Regarding '97 Cooling Mod

[rnash4]

In another forum this statement was made recently by one of their "gurus"....."Running the dual t-stat setup without the BRF (bypass restrictor fitting) tends to cook the #7 and #8 cylinders." And it was stated as an undisputed fact. Wasn't this the reason GM designed the '97 cooling upgrade (w/o BRF) to begin with? To stop head cracking and cooking the rear cylinders? And increasing flow through the heads and block by 74%? :confused:

[DmaxMaverick]

Yeah, because more coolant flow results in greater heat. (not)

The "theory" may sound good, but it only looks good on a temp gage. It's the same heat. If you aren't seeing it on the gage, it went somewhere (or, in fact, didn't go anywhere, which is the problem). All else being equal, a higher reading from a temp sender shows more heat moved away from the source. Isn't that exactly what we are trying to do? Hogwash, at its best. The same applies to the "rear head coolant bypass". If you feel better that your gage is indicating a lower temp, you're talking to the wrong end of the horse.

[rnash4]

Yeah, because more coolant flow results in greater heat. (not)

The "theory" may sound good, but it only looks good on a temp gage. It's the same heat. If you aren't seeing it on the gage, it went somewhere (or, in fact, didn't go anywhere, which is the problem). All else being equal, a higher reading from a temp sender shows more heat moved away from the source. Isn't that exactly what we are trying to do? Hogwash, at its best. The same applies to the "rear head coolant bypass". If you feel better that your gage is indicating a lower temp, you're talking to the wrong end of the horse.
Some other sites do have some good info, but a lot of it is aftermarket huckster BS. Lol. This site tends to keep me grounded with honest practical information. Thanks for the reply Dmax.

[56pan]

I saw the same post on that forum that rnash4 quoted. My BS detector pegged in the red. Thank you Dmax for a lucid and common sense explanation of this issue.

[Kennedy]

In another forum this statement was made recently by one of their "gurus"....."Running the dual t-stat setup without the BRF (bypass restrictor fitting) tends to cook the #7 and #8 cylinders." And it was stated as an undisputed fact. Wasn't this the reason GM designed the '97 cooling upgrade (w/o BRF) to begin with? To stop head cracking and cooking the rear cylinders? And increasing flow through the heads and block by 74%? :confused:

100% Pure BS from an untrustworthy vendor likely from TX who just happens to make said restrictor. This and the "balanced flow" water pump claim make me want to kick these guys in the nuts...

P.S. It's been a while since I have handled one, but I believe the bypass was enlarged on these compared to prior models.

[rnash4]

100% Pure BS from an untrustworthy vendor likely from TX who just happens to make said restrictor. This and the "balanced flow" water pump claim make me want to kick these guys in the nuts...

P.S. It's been a while since I have handled one, but I believe the bypass was enlarged on these compared to prior models.

Just yesterday he told a guy to add the BRF to "balance the flows" to prevent cooking the 7 & 8 cylinders! LOL (It wasn't the vendor from Tx) :D

[Robyn]

There has been more hocus pokus about the cooling system on the 6.5 than I care to hash out

The GM update to the dual stats and high volume pump worked pretty well.....

Even the original single stat and standard pump was not too bad as long as the radiator was in good shape and the fan clutch was working right....

The rear two cyl's were set with .0005" (Half thou) more clearance on the pistons.....

[sctrailrider]

It wasn't the one from SC either, I call the others out when ever I see those stupid post...

[Robyn]

The part that sucks is that GM should have cast the heads to flow better .....

The 6.5 Turbo cooling system was/is always right on the ragged edge of NOT ENOUGH.....Even when new.

Add some miles and crap in the cooling stack and all bets are off.

Another Fubar was that GM had some really good fan clutches back in the 80's that really came on and would howl like hell until the temps were where they belonged.

People started whining about the noise...so GM bumped the lockup temp up some.

Ya really had to get them cooking hot to get the clutch to bring the fan on hard.

So a whole batch of rigs were unfit to cool well because of whiners.....

Also...many folks would take their rig in complaining the the tranny was slipping.

I got into one of those bru ha ha's

Customer kept telling me his tranny was slipping

No factory tach.

Installed a tach and romped the rig until all of a sudden the fan started howling like a banshee.

Tach was rock solid....Customer screamed to hell and back.

I bought the rig off him ...Had 20k miles (K2500 Burb)

I ran it 250K miles with zero issues....350 V8 TH400

Sweet truck

Gm's decision to cave to stupid customers instead of educating them was a dumb move..

[Yukon6.2]

That's the biggest problem...
Education
Nobody does it anymore,just build everything and make rules for stupid humans.

[Robyn]

Far too many people know absolutely NOTHING about the rig they drive and they are the ones that bitch the most.

The old fan clutches were great./

When the temp got just a whisker above the 190 F mark the fan howled...

That was a great setup.

AND IT WORKED WELL.

Now they put the RED ZONE on the gauge at 260 F :eek:

Wrong answer....

[Kennedy]

If I had a 93-96 with single stat and no dual stat setup I'd consider running the big water pump and REMOVE the bypass block off on the OE thermostat.

[rnash4]

If I had a 93-96 with single stat and no dual stat setup I'd consider running the big water pump and REMOVE the bypass block off on the OE thermostat.

I have been thinking about doing that on my '95. I don't pull heavy and no cooling issues so far. But whenever my pump needs replacing sure would like to put the HO unit on, less the bypass block off.