Truck Repair oil pressure problems

oldhippietommy

Well-Known Member
my c15 oil pressure usually runs around 60 ,maybe a tad bit more
lately it runs steady on 60 for about 3-4 weeks (about 7000-10,000 miles) and then slowly starts to fall to about 30-35
I change the oil and filter or just the filter and it jumps back up to 60 for another 3-4 weeks
I am going to change the oil and filtet again this weekend and I am thinking of running something thru with
the old oil to help clean the inside then changing the oil and filter.
my mechanic buddy says pour in 1 gal of diesel fuel and let it idle for about a hour
then drain it all out and add new

any thoughts on this or something else to add to it?
 

ironpony

Professional Pot-Stirrer
Supporter
If you have a problem developing, the wear metals could tell you something about it. I'd get a full service analysis done (not a benchtop test) before you try ta blow up your engine with diesel fuel in the oil.
 

oldhippietommy

Well-Known Member
I agree
any suggestion on a oil analysis place?
None locally so i better look online
 

dave350

Well-Known Member
I used Blackstone Labs. I had CAT pull one when they did oil change for me while I was on the road.

Blackstone Labs
 

dave350

Well-Known Member
its been a while but when I used Blackstone they would compare my sample to the average of other engines of my spec (3406b) and mileage. Maybe call and ask if they still do.
Oil samples are the most useful when done in secession as the engine wears but I think it’s worth it for you to have one done.
 

oldhippietommy

Well-Known Member
no local places capable of testing but there is a CAT about 25 miles south.I `ll probally run it over there,seems like the best bet

tks
 

mndriver

curmudgeon extraordinare
Supporter
The program I use is the cat SOS fluid analysis. Easy peasy and they have a record.

Go to your local cat parts counter and ask for the sample kits.

Cat | S•O•S Services | Caterpillar


Loss of oil pressure is generally an indicator of bearings failing and getting excessive wear. So analysis is critical as well as not operating the engine till you figure it out.

It's only $20,000+ to rebuild it after all and $40,000to replace.
 

oldhippietommy

Well-Known Member
I`ll check with them.I called them about a month ago and discussed a inframe,he said a ballpark figure was 30,000
including the twin turbos and a 4 year unlimited warranty.
A buddy got his done there,it ended up about 27000.He has the same cat motor I have and he got his hp cut up to 550 hp and 99 mph top end included
 

mndriver

curmudgeon extraordinare
Supporter
If it were my engine,...

I'd have gotten an oil sample sent in and then cut open an oil filter. Cutting open an oil filter is often faster and more telling than an oil sample.

Make sure you notate on the label you send with the sample it's due to falling oil pressure. It's a critical piece of information for the lab. Tells them there's a failure in the engine and they'll possibly be prepared to due additional testing.

The lab results are compiled over time so ever.

Trying to upload one of my reports
 

Hammer166

Instigateur №166™
Supporter
Sounds like the filter is plugging and the bypass value is opening.
 

oldhippietommy

Well-Known Member
I just went to Cat and got 3 kits
planning on sending one in today
I was told by a cat guy to do more than one to see a developing pattern.
 

dave350

Well-Known Member
I just went to Cat and got 3 kits
planning on sending one in today
I was told by a cat guy to do more than one to see a developing pattern.
You can buy a kit that will allow you to draw some oil out of the crankcase using the dipstick tube if you want to do a shorter interval than your scheduled oil change. I bought one from Blackstone long ago. Maybe CAT has one available as well.
 

mndriver

curmudgeon extraordinare
Supporter
I put a sampling valve on my oil bypass filter inlet.

They make a vacuum pump for drawing samples, but as frequently as I sample, it's easier and cheaper to put a valve on.

IMG_20170331_185524553.jpg
 

oldhippietommy

Well-Known Member
it is a good idea
I don`t have one but I intend to get on on mine
 
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