1998 k2500 454 getting hot

[454cid]

Filling in some blanks here...

There are two coolant circuits to consider, and one pump.

Thank you for that. I was not thinking about two circuits..... this leads me to wonder about something. Did the OP's bypass hose get removed/plugged/disabled?

 

[1998_K1500_Sub]

I was not thinking about two circuits..... this leads me to wonder about something. Did the OP's bypass hose get removed/plugged/disabled?

I've wondered the same. I think if the bypass was inoperable it would really screw up the temperature management in the engine and he would have much bigger complaints.

I did something similar on an L31 retrofit into my S10 (I screwed-up the engine coolant routing by not providing sufficient bypass flow across the thermostat) and the resulting engine temperatures were uniform at times and then erratic / inexplicably high at other times. That was 20yrs ago and I've learned a bit since then (and still have the S10 w/ L31).

 

[Supercharged111]

Thank you for that. I was not thinking about two circuits..... this leads me to wonder about something. Did the OP's bypass hose get removed/plugged/disabled?

Or did he put the correct style thermostat in with the bypass flappydoodle?

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Not sure what the effect would be of putting one in without.

 

[454cid]

Or did he put the correct style thermostat in with the bypass flappydoodle?

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Not sure what the effect would be of putting one in without.

I don't see how a thermostat with the tiny valve in it, would do the same job as a short piece of heater hose. The flow rates would have to be vastly different.

 

[Supercharged111]

I don't see how a thermostat with the tiny valve in it, would do the same job as a short piece of heater hose. The flow rates would have to be vastly different.

Are we talking about the same thing?

 

[1998_K1500_Sub]

Are we talking about the same thing?

I believe we are.

The flappydoodle would allow air to escape (in a newly-filled system) and a very minor amount of coolant flow through the radiator circuit.

The bypass hose @454cid mentioned on a BBC provides significant coolant flow through the engine circuit.

A similar bypass hose is used on the SBC L31. Older SBC heads had a bypass circuit through a path in the cylinder head that lead to the pump; Vortec heads do not have that passage.

 

[454cid]

Are we talking about the same thing?

Are you not talking about using a thermostat with the tiny jiggle valve in place of the normal bypass hose? The thermostat for the 454 doesn't normally use a one of those jiggle valves.

 

[Supercharged111]

Are you not talking about using a thermostat with the tiny jiggle valve in place of the normal bypass hose? The thermostat for the 454 doesn't normally use a one of those jiggle valves.

Mine does just like my 350, so without it I figure it must disrupt something.

 

[Supercharged111]

I believe we are.

The flappydoodle would allow air to escape (in a newly-filled system) and a very minor amount of coolant flow through the radiator circuit.

The bypass hose @454cid mentioned on a BBC provides significant coolant flow through the engine circuit.

A similar bypass hose is used on the SBC L31. Older SBC heads had a bypass circuit through a path in the cylinder head that lead to the pump; Vortec heads do not have that passage.

Would you have a flap and a hose? What I'm getting at is has OP made his truck not factory with respect to bypasses.

 

[1998_K1500_Sub]

Would you have a flap and a hose?

The hose is a necessity on the BBC IMHO, GM designed the hose for bypass. The hose will pass a lot more coolant than the flappydoodle, that's my observation, but one could have both if one wanted.

What I'm getting at is has OP made his truck not factory with respect to bypasses.

Good question. OP AFAIK hasn't said, although OP said he's had the problem with the first (presumably OE) engine and, now, with the replacement engine. I might assume the first engine had the bypass hose, but it has yet to be proven.