Still no oil pressure after replacing pump and filter

[Brockybwoy]

On first outing after a top end rebuild of my '89 2.1 waterbox (104K )by local specialists ,after 3-4 miles at 50mph the oil pressure warning lights and buzzer came on, and I limped it back home. On subsequent starts warning lights came on and buzzer sounded as soon as revs increased . At 1st I suspected perhaps faulty sensors /controller board, as engine ran without problems before rebuild .I bought a cheap oil pressure gauge and connected it to the low pressure sensor port between cylinders 3-4. It showed no pressure at all . I wondered perhaps if the gauge was faulty ? and tested with an airline. It works . I replaced the oil pump and oil filter ( a new one was fitted during rebuild ) and topped up with 10-40 semi synthetic .

On Starting engine warning lights came and stayed on as before followed by buzzer . I tested with the pressure gauge and still no pressure . I'm at my wits end with this (used nightmare too many times already ) Any suggestions ?

Thankyou for your patience

[maxstu]

Top end rebuild includes? Just new water jackets and new oil pump?

Have you tested both oil switches and wiring connections are correct? Also, did your mechanic (and yourself) prime the oil pump?

Take off a rocker cover and see if new oil is in that area. Least that shows some oil is circulating

[Stesaw]

Check the oil pump and also the relief valve.
If he had oil pressure then it stopped could be the pickup possibly.

[maxstu]

Good call.

How ya doing, Steve?

[Brockybwoy]

Top end rebuild included fitting a full set of pistons .
I don't know if they did oil pressure test after putting engine back in though . I replaced the pump myself the other week .I've taken off rocker cover, given it a clean and run engine again to see if fresh oil was circulating but nothing to suggest any pressure. Inside of cover was still clean and dry . Checked dipstick which is showing oil near to max level . I took off new oil filter I put on this morning to find that
it's completely dry - no oil in it at all. The engine has run 5-10 mins since I fitted it . I'll will drain the oil and check that the relief valve isn't stuck or full of crud .

[Stesaw]

Did you fill the oil pump with assembly lube or thin grease before putting the gasket and cover on?
You need to so it primes it. Make sure that the gears in the oil pump are ok and the drive one is in contact with the camshaft.

Also never run the engine with no oil pressure, I just disconnect the coil live and cut off solenoid on the carb..If your using fuel injection remove the fuel pump relay so you aren't flooding the engine then crank the engine over.. it might help to take the plugs out so it turns quicker. Once the oil light goes out put the plugs in and reconnect coil and solenoid.

[silverbullet]

I have never primed the pump on a full rebuild, but I do always completely fill the new filter and then crank the engine with no plugs fitted (and no fuel feed) until it shows pressure on a wet guage screwed into the main gallery. Then the switches go on.
If the switches were in the wrong positions than you would get false earthing to trigger the BOD

[Brockybwoy]

Thanks everyone for your useful suggestions .

I went to bed early last night so didn't see Silverbullet's post. I got up and ploughed straight on and removed the oil pressure relief valve .Nothing in my toolbox with thick or wide enough blade to undo the screw so I got a medium width brick chisel and ground it down to make a giant screwdriver
I was expecting a lot of oil to come out of the hole but hardly a drop. The valve and spring assembly was clean .
After work , I'm going to try Silverbullett's suggestion and and put the the filter back in full of oil , remove plugs and disconnect injection relay.
Fingers crossed.

[Brockybwoy]

I tried removing spark plugs ect but still no pressure or evidence that any oil is moving except in the sump I've read posts on other forums recommending fitting oil pump without paper seal ect but I think that I'm on another hiding to nowhere if I remove and refit the pump . Oil lights were coming on before I sent the van for rebuild (which due to ignorance thought was due to low oil level rather than pressure ) On the 2-3 mile drive home lights stayed off doing no faster than 30 for 10 mins . I'm guessing that if had we run it for longer that lights and buzzers would have come on
I'm so gratefull for all the sound advice I've had on the forum over the last couple of years I've been trying to fix the van but after fitting a new driveplate (its an auto) 4 new pistons , an oil pump,starter motor, fuel regulator and 2 batteries , I think perhaps dropping a replacement engine in and keeping new parts for future is the best way forward .

[ajsimmo]

Which oil pump did you fit?
If you have a standard dished cam and mistakenly fitted the wrong 30mm pump (for a flat 3 bolt cam), you may have the exact symptoms described - oil pressure at first until the tiny contact points at the tips of the drive wear away, then suddenly no drive and no pressure.


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[colinthefox]

The only time I've ever built a flat four, the oil pump cover gasket came as 15 thou thick, whereas it should have been much thinner (4thou?). The result was the pump wouldn't suck up oil at all. I swapped the gasket for a smear of Hylomar and it self primed straight away. I've brought up the subject before, but as far as I know, the gasket kits still come with two thick gaskets.
Don't know if that is your problem but perhaps worth a look?

[Brockybwoy]

Hi,Ajsimmo
I replaced pump with 26mm Shadrek bought off e-bay a while ago .
Seller listed it as for '71 bug onwards and T25's to '92 but could have been mistaken (I messaged him - and he wasn't sure ) . I found a photo of all 3 VW water pumps together earlier on TheSamba.com forum , and measured driveshaft on the old one (4mm longer for dished cam ) . I remembered that new pump had a much thicker lip than the old one so I'm now pretty certain I have fitted a 3 bolt pump. It explains not only why I'm not getting any pressure, but also why I had to grind down lip of cover plate to fit engine snug to the mounting frame as if I had fitted 30mm pump .I can't say I'm looking forwards to taking it off again (I might as well buy a 30mm pump now I've ground down the lip anyway ) but much better than having to PX an engine with premium new parts for a rebuilt one if we are going to get away in it this summer