That’s nice, I hate where it is on the squares
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
White Elephant 01 8.1 burb.
- Thread starter Wes Harden
- Start date
Welcome to 8.1 life. But depending on your average fuel economy, your consumption numbers are not off the average I've ever seen on 8.1s. Remember GM's horseshit rating on these big dogs was 1qt per 100 gallons of fuel ran through the engine. Just for easy math, at 10 mpg you'll use 100 gallons of fuel to go 1,000 miles. So if you are getting better mileage, it stands to reason, it will go further on a quart. But the general rule of thumb is to check the oil at or around 1000 miles until you have a handle on what yours does.
Mine uses a quart between 1500-2000 miles. It's pretty consistent there. But Larry's three use a different amount.
I think the GM rating is a bit of a cop-out, as they never really addressed the crappy PCV system that is a known point for sucking oil. They did have a couple of bulletins relating to oil consumption from the point of intake manifold bolts due to a change in the design. Larry's got the bulletins in the 8.1 thread. There are a few 8.1 folks that have modified the stock 8.1 intakes to work more like a conventional older pcv setup. The main one does involve chopping off the bottom of the plenum to do the modification so unless you are a wiz with a tig torch or know somebody that is, it's not an easy modification to do.
What it means is 8.1 owners need to check oil level regularly. I'm sure Wes was, but it is always good to have a reminder when the discussion comes up. I may have already in this thread... I don't remember.
Mine uses a quart between 1500-2000 miles. It's pretty consistent there. But Larry's three use a different amount.
I think the GM rating is a bit of a cop-out, as they never really addressed the crappy PCV system that is a known point for sucking oil. They did have a couple of bulletins relating to oil consumption from the point of intake manifold bolts due to a change in the design. Larry's got the bulletins in the 8.1 thread. There are a few 8.1 folks that have modified the stock 8.1 intakes to work more like a conventional older pcv setup. The main one does involve chopping off the bottom of the plenum to do the modification so unless you are a wiz with a tig torch or know somebody that is, it's not an easy modification to do.
What it means is 8.1 owners need to check oil level regularly. I'm sure Wes was, but it is always good to have a reminder when the discussion comes up. I may have already in this thread... I don't remember.
Been averaging 12.x so 4 in 5k is about right.
On the bright side….
You’re never running dirty oil, spin a a new filter on at 5k and you’ve basically done an oil change
You’re never running dirty oil, spin a a new filter on at 5k and you’ve basically done an oil change
That stupid valve isn't just an 8.1L thing, it's all of the GMT800s and I think 900s.
That reminds me of once checking the port on an acquaintance's 20+ year old Camry as he was complaining the AC was getting warm.
As soon as I bumped it with the gauge the valve shot out over my shoulder and the corroded end bits exploded. Naturally the remaining Freon in it PSSSSSSSST out in about a second and he got all grumpy that now it definitely didn't work.
I let him fix it.
I also found out why the beastie is spotting the driveway, one of the plastic heater hose connectors is dripping on the right rear valve cover. Got all 4 pieces (rear heater) today will get those swapped tomorrow.
Desert Storm https://www.desertstormlhc.com/ starts tomorrow, thing to do and see, then we leave for 3 days in Sedona on Sunday, not more will get done till after.
Desert Storm https://www.desertstormlhc.com/ starts tomorrow, thing to do and see, then we leave for 3 days in Sedona on Sunday, not more will get done till after.
Yesterday I was able to replace the high side line, to replace the cheap fake service port shrader,
For a real SHRADER valve.
I also opted for a variable orfice tube, listed for extreme heat environment, which is my town.
Not sure about this orifice tube, yet.
Not a horrible job to do the tube.
I also did my leaking heater hose quick connectors. Which are not quick to remove. I just used a cotter key remover to snap all the plastic slots. Much easier than trying to work the tabs.
I bought all dorman, 800-413cd, 800-414cd, and 2 800-403.
The 2 tees have the same size nipple for heater hose connector, but one of the 2 800-403 would not go on no matter what I tried.
I went and got one form O'Reilly.
Dorman quality strikes again.
While doing the heater hose connectors, was vacuuming the ac system, @ 40 mins. Leak down test over an hour, low side needle might have moved, but I move the gauge set around a few times.
4 12oz cans r134a, is 3pd system. @80 degrees in garage last evening. Low side drew down to 32psi, a little low, but high side was going over 325psi. Both ac running, rear was freeze your butt cold, front not so much. I know the blend door actuator is turning, am thinking the door is not closing completely. Further investigation is needed.
Also has anyone got any experience with variable orfice tube?
For a real SHRADER valve.
I also opted for a variable orfice tube, listed for extreme heat environment, which is my town.
Not sure about this orifice tube, yet.
Not a horrible job to do the tube.
I also did my leaking heater hose quick connectors. Which are not quick to remove. I just used a cotter key remover to snap all the plastic slots. Much easier than trying to work the tabs.
I bought all dorman, 800-413cd, 800-414cd, and 2 800-403.
The 2 tees have the same size nipple for heater hose connector, but one of the 2 800-403 would not go on no matter what I tried.
I went and got one form O'Reilly.
Dorman quality strikes again.
While doing the heater hose connectors, was vacuuming the ac system, @ 40 mins. Leak down test over an hour, low side needle might have moved, but I move the gauge set around a few times.
4 12oz cans r134a, is 3pd system. @80 degrees in garage last evening. Low side drew down to 32psi, a little low, but high side was going over 325psi. Both ac running, rear was freeze your butt cold, front not so much. I know the blend door actuator is turning, am thinking the door is not closing completely. Further investigation is needed.
Also has anyone got any experience with variable orfice tube?
I tried it and wasn’t impressed.
forgot also did ac compressor belt and tensioner. It was due. The bearing was very dry, and had a little wobble, spring was a little soft compared new GM unit.
Mine was not on a front and rear system, just the k10 standard cab. It worked, but no different from the 4 dollar white.
I really think something is up with the blend door, just one click up from full cold make the temperature to hot, even when in Truckee ca in December.
Actuators can be an issue on the HVAC system in 800 trucks like yours. Is yours a dual zone front system or single, i.e. separate controls for driver and passenger for temp?
I'm curious if it is the dual zone if there is a difference between the driver and passenger controls for temp output.
One thing to not overlook is the cabin air filter. I can't remember if you had already changed it or not. A dirty cabin filter will impact temp output and volume of air coming out of the vents.
It is a single zone in front. The cabin air filters were changed previous oil change, @5k miles. I am going to mark shaft position tomorrow, and remove the actuator and see if the door moves further.
So you replace that whole line? Have the part number? I remember wanting to remove that port and replace or use something like a 134a conversion fitting, but saw no easy way to do it.
I used the VoV many years ago and liked it, but after it plugged up on me I found the performance wasn't much different, so I stuck with blue tube since then. But this was on the K5. My 800s and 900 have stock A/C.
Last edited:
Yes I have the part number. Is for front and rear ac system. Four seasons 55942
Reading up on it just now, people are saying the ball valve does leak a little sometimes, but the cap is not just a dust cap, but the main seal.
Also, it seems you can replace the service port with something like Dorman 800-955. It takes a special socket, but maybe just adjustable wrench?
https://www.thetruckstop.us/forum/threads/ac-high-side-valve-removal.24554/
Also, it seems you can replace the service port with something like Dorman 800-955. It takes a special socket, but maybe just adjustable wrench?
https://www.thetruckstop.us/forum/threads/ac-high-side-valve-removal.24554/
Yeah I could not get the valve apart. While charging the low side pressure blew right through the capped valve, and was only 1/3rd full at the time.
Much happier with the larger high port and substantial sharder valve.
Edit: Since r134a is scheduled to phased out soon, I am keen on having even a tiny leak at a stupid excuse for a sealing valve.
I have serviced them before on late model trucks, we had in our fleet. Purchased the seals by the dozen. Not my trucks or my money. Modify was a dirty word to Fleet Management.
Much happier with the larger high port and substantial sharder valve.
Edit: Since r134a is scheduled to phased out soon, I am keen on having even a tiny leak at a stupid excuse for a sealing valve.
I have serviced them before on late model trucks, we had in our fleet. Purchased the seals by the dozen. Not my trucks or my money. Modify was a dirty word to Fleet Management.
Well I marked the blend shaft and pull a the actuator. The door swings easy and certainly sounds like it closed in ea direction. The mark I made also seems to line up with full cold.
The front air is not as cold as it should be.
The pipe after the orfice is cold, I think it needs insulation.
When I bought this truck last summer the front ac worked well, esp for west central AZ where 115 is normal.
The old orfice tube is nice and clean, I suspect a bad compressor, or destroyed desiccant. I think it just went low because the crap seal at high side service port.
I need to drive it, I didn't have any other air at condenser other than the engine fan.
Still with the evsp pipe as cold as it is I would expect lower temps from dash regulators.
The front air is not as cold as it should be.
The pipe after the orfice is cold, I think it needs insulation.
When I bought this truck last summer the front ac worked well, esp for west central AZ where 115 is normal.
The old orfice tube is nice and clean, I suspect a bad compressor, or destroyed desiccant. I think it just went low because the crap seal at high side service port.
I need to drive it, I didn't have any other air at condenser other than the engine fan.
Still with the evsp pipe as cold as it is I would expect lower temps from dash regulators.
2nd issue with this thing ATM. No reverse lamps. 2 fuses 1 for trailer plug that one is good, 2nd 15 amp for vehicle back up. Vehicle back up blows as soon as reverse is selected.
18 ohm resistance to ground at the under hood fuse box, where fuse is located.
I have inspected under that fuse box, no rodent damage or evidence of rodent occupation. Pulled the bulbs. Inspected all the connections and added wiring for reverse camera I did last November.
Trying to find a wiring diagram online but Google fu is just not cutting it today.
Any thoughts on the neutral safety switch? I thought it only talks to ecm/bcm, and either of them operates the lamps. Can't confirm this.
After I finish bbq-ing I'll disconnect it and see if my ohm reading changes
18 ohm resistance to ground at the under hood fuse box, where fuse is located.
I have inspected under that fuse box, no rodent damage or evidence of rodent occupation. Pulled the bulbs. Inspected all the connections and added wiring for reverse camera I did last November.
Trying to find a wiring diagram online but Google fu is just not cutting it today.
Any thoughts on the neutral safety switch? I thought it only talks to ecm/bcm, and either of them operates the lamps. Can't confirm this.
After I finish bbq-ing I'll disconnect it and see if my ohm reading changes
