prix57

Hello my apologies if this has already been posted.

I have a 1997 Firebird Firehawk M6 5.7L LT1.

I would like to know the process to get air out of my cooling system, I do not need to do a coolant change or flush.

My temp gauge has been shooting up into the red randomly when driving and I can hear the coolant gurgling really loud after a shut the engine of and even when I come back from a 15 min drive.

I also see there is coolant spewing out from the front passenger side (could be from overflow, rad cap, waterpump) but I have yet to jack it up and check underneath which I will do later today.

My engine was rebuilt few years back by previous owner and when it was rebuilt they switched it from using dexcool to regular green coolant.

I did get a new delco rad cap which I will use once the air is out.

If i need to replace the thermostat what is the recommended temp I should replace it with?



Thanks!

handyandy496

iTrader: (9)

Keep squeezing the top radiator hose and filling till no more air comes out.

RPM WS6

iTrader: (3)

What makes you certain that air in the system is the problem here? Did these issues happen immediately after a coolant flush?

B52bombardier1

If your engine still has a hose on the steam vent line, simply remove the distant hose end from wherever it is attached and aim it into a catch can. If the engine is hot, use caution as this is very hot coolant water if your engine is up to temperature. The steam vent lines are at the top of the engine so any air in your water jacket will find its way there. You may need to add coolant to the system a few times to get all the air out and again, use caution around hot coolant.

You did not mention what engine or what year so it is impossible to give you guidance on a thermostat temperature. Could be 185, 195 . . . hard to say. You might also need a new water pump.

Rick

prix57

Oops sorry my bad. I just updated the post.

I have a 1997 Firebird Firehawk M6 5.7L LT1.

I have not changed the coolant or done a flush as its been less than 2 years.

The reason why I think there is air in the cooling system is a few months ago I would notice the car making loud coolant flowing gurgling sounds after I shut down from a drive longer than 15 mins. Then my low coolant light on the dash started coming on. I checked the coolant overflow dip stick when engine was warm and cold and the level indicated coolant was low. So I topped it up with 50/50 prestone green coolant. The light went away but would always come back when I start the car. I checked the coolant level again (during cold and hot) and now the dipstick shows it is overfilled. After shutting car down now I also noticed coolant dripping from bottom passenger side by the overflow tank. Then few days later when driving I would notice the temp gauge going into the red then "check gauges" light comes on. I shut off engine and hear coolant intensely gurgling when open the hood. I wait a few mins and it cools down but then randomly when driving same thing will happen again.

I did not see any leaks under the hood. I didn't get a chance to jack up and look underneath.

Does this seem like there is air in system?

bammax

LT1 should have a bleed screw on the thermostat housing. I pulled mine and replaced it with a 90 elbow shutoff valve and ran a section of hose from there to the lowest bracket I could find and ziptied it away from the pulleys and belt. Run the engine until it gets hot then crack open the screw and wait for the coolant stream to be solid instead of bubbling.

If you're getting big glugs and random temp spikes it sounds like you either have a leak that's bleeding off pressure or you have a clog that's moving around a bit. It's usually heater core but sometimes it's the bottom edge of the radiator.

LS1121

iTrader: (17)

Is your thermostat sticking? randomly?

BALLSS

OP

your T stat may be sticking and/or you have a leak in system that has introduced air into it.

You can pull the T stat and check to see if it opens all the way if you drop it in a pot of boiling water...or just replace it.

If your car has not been programed to run a 160 stat and fan temps that come on earlier, that is a good mod. Otherwise just get the correct stat for it. 180 or 185, I can't remember as it's been 20 years since I put a 160 in my LT1

Bleeding you should have the car level, not with front of car pointing down (like on a sloped driveway).

prix57

Thanks for the info.

Looks like my thermostat is shot and needs to be replaced. Just picked up a 180 degree one hoping to change it soon.

Removing the ram air intake to access the thermostat should be be pretty straight forward right?

01ssreda4

iTrader: (96)

LT1s have multiple coolant/air bleeds

99 Black Bird T/A

iTrader: (4)

Also check the radiator for leaks around that low coolant sensor. iIRC it's a press in. Sometimes they are prone to leak.

FWIW - LT1's can be hard to bleed.
Sometimes get the the nose up at a 30+ degree angle helps.

prix57

Sorry for the late reply, was a hectic few months.

Update on this issue:

The radiator was low so I filled it up. Started up the car and let it run but this time I had the heater on full blast and once it got warm I saw a leak in the heater hose at the front, it was shooting out coolant towards the lower passenger side. This appears to be the heater hose that is connected to the bottom of the water pump. It's spraying out coolant right in the middle of the metal section of the pipe.

Does anyone have the part number for this hose? I tried to find it on rock auto but was unsuccessful.

I can post a video clip of the leak if that helps.

Thanks again!

prix57

Issue has been fixed.
Got a new heater hose assembly (GM# 10261147) to replace old one.
Installed it and refilled coolant bled out the air.
Temp is back to normal and no more leak.