Can the radiator/cooling system be bled by removing the radiator cap?
Or is it absolutely necessary to loosen the bleeder valves? Thanks

 

You need to use the bleeder valve (only have one on my '96). It's real easy - just pack rags around the bleeder, crack it and close it as soon as you see a stream of solid fluid.

 

Right, doing the cap only does not get it all. You need to do the bleeders, too. As said, it's really easy to do and if you watch it you'll only get a couple of drops. Did mine when I flushed the system and installed a 160* thermostat.

 

Why would ANYONE install a 160* stat?

 

Would you happen to know where the bleeder valve/s(more than one?) are located on a 1992 LT1????

 

Here is a good place to put in a plug for the electric water pump. Bleeding the air out is easy with the electric pump as you turn it on without the engine running and the air comes to the cap. Otherwise you have to run about 3 heat cycles to get the air out using the bleed valves.

 

One is on the thermostat housing and one is on the front of the throttle body, below where the bellows connects to the throttle body.

 

 

Please explain? Where is the "good place" for what kind of "plug" for an
electric water pump? Also, by "run 3 heat cycles" — do you mean, while
the engine is running, bleed for the 1st cycle — turn it off, re-crank for
the 2nd and so on? Please Explain.

 

By "plug" he meant "endorsement" - it's just a bit simpler to bleed the system if you have an electric water pump.

Bleed the system after filling it. Then bleed it again after the car has been run to full temperature, and if you get any air, let it cool down, run it again and bleed it a 3rd time. I've never had any air the second time.

 

by full temperature, he means the temp at which the thermostat opens. DO NOT PUT THE CAP BACK ON, TIGHTEN IT, run to thermostat temp and remove the cap. you will get yourself scalded.
he means leave the cap off, get it to temp, speed up the throttle with your left hand, and with your right hand add fluid because the thermostat opening will released trapped air, and then you can add coolant. THEN you can put the cap back on and THEN let go of the throttle, you want to see about 1200 RPM's



does anybody want to clarify this?

 

With the design of the C4 the Chevy engine always runs hotter than other cars its used in. As a rule they run hotter 20-30 degrees then other cars[caprice,pickups,etc] So a 160 is a good idea. A cooler engine displays less wear. Kinda evens the feild? GM only puts the hotter thermostats in for emmision reasons. Its great if your C4 is driven alot in warmer climates. But the downside? Good luck getting heat out of it on a really cold day.

 

So the stock stat ("stat" being the thermostat — right) number is what
on a 1994 LT1?

 

180*

 

A 160* is not going to make your engine run cooler. At 160* that stat is wide open and will remain wide open until the temp falls below 160* degrees. How often is that car going to run below 160*? At start up. But, as soon as it gets to 160* the stat will open and remain wide open for the duration or until the car is shut off and cools down. If your car is running BELOW 160*, under normal operation, then you have a problem. A car running that cool is going to have some closed/open loop problems and is prematurely and unneccesarily wearing that engine. SBC engines, as most engines do, have been known to have problems with head gasket failure with engines that run as hot as the Generation II LT1 do but with the reverse cooling that the Gen. II LT1 has this greatly reduces the risk or potential risk of this occuring since the heads are cooled first instead of the block. GM got is right this time. Also, by running a car's engine too cool (if you can get it to run in the 160* range under normal operating driving) you are also reducing the oil tempertaure. Since the oil temperature under these conditions is far below the reccomended operating range that oil isn't getting hot enough to boil off the contaminates. You are asking for trouble eventually.

 

Do you happen to know where the coolant bleeder valve is on a 1986 corvette?

 

Your logic is dead on. I agree 100% but it simply has not worked for me that way.

I replaced the thermostat in 3 S10 4.3's with Corvette 160 thermostats. All 3 of them ran cooler in the summer afterwards. I have not tried it in a vette, but I have one in my driveway waiting for me to install 160. The kid who owns it wants to see if it will keep it cooler on the track.

Logically, it will make no difference. But I will be watching to see if it helps.

real world experience says it does make some engines run cooler. I plan to try it on mine after a few more track days. I hate seeing the car get so hot on the track. Don't say to clean the radiator. It is.

 

Based on my own experience and reading, putting in lower temp thermostat just makes an engine take longer to get up to operating temperature.

The way I get rid of as much air as possible in an 86: cold engine, take the radiator cap off and using a clean plastic liter pop bottle cut off the bottom so it's at least 3-4" left. Put the open top in the radiator neck and tape it onto it. Run the engine till the thermostat opens and the coolant level drops then fill it up and cap the radiator with the engine still running. The reason for the pop bottle is because the coolant will rise in the neck right before the thermostat opens, so it keeps from making a mess.

If you have something like a heater core that's airlocked, with the radiator filled as best you can then find something like one of the old parking ramps where there's a steep incline between the floors. Heater setting to high, engine hot, tranny in low and run up the thing with as high an rpm as you can safely do. With luck it will push the air out of the heater or wherever it's trapped and push it back into the radiator. Once done, if it's holds you're done. If not, repeat both steps.

That's what I've done before and it's worked for me.

 

Transmission in gear? Good Lord, why????

For the purposes of bleeding the cooling system, the water pump only knows that RPMs are RPMs. Putting a load on the engine makes no difference except *maybe* to increase the engine temperature, but your example already has the engine hot. What am I missing?

 

You're driving up the ramp, up the incline. Keeping it in low with the heater on high has everything opened up internally so with a little luck the coolant flow will be high enough to push any air bubbles through the system into the radiator. If everything works right by driving 'up' the ramp you elevate the front end to encourage the air to pass out of hte heater or engine. Again, just like normal operation, as the coolant gets hot excess is pushed out to the overflow. In this case air would be the first thing to be displaced. When it cools down later, it returns coolant from the overflow back to the radiator instead of air.

Hope that makes sense and sorry if I didn't explain it well enough earlier.