I got a new radiator cap today and that solved the issue with old one leaking pressure. After installed new cap air pressure in system is OK up to about 10-11 psi, but it should hold up to 15 psi, that is how much you normally should have then testing the system (15 psi = 1 bar) . I have used a radiator test tool (photo) to ceck the radiator system.


If I pump up the air pump tool to 15 psi it's slowly moves down to 10-11 psi and stays there (with old cap the system didn't hold no pressure at all).

 

Are you testing the system cold or hot? You should be doing both. I have seen leak show up cold that would seal up pretty good hot. One common mistake I have seen is people forget to check their tester for leaks. A little spray bottle with soapy water sprayed at every connection on the tester might be worth while to check.

Your system should be holding 15 PSI.

 

Never seen a kit quite like that, but whatever works.

 

bleed it, bleed it and bleed it again. sure sounds like air in the system. bad cap will let it in so you may have found the issue, lt1 has spots at the back of the heads that likes to hold air, its why they have steam line at the back of the heads. https://camaroforums.com/forum/lt1-l...42/#post593089

 

Yes, bleed again. Coolant system pressure should be at stamped cap pressure rating.
A good coolant system tester should have the provision for checking cap pressure by itself.

 

I have now used a vacuum air bleeding tool but still gets same problem temperature goes fine up to 210 F then fall back to about 180 and turns up again to 210 and start doing this all time.


Before I have bleed the two bleed nossles both then engine is cold and and hot several times, so if any air trapped I think it should have been away by now - especially after using the vacuum tool.

One interesting thing is that the serpentine belts start to squeak few minutes after the air have turned up to 210 F and the temperature is falling, like water are leaking on the belt. But no leaking coolant water to find visible or smelling.

I have confirmed the temperature with both digital meter and OBD reader.

My idea for the moment is to look for cracks in the houses (they are correct attached) and next if I need replace water pump. It all indicates there are a leak some where near the serpentine belt, makes the belt squeak.

 

Are you trying to fix a leak? Can the system hold pressure? Your system not being able to hold pressure is an issue. Check the weep hole on the water pump, This is on the bottom of the water pump. If the pump has been leaking you should see staining, green or orange depending on the coolant you use.

I would not consider the temperature cycles a big deal. 210 is a normal temp and the cycling is either from the thermostat or the fans. I can not remember a real problem caused by a small temperature change nor do I remember it being a symptom of the beginning of a problem.

 

i dont think a vacumn bleeder is going to make much difference if you have air stuck at the back of your heads. mine boiled over when it was not blead right though so not so sure about what your issue is. steam line could be plugged or leaking, block/head cracked, pin hole leak in a hose or failing hose connection, failing water pump,

 

I think I'm into a solution. I noticed that fans starts before 210 F. I disconnected the fans and run the car and the temp is not going down, and passed 210 F, before I turned off engine and reconnected fans and got down in temp to 180 again.


So now to next question: How do I adjust fans to wanted start and stop temp? I think this is possible using a OBD tool, but do I have to get a Tech 2?

 

The temperature is going to climb uncontrolled without the fans while sitting still, that's a given fact. No air flow equals higher temperatures.

180 to 210 is totally normal man. That's what mine has always ran at, I don't have any problems.