Hi, When I idle my D4H cat (3304 engine) before shut down, the warning light and buzzer come on. I ran an oil pressure check and it is running lower than it should be. I changed the oil and filter and checked for debris in the filter and no trouble there. I've checked the oil filter bypass and it looks o.k. I have the service manual but it's not helping me with locating some other "easier" sites to check before getting into the more difficult stuff. I'd like to check the oil cooler bypass but can't find it. Any other thoughts on what to do next? Any suggestions would be appreciated.
Have you checked the pickup screen in the oil pan?
While you have the pan off also check the relief valve on the engine oil pump. What oil are you using ..?
d4h oil pressure problems No, we haven't had the oil pan off - I didn't realize that is where the oil pump is located. Is there anything I should know about taking the pan off before I wreck something? Thanks
d4h oil pressure problems Hi - is the pump going to be obvious when I take the pan off? Is there a gasket I will have to replace - I've never had the oil pan off before. I'm using 15-40 oil. Thanks
Be careful with the pan. on some later models they are made out of cast aluminum and break quite easily.
Have seen suction bell break off and pieces lodge in relief valve on a 3304 causing low pressure. Either way you dont wanna run it too long if the pressure is low.
You'll definitely need an oil pan gasket, the old one will break as you take the pan off. Whatever else you need will only be determined by what you find when you pull the pan off. It may need a complete oil pump replacement if the pump's goosed. I may be missing something here (never worked on anything that small) but isn't the engine in the D4H a 3204 not a 3304 ..?
nope, 3304
In total there are seven different Serial Number Prefixes for D4H. Out of those 7 only 3 (4NK, 8PJ, & 9GJ prefix) have 3304 engines, the other 4 have 3204 - that's why I asked.
your right Nige, the series 3's had the 3304
The oil pressure R/Valve on the 3304 is slightly different to the common style valve its made up of dome shaped washers (belville Washers) these are not uncommon to crack, when this happens the high idle oil pressure often seems to be around 20psi??? with the low idle in the very low section of the gauge, the big lump under the engine is called the oil pan in CAT words with the steel plate that is the next section is called the sump, please be aware that if you remove the oil pump from the engine the Lanchester style balance shafts will require re-setting, this is a simple thing to do if needed, all the crank bearings can be swapped out from underneath without any problem, if you remove the oil pan the sump plate can curl down damaging the joint between the plate and the cylinder block, the oil pumps are not very costly with the after market ones being good (Italy), its best to pin up the flywheel and balance shafts before removing the oil pump if things go this route.
Had low oil pressure on my 3306 (much the same as your 3304)....ended up being two problems. The gasket between the oil pickup tube and the pump was half missing because the bolt holding the outer end of the pickup tube wasn't tight (too long of a bolt) allowing the tube to vibrate. Also the bypass on the pump was weak (belville washer type) and didn't have much tension. The new one was REALLY stiff. After fixing these two problems the oil pressure pegs the gauge again.
d4h oil pressure problems Thanks for the info. I re-checked my oil pressure with a brand new oil pressure gauge and it seems to be in the right range. I ran it for 2 or 3 hours and let it idle down and no warning lights or buzzer this time. I'm going to run a gauge directly into the cab, cross my fingers and hope that maybe the filter bypass was stuck open. Sure appreciate the input.
I can see why you're reluctant to start tearing into the engine. What oil pressure do you have at the following RPM with the engine coolant at normal operating temperature - Low Idle, High Idle No Load, & with transmission stalled in 3rd gear. Post the results on here. I suggest you keep a log of all these 3 pressures on maybe a weekly basis. Then you will immediately see if the oil pressure starts to drop. That might be a determining factor in how often you change the oil & filter. Just to give you some idea the oil pressure for that engine when new/rebuilt is supposed to be a Nominal 50psi at Low Idle and Nominal 58psi at TC stall RPM with the engine at normal operating temperature. Don't expect a used engine to give you those pressures though. What brand of oil and what make of filter are you using BTW..?
Leigh if its the 3204 the oil pump is built into the backside of the front cover. its a gearoter pump the bushing is in the front cover the gearset fits inside the relief is right beside the pump.
if its the 3204 its got a gearoter pump on the back side of the front timing cover. They are good pumps and dont give much trouble. the relief is in the cover also but seperate fromm the pump. i would check my oil pressure switch on left side back of head they do give problems. pumps on a used engine idle from 15 to 30 hot from the gearoter set up
Leigh there is now way i would pull the oil pan before first checking oil pressure switch that works the light and not sure but i think a seperate one for the buzzer. i can see why your reluctant to tear into an engine that more than likley dosent need torn into pressure switches go bad more than oill pumps. maby at a 100 to 1 ratio give or take