Low oil pressure

Good afternoon from Canada
So, our freelander with the kv6 has recently developed low oil pressure issue, only after it get up to operating temperatures. So a 10 min drive on the highway at 100 km/h get us into the city and then the low oil pressure light flickers at idle. So upon searching it says do an oil change, so it has new 10w50 and a new filter. Still has low oil pressure, so the next was change the sending unit, still low oil pressure. Since my test oil pressure test kit had not come in, I dropped the pan and cleaned out all the gunk inside the pan and pick up tube, there was a fair bit of sludge built up and the pick up tube had a large section blocked off. Cleaned it all out as best as I could, still low oil pressure light flickering. So finally my oil pressure test kit shows up ( had to buy one so I had metric thread, easy to find standard pitch thread but metric......,) and confirmed that the kv6 has low oil pressure.
So on start up in the garage, it had 35 psi ( 241 kpa approx) and only went down from there. With the eng up to operating temps, and at idle we were 7 psi ( 48kpa ) and at 2500 rpm we had 26-28 psi (179-193 kpa).
So upon start up the hippo has a little bit of piston slap, but goes away in a few mins, so I'm not too worried out it.
So there is the back story, now comes the questions
-where does the oil pressure sending unit get it's pressure from? Before or after it's going thru the eng? Right after the oil pump? Before the filter after the filter?
- does this sound like an oil pump failing? Or something sticking inside the housing?
- I have not done an oil system flush as I think it's snake oil, but any one had success with doing one?
-will running a heavier weight oil help the issue? I think I can only get up to a 20w50 synthetic for diesel engs, but I'm already running a 10w50, so........
- if main bearings are worn out, can they be changed in the car or do I have to pull the eng to swap in new ones? I've done it to other vehicle, drop the pan and start pulling caps and sliding in a new shell.
I'm running out of ideas to keep the hippo running, a new eng is out of the question as they are very expensive here in Canada, and they were only used in the freelander, so they all have some kinda issues. You find beautiful hippos here with bad engines, and nothing to replace the eng with, as they all did the same hgf, or timing belt failure, so no good used engs sitting around.

Sorry for the long read and thanks for the help

I can't help you with your problem - but if there are lots of dead engines through HGF, presumably there's a lot of working oil pumps going cheap!

Ok. The KV6 can suffer from pump wear which will lower pressure. Have you removed the oil pick up pipe? If not then it's worth taking it off to check the O ring. They have been known to split, causing air to be sucked in with the oil. Additionally I've seen the oil pressure relief valve stick open with gum on occasion. I've come across 1 case of a broken pressure relief spring.
Putting thicker oil in won't actually increase pressure that much but will probably make the engine smoke as it's not designed for heavy weight oils.

For reference. The correct oil pressure is as follows. All hot with 10w40 semi synthetic oil.
Idle 1 Bar or 14.7 Psi minimum.
2500 Rpm 3 Bar or 44.1 Psi
Relief pressure 4.1 Bar or 60.2 Psi

It's not possible to change main bearings while the engine is in the car. There aren't separate caps for each bearing. The crank is supported on a ladder frame, meaning all the caps are joined to the ladder. It's a radical design but isn't easy to repair in situ. It's unusual for main bearings to wear that much unless many oil changes have been missed?
Check the points above before venturing further.

Sorry forgot to mention that I had removed the oil pick up pipe and the "O" ring was good, then replaced with a new one.
How do I check if the oil pump relief valve is good, or the springs? Do I have to remove the eng to do this or can I pull them insitu?
From the looks of the online manual, I have to pull the pump assembly, I really don't want to pull the eng if it's not nessary.
Thanks

The oil pressure relief valve is under the hex plug behind the oil filter. Removing the plug allows the valve to be accessed. Don't let it drop out when you remove the plug.
Edit:
Whilst you are checking the relief valve. It's worth making sure that the oil cooler is completely clear of gum too. It's a full flow design, meaning all the oil from the pump passes through it.

Nodge68 said:

Edit:
Whistle you are checking the relief valve.

Click to expand...

Is this a new thing? Freelander whistling, is it like horse whispering? One of the dark arts performed by the Knights Templar

Skinny Mike said:

Is this a new thing? Freelander whistling, is it like horse whispering? One of the dark arts performed by the Knights Templar

Click to expand...

Actually my old V6 did whistle at full throttle until I trimmed the throttle plate retaining screws!!
However in this instance, auto correct turned whilst in to whistle!! Funny though.

Awesome, thank you Nodge, I guess I know what I'm doing this afternoon, instead of playing with my triumph tr2! I went out to the auto wreakers and all the freelanders are gone, so if it's the pump I'll be searching for another freelander to show up in the yard! I sure hope it's just the relief valve!
I'll let you know what I find either way!
Cheers

The pump can be removed for checking but if you are doing that, you may as well replace it.
Do you know if it's had the correct oil at the correct time? Bearing wear isn't common but can happen is services are skipped.

I'm the .......3-4 owner maybe not really sure. I didn't get history with the car, when I got it it had a bunch of minor issues that I've fixed over the last year or so. I'm currently on the hunt now for an oil pump, wait untill one showed up in the wreaking yard so I can get the parts. I'm pulling the relief valve after coffee, had to buy hex sockets that would fit, I only had small ones here at the house.

The hex is large. You can use a bolt head that fits with a couple of nuts on the bolt locked together to make a rudimentary removal key.
If you are thinking about changing the pump, buy a new unit. They aren't that expensive, even if you have to get it shipped from the UK. You'll need a new set of belts anyway to go with it.

So I pulled the relief valve out, it was fairly clean, but I cleaned it anyways. Well it didn't help at all, I still get the light flickering on at idle. I didn't clean out the cooler yet, but that's gonna have to wait untill my days off again. I'm gonna try and get a pump order up so I can change it out first thing come days off
Thanks for the help so far.
Cheers

So, still have the issue, been searching for a freelander with a bad engine to scavenge an oil pump from. No luck over here on this side of the pond, there were a bunch when I was having issues, and now that I'm needing parts they are all gone. So does anybody have a oil pump from a kv6 sitting around that they would be willing to sell/ship to Canada?
I'm hesitant to buy a new one in case it doesn't fix the issue and I've wasted $500 Canadian. If this would fix the issue I'd do it in a heart beat, but I'm not sure...... I've changed lots of parts and cleaned the oil system, now it's to the expensive parts.

Watching with interest. my thinking went like this:
Low oil pressure:
low oil level? √
incorrect grade of oil? √
faulty sender unit? √
incorrect filter / partially blocked filter?
pressure relief valve - sticking/ stuck √ / spring weak/incorrect spring?
blocked oil pick-up? √
worn oil pump?
worn motor - bearings ...?
oversized oil ways - someone's done an unwise mod somewhere
√ means checked and ruled out.

I'd not looking to replace an oil pump without first finding out if it's worn. This is reasonably easy once it's off the engine and on the work bench.
If you need a new pump, here in the UK they aren't to expensive.
Dmgrs sell them for about 100GBP and shipping to Canada isn't that expensive. Order other consumables at the same time to make the shipping better value

htr said:

Watching with interest. my thinking went like this:
Low oil pressure:
low oil level? √
incorrect grade of oil? √
faulty sender unit? √
incorrect filter / partially blocked filter? Filter changed with a new one still had the same issue
pressure relief valve - sticking/ stuck √ / spring weak/incorrect spring? It was fine before, we have out many miles in it
blocked oil pick-up? √
worn oil pump? Next easy thing to change
worn motor - bearings ...? 150000 kms on it
oversized oil ways - someone's done an unwise mod somewhere, it didn't do it before this is a new issue.
√ means checked and ruled out.

Click to expand...

Nodge68 said:

I'd not looking to replace an oil pump without first finding out if it's worn. This is reasonably easy once it's off the engine and on the work bench.
If you need a new pump, here in the UK they aren't to expensive.
Dmgrs sell them for about 100GBP and shipping to Canada isn't that expensive. Order other consumables at the same time to make the shipping better value

Click to expand...

100gbp turns into 200 canadian, plus shipping, so it's minimum 300 to the door, the last time I searched I was closer to 400 with shipping. I can't have the car down for repairs for long, so I'd rather swap out the pump with a different one, just time wise. And if it's not the pump, I'm gonna drive the car untill it puts a huge whole in the eng, or bits come out the top end!

wrong pump found still searching

I am not well up on this engine type, what cars did this engine go and what years. I think this pump is for an older engine type but not sure.

Think this is correct pump and it is only a few miles from where I work. So I could easily go and check its correct. Shipping surely cannot be that much.

both the above are the wrong pump as they sensors fitted. this looks the correct pump, its 190 dollars shipped from america to uk and includes 40-50 dollars import tax. not sure what it would cost you but must be less than 190 dollars, half of what you thought. would that be acceptable
moderators, please would you delete the three posts of mine above, they serve no purpose