolant flow (slightly) when cold and helps to warm the thermostat so you don't get those (dangerous) temp spikes before the stat cracks open. I've had more consistent and stable temps with this little trick. Actually all of your more expensive high performance or high flow style thermostats already incorporate this trick.

The intake runs about 10 degrees cooler than the cylinder heads, something to keep in mind.

[donut]

On the thermostat delete, bad idea. IMO, especially on a daily driver.
Had an old Ford van, used to run hot/overheat after about 50 miles of driving. Older gent told me to pull the thermostat out, 10 miles overheated.

Rad was to small (302 rad, 351 engine) and in the Phoenix metro area, so it was hot anyway.

csb#356 hit it on the head, fluid moves so quick, it won't shed the heat it's carrying.
BTW, lot's of good info here.

[savatreatabvr]

I agree, lots of excellent info, thanks! You all have changed my mind, it gets awful hot here in Phx so I'll put a 165 degree stat in it and hope for the best! I had a 350 Z28 that overheated so bad it wouldn't rev over 3000rpm, shut it down, cooled it off, put water in it and it ran like a charm! Can't say enough about that good old Chevrolet engineering!

[Rich84]

If you want more stable temperature drill the holes in the stat. It gets rid of the temperature spike. And it does make it easier to fill with coolant after repairs because it lets the air out.

[1bad87]

would any of u have pics of this drilled Thermostat nice info

[Maxzillian]

Part of your problem could be air in the system, but I've noticed that after converting my truck to fuel injection that the temp sender hooked to the PCM would read 195-200 F while the stock temperature gauge in my '85 would read 210.

Verify the gauge is right before you get too bogged down.