Okay i have a 97 lt1/lt4 hybrid that for some reason blows its antifreeze out of the radiator cap which is brand new and it did it with the old one as well. I have no idea how and every time I start the car when its cold the low coolant light is on. after it warms up and i start it the light is off, but after awhile to much leaks out and it stays on no matter what so i always have to add more...I have no idea why it always goes out the cap to where there isnt enough i wouldnt think it could get that much pressure but it does. Does anyone by chance know why its doing this cause I hate going through 13 bucks a week in antifreeze ......Thanks!

 

Possibly have a headgasket on the way out

 

its not burning the antifreeze though its actually coming out of the pressure cap or is that a sign of a headgasket going out as well?

 

+1 on that.. its definitely possible, if you have a coolant pressure tester, hook it up to the radiator without pressurizing the coolant system, then start the engine... if it builds pressure within the first minute or so most likely its a head gasket... this same thing happened to one of the cars I use to drive, and it also did not "use/burn" any antifreeze.

This is another way to check for blown head gasket.

Engine cold, pressurize coolant system with coolant pressure tester and let set over night. In the morning if the coolant pressure is zero remove spark plugs, and use a bore scope through spark plug hole to see if there is coolant on top of the pistons.

I know most people do not have a bore scope, but not all times does a compression test reveal a blown head gaskets.

Chris

 

is the thermostat stuck closed since you said its coming out of the cap maybe its building to much pressure because isnt there a thing on the cap to releave it if there is to much pressure?

 

im not sure it never even over heats it doesnt even get hotter than about 195..could there be to much air in the radiator or something?

 

Corey, been there before man. I would do a system pressure test like mentioned before. You can rent a tester from AZ and do it, pretty self explanitory. Just remember to only go up to your rad. cap's # rating. You say it never goes above 195* so we can pretty much rule out that your cooling fans are coming on. Along with a pressure test also like mentioned you might wanna try swapping out thermostats. Check for a blockage: radiator flush maybe in line or one of your radiator hoses as well(may be blocked/kinked) Make sure the coolant system has been bled, via the 2 bleeder valves. the last thing I'd do to ensure it was a head gasket is to drain your oil and examine it for any signs of contamination. When I had my 97 30th Anv Z28 I had the exact same sympoms you did. The only time mine would get hot was in heavy traffic and then when i would shut it off it would puke coolant out as well.

 

I also forgot to mention that it had new gaskets put on 35k ago when the lt4 top end swap was done

 

Did you replace the headbolts? You are aware they are torque to yield one time use bolts!!!!!

 

i believe he said he did.

 

anyone else have any idea's?

 

So i take it you already....


did a coolant system pressure test

checked for a clocked radiator hose

had the radiator flushed and made sure you cooling fans were coming on

you've drained the oil and inspected it

you've done a complete compression test on each cylinder


Well my friend the best thing i can say is roll up them sleeves and grab spme tools. I would take the heads get them cleaned up, new valve stem seals all that stuff get the ported (if they're not already along with the intake, if theres room on an LT4 intake) get some stock GM head gaskets and some NEW ARP head bolts throw her back together and watch....

 

^^^What ended up being ur problem when yours did the same thing?

 

ok well i looked in the oil filler neck tonight and there was an orange slimy type stuff around the top....(I googled it and it said it can be cause by cold weather which it has been cold latly) Then I took the radiator cap off to add more antifreeze because it all blew out the cap and there wasnt any pressure it was more like a vacuum tight sound that came from it when I took the cap off.....dunno if this helps any more but does it sound like a headgasket or coolant system issue and can that orange slimy stuff really be from the cold?

 

??????

 

Well seeing as how you've already done everything else that I mentioned and others have the only other thing that I can think to add to that list is the next morning you go out and start the car up look for 2 things....


1) Do you see any WHITE smoke coming out of the tail pipes, not condensation from moisture(in the exhaust system) but real WHITE smoke??? Hold your hand over one of you tail pipes for a few seconds if it smells at all like antifreeze you won yourself a HG job

2) WATCH your oil pressure gauge. If you notice the needle kinda fluctuate at all thats a deff. indication that you oil and antifreeze are doing "the 2 step" together

 

What's the dipstick look like when you pull it out. Have you tried changing oil to see if there is coolant mixed in. Everything you are saying is pointing at headgaskets and or cracked head. Did you use a torque angle meter when you torqued the heads. That is the only way you will get a proper torque on the bolts. IF you did it any other way that is more than likely where your problem is. Is this your car or a friends car. Above earlier it sounded like it's a friend that is having this problem. Also as a mentioned earler the bolts have to be replaced every time the heads come off. However, running a compression test like someone else mentioned earlier is the surefire way to know. If it's blowing the pressure cap then a compression test will nail the problem. Approach this well informed and knowing what to look for. If you guess it will cost you in the long run.

 

I don't think any of whats been suggested to him has been done. This kid is looking for the fast and quick answer of "oh go to AZ and buy 'bottle-of-crap' and it'll fix that head gasket in no time..." No, thats simply no the solution. Oh well corey, enough tips and trouble shooting advice has been posted in this thread; what you choose to do from here on out is on you. Good luck

 

i agree

 

well no duh i want a quick way out im in school and work and dont have alot of time to work on the car or money to pay someone ever think of that?????....and no why would i waste money to cheap AZ stuff but thanks for ur sarcastic remarks anyway...and also thanks for the other help people gave