MF-135 oil pressure fluctuations

[flusher]

My 1964 MF-135 diesel is showing unusual oil pressure fluctuations. Oil pressure before this problem arose stayed in the 50-60 psi range constantly.

Now after engine start the pressure rises to 30 psi at 1300 rpm, fluctuates between 20-30 psi for 7-8 minutes and then drops to zero or near zero in about a minute. Shut off the engine immediately. Got a little coolant dripping out of the radiator overflow.

Repeated this behavior 3 times before stopping to think about the problem.

Checked the oil level; it's OK. Just a little oil leakage (less that a teaspoon) after engine shutoff, probably from the breather tube on the valve cover. No unusual smoke from the exhaust pipe.

The oil pressure gauge is a mechanical gauge with small diameter metal tubing to the engine.

Disconnected the oil pressure line at the engine and got a small pressure release and a little oil dribble from the fitting on the block.

There's a check valve on the outlet of the oil pump. Is this accessible by removing the oil filter plate on the block?

How about crankcase flush? Any recommendations?

Anybody have experience with Lucas Heavy Duty Oil Stabilizer?

Well, I finally found some time to work on the MF-135 oil pressure problem.
Decided to try the ATF flush method.

Got a nice new pressure gauge test kit from Amazon.com ($25) for measuring oil pressure and transmission pressure. Removed the oil pressure gauge that has the small diameter copper tubing and removed the oil pressure switch. The test gauge comes with a handy 4-ft hydraulic hose so you don't have to get off the tractor to read the gauge. Screwed the end of the hose right into the block.

Started the 135. Checked the oil pressure with the test gauge. Fluctuating between 10psi and 30 psi. Ran the engine for 15 minutes without any change in these fluctuations.

Drained the old 30W oil, removed oil filter. Added new 30W oil, new filter and 1 qt of Dextron ATF. Ran the engine at 1000 rpm for 10 minutes.

Pressure fluctuated as before between 10 and 30 psi. After about 3 minutes the pressure jumped to 60 psi and fluctuated between 30 and 60 psi for several minutes. Then the pressure evened out at 60psi. Shut down the engine after 10 minutes. Drained the oil, which looked like cream of tomato soup.

Replaced the oil filter, refilled with fresh oil. Ran engine for 10 minutes. Rock steay at 60 psi, which is where it was when I bought the 135 in July06.

I dodged a bullit on this one. Thought for sure I'd be replacing the oil pump. Was not looking forward to dropping that heavy oil pan.

 

[Soundguy]

I wonder if something like the oil pressure relief valve was stuck open? Not sure what method they used on that engine.. but on ford it is a spring and pluger setup..

soundguy

 

[Farmwithjunk]

I wonder if something like the oil pressure relief valve was stuck open? Not sure what method they used on that engine.. but on ford it is a spring and pluger setup..

soundguy

Perkins diesels use a spring and plunger, internal to the oil pump itself. Not saying it's IMPOSIBLE that it stuck "open", but I've never heard of one doing so. They will stick "closed" and hold too MUCH oil pressure. They've been known to do that quite frequently. The spring in the relief is a very stout little sucker! ANY sludge at all, along with that stiff spring, and it tends to freeze in place. And they stick most frequently when using NON detergent oils ("straight weights") Perkins diesels LOVE modern multi-weight detergent oils (like 15/40's).

"Gut instinct", I'd bet the oil pick-up screen was partially clogged and the ATF dissolved some of that. We may never know.....

 

[flusher]

Perkins diesels use a spring and plunger, internal to the oil pump itself. Not saying it's IMPOSIBLE that it stuck "open", but I've never heard of one doing so. They will stick "closed" and hold too MUCH oil pressure. They've been known to do that quite frequently. The spring in the relief is a very stout little sucker! ANY sludge at all, along with that stiff spring, and it tends to freeze in place. And they stick most frequently when using NON detergent oils ("straight weights") Perkins diesels LOVE modern multi-weight detergent oils (like 15/40's).

"Gut instinct", I'd bet the oil pick-up screen was partially clogged and the ATF dissolved some of that. We may never know.....

Thanks for the analysis. Looks like I'll change to 15/40 oil in the future. Use 30W now because that's what the previous owner used.

 

[Soundguy]

Yeah.. it was a long shot guess.. but you are probably correct.. the atf solvated something that was blocking flow somewhere.

That would make me want to change the filters after that for piece of mind.

soundguy

Perkins diesels use a spring and plunger, internal to the oil pump itself. Not saying it's IMPOSIBLE that it stuck "open", but I've never heard of one doing so. They will stick "closed" and hold too MUCH oil pressure. They've been known to do that quite frequently. The spring in the relief is a very stout little sucker! ANY sludge at all, along with that stiff spring, and it tends to freeze in place. And they stick most frequently when using NON detergent oils ("straight weights") Perkins diesels LOVE modern multi-weight detergent oils (like 15/40's).

"Gut instinct", I'd bet the oil pick-up screen was partially clogged and the ATF dissolved some of that. We may never know.....

 

[Ortis]

Can you educate me on the ATF flush method? Will any ATF work? How much? how long do you run the engine after adding it? Is ATF better than the engine flushed you can get at the Auto Parts places?

 

[Soundguy]

It's probably less agressive than an engine flush at an auto store.. and may have more lube properties. The flush from an auto store likely has lots of things like stoddards solvent, MS, kero.. or similar 'petroleum distilates' in it...

I would change the filters int he tractor an hour after the flush, and then do an oil change completely, a few days after the flush.. if not the same day, after running her and letting her get up to temp and worked lightly.

I usually do that on real dirty antiques i get. I run down to walmart and pick up a couple 2g jugs of their cheap supertech oil, and some atf fluid.. and do a flush ( or two ) if they are real nasty.. plus a disposable filter, and a 'keeper'.. perhaps a fram/wix combo.. ( keeping an eye on the OP gauge the entire time I might add!!! )

soundguy

 

[LtCollins]

Wow.. I am having the same problem with my 135, and was dreading the thought of breaking the machine in half, as I don't have a shop yet. I think ill try the trans fluid flush option first as well.

 

[Soundguy]

welcome to tbn!

 

[The kid]

I'd go along with the other advice.. replace the oil gauge, and blow out the oil line.. reconnect and burp the line, then see what ya got.

soundguy

Is burping the line the same as priming it while running loosen the line till oil shows then retighten. I'm replacing all my gauges and this is what I wasa going to do on my oil pressure gauge. Please explain. -robert