Oil pressure changes from startup

[tsivey]

I had some questions about my oil pressure dropping down from 50 cold idol to 10 hot idol. After looking over the forum I think my truck maybe making oil. After driving it about 400 miles It is showing about 1 1/2" over the full mark. So, where should I start looking first or what seals should I replace first? Thanks

 

[sandcobra164]

Do a search for ¨FDC Bypass¨ and see if this has been done to your injection pump. If not, try that and change oil, repeat trip and check oil. If it rises again, do a search for Hydraulic Head and you should see some threads about changing the O-rings that seal the Hydraulic Head to the injection pump. Neither are bad jobs and they can be done without removing the injection pump although the latter does involve a bit more work and removal of the injector lines and a critical step of timing the injection pump in order to remove the hydraulic head. This has been done by many on here including myself so you've got quite a support system on here if you need it. Please Search though as the Moderator's on here don't like duplicate threads.

 

[61sleepercab]

First: oil pressure change If oil is normal and not old or thinned out with fuel you should have same oil pressure at running speed hot or cold.
50 cold is good which should mean your bearings are at least ok, Drop when hot idle , you have less rpm on oil pump and therefore less volume output. Does the oil pressure pick up to near normal when up to regular rpm ? If so I would change oil and see what old oil looked and feels like in thickness.
Second: gaining oil STOP RUNNING TRUCK MOTOR AT ONCE!!! Drain oil and smell it for fuel . Check oil pump screen and bottom of oil pan for crud and blockage as you have unknowingly preformed engine flush.
If you have fuel gaining that fast you have to look for for fuel crankcase interface areas....... any mechanical fuel pump on the engine and the injector pump pump itself. I am not an injector pump doctor but something has to be leaking a lot to gain that much fuel oil. Have you chewed up a shaft seal somewhere?

You do not report any extra smoke so injectors are not at fault. Hope this helps a little. Mark

 

[brianp454]

I agree with sandcobra164. The FDC has a leak path that can allow fuel to leak into the oil. If you bypass it you may solve the problem and you'll likely appreciate the change in performance. I have a video on youtube that kinda walks you through it.

 

[tsivey]

I agree with sandcobra164. The FDC has a leak path that can allow fuel to leak into the oil. If you bypass it you may solve the problem and you'll likely appreciate the change in performance. I have a video on youtube that kinda walks you through it.

Thanks, I'll check out your video.

 

[Woodsplinter]

How are you checking the oil? If you run the engine, shut down, then check after one minute you will get an accurate reading. I found that if I wait longer, the level indicated on the dip stick will climb.
I do not have spin on filters and don't know how that affects the issue.

This would probably be a good time to get a baseline oil test done on your engine and tranny oil. This will confirm the presence or lack of fuel and antifreeze in the oil.

Test kits are available on-line and from places like NAPA. Usually in the $15-25 range.

 

[JasonS]

First: oil pressure change If oil is normal and not old or thinned out with fuel you should have same oil pressure at running speed hot or cold.

Only if you are up against the relief valve. Otherwise, the oil pressure will be lower hot than cold.

 

[Woodsplinter]

Your oil pressures sound normal. If the truck is new to you it might have been overfilled to begin with. Why do you think you're making oil? Does it look or smell funny? I would make sure that is what is happening before I began replacing or changing things that may not need it.

Hope this helps.

 

[tsivey]

Your oil pressures sound normal. If the truck is new to you it might have been overfilled to begin with. Why do you think you're making oil? Does it look or smell funny? I would make sure that is what is happening before I began replacing or changing things that may not need it.

Hope this helps.

It is a new to me truck, I picked it up last week. I had checked to oil when I picked the truck up and it showed about half inch over full. I assumed the seller over filled it a bit, the truck had been run before I checked the oil. I finally got all the paperwork legal and was going to take it out, checked the oil it showed to about 1 1/2" passed the full mark. Would it show that high after setting and cold? The oil does look a little thin, it may also be me looking for problems too.

 

[topo]

If you put a drop of motor oil on a hot manifold or a hot turbo even better it will run off. A drop of diesel will quickly evaperate . Try a drop of oil from your engine and see what it does ?

 

[sandcobra164]

If you read what was stamped into the dipstick, it says to wait about 2 minutes after shutdown to check the oil level. I agree that you should smell it to make sure you don't smell any diesel but if left sitting over a period of an hour or so, they read high on the dipstick. Also, mine will idle around 60 psi cold, 90 psi above 1,000 rpm but when warmed up, about 25 psi at idle and around 55 psi at 2,300 rpm and running down the road. I know mine is not making oil.

 

[Woodsplinter]

My oil shows way too high on the dipstick after the truck has been sitting for a day or more.
Start it up, let it run for a few minutes then shut it down. Wait one minute, pull the dipstick and wipe it, then reinsert. (Don't screw it back in) Pull it back out and read the level.

 

[welldigger]

I had some questions about my oil pressure dropping down from 50 cold idol to 10 hot idol. After looking over the forum I think my truck maybe making oil. After driving it about 400 miles It is showing about 1 1/2" over the full mark. So, where should I start looking first or what seals should I replace first? Thanks

Call me tomorrow evening.

 

[tsivey]

Call me tomorrow evening.

K

 

[tsivey]

My oil shows way too high on the dipstick after the truck has been sitting for a day or more.
Start it up, let it run for a few minutes then shut it down. Wait one minute, pull the dipstick and wipe it, then reinsert. (Don't screw it back in) Pull it back out and read the level.

I have been working on engines for over thirty years, cars, trucks, tractors and even airplanes, I have never seen an engine you had to run before you checked the oil. I guess an old dog can learn new tricks after all. Did what you suggested and it shows about a quart low. Odd way of checking the oil, but OK. Crises averted, thanks for all your help.

 

[Warthog]

How are you checking the oil? If you run the engine, shut down, then check after one minute you will get an accurate reading. I found that if I wait longer, the level indicated on the dip stick will climb.
I do not have spin on filters and don't know how that affects the issue.

The stock oil system will drain the entire gallon of oil from the filters back into the pan when the engine is off. This will cause the oil level to rise on the dipstick

Check it after it is run, get it to the correct level and then recheck when it is cold. Make you a "new" full mark and then you will be set.

 

[Woodsplinter]

I agree it's a strange way to check the oil. Hopefully that's all it was- keep us posted if you have further issues.