Looking for some opinions before i start getting angry and throwing wrenches etc.

The other night i took my car out. It ran fine all night. I ran a couple people etc. Well just cruising home i look down at my temp gauge and its buried in the red! I quickly pull over and pop the hood. A small amount of coolant was coming from the overflow tank cap. The car cooled down a bit (to just below operating temp) and i tired to drive it, went fine for about 15 seconds then started heating up like a bitch again. Pulled over one final time and called AAA. I got the car home, pulled the plugs and they were fine. There is no oil in the coolant and there was no smoke or steam from the exhaust. I haven't had a chance to examine any further due to it being exam week at school. What do you guys think is up? It doesnt SEEM like a headgasket, unless its not getting into the combustion chamber and just pressurizing the coolant system? The car has basically BRAND NEW MLS gaskets. My friend who is a GM tech suggested that possibly the thermostat took a dirt nap?

what do you guys think/suggest/hypothesize?

 

first thing first is to just check for low coolant level. than possibly burp out the cooling system. it might have gotten air in it. than if all is good worry about the thermostat and water pump. also check to see if the thermostat or water pump gaskets are leaking.

when did the head gaskets get changed?

 

I put trickflow heads on the car this past winter. I have driven the car for 250ish miles since, that is including getting it tuned and a few races, so it wasn't the first time it was beaten on. The waterpump and what not don't look to be leaking, also the coolant level in the radiator and on the reservoir dipstick are not very low at all (i am assuming what was lost is what came out of the reservoir breather cap. I filled it with all new dexcool after the head swap, so i guess it could be an airbubble but wouldn't that work its way through by now?

 

Most common solution is that there is air in the system as said above. Especially on ls1s because the radiator is so low and the way the hoses are positioned there are lots of spots for air to get trapped. You just did the head swap so im willing to bet money thats ur problem. Jack that front end up as high as u can get it pop the cap off the radiator and start the car get it HOT, It will bubble out and be fine. It was a bastard trying to bleed the air out in my old iroc with the ls1 if you remember.

 

Thanks mike, i will try that! That would be fantastic if that is the only problem here!

 

While your mess with it change our the thermostat what are they $10?

 

They are like 50 bucks.

 

$22 autozone :-)

 

oh whammy! i will have to do that then.

 

You could also have a bad radiator cap, or debris in the filler neck not allowing it to seal completely. You could have it tested, but I would just replace it and clean the filler neck thoroughly.

Also you might check to make sure you didn't get a Walmart back or more blocking the radiator airflow.

 

With My Mom's Northstar , the only way I was able to get the air out completely is (as per GM's instructions) to vacuum pump out the air , then let the vacuum pull in the dex cool/ water mixture . I'd be surprised if that's not normal procedure for LS1-6's etc ......Good luck

 

Well i started up the car on stands with the front up in the air and the rad cap off. It heated to operating temperature.. got a tad past 210 and the thermostat opened up and sucked down ~1/4 gallon of coolant, temp went back to normal and remained there for 15 mins or so, just shut it off.... So far so good.... chalk this one up to an air pocket?

 

Burping procedure:


Start w/ a cold engine
Remove rad. cap
Idle for 1 minute
Install cap
Cycle RPM from idle to 3000 until coolant reaches 210F
Shut off engine
Remove cap
Start engine
Idle for 1 minute
Install cap
Cycle RPM from idle to 3000 until coolant reaches 210F
Shut off engine
Remove cap
Top off

 

OHHHHH YAAAAAA!! I'd say your ready to PwN some stangs again buddy! Hopefully you won't have any more issues.

I dont believe there is a procedure haha bottom line air goes to the highest point in the system, jack the front end up so that the water level in the radiator is the highest point above the engine itself, the cylinder heads have a lot of crevisis, just have to get the radiator hose and radiator above the heads. I ran my IROC for a good 30min with the front end 4ft up on jackstands to get an air pocket out, squeezing the radiator hose top and bottom helps too while its running. Gives a little push/pull action in the system and sometimes helps work the air pocket out. I've only had issues with this on LS engines because the top radiator hose is below the heads where air gets trapped. On GenI small blocks the top radiator hose goes right onto the intake manifold which is the highest point above the heads, i dont even have to jack the front end up.

I want a ride in that beast this summer JT!

 

Drove it tonight, did a 2-3rd pull and its 100% fine. Dodged a bullet there, thanks guys!

And of course mike, you can even drive it. Then it will make you mod the white SS Muahahaha

 

not a problem. glad i can help.

 

hey jt, just curious but the last time you drained your radiator did you have any debris flush out? i had this same problem with mine and did the same thing, just jacked it up on my steep *** driveway and wallah, fixed. but first i had to flush my system like 3-4 times to get all the old crap out of the radiator. i wonder if this made it harder to bleed the system the first time?

 

So does it pull A LOT harder now with the trickflow heads ? happy with your setup?

 

No debris, just nice clean dex cool. It was a **** ton of air, when it burped it sucked down about a gallon of coolant.

Oh yes, it is MUCH faster than it was. Cam only, my car would trap anywhere from 118-120 N/A..I made up 6-7 car lengths on my friends big cam vindicator car! He was pulling me by 1-2 cars last year, not anymore! I would assume i am in the mid 120's now

also ran my friends roush stage 3 with full exhaust, supercharger pulley, intake and all kinds of crap, i had to start in 2nd from 35ish because it just spins in first, heres a vid:
http://www.youtube.com/watch?v=25ccEEkOtwE

 

Glad to see you got the air out!! Are you running 373 gears?