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Post by ozriderp5 on Nov 6, 2017 23:47:20 GMT
Hi All
Firstly I have read everything I can find in search.......
Car is running great, smooth, no smoke and pulling fine. Temperature sits on normal and doesn't move.
Oil is black but has only been replaced in the last few thousand klms, I will be changing it when I get a new filter.
My issue..
After running at freeway speeds (100 -110kph) the Oil Light is coming on when I slow down to stop, it usually just needs a few more revs and it goes out.
Yesterday I ran it over 160 klms over different road conditions to check for any pinging etc and it did the same when slowing down into a town, however it didn't go off when I revved it. I pulled over and checked all the obvious and all was fine, I restarted the engine and everything was back to normal.
I headed for home, as I backed off the throttle moving from a 110kph zone to a 100kph zone the light come on again and stayed on.
Again, everything sounded OK, temp was good so I kept going the last 5 klms to home. Again, when I got there everything was fine, and when I restarted the car the oil light went out.
I have pulled the wire from the switch and the light goes out so at least the switch works.
Question...
How do I test the switch?
How do I fit an Oil Pressure Gauge?
Where does the sender unit get fitted?
Any advise or preferably pictures would be greatly appreciated.
Remember this is a 3L 6cylinder not the V8.
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Post by djm16 on Nov 7, 2017 3:24:54 GMT
The oil pump pick up in the 3L is very posture sensitive. It does not take much of a drop in the oil level for the pump to start sucking air on deceleration and downhill and the oil light to come on. Mine does this when it is about a litre down.
It is also a greedy beast, so 500km at motorway speeds will easily use up a litre.
In addition, wear in the engine will lead to lower oil pressures all round, so that I am current running on 25W-70 from Penrite. Result, quieter engine, oil pressure better sustained even when hot.
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Post by Phil Nottingham on Nov 7, 2017 9:15:50 GMT
It more often the switch and the only way to test it is to replace with a new one. The series Land Rovers with the 4 or 6 IOE engine use them.
Secondly the bypass valve in the oil filter head can stick. If its clogged it can cleaned but another one may be needed again the IOE LR part is the same but you may need to replace the filter housing to match it
Thirdly the mesh in oil pick up may be clogged and there is no harm in removing the sump to clear out the sediment/sludge of many years
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Post by enigmas on Nov 7, 2017 21:19:16 GMT
You didn't mention the viscosity grade of the oil OZ. If it's an engine of unknown history and 'long in the tooth' using the grade oil that DJM16 specifies (Penrite) would be a good move. Having recently removed and cleaned both the sump and oil pick on the engine in my car (albeit a V8) is well worth while as Phil suggests...crud does build up over the years in these areas. The oil pick up mesh does clog over time.
Also why not fit a mechanical oil pressure gauge (as I did recently) rather than rely on a 'blinking' light that really tells you nothing.
NB.
The WSM makes reference to removing and replacing the oil pressure relief valve spring if lower pressures are indicated. Phil perhaps could chime in here.
The oil pressure warning light sender can be removed and a suitable oil pressure gauge line connected at this point.
Oil pressure should be 40 - 50psi at 40 mph or 64kph (WSM reference).
* Why not substitute a dual fitting at this point so that you can run both options simultaneously. Hydraulic hose/fittings shops such as ENZED have a myriad of fittings/unions available to sort things like this.
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Post by ozriderp5 on Nov 8, 2017 2:11:50 GMT
You didn't mention the viscosity grade of the oil OZ. If it's an engine of unknown history and 'long in the tooth' using the grade oil that DJM16 specifies (Penrite) would be a good move. Having recently removed and cleaned both the sump and oil pick on the engine in my car (albeit a V8) is well worth while as Phil suggests...crud does build up over the years in these areas. The oil pick up mesh does clog over time. Also why not fit a mechanical oil pressure gauge (as I did recently) rather than rely on a 'blinking' light that really tells you nothing. NB. The WSM makes reference to removing and replacing the oil pressure relief valve spring if lower pressures are indicated. Phil perhaps could chime in here. The oil pressure warning light sender can be removed and a suitable oil pressure gauge line connected at this point. Oil pressure should be 40 - 50psi at 40 mph or 64kph (WSM reference). * Why not substitute a dual fitting at this point so that you can run both options simultaneously. Hydraulic hose/fittings shops such as ENZED have a myriad of fittings/unions available to sort things like this. I've ordered a new switch, filter and sump gasket. I will replace the oil with penrite classic, can't recall the viscosity. I have a gauge to get hooked up, can the sensor just replace the switch?? |
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Post by enigmas on Nov 8, 2017 4:45:41 GMT
Of course it's entirely up to you and what you want to retain as original either on the dash or to the car. I'd retain both, but hey that's just me! The black in the oil is carbon (an abrasive...so I'd want it out) The 25/70w Penrite that DJM16 references would be good for your engine if it's had a long life. Don't confuse the lubricant use needs for these old engines with any of the super low viscosity oils you may add to your OHC ECU modern. You can't go far wrong with all the options Penrite offer for classic and historic vehicles.
PS. Oz I presumed you were fitting a mechanical oil gauge (with a feed line to the gauge) not another 'sensor'?
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Post by ozriderp5 on Nov 8, 2017 7:50:43 GMT
Of course it's entirely up to you and what you want to retain as original either on the dash or to the car. I'd retain both, but hey that's just me! The black in the oil is carbon (an abrasive...so I'd want it out) The 25/70w Penrite that DJM16 references would be good for your engine if it's had a long life. Don't confuse the lubricant use needs for these old engines with any of the super low viscosity oils you may add to your OHC ECU modern. You can't go far wrong with all the options Penrite offer for classic and historic vehicles. PS. Oz I presumed you were fitting a mechanical oil gauge (with a feed line to the gauge) not another 'sensor'? I'd prefer both, an idiot light catches your attention... Looks like the one I have is just a sensor, no problem, mechanical ones are pretty cheap anyway. Checked the oil, it's actually Valvoline Classic, 20W50. I'll save it for the XR8. |
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Post by enigmas on Nov 8, 2017 9:24:50 GMT
The viscosity level of the Valvoline motor oil should be fine.
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Post by ozriderp5 on Jan 4, 2018 23:41:49 GMT
Finally got around to fitting the new sender switch. I'm guessing the issue was caused by a leaking sender, as per below, it is full of oil.....I'll take it a run later today but doubt there will be any issues as the warning light basically turns off now when turning over the motor to start it.   The sender thread on the oil pressure gauge is a different thread so I'll need an adapter to fit that as well.. |
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Post by ozriderp5 on Jan 5, 2018 1:03:57 GMT
Took it a run for about an hour, the light comes on stopped at lights etc but that's probably due to he revs dropping to about 600rpm in drive.
In neutral it's ok.
I still have to change the filter, oil and clean out the sump.
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Post by Ken Nelson on Jan 5, 2018 5:11:56 GMT
Recently after taking my Rover 3-litre Coupe for a 120 mile journey I noticed that the engine oil light would occasionally come on at speed on the highway. Previously it would occasionally come on only when at idle with a hot engine, but go out quickly with increasing speed above idle. The car ran fine throughout, and since mine is a Coupe it also has the oil gauge in place and this read completely normal the entire time. So I presume the oil light sender unit is likely bad, although I'm not sure where the gauge gets it's signal from. I haven't investigated yet (car is now put up for the winter). Any advice?  |
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Post by ozriderp5 on Jan 5, 2018 6:38:22 GMT
Ken, the oil pressure light sender switch for mine is at the back end of the motor on the oil filter side, I was advised just to change mine as it has no test for functionality.
I'd be interested to see where your oil gauge sender is??
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Post by Phil Nottingham on Jan 5, 2018 19:34:45 GMT
The coupes oil pressure gauge sender is in a tapping in the oil filter long block mounting casting. The gauge is purely decorative and should never be relied on any more than the sender for the light.
It is quite normal on a well-used IOE engine for the light to come on when oil is hot and thin
The usual method to mount the sender on the saloons is in the T piece for the light sender/rocker shaft
The relief valve spring can compress and a new one may help for a while
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Post by Ken Nelson on Jan 5, 2018 20:44:47 GMT
Thanks Oxrider and Phil. I can see this will require a bit more investigation! When the temperature outside warms up above 10 degrees F I’ll go to the garage and report on what I find. The engine was completely rebuilt about 2000 miles ago and runs quite nicely so I doubt a serious problem.
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Post by ozriderp5 on Jan 5, 2018 21:25:36 GMT
We're on track for 42C today.....10F would be great.
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Post by enigmas on Jan 6, 2018 0:06:13 GMT
Here's a couple of images of an additional oil pressure gauge (mechanical) that I fitted to the lower instrument pod of my coupe recently.   |
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Post by Phil Nottingham on Jan 6, 2018 6:33:13 GMT
Neat - Enigmas
Ken - if engine was rebuilt a new spring should have been fitted
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Post by djm16 on Jan 11, 2018 10:00:25 GMT
If the engine was rebuilt by anyone apart from Rover circa 1963 (or Phil N) then I reckon you can guarantee that a new spring would not have been fitted.
If when you check the oil pressure with a quality gauge you find that the oil pressure is not maintained below 1000 rpm, you will likely find that the camshaft bearings are original and worn (despite the nominal "rebuilt" status).
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Post by enigmas on Jan 11, 2018 10:13:42 GMT
Old, (read worn) cam bearings will definitely cause a pressure drop in the system. I can't imagine anyone doing a 'quality' rebuild side stepping the fitting of fresh cam bearings. What viscosity engine oil are you running Ken? |
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Post by Ken Nelson on Jan 11, 2018 18:29:34 GMT
I run 20W-50 Castrol oil in the car. I can't recall specifically if cam bearings were replaced when engine was rebuilt, but I doubt that I wouldn't have had them replaced. The speedometer only has about 85,000 kilometers on it (car went to West Germany originally), but the speedometer was broken when I got the car. Engine was rebuilt because it had seized up from sitting unused for so long. I did just order a new oil sender unit and oil pressure relief spring and ball from JRWadhams to try. Nothing else seems to indicate a worn or poorly running engine (ie not smoking, no excess oil consumption, noisy lifters, etc), so I'm still betting on this being a bad oil sender unit.
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Post by enigmas on Jan 11, 2018 21:34:10 GMT
Do you have receipts outlining the work done Ken. It's quite unusual for an engine to self seize because of lack of use or non use even over years unless its been left in the open and the elements have got to the internals. I'd also check simple things like clearances within the oil pump. Also try changing oil...something like Penrite Classic Light...you might find that's all it requires. Most current oils are formulated for modern, tight clearanced, multi-valve OHC engines. Castrol might have been fine in 1964...but not any more! www.penriteoil.com.au/products/viscosities/20W-60/classic-light-20w-60-mineralNB. The oil pressure relief valve is there to drop pressure if it gets too high. It's designed to bleed off excessive pressure. This usually occurs on a cold engine when the oil viscosity will be higher. I doubt its the relief valve or spring if the oil pressure is good with the engine cold. Try the Penrite (easy) then assess the pump clearances. |
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Post by Ken Nelson on Jan 14, 2018 16:10:00 GMT
This engine didn't exactly 'self-seize' from sitting unused. It had help. The car had been sitting in a farmer's field for years with a rusted out exhaust down pipe. A mouse family found its way upstream and had a nice home in cylinder #5 by way of an open exhaust valve. The mouse excreta had oxidized the aluminium piston to the iron block. Much work had to be done cautiously with drills, cold chisel, and mallet to remove said piston in tiny bits and preserve the cylinder before the machine shop received it for rebuild. Said mouse had vacated the premises before that!
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Post by Ken Nelson on Oct 29, 2021 22:54:17 GMT
Well, after replacing the 10 volt regulator for the oil and other gauges in my P5 Coupe I had everything working nicely and seemingly accurately. Then I spoiled it all by forgetting to reconnect the wire to the oil gauge sender (not the warning light) after working on the car. I drove it around and noted the oil pressure needle off the scale and remembered the wire. But not before getting home when the oil pressure needle went to zero, and I discovered that the unconnected sender wire had shorted out onto the exhaust downpipe. Now the needle only rises about 1/4 of the way and stays there when running. I know the pressure is fine, but did I burn out the gauge, or short out the 10 volt regulator? The temp and fuel gauge and ammeter all work normally. Any advice?
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Post by Phil Nottingham on Oct 30, 2021 6:27:42 GMT
The gauge may be damaged but note that it does not feed via the regulated 10v although it is fed by its 12v supply. Check your cable connection on the stabiliser!
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Post by MK IA Norway Viking on Nov 1, 2021 17:24:18 GMT
I have two MK IA and suffer the same issue with oil pressure warning light (green) coming on at idle or - when engine is hot - at low RPM. The original oil pressure relief spring is still in place. I am recommended to make it longer by pulling it, so that it requires more force to compress to a point where the warning light comes on. I am scheduled to do this to one of the engines very soon, and will report the outcome.
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