2500 Oil Pressure Gauge Readings

[amx390]

Was wondering if a few 2500 8.1L owners out there could post there finding on oil presssure gauge readings. I'm a happy to report I am a new AV owner with only 250 miles but am concerned with the oil pressure readings as they seem to fluctuate greatly. Also at times, keeping the throttle constant, the gauge fluctuates up and down 5 psi's rapidly.

Cold Start: 75-80 psi
Hot at throttle: 70-80psi
Hot idle: down to 25-30 psi.

Have had many cars/trucks with oil pressure variances but this certainly has the most range I've ever experienced. Just wanting to compare before I get conerned and check in with the dealer.

Another concern is that at startup and for about 10-15 seconds it sounds like the injectors/valves are noisy (like a mild diesel engine), but things quite down (considered normal) a little while after leaving it idle.

Appreciate everyone's comments and comparisons on these items.

 

[gandolphxx]

Welcome to the world of BigBlock - you numbers are quite normal.

Also expect 1 qt/1000 miles usage for the first 3-4K miles - also normal.

The restroked 454 tends to sound a bit like a diesel on startup - get it broken in and see how it does.

Welcome to the board and your new truck.

 

[JoeZ]

I have had two 2500 Avalanches. The first ran at 65 to 70 cold, and 55 to 60 hot at highway speeds. It idled at 25 to 30 hot. The second one runs 60 to 65 cold and 50 to 55 hot at highway speed. It idles at 20 to 25 hot. These use an electronic guage and are not too accurate. Soon after I got the second Avalanche I noticed the pressure difference and put a temporary manual guage on it to check. The manual read 80lbs at the same time the electronic read 65. I have a C-30 Chevy truck with a 454 and once a year it looses oil pressure and I change the sending unit and the pressure returns to normal.

 

[jeter]

my av has 12,000 miles on it and the oil presure does read up and down as you all have indicated. my problem is oil consumption. my dealer says the general allows 1/2 quart per 3000 miles. my dipstick reads three holes down. they say each hole represents 1/8 of a quart. that does not seem correct. the general recomends changing the intake manifold bolts which i had done. it did slow the problem. any ideas or comments will be appricated. i do have the 8.1 2500.

 

[amx390]

Thanks everyone.... I'll keep a check on the oil consumtion as gandolph states. I'm glad I found this board as it put to ease my concerns regarding what's normal. BTW the owners book doesn't state what is normal presure readings, which I would have thought this is where such information would be.

I'll post my findings again later on when the beast gets some miles put on.

One Question for everyone: What has been everyone's experience on when the truck will complete it's breakin period and how the trucks been driven? Book says keep it under 55mph (yeah right) and not keep at a constant speed (ok, no problem) for the first 300 miles. Can then compare if there's anything related here for allowing a breakin according to GM vs oil consumption & oil pressure based on how the truck is driven.

Thanks

 

[gandolphxx]

The 496 [8.1L] has been aroung for a long time - 454 restroked for more power - don't sweat the engine, just drive it - it is tougher than a junk yard dog and reacts accordingly.

The oil consumption is just part of the behaviour, get used to it and you willl enjoy it more.

Cheers

 

[aprgriggs]

The 496 [8.1L] has been aroung for a long time - 454 restroked for more power - don't sweat the engine, just drive it - it is tougher than a junk yard dog and reacts accordingly.

The oil consumption is just part of the behaviour, get used to it and you willl enjoy it more.

Cheers

I agree, i drive the hell out of mine and it is a horse. the oil consumption is a small price to pay for all that power and fun.

 

[Congelado]

The oil pressure gauge in our Av seems to fluctuate quite a bit also, but only when the RPMs fluctuate. When the engine is at a steady RPM, the gauge stays pretty steady.

Regarding the oil consumption, I recall reading in one of the manuals (can't remember which one) that excessive oil consumption is buring more than 1 quart of oil within 100 gallons of fuel used. However, during initial engine break-in period (3,000-4,000 miles) oil consumption may exceed over 2 quarts per 100 gallons of fuel used.