Michael Clayton

2 new thermostat and noticed today the top radiator hose had alllot of pressure couldn't even squeeze it

94Z28LS1toLT1

Are u using the correct t stat for the lt1 engine it's the long one

gaedbo

Maybe read thru this from Shbox, and see if you followed the procedure he outlines. You might not be doing the bleeding correctly for this engine.

4th Gen LT1 F-body Tech Articles

http://shbox.com/1/bleeders.jpg

http://shbox.com/1/4th_gen_tech2.html#thermostat_change

http://shbox.com/1/tstat.jpg

94Z28LS1toLT1

Yea definitely all that too,bleeding coolant procedure is common issue with running hot/overheating

96 Z 28

When I changed my Thermostat - I had to bleed it 4 times....

And I followed the shobox methods and recommendations - it just takes a lot of bleeding to get all the air out...

Michael Clayton

I didn't bleed it I will do it this weekend thanks allot guys!

ACE1252

Guys, if you are having to do a bunch of "air bleeding" then you are filling the system wrong. The bleeders are for filling the system only. You do not open them after you fill the system with coolant(ie open them with the engine running). No where in the factory fill procedure does it state to open the bleeder valves with the engine running. People constantly don't get this point and end up shooting themselves in the foot when dealing with this cooling system.

The general fill procedure goes like this....

• Protect the Opti with paper towels. Stuff them under the bleeder hose and around the water pump neck(the one with the bleeder) to absorb coolant running out of the bleeder valves.
• Fill the coolant reservoir to FULL HOT
• Open both bleeder valves.
• Fill the system until you have a steady stream of coolant running from each bleeder valve. The water pump housing bleeder will stream first, then the hose bleeder. So you will close the water pump housing bleeder first, then the hose bleeder once you see a steady stream from each.

From there you can do 1 of 2 things.

Option 1

• Fill the radiator full up to the neck
• Put the cap on the radiator, turn your heater system in the car to full hot, HVAC fans on max
• Fire up the car and bring it up to normal operating temp(~190* if the stat is stock). As it's coming up to temp, blip the throttle a few times. If any air is in the heads, this will help push it out into the radiator.
• Once up to normal operating temp, shut off the car and wait for it to completely cool back down(as in stone cold).
• Next check the radiator level and coolant reservoir levels. If the radiator is low, top it off. If the coolant reservoir is not at the full cold level add coolant to it.
• Check the levels in both the radiator and coolant reservior after one complete drive cycle(after the engine has cooled back down...stone cold). They might need topping off once more, but that should be the last time needed.

Option 2(this is what I use)
This option is the same as above, only I use a Lisle spill free funnel instead of capping off the radiator when coming up to temp with the engine. This allows me to view the coolant as I blip the throttle to see if air bubbles are rising to the surface. They have always been minimal. Once up to temp, I shut it down, let it fully cool down, then top off the radiator. I also add two system sealing pellets to the system as recommended by factory manual, but some people advise against it.

In using option 2, you don't want to get close to 210* or you will have a boiling mess on your hands. 180* is as hot as I let it get with the radiator open(1/4 mark of the gauge).

For each of the above options, you should only have to top off the radiator once after the final top off in those steps. Usually, I will drive the car, let fully cool down then check the level. It should be good from that point. I'll spot check it for a couple of weeks...always checking it stone cold.

If you have to continually top of the radiator, you have a coolant system leak that will have to be found.

bw_hunter

Good post, Eric.

In addition, I've found raising the front of the car when filling the system help the air escape. I've rarely had to top up the system after filing this way...

ACE1252

That's a good idea too. I've done it level and with it on ramps. I most certainly would not have have the nose lower than the back of the car.

I did forget one important point on option 1 vs option 2. When the car is coming up to temp, the thermostat is going to be closed and the coolant level will rise in the radaitor. That is why you have to either put on the cap or use the Lisle funnel to keep the thing from overflowing....

However, once the thermostat opens, the coolant level radiator can fall like a rock as the the system starts flowing and pushes any trapped air out of the engine block and heads. With option 2, you can add coolant(as the radiator is open) to keep the system full as it's coming up to operating temp. I think that presents an advantage over option 1 as you are making sure the radiator is full at all times.