lt170chevelle

iTrader: (2)

Ok a little history..recently had a headgasket slowly pop..most likely from a failing tranny and cheap gas..10lbs of boost.. i know stupid of me.. at that time i replaced waterpump thermostat and radiator cap to try to aid the previous overheating issue..but got to the point of losing coolant and finally started filling a cylinder and coming out the exhaust..
So i replaced the headgaskets ..have bled and bled any possible air out of the coolant sytem and am losing absolutely no coolant . if i drive for maybe 30 minutes the temp will slowly get higher and higher .
I did notice that when i have the radiator cap off and start the car the coolant doesnot jump down like ive always seen in the past years..could this be the remanufactured waterum not flowing or maybe even the coupler stripped out.. im banging my head against a wall trying to figure this out and need a second opinion before i start throwing money at it.

SS RRR

iTrader: (2)

Without the pump functioning the engine would overheat much sooner than 30min. How are you bleeding the cooling system?

lt170chevelle

iTrader: (2)

Ive bled the cooling system with both bleeders open engine off radiator topped off. then closed bleeders and start engine with no coolant movement in radiator and bled the thermostat bleeder with absolutely no air coming out..maybe my steam pipe is clogged..i cleaned it out last year because it was stopped up.

Big Al

iTrader: (1)

First, is it really overheating? Does it boil over? If it had electric fans or fan, is it coming on?

Is the radiator getting hot? Look at the cold side with a infrared temp gun and make sure. If the radiator is "overheating" the water pump is doing its job and moving the heat out of the engine.

After you discover if the engine is overheating, and the radiator is hot or cold. Let us know.

Al

lt170chevelle

iTrader: (2)

I havnt seen it boil over yet but have an 18lb capon it.. i have the fans bypassed to a switch..the radiator gets hot enough to almost singe skin i have a 160 thermostat in it and never even stops at 160 just steadily keeps climbing.. I just opened the steam pipe to see if it was clogged and water is freeflowing through it..even ran some wire all the way down it with ease.

lt170chevelle

iTrader: (2)

And i just verifyed the sensor is reading the same as the one in the waterpump..

Big Al

iTrader: (1)

So the "cold" side of the radiator is too hot. Are you sure of that? That would mean a lot of heat was coming off the fan. Is that true? The hot side of the radiator is always going to burn you. It's the other side that's important.

One of the common cause of overheating when the radiator is too hot is plugged exhaust. Don't start chasing your tail, make damn sure the radiator is too hot. You can just pour water on the cold side and see if it boils. On side tank radiators the side with the cap is the cold side, on top/bottom tank type it's the bottom.

Al

lt170chevelle

iTrader: (2)

I let it get up to 230 idling in the driveway and shut it off felt the upper hose and is boiling..can barely feel it but it is boiling..

Any ideas?

lt170chevelle

iTrader: (2)

its stayin about 230 so far but with me pouring water on both hot and cold tanks the water is just evaporating slowly... this is on an all aluminum radiator. Will the water boil and evaporate quickly at 230?

lt170chevelle

iTrader: (2)

also this is a 94 lt1 in a 70 chevelle with a big turbo and free flowing headers and exhaust no muffler

lt170chevelle

iTrader: (2)

well i let it get to 260 according to the guage and i poured water on the tanks and still not even close to steaming off.. im guessing the guage is grossly off? whats your take on this?

Big Al

iTrader: (1)

Are you sure the thermostat is open? Better look at it.

Al

95 mystic ls

iTrader: (12)

Mine was doing the same thing. I changed the WP and the thermo.,nothing changed. Had it checked to make sure the fans worked and they did. My fix, a new radiator.

lt170chevelle

iTrader: (2)

well im pretty sure the thermostat is opening cuz the radiator is getting pretty hot..the radiator is an aftermarket aluminum one with 2 1"cores everything inside is clean so i dout its clogged

95chevyz28

What about a blocked heater core?

SS RRR

iTrader: (2)

What kind of temp gauge are you referencing and where is it getting its reading?

94fixerTA

iTrader: (5)

Borrow or rent a coolant pressure tester. Pump it up to the operating pressure listed in the cap and bleed the air out through the bleeder screws. I had the exact same problem your having so I actually bought one off the mac tool guy. It's alot nicer and cleaner than the rentals at parts stores. So I don't have to worry about trying to rent one.

lt170chevelle

iTrader: (2)

Would a blocked heater core cause an overheating issue? I thought the thermostat was designed with the bottom valve as a bypass?

Im getting my reading off the stock 94 camaro cluster and have identical readings off both the head coolant sensor and the on in the waterpump.

I havent had any luck getting anymore air out of the system just steady streams. But that is one handy tool i do need to buy for the garage.

lt170chevelle

iTrader: (2)

Also on that heater core..i did have to flush it out , a few years back , because it was clogged and didnt have any heat in the car but never overheated driving it everyday to work while clogged.

3 pedal SS

iTrader: (1)

It sounds like either a stuck thermostat,or the pump isnt turning. Remove the tstat and place it in a pot of water on the stove to see that it opens fully.