Cat 3406E Low oil Pressure - Diesel Forum -
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post #1 of 5 (permalink) Old 09-29-2005, 09:55 PM Thread Starter
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Cat 3406E Low oil Pressure

At work we have a 3406E with low oil pressure only when engine is warm. They had the oil pump replaced, and that fixed the problem for 2 months/7000 mi.

We tore the oil filter housing off and inspected the cooler and filter bypass valves, they are OK. We also dropped the pan and inspected for damaged inlet or discharge lines and o-rings from the pump and replaced mains and rods because of mileage on truck, all are OK.

Has anybody else ever come across a problem like this or does anybody know of any other part that could cause this problem?

On Edit: Engine cold has 55-60 psi throughout RPMs, when hot, drops to 40-42psi throughout RPMs. This truck just started doing this before replacing oil pump.

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post #2 of 5 (permalink) Old 09-29-2005, 10:59 PM
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Re: Cat 3406E Low oil Pressure

What's the S/N? I can look up the spec data for it. If I recall 42 psi warm is not out of spec. Worn cam bearings can create low oil pressure also.

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post #3 of 5 (permalink) Old 09-30-2005, 09:01 PM
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Re: Cat 3406E Low oil Pressure

Assuming you checked everything on the bottom end... If that motor is equipped with an engine brake I'd also be looking up top for leakage at idle with the valve covers off and down in around the cam with a good spot light. The E model 3406 should have more oil pressure than that.

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post #4 of 5 (permalink) Old 09-30-2005, 09:59 PM
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Re: Cat 3406E Low oil Pressure

Another thought, on the brakersaver engines with remote oil filters, the two connecting hoses can in some cases be reversed. We had a truck with this condition, & it had a very negative effect on the oil pressure.

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post #5 of 5 (permalink) Old 10-01-2005, 11:31 AM
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Re: Cat 3406E Low oil Pressure

If I recall 42 psi warm is not out of spec.

[/ QUOTE ]

Don't know about spec but mine has 45 to 50 at idle and almost 70 PSI under load.

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