Lately I’ve noticed having zero oil pressure on cold starts, or after not having driven the car for several hours. Takes about 4-5 seconds to go to 3 bar. It used to be at 3 bar almost instantly after startup. If starting within a couple hours of last running, it hits 3 bar instantly after startup

With the hope of fixing this, I changed the O rings on the oil filter rod. Didn’t help... Is frequently dry starting like this something to worry about?

Probably not the gauge, JamesDean has been through it in the past few years.

I’ve read that Stretch found check valve leak down after 1 hr to be acceptable.
Thoughts??? Leave it an motor on?? Maybe time for an engine oil flush to try to clean the oil filter housing check valve?

replace the orings on the oil filter covers stem. Which I see you did. Other than that..hmm Maybe you have a good leak in the system preventing the pressure to build?

You did the right thing there. I have never had mine apart but inside of that stem is a one way spring loaded valve. One of our member said he found stringy cotton material from the bypass section of the Oil Filter in the valve mechanism.

Note that the valve is supposed to keep the oil from draining out fast inside of the Oil Filter Housing. (The Oil that goes through there goes directly back to the Oil Pan.)

In the diagram #19 in the red circle and lines shows where the valve is and for reference the green rectangle and lines shows were the O-rings on the stem are.

I have never had mine apart so I don't know for sure but I think the lower end of the stem screws off to get at the valve. Keep any sort of vice grip or plier type tools away from the O-ring area.

After that suspect the Oil Pressure Gauge. Unfortunately there is no easy way to connect a test gauge.

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84 300D, 82 Volvo 244Gl Diesel

I've cleaned out the passage in the oil filter tube with compressed air and solvent. Mine had a piece of plastic wrapper in it from an oil filter package. It's a messy job, lots of spatter, wear eye protection.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I guess I’ll pull the filter out and try to snake the aforementioned stem with a pipe brush. Kinda unlikely that there’s foreign debris in there - I’ve been changing the oil myself on this thing for the past 10 yrs...

Is dry starting like this super bad for the motor?

Putting something in it like a pipe cleaner may make a problem. I'd try an aerosol solvent and compressed air first.

How many seconds does it take for pressure to come up? Is it a full 4-5 seconds? If yes that would concern me over the long term with frequent short trips.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Since the valve is one way the only way to clean it would be from the top down.
I really did not want to mention this. The tube is pressed into the top of the cap. I don't recall having trouble removing the Tube from the Oil Filter Cap when I had the need to drill the Cap from the inside out to install a fitting in the top of the Cap which I used to attach an oil pressure gauge (I also drilled through the cap from the inside out closer to the edge and put a fitting not shown in the picture.)

Once the tube is out you can use compressed air to blow down into it (wrap a rag around so it does not blow back onto you). However, that does not let you know for sure if you got stuff out of the valve.

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84 300D, 82 Volvo 244Gl Diesel

I might suspect the plastic tube which feeds the oil pressure guage... a kink will make a small hole. Possibly might also rub against something sharp.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

OK, back at it again.

There's an oil leak at the back of the head. It's either the turbo supply line or the head gasket. More likely the HG by the looks of it. Not a squirting leak, but is about 2-3x what i'd consider as "weeping"

How likely is it that the externally leaking HG is causing no oil pressure on start up? Is that eve physically possible given how the lubrication system is set up? For that to be possible, oil pressure would be draining down, then needing to be reestablished...

I doubt that a leaking hg would cause that.

Since you replaced the o-rings on the oil filter rod my bet is on the return valve in the oil filter housing.

more about it:

https://www.youtube.com/watch?v=YoYEDC-LjHQ

.

Does this apply to the OM601 as well?

Rather than cleaning the stem perhaps just grab a cap and stem from a wreck. It is the most probably culprit but nothing is certain in life.

Can anybody confirm this notion? Really would like to delay the HG job...

What do you guys think about replacing the oil filter housing? That’d give me a “new” used check valve.

As for the turbo oil supply line, I don’t see how that could be a cause. It’s high up on the filter housing and would cause a massive mess if the line was cracked. Should be under pressurized oil...

If there is a kink in it I'd replace it. Also what kind of oil you using? Too thin oil will run down faster and show up as low op on the gauge. Just because gauge is slow to come up does not necessarily mean your bearings are dry.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

X2 christuna... I don't see anyway a leaking headgasket could be related to the lack of pressure on a cold start unless it was gushing out. It would have to be so bad you wouldn't be driving it. Another oil filter cap would be my next step after looking at the gauge feed tube for damage.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer