Thread: No oil pressure in 3.5 V8

Originally Posted by Roger_Wilkinson

Hello all, I just went out to use my Stage 1 V8 truck and it has no oil pressure. Warning light on, nothing registering on the gauge. I turned it off quickly and came inside to look up the books. According to the Series 3 V8 repair operation manual supplement, the oil pump can lose prime. Could that have happened in this case? Apparently to prime it you remove the oil pump cover and pack it with petroleum jelly. I've never heard of anything like this happening in any other vehicle. I haven't started it for a month and it was working fine then. I haven't done anything to it since then. The oil level on the dipstick is fine. Any thoughts?

Roger

Yeap thats right take of the oil pump cover and pack Vasoline in there (nice job )
just don't do what i did and go to the local chemist across the street and buy one tub of vasoline and then don't do it properly. And had to go back and buy another tub of vasoline. Got a funny looks for the girl in the chemist. I told her what i was doing and she siad mmmm I've heard some excuses in my time but that one beats the lot

This a pick of the pump. But this is from the top. You will see it from the bottom One will be lose and you have to pack it into these and then put the cover back on and job done

Thanks. Presumably I just remove one of the gears (the one without the shaft), pack in the vaseline, then put the gear back. Or should I remove both gears? How much vaseline will I need? And how on earth does it lose prime in the first place?

Roger

Originally Posted by Roger_Wilkinson

Thanks. Presumably I just remove one of the gears (the one without the shaft), pack in the vaseline, then put the gear back. Or should I remove both gears? How much vaseline will I need? And how on earth does it lose prime in the first place?

Roger

Just remove the idler gear and pack it as tight as possible with vas, if it doesnt prime in a few seconds of starting you may need to do it again so get a large tub of vas.

Well mine went when i changed the oil for the first time on my v8. I had always had diesel and just took of the oil filter and put on a new one and drain all the oil at the same time. But this is ok in a diesel but not in a v8. This ran the oil pump dry and hence why i had to do this.

The main thing that causes this is too thin oil. V8's are old design engines and therefore need thick oil for the pump to keep its vacum. Seen many people with rangies put mobil 1 in then be told by me and other to take it out as the horible noise coming from their tappets is not a good sign. Go and buy some cheap oil and not that expensive stuff which will blow up your V8

Normally the pump and housing are submerged in the oil in the sump.
Perhaps it was left on ramps ?
The level of the oil would need to be lower than the oil pump, but then they dont really lose the prime during oil changes, so it is a bit of a mystery.
You can leave the gears in place as long as you smear enough jelly around. I had half a jar left from the effort b4 last.
The last time I had the dizzy out, so I put a cordless drill on a slotted 3/8 piece of rod and primed the pump up with the motor turned off. You could see the oil running into/ under the valve cover.
Less pain for the motor I figured as it was already lubed the first time I re- started it.

G'day Roger_Wilkinson

If the vehicle has just been sitting undisturbed for a while you could try removing the Coil lead, pop a few spark plugs and wind it over, this was a trick that service used to use some years back.

not a bad idea uncleho, better Idea Deejay.


the pump should be a positive displacement and should in theory never loose its prime.. If it does its worn and you might want to consider a rebuild/replacement.

Thicker oil will help stop it from loosing prime again but be warned, thicker oil is a lot harder for it to pickup, If for some reason it runs dry (wierdo angle while off road and a low oil level) it will have a bugger of a time repriming again...

its an old trick but try using a thicker oil that yovue diluted with some kero or metho (keros better, metho works in a pinch but should be avoided due to its ease of combustion and the film it leaves behind) when the engine warms up the kero will evaportate.

about 1l of kero to each 3l of oil is as far as youd want to go, make sure that the crankcase ventilation system is up to speed and drawing into the intake and so long as you dont run it hard (till the keros gone) you can overfill the sump to assist in pickup.

Originally Posted by DeeJay

Normally the pump and housing are submerged in the oil in the sump.
Perhaps it was left on ramps ?
The level of the oil would need to be lower than the oil pump, but then they dont really lose the prime during oil changes, so it is a bit of a mystery.
You can leave the gears in place as long as you smear enough jelly around. I had half a jar left from the effort b4 last.
The last time I had the dizzy out, so I put a cordless drill on a slotted 3/8 piece of rod and primed the pump up with the motor turned off. You could see the oil running into/ under the valve cover.
Less pain for the motor I figured as it was already lubed the first time I re- started it.

As deejay said ive done the same trick with a rover v8 after ive rebuilt it a large screwdriver with the handle cut off use a drill = wonderfull oil pressure