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Oil Pressure guage question.

GM Guy

GM Guy

Manual Trans. 2WD Enthusiast
Messages
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Location
NW Kansas and SC Idaho
Dad and I are a bit concerned about the oil pressure on the 92 C3500HD in sig. with the engine off and the key on the guage reads 40 psi. does this mean that 40 is actually zero?

If so, that is not good news, as when good and warmed up, it reads just over 40 (about 45). When you start off cold, it will read 75-80, but as it warms up, it tapers off.

To at least fix the guage issue, can we change it out with another? Does the new guage need to come from a 92 diesel cluster, any diesel cluster from 92-94, or will one from any 92-94 cluster work?

And as far as the motor, it seems in good shape, so can we start off by just replacing the oil pump?

Any input appreciated, thanks!
 
Even if you're going to replace the stock gauge, you should hook up a mechanical gauge, even if it's temporary. That will tell you for sure what the true oil pressure is.
 
Oilpump failure is uncommon in these engines,but not impossible. Try the mechanical gauge before throwing parts at it.
 
Oil pressure dose drop off some from cold start to warm up. thats normal but it shouldn't almost drop in half unless your running some cheapo wal-mart oil even then it dosent drop almost 50%.

From cold start up to operating temp you shouldn't be losing any more than 10psi -12psi max your losing about 30psi. i would first off change out the pressure switch sending unit for your gauge.

Other wise the best system a set of after market Mechanical gauges.

Mike
 
sorry for not getting back, had the flu...still have it actually. Thanks for the input guys, We will plug in a mech and then change the sending unit, as those are the cheapest ways.

Where is it easiest to plumb in a guage?

Thanks!
 
You could plumb a "T" into the oil feed line on top of the turbo. It might read a bit lower than at the core, but should be fine.

By the way, the dash gauge will read much higher than actual at low rpm's. By the time you get to about 2,000rpms the dash gauge will be closer.

But, it will be good enough to figure things out - plus it's quite easy! :smile5:
 
One quick note. When getting the oil gauge pick up a copper line install kit & toss the plastic line that comes with yours away.So that you're not having to replace the line and clean up sprayed oil because the line melted on something or your oil pressure reading wacky because the line got pinched somewhere.
 
How them 350's keeping with the diesels ?
I have been threw 7 350's so i tried a 6.5TD going to see how it holds up.

If your working them hard and loading them heavy i would be running 19.5s wheel and tires Single rear wheelers and duel rear wheelers for sure.

My GMC 2500 will be going from 7.50-16s to 19.5's soon enough. as the 77 Ford and 62 GMC have them and they work awsome. . .the 62 GMC camwe with them i switched the 77 ford over and wow I can run the heavy lug Mud tires and still get more mile out of them than any 16 hiway tire Of course i almost never do hiway treads cause if they ain't howling i'm getting stuck.

Mike
 
The two regular 3500s are DRW, so even with LRD 225/75R16s, they still have excess capacity. roughly 25xxLB x 4 = close to 10K rating, and the axle is rated for like 8K, and suspension rated for about 7600 (info from brouchure)

So we are sticking with the little ones, keeps speedo accurate, and makes it easier on the truck pulling light in OD or heavy in Direct.

The 350s seem to do fine, trailering mileage not great (10-12) but not bad, power is fair, unladen mileage is fair to good, the 98 hit 16 once. Keep in mind grain trucks around here run 350s, so it is a matter of gearing, some act like 350s should be illegal in 3500s!

As far as keeping with the 6.5l, the 6.5L has a deeper 1st NV than the others, so the 1st gear launch is better, and we still need to find out what gears it has, 4.63 or 5.13. So considering its superb gearing, it does quite a bit better.

Pulling, it accelerates better, coming alive at 2K RPM, when it wakes up the ol Snail Shell, and it sounds happy as a clam at 1800 and 58 or so MPH. Bringing it home empty for the first time it got us 14 mpg, so cant complain, and it does 10-12 mpg pulling, and the loads are heavier. Only complaint is the small midship tank (22 gal i think) But we love the axles, springs, frame, fact. body lift (bitch to enter/exit though! :) ) and tires, which wear nice on these trucks. the HD is one stout truck, so for real comparison, we need a 350 powered C3500HD, which they made through 95.

But there is a place in the fleet that each one meets, and so as a group, we are quite happy with them.
 
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My 62 GMC is a Gasser 379M-V6 (http://6066gmcguy.org/ ) it came with 19.5's and has no shortage of power at all tho road speed would be nice but it ain't the worst either truck cruises 62.5MPH@3,000RPM in 4th gear and sound nice clean and happy tho i am told this engine was designed to be ran 3,250Rpm in high gear i just don't feel comfortable Reving it up that high. truck came with 8-19.5 tires which i ran the Mudders as those work best for me, but they got discontinued so i now will be running 245/70R19.5s in a Mud tire. . .the 8-19.5 biasply is taller then the 8R19.5 radial by a good bit and noticeably Wider. . .so i didn't go with the 8R19.5's. . . the 245's are still a bit shorter. . .the 8-19.5's measure 34.2" x 8.50" so there the width of the 225/70R19.5 but the hight of the 265/70R19.5, tire shop said if they ever offered a 235/80R19.5 that would be a direct swap out.

The 1977 Ford F-350 had Tube type 16's which i replaced for tubless 16.5's bad idea 3 set of tires later they where about obsolete so i went to a 225/70R19.5 Traction tire, and swapped the 3.73 gear gears for a set of 4.10's and flip switch locking carrier. the tire wear difference is insane going from a load Range D biasply traction tire to a Load range F Radial traction tire. Built 351M 4spd manual 4.10 gears n 19.5's tough truck, tho its still a :eek:FORD:eek: i haven't any issues with it so far. . .

Thats my 19.5 trucks...

Mike
 
we still think that if a frito or bread truck is found, and it is so damn handy, we would put frito wheels on the regular 3500s.

(If you don't know, there are frito trucks that are chevy chassis, 8 lug (with appropriate hub pilot measurements) and 19.5 tires.)

but otherwise, them 225s are cheap! :) if one is damaged by road debris, one feels less bad letting it go...but then again 19.5s would resist more damage....oh well, pros and cons to both!

(we also have some railroad truck wheels with 8 on 6.5 budd pattern and 19.5s :) but only two :( so the search continues.. :))
 
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I'm also in search of some "COST EFFECTIVE" Single Rear wheel 19.5 Rims for my 6.5T 2500. this unit is my driver so i'm not going to spend a ton of money on wheels for it like i did the Ford, i got some steal wheels from pioneer rim n wheel for a good price better then that ricksons truck guy but still spendy. . .3 months later the local salvage yard ends up getting 10 19.5 wheels which they thought where of no use to anybody so i got them for a song. . .To bad i didn't wait on the ford a while could have saved a ton of money but that was years ago now...

Sadly when i was looking for duels all i could find was single wheels now i need singles and all thats around are a few duels here n there never a full set tho...
I'll keep an eye open for more 19.5 wheels you need duels or singles ?

Mike
 
a little bit of both, but really don't need any right now, as dad has a friend that buys trucks from railroads, and he got a clean 98 C2500HD 5.7L auto with a full set of 19.5s that we are eyeing (for 2,600 bucks, cracked out bed from insanely huge crossbox, and an auto that shifts fine, but the lever is tough to pull in (interesting :) ))... and of course we are looking out for a Frito truck!

but we won't be upgrading unless it is really cheap, as it needs to be really cost effective before we upgrade.

in the immediate future, we are really concerned about getting 8 bolt 17.5 wheels for the flatbed machinery trailer, as 19.5 is too tall, and we need higher load capacity over the 16s.
 
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