ARCTICWHITE98Z28

iTrader: (1)

I am having a hard time figuring out wht the heck the deal is with my cooling system. My car still runs hot in traffic or at idle and has no heat. It blows cold air and the vents appear to work normally. I have used a Prestone flush kit which did not help. I did use 50/50 Dexcool/water after the flush. I also replaced the tstat and the waterpump is only a few months old.

This whole issue began because I had no heat, but my car was not running hot at all. So I decided to flush the system and change the tstat. After that I had heat for a day or so and then no heat. The crazy thing was that immediately after changing the tstat and doing a flush the car started running hot.

I am thinking that there may be air in the cooling system. I tried to bleed the system but the coolant level never dropped after the system heated up and it began bubbling over with the cap off at around 210 degrees. I also removed the small hose that runs from the top of the radiator (near the cap) to the passenger side of the throttle body while the car heated up during the bleeding process. Lots of hot coolant ran out from both ends but the coolant level in the radiator never dropped. The fans kick on and seem to work fine. The temp drops if you give it gas when idling or if you are driving at any speed. There is never heat out of the vents at any time.

Any ideas on what I should test next? Also did I bleed the system correctly? Thanks.

JohnnyC

Could be a heater core problem -try bypassing the heater core. Maybe when you flushed the system you knocked some crud loose and it is clogging up the heater core or other coolant passages. Also, make sure the Tstat is opening properly, and you have enough coolant in the system - including the overflow can. The air usually works itself out if you have proper flow and level.

98redM6

iTrader: (39)

I've been having a similar problem as you and can't find the solution. Instead of my heat not working, my a/c isn't working and the car gets up to about 210*. I've also changed out the t-stat and waterpump, my fans work, and my radiator isn't being blocked or anything. I haven't tried to bleed the system of any air. Someone mentioned replacing the fuse, but I don't know what they are talking about. I haven't tried a system flush, but I don't think that is the problem. I switched radiator caps with my brother, but the temp stayed the same.

I don't know what the hell to do if the problem is not air in the system. I realize the a/c could be because it needs a recharge, but I'm more concerned with the operating temps. Could the a/c needing a recharge or a bad heater core cause the engine temp. sensor to read incorrectly?

rocketman442

iTrader: (8)

I've never had any problems with the LS1's but LT1's are a bitch to bleed the coolant so I park them on a steep hill by my house to make the rad cap the highest point hold the motor at 2500 and that always did the trick for me. on LT1's at least

ARCTICWHITE98Z28

iTrader: (1)

I should also mention that the top radiator hose is pretty hot and is mostly hard (it has a little give when squeezed), the bottom radiator hose is cold and it gives a lot when squeezed, one of the heater hoses that connects to the waterpump is fairly hot while the other heater hose that connects to the waterpump is cold. Hope that helps provide some more feedback. THANKS.

jmm98LS1

iTrader: (28)

Clogged heater core.

joecar

Sounds like you have several clogs someplace.

1320 killer

iTrader: (6)

I heve never hasd this problem w/ my ls1 but had a similar problem w/ my lt1. the coolant was full but the car would run hot. I figured out that there was a bleeder valve on one of the lines that was going to the tb. I opend that up and a hissing sound started and after a minute coolant started to spray out and that bled my system.

JohnnyC

I have heard of bad A/C compressors heating up and causing high coolant temperatures. Check out the link:

https://ls1tech.com/forums/general-maintenance-repairs/491395-overheating-solved-you-d-never-guess-how.html

Just something to think about.

Viper

iTrader: (6)

Bad / plugged heater core. I replaced mine this summer and did a huge write up on it, search for my name, took me 2 hours or so.

ARCTICWHITE98Z28

iTrader: (1)

I flushed heater core and the rest of the cooling system this morning and all is good so far. Now I can drive my car for another month or so without freezing my butt off before the snow here in Michigan forces me to drive my beater. Thanks for the replies.