1997 K3500 454 Vortec Tune Up Parts Advice.

[Erik the Awful]

GM deliberately restricts the heater supply using the quick-connect. Prevents over-pressurizing the heater core. Also slows down the coolant flowing thru the underside of the TBI intake manifold. I don't know about Vortec manifolds.

An unrestricted barbed fitting is a bad idea.

You keep saying that, but have we found anyone who's had a failure from using an unrestricted fitting? I used the Dorman on my Suburban, but I won't knock anybody who uses a standard fitting.

 

[Schurkey]

The restriction may serve an engineering purpose... ...GM's original uses a through-hole of 1/4".

Not even 1/4".

The hole was about 1/4", but there's a plastic divider inside taking up room. Sort-of visible here, lower left corner:

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You keep saying that, but have we found anyone who's had a failure from using an unrestricted fitting? I used the Dorman on my Suburban, but I won't knock anybody who uses a standard fitting.

I first heard about it in the Oldsmobile world, where folks were having repeat heater core failures after removing the OEM intake manifold heater nipple for some aftermarket crap. Worked great...until they stood on the gas pedal and the RPM went way up.

Later, I heard that Pontiac was doing the same thing in a different way--with a metal helix poked into the heater nipple to reduce flow.

It's not like the heater core needs a huge amount of hot water to provide roasty air.

That's when I looked inside the Quick-connect fitting...

 

[wirlybird]

So for ACDelco plugs it looks like it is the double platinum 41-979 or 41-902.
What's the difference?
No iridium one available but that's ok I guess. Some say the cost isn't worth it.

 

[Schurkey]

The Vortec 7.4 engine has a distributor. "Double" Platinum would be a waste of money. "Single" Platinum works just as well when there's no reverse-polarity ignition pulses (Waste Spark style.)

"Double" Platinum won't hurt...just won't provide any benefit over "Single" Platinum.

 

[wirlybird]

They are both listed as double platinum. Only other Delco plug listed is a standard copper. People are saying they are using platinum or Iridium plugs but none listed for the 454 Vortec.
Just trying to find the best Delco plug for this truck! Wires next.

 

[TexasAggie]

I see vehicles running original O2 sensors for FAR too long.

What's the benefit of replacing these sensors if they aren't throwing codes?

Any special trick to cleaning the throttle body on these motors?

 

[Erik the Awful]

What's the benefit of replacing these sensors if they aren't throwing codes?

Bosch needs money.

There's no point replacing the O2 sensor if it's still working...

...but...

...most people don't recognize it when the O2 sensor fails and drive around with a bad O2 sensor for too long, which can kill the catalytic converter. Bosch recommends replacing your O2 sensors every 30,000 miles. Most O2 sensors last 150,000+. If you're into high-time replacement strategies, I'd go with replacement every 150,000 miles on our trucks. For even newer vehicles, I'd go with 200,000 miles.

 

[Schurkey]

1. Sensors WORK, but they don't work as fast as they age. Sorta like me. They get "lazy" as they get old, so that they're not reporting rich/lean values as rapidly as they're supposed to. This results in reduced fuel economy LONG before there's a code set. Maybe even driveability issues, which could potentially set OTHER codes. Of course, no-one actually does this before the sensor actually fails. This is why O2 sensor cross-count values; or the graph of voltage vs. time on the scan tool is vitally important. You're getting solid data on the speed of the O2 sensor.

I don't know about OBD-II engines; I suppose the sensors last longer because the fuel and ignition systems are more-tightly controlled. Maybe. On pre-OBD-II vehicles, I start suspecting the O2 sensor is getting wiped at 50K miles; and I've seen them totally shot by 80K. 150K is insane. Don't get me started on vehicles that burn oil excessively, or dump steamed coolant into the exhaust.

2. Everyone bitches about O2 sensors being seized in the pipe or manifold. Duh. PULL THE FRIGGIN' THING OUT at 30K or 50K, even if all you intend to do is apply fresh anti-seize and screw it back in. This is EXACTLY the same advice they give for spark plugs, with only the service interval changed. (Iridium plugs in aluminum heads should come out at/before 100K miles, even if all you do is apply fresh antiseize and screw 'em back in. The plug may be perfectly useable, but waiting beyond 100K is begging for it to be seized in the head so bad you wreck the threads in the aluminum head taking them out later.) Of course, no one actually does this until the sensor (or plugs) are seized.

Foookin' people won't empty the crumb tray on their toasters, and that's free. Can't expect 'em to take care of their vehicles when it actually costs money.

 

[wirlybird]

I'm going to go with Delco 41-993 plugs for the '97 Vortec 454. I am correct that these will be ok? Fit correctly?

 

[Erik the Awful]

Everyone bitches about O2 sensors being seized in the pipe or manifold. Duh. PULL THE FRIGGIN' THING OUT at 30K or 50K, even if all you intend to do is apply fresh anti-seize and screw it back in.

I think this is a regional problem. Here in Oklahoma, it'll be tight, but cut the tail off and put an impact socket on the old O2 sensor, work it a bit, and it'll come out. I've done it plenty of times.

I do agree that O2 sensors slow down rather than fail outright, and that's why most drivers don't recognize the problem until it's significant.