Thread: 3.5L oil pump

Originally Posted by 2door grover

Hi i'm new to the range rover thing. the range rover i picked up is running low oil pressure buy the gauge.

!st question is do the gauges read right, i know kingwood gts gauges always read low. that what i've played with most of the time with oil pumps

2nd question is is it worth rebuilding the pump ( any tips on upping the volume and idle psi would be good) or should i just buy a new one? if i get a new one whats it going to cost and who makes them, are they hi volume.

any help would be great

With early Rover V8s oil preasure can be scary.
A bad earth or voltage loss can cause cauge to read incorrect. Also if oil light comes on at idle can be the preasure switch wich will be likely leaking.
I always use a mechanical cauge to test if concerned. If low can be by pass valve stuck or buggerd spring.
There is a over length oil pump gears available that mill them selves in that can help if T case pump housing is worn.
Other wise your donk may be tired
I've seen these things do big Ks with less than 20 psi in standard form

Tony

The gauge on early Range Rovers can give some crazy readings. I've had several transducers fail, they usually start seeping oil out of the connector end. They are apparently a metal diaphram with a little arm that rubs up and down a rheostat. Any slight dirt or oil and the gauge goes crazy. Usually reads very low. Apparently the plastic peg that the little arm pivots on breaks too.

Another issue I have had is the oil pressure relief valve. It's a little metal plunger sitting in the bore of the oil pump housing. It wears a little ridge in the bore at it's normal running pressure, and can stick there. The result is reasonable pressure when under normal to high revs, but very little pressure at idle.

The oil pressure relief spring also loses it's tension which will result in low maximum oil pressure.

The pump housing can be taken off with a few bolts and re machined flat. But you will need to source a oil pump rebuild kit which includes a new gasket and relief valve/spring etc. Not expensive perhaps $50 last time I got one. If there are any scores or ridges in the relief valve bore then you could take it to a decent machine shop to have it reemed and sleeved to size.

And the standard oil pressure is

30 to 40 lbs @ 2400 rpm .... and around 20 to 25 lbs at idle

Thanks for the quick answers!

I'll check the pressure with a good gauge but am pretty sure it's running low as its got some lifter noise at idle ( are they hyd lifters in the 3.5, or do i need to set them) but is fine when the rpm rise and the gauge goes up.

Think i'll just rebuild it if the kit is only around $50. The engine has about 220 on it.

Thanks for the tips

Originally Posted by 2door grover

Thanks for the quick answers!

I'll check the pressure with a good gauge but am pretty sure it's running low as its got some lifter noise at idle ( are they hyd lifters in the 3.5, or do i need to set them) but is fine when the rpm rise and the gauge goes up.

Think i'll just rebuild it if the kit is only around $50. The engine has about 220 on it.

Thanks for the tips

Check the oil pressure before rebuild // nice to know where it is & where it went (before / after)

Hydraulic lifters

.... would check the rockers first ... if it rattles

Its more of a tick not a big rattle. might be a dead or sticky lifter.

Just had a look on ebay for rebuild kits and they were $350 plus postage from uk. I'll let people know what i end up doing. have to get the new dash in before i look at it so might be a week or 2.

Originally Posted by 2door grover

Its more of a tick not a big rattle. might be a dead or sticky lifter.

I would look at the rockers first .. before you change the lifters .... use a hose on your ear to find it .... then have a look at the area of where "the ball of the push rod fits into the rocker" and compare it's depth with the others

I have replaced 6 of them so far Also check / compare the rod length

Originally Posted by mike 90 RR

I would look at the rockers first .. before you change the lifters .... use a hose on your ear to find it .... then have a look at the area of where "the ball of the push rod fits into the rocker" and compare it's depth with the others

I have replaced 6 of them so far Also check / compare the rod length

Ok will do.