Ok fella's.. I just joined a bit ago so here's the background.

I have an 88 Iroc with 5.7 and it's bone stock. Not my first hot rod but it is my first chev.



The lowdown:
Bought the car and drove it 2hrs home a couple of weeks ago. Ran 220* all the way home at 70 MPH. Drove great to me...Someone told me they run in this zone all the time. Next day tinkering, notice coolant level in overflow was way below the cold mark. Bought some, mix in a touch of h20 and brought it up to cold level on o-flow tank. Check the rad itself and she's full. Haven't driven it again until this last Saturday.


The WTF Moment...
Took my son to the local A-zone to pick us out a bowtie key chain. Noticed it was running 220 in town, in stop and go.. so I got curious. Left it running when we went in. Came back out approx 10 min later and she's pegged out. So jumped in (no coolant on ground leaving) and found a nice open lane to get some air down her gullet, great! -back down to 220 for the ride home. Now this was only a 4 mile drive from the house mind you..pulled in the garage to check the coolant. There is barely any in the overflow, and none dripping/seeping anywhere. Waited for her to cool down and I can see 3 inches down into radiator.


The Double-Check:
OK -air dam in place, not cracked =check
No coolant in the oil =check
Have not checked the fans yet because I thought I would ask the board which direction is this going..

I'm thinking T-stat and/or fans or am I going the wrong way here??

 

Also need to add, I forgot to listen if fans were running when coming out of store , caus I wanted to get some air on her...and that she doesn't so much as even have a drip on the block or in the garage floor.

 

The way a cooling system works is that, like most things, it expands when it gets hot. Once this expansion exceeds the pressure rating of the cap, it forces air and liquid over to the overflow reservoir. As the system cools, it contracts creating a vacuum in the system, and with a properly filled overflow reservoir, that vacuum draws coolant back into the system. If your system was low to begin with, when you add the system it will self purge most air out of the system and can drain the overflow reservoir of extra coolant. Simply filling the radiator does not ensure there was no air in the block, hoses and heater core. If there was a recent service (hose replacement, heater core replacement, radiator service, etc. it could take a while to get air out in the method of just topping it off.

The question to be concerned with is why was it low in the first place. If it wasn't serviced recently, you should be renting a Cooling System Pressure Tester to check for blown head/intake gasket or cracked components. Do you ever have any white smoke from the exhaust or does the exhaust have a sweet odor to it?

 

no sweet odor, nor any smoke. It runs rich because the guy I bought it from ran a straight pipe into an aftermarket exhaust. No Cat and no O2 sensor. That will be fixed soon because I can't stand the check engine light... thought if I had a Blown gasket, I would see a sign of it in the intake galley or a tell-tell sign along the heads, not to mention milky oil in the crankcase..all hoses look to be orig.

 

If it's a gasket, it will depend on what part is blown out (or if there is a crack in a cylinder). That's where a pressure tester will come in handy so you know what you're looking for before you take it apart.

 

thanks lurbie...Looks like I'll be takin it to the mechanic I trust.

 

Any coolant problem deserves a new cap.
Most chain auto parts stores will lend you a pressure tester if you leave a deposit. You get your deposit back when you return the tester.

I think you might find with these cars, as most of us have, that you become a "backyard mechanic" in a fairly short time.

Welcome to the club.

 

Your car does not have an O2 sensor behind the cat. No cat will not cause a ses code or drivability issues. If your ses light is on I'd pull the codes and look into that.