Engine overheating problem

[1971442convertible]

I am new to big blocks and there heat problems. When the engine is first coold it runs will, as soon as it gets hot it starts pinging real bad and i can't get it to stop. i tried adjusting the timing, no good. i installed a hotter platinum spark plug, no good. i don't know how hot it is getting bc i don't have a temp gauge yet, installing it tomorrow to see how hot she is getting. The 455 is pretty stock, I have tried to repair most all the sins of the PO and under the hood most everything is stock. it does have later model HEI. sorry for the long post, just wanted to get all the facts strt.

I also have another problem. My torque converter is knocking. i checked the bolts and none were loose and i don't see any cracks. but the noise is definitely coming from the converter. does not matter if it is warm or cold. at idle there is just a low dull knock knock sound coming from the converter.

thanks for any help you may have. Mark

[Oldsmaniac]

A crack in flexplate is hard to see at times but surely will cause knocking down there. The crack opens when the engine is turning....look closely at that and also trans to engine bolts. My trans bolts to block were loose once and the torque converter was hitting the housing. As for engine temp you need a gauge, still seems like a timing issue. Try some octane boost and premium fuel. If engine temp is too high check thermostat and radiator condition.

[1971442convertible]

we installed the temp gauge and the engine went to 230. we removed the thermostat and it went down to 190? so any ideas?

as for the TC. we don't see any cracks, but as you said could be only visible at speed. is the TC supposed to wobble so to speak? if i put a tool against the TC it is definitely not running true? the knocking sound is loudest at the TC/flex so that is why i think it is coming from there. thanks

[Oldsmaniac]

Did the pinging go away at 190 degrees?....What was the T-stat value that you removed?...I would suggest a 160 or 180 stat....also make sure fan shroud is in place and operational thermostatic clutch on the fan.

[Jim's rare 80]

Hi. Temp problem sounds like a thermostat. From what you are sayin about the Knocking in the tourque converter, If it's not spinning true, You have a bent flywheel. Let us know. Jim.

[1971442convertible]

Originally Posted by Oldsmaniac

Did the pinging go away at 190 degrees?....What was the T-stat value that you removed?...I would suggest a 160 or 180 stat....also make sure fan shroud is in place and operational thermostatic clutch on the fan.

maniac, the pinging increases as the temp increases. with the t-stat removed the car runs cool, 190ish. the t-stat was new so i guess i need to try another one? my mech was trying to tell me that a big block needs to flow more that the t-stat allows and should stay out of the car. my logic tells me that is not true bc it would not have been designed that way. what say you guys?

[Oldsmaniac]

You must keep the thermostat.....as said use a 160 degree or 180 degree max thermostat....then see what the temp is.

[88 coupe]

Originally Posted by 1971442convertible

I am new to big blocks and there heat problems ........

I am not aware that any Oldsmobiles have, or have had, "cooling system problems".

Originally Posted by 1971442convertible

........ I have tried to repair most all the sins of the PO ........

What needed repair?

Originally Posted by 1971442convertible

........ the engine went to 230. we removed the thermostat and it went down to 190? ........

What are the ambient temps. Is 230° normal for that combination on the highway? In the city? At idle?

When you removed the stat, you removed a restriction which brought the temp down.

Originally Posted by Oldsmaniac

........ I would suggest a 160 or 180 stat ........

A stat that is fully open at 160° or 180° cannot cause that 190° or 230° temp to fall.

Originally Posted by Oldsmaniac

........ also make sure fan shroud is in place and operational thermostatic clutch on the fan.

Good advice, if the problem only occurs at speeds below 30 miles per hour. He has not said whether it does, or does not.

Originally Posted by Jim's rare 80

Hi. Temp problem sounds like a thermostat ........

Only if it was stuck in the closed position. If it was, the temp would have gone a lot higher than 230°. If it was partially closed, coolant temp would have gone down considerably, when it was removed.

Originally Posted by 1971442convertible

........ my mech was trying to tell me that a big block needs to flow more that the t-stat allows and should stay out of the car ........

A big block with a restricted cooling system, is no different than any other liquid cooled engine with a restricted cooling system.

You need to find another mechanic. Best place to look, in this case, is in a radiator repair shop.

Norm

[1971442convertible]

What needed repair?
You name it, it needed repair. bascially the car had been neglected of any quality mechanical work. the engine compartment was a mess. i relied on the build manual to put it back to stock. i am kind of anal like that. but unfortunately I am not a mechanic so i have to rely upon my "inhouse" mech who is really good at small engine repair and "ok" with cars, esp. classics if you get my drift. but for not that is what i have to work with so i have to baby sit him and make sure he does it right. the language barrier is also a real challenge.

What are the ambient temps. Is 230° normal for that combination on the highway? In the city? At idle?

ambient temp was in the 90's. not city driving, not much idel.

When you removed the stat, you removed a restriction which brought the temp down.

sounds like it could have been a restriction issue as noted below, if it did not work it would have cooked the engine vs. just getting really hot.

A stat that is fully open at 160° or 180° cannot cause that 190° or 230° temp to fall.


Good advice, if the problem only occurs at speeds below 30 miles per hour. He has not said whether it does, or does not.


Only if it was stuck in the closed position. If it was, the temp would have gone a lot higher than 230°. If it was partially closed, coolant temp would have gone down considerably, when it was removed.


A big block with a restricted cooling system, is no different than any other liquid cooled engine with a restricted cooling system.

You need to find another mechanic. Best place to look, in this case, is in a radiator repair shop.
see above

thanks Norm for all the great advice. i will work on it this week. first thing is to get another stat.
Norm[/quote]

[Oldsmaniac]

"A stat that is fully open at 160° or 180° cannot cause that 190° or 230° temp to fall."


Running with no thermostat can cause higher temps than with a thermostat. Coolant is moving so quickly that it doesnt have a chance to cool down in the radiator. I have not experienced this myself but have read it more than once.

[88 coupe]

Originally Posted by 1971442convertible

........ You name it, it needed repair ........

Engine? Cooling system? Ignition?

What was done?

........ ambient temp was in the 90's. not city driving, not much idel ........

Highway?

On a 90° day, what temp do you see (with or without a stat) at idle? at 30MPH? At 70 miles per hour?

Norm

[88 coupe]

Originally Posted by Oldsmaniac

Running with no thermostat can cause higher temps than with a thermostat ........

I will rephrase: By design, a 160° or 180° stat will be fully open at its design temperature.

If the system is at 190° with no stat, how could a fully open 160° make it run cooler?

........ Coolant is moving so quickly that it doesnt have a chance to cool down in the radiator ........

It is also moving so quickly that it doesn't have a chance to heat up in the engine.

........ but have read it more than once.

So have I.


OP still has not given us enough to work with.

Norm

[Topless72]

Similar thing happened to me once. Cool highway, hot around town.
Ends up the fan clutch went bad.... Popped on a new one and all was well again...