accelerate then brake...oil pressure drops to 0

[EscaladeDiesel]

This evening while on the freeway in an unknown area, I had accelerated to pass a veh, then realized I needed to exit, the exit was short and I had to break quickly, when I did this the oil pressure when to zero, and the check gauges came on, I rev' d the engine once, but no reaction, then rev' d it again, thinking I was about the have another engine failure, and the oil pressure came back up to about 35. I drove another 10 miles and the pressure seemed ok. Am I about to have some catastrophic failure again? Gawd I hope not as everything I have will be in the shop

[twaddle]

Hi there, check the connector and wires for the oil pressure sender switch at the engine block, it sounds like you have a loose connection somewhere.
When you brake the engine movement may be causing a loose connecting to lose it all together.

If the problem persists you need to connect up a test gauge to the oil pressure gallery, even if it's just for peace of mind.

Hope it's nothing series.

Jim
Biggar, Scotland.

[markrinker]

God did this to you because you were driving like a maniac. smile.gif

Assuming you are 1) full of oil and 2) have good oil pressure now, I'd check wiring to and/or replace the oil pressure sender first, watching your oil pressure guage like a hawk. After that, if you see the intermittant zero readings again, I'd replace the gauge.

How many miles on the current engine and oil pump? The fact that this happened under extreme braking also makes me wonder if you dislodged some 'bottom of the pan' sludge or object, temporarily blocking the pickup screen on the oil pump.

Did you shut off and restart to re-establish oil pressure, or was the truck running during the whole scenario you mentioned?

[ 12-19-2004, 04:13 AM: Message edited by: Mark Rinker ]

[EscaladeDiesel]

The engine is partially rebuilt, not to go into the entire story, but my oil line failed last year, lost oil, had engine apart, was told it was ruined, but after three mech's, there was no sludge & ultimately it was just a failed rod bearing and scored crank. All bearings were replaced as well as the crank, harmonic balancer, rod, gaskets, etc, etc....I have an IP issue as when driving there lots of extra clatter, but engine performs good.

[HowieE]

If your problem does not turn out to be loose wiring, which I doubt. After the engine has sat for several hours check the oil level, then run the engine for several minutes, turn it off and check the oil level ASAP. If there is a signifant differance, 2 qts or so, the return galleries from the valve covers may be clogged and you did in fact starve the oil pump when you stopped.

[catmandoo]

i had that happen all the time on my old pontiac,thing liked to drink oil.that was my indicator that i was low on oil.car wasn't worth fixin,put 75,000 miles on it in a year and a half,til the tranyy took a dump.

[MTTwister]

It does sound like most of the oil was in the top end, and heavy braking sloshed the remainder int he pan forward, away from the pickup. - Keep driving like that, and you'll need a baffle in the pan smile.gif .

[EscaladeDiesel]

It appears my oil level was almost 4 quarts low. I am guilty of not checking it the last 4 or 5 times I filled up. Guess I wont do that again.

[john8662]

Originally posted by EscaladeDiesel: It appears my oil level was almost 4 quarts low. I am guilty of not checking it the last 4 or 5 times I filled up. Guess I wont do that again.WHOA! Any idea where all your oil went? Thats quite a LARGE sum of oil consumption and or loss!

[EscaladeDiesel]

There is no leak, so it must be burning it. I figure it's about 1 qt every 1000 miles. I drive almost 100 miles a day EVERYDAY, and its been about a month since I checked it. So from this point on I will be more diligent in monitoring it to make sure just what's going on. Not sure why it would be burning oil...could something need adjustment?

[eracers999]

Id be looking in the intake at how much oil your suckin in. Id be looking at the blo by situation and be questioning the CDR valve. Personaly if it were me i would run a hose off CDR pipe to the atmosphere under the truck and plug off the intake boot cause i havent seen one yet that didnt pull oil in to the intake. I do not prefer oil injection if you know what i mean.

Kent

[EscaladeDiesel]

What kind of hose? Have a picture of this kind of setup?

[john8662]

Kent

While I agree that the CDR valve is suspect on these engines I do not believe that venting these engines to the atmosphere is a good idea. The 6.2 and 6.5 both make a little blow-by no matter the condition of the engine. The cummins for example doesn't make as much blow by and can be vented in this manner. My only worry with venting a 6.5 underneath the truck is that you'll still get to smell the blow-by smell (it has its own smell) and it makes me sick to smell it. A 6.5 will always have a steady stream of blow-by, when up to full operating temp, can't be good to breathe this stuff!

EscaladeDiesel,

Do some checking on your engine, is your engine "weeping" oil at all the intake connections (turbo boots, the upper intake bolts, intake sensors)?

When your engine is up to full operating temperature, open the oil fillter tube with the engine running, how much smoke do you see coming out of the tube?

How many miles are on your engine since the tear down and re-assemble? Were any of the pistons removed from the engine? Or was the engine just taken apart from the bottom end?

[EscaladeDiesel]

There seems to be some weeping at the connections.

when you take off the filler cap there is not much smoke, but there a metallic rattling that cannot be heard when the cap is on. Not sure this noise is normal or not, sorta sounds like something is loose. I don't recall that I ever had the filler cap off while the engine was running before so I don't have a baseline.

The #8 piston was removed and new rings installed.

Also, there is what I assume is the smell you are talking about. When at idle the exhaust has a different smell than it used to.

[john8662]

The smell you're smelling at the exhaust is normal, thats because it has a cat on it. When I removed my cat on my 6.5 for the new exhaust the exhaust started smelling like a diesel should. Othewise a sweet stinky (I used to call it powerstroke) smell existed, its the cat.

The sound from the oil filler tube is normal, it has a rattly sound.

Just out of curiousity, did they hone the cylinder that had the piston replaced, that got the new rings? Maybe the rings haven't sealed yet, giving you the blow-by you're seeing. From the destription you gave about how much blowby you saw points toward your oil consumtion.

One last question, how many miles are on the engine since you had the work done?

[EscaladeDiesel]

The cylinder was not honed, and the original piston was re-used, it just had the rings replaced and a new rod installed.

I have driven it about 4000 miles since rebuild.

[Turbine Doc]

Not honed might be having poor ring to cylinder seal, was it ridge reamed you might have a cracked ring if new ring hit high metal; is that possible in a Diesel.

I'm relating to a cheap rebuild I had done on a gasser once. I'd start paying close attention to oil consumption so you can get accurate idea of consumption of oil.