My Mack CX613

[Richard Surman]

2002 CX613 Low oil pressure. Mechanic can't seem to figure it out, Any ideas?

This is a never ending story. . .

Purchased truck in Memphis while driving it home about 300 miles I discovered oil in water. At that time oil pressure 60 psi.

Brought to mechanic, did In Frame. brought it home thought we was good to go. Started it up went down the road a few miles and oil pressure dropped. Cold start 20 psi, running drops to 18. Mechanic has put new rods and mains, head gasket, new sleeves, new oil pump, new accessory shaft, new bypass oil pressure regulator , rings, checked Jake brakes, checked rocker arms. Now mechanic says its the cam bearings. Cold start 20 psi 15 min later 18 psi engine shuts down. 8 weeks later no solution. Picked truck up and now she sits. Anyone had this problem?

[Freightrain]

Welcome to the forums. Can't give you any insight personally, but there are guys here that can give you some ideas.

[Richard Surman]

Thanks

[Dirtymilkman]

Sounds like the oil cooler. It should have a updated oil cooler that looks like plates stacked together

[Challenger]

Are you using a electronic or mechanical oil pressure gauge? Have you verified the oil pressure with another gauge?

When the oil pressure drops while running, does the engine brake get weaker?

[staxx]

Did the correct size bearings get installed , had a truck few years back that someone else had rebuilt the engine turned the crankshaft down and put stock bearings in = low oil psi . I had to remove bearings and install correct oversize bearings and all was good. Need to make sure oil is not being duluited with fuel also this is common low oil psi issue.

[Dirtymilkman]

He did say he has oil in the coolant?

[Mackpro]

Piece of trash stuck in the oil pump by-pass valve?

[thomastractorsvc]

He did say he has oil in the coolant?

if you read it that was the reason for the in frame now that that is done he has no oil pressure and it shuts down, I would trouble shoot with looking at the receipts for the parts and verify they were correct, then mechanical oil gage, then pull the oil pan check oil pump by pass then keep working my way until the problem is found. The mechanic/shop that worked on it should be coming good for the work otherwise I wouldn't pay or try and get my money back if you paid by credit card contact them and dispute the charges

[Richard Surman]

No fuel in oil. Mechanical and manual oil gauge used. Changed oil sensors, oil pump, new oil pressure regulator, warning buzzer comes on within 15 minutes of truck running and shuts down. truck doesn't run long enough to check brake. blocked Jake brake, no change in psi. Rocker arm caps aren't leaking, Mechanic called said he felt only thing it could be was cam bearings.

Edited January 16, 2014 by Sir-Man

[br549]

The early etech had freeze plugs in the ends of the rocker arms, seen alot of them pop out but probaly all 4 would have to come out to loose that much oil pressure, seen oil pressure drop when wrong centrimax oil filter installed there is a big hole and a small hole one that fits those engine or maybe they left out the centrimax filter, good luck.

[staxx]

Have never seen cam bearings on etec cause oil psi so low that it caused low oilpsi and shutdown to come on . See if he still has the old main bearings and check to see if they say deltawall on the back or P1 or P2.

[Challenger]

If you would've said, low oil pressure and not had any repairs, Rods, mains, and oil pump would have been first choice. You probably should check the rod and main bearings as Staxx suggested and check the oil pump as Mackpro68 suggested. Its hard to condemn new parts but shit happens.

Ive also never seen cam bearings cause low oil pressure and shutdown. Cam bearings could cause low oil pressure to the jakes, but that isnt your problem.

[Richard Surman]

I checked the oil pump and made sure no debree and gears aren't broken on new pump also blocked off hoses to jake brakes I was wandering how much oil should be getting to the rocker arms and vales it seems like very little to me I also installed relief valve or by pass spring in filter housing is there anything else that could cause low oil pressure after 15 minutes of running seems as soon as oil get warm oil pressure drops

[staxx]

Make sure oil pump block off plate gasket is good and pickup o-ring to pump is good.

[Richard Surman]

I pulled main bearing down and did a plastic guage 6 thousands on the bearing clearance is this ok or to much lost at what to try next

[Richard Surman]

we already checked oil pump o ring and checked gasket the other mechanic still say cam bearings any other sugestions

[Richard Surman]

I just tore it down, have one lower main bearing in hand. Has noticeable groves, and a few burrs, less than 300 miles on these bearings. Top appeared to be fine. I have yet to check other bearings. Did plastic gauge and measured six thousandths. Mechanic does not have old bearings available for comparison.

[rickykarenpr]

do you Have a pic of the truck??

[staxx]

Crankshaft main journal to bearing clearance .0022 - .0056 in. Make sure if engine is in chassis to support the crankshaft to measure with plastic gage to get a good reading. Rod journal clearance .0012 - .0054 in. If the crank has been turned down they are usually marked ,stamped at front counter weight somewhere.

[james j neiweem]

.006 seems a little sloppy. The other mains might even be worse. I believe some of the newer cars are in the .oo1 range.

[Richard Surman]

Pulled two main bearings, one has hole and groove in center, one has offset hole and groove. Are there two different types?

[gearhead204]

upper and lower bearings can be different, lower shells typicaly have more surface area than the uppers since thrust force on the crank is down.the milled grove in the upper allows for oil to enter the crank journal and supply oil to the rod bearings. did you plastigauge the rods? it sounds like either wrong bearings got installed or other component is improperly installed. you drove truck to shop with ok oil pressure and cant drive it out with good oil pressure. something is like cam bearings don't fail in the shop when the eng isn't running. unless it spun a cam bearing it start up. This will be real messy but you could pressureize the oil galley with a external oil pump and with the pan off see whats leaking too much oil

[Richard Surman]

was reading your response and was not understanding how to pressurize with external oil pump were do u get the oil pump from or do I use my oil pump and what is the best way to do so

[Richard Surman]

March 27, 2014. Problems and issues resolved. Four months and she's ready. New mechanic investigated for about a week. Oil pump and filter was incorrect. Leaking oil by oil cooler that mounts to block. The Etech and the E7 appear to have same oil pump. However, Etech pickup and discharge are opposite of E7. I needed a 12 tooth but had a 13 tooth that created the low oil pressure. Watched quite a few mechanics scratching their heads. The new mechanic took the challenge and solved her problems. Thanks to all for your advice it sure helped. Now I'm off to hit the road. Richard