Hydraulic followers, and wrong grade of oil.

Your advice please gents, could hydraulic followers "pump up" if too heavy a grade of oil was used?

I have had difficulty starting when hot on my 3.9 Disco, ( symptoms appear to be low compression and flooding) , testbook reveals no problems with the fuel system, ignition has good spark when the fault occurs, only way to start engine is to pull the fuel pump fuse, crank as per flooded engine on full throttle, and then bung the fuse back in when it catches.

Trouble is, it won't always repeat the fault, but GF noticed last time it happened, engine seemed to be turning over as if plugs were removed.

Its only happened since the last service, (and the hotter weather) and I believe 20w50 was put in.

Your collective advice keenly sought.

Lofty

Reply to
Lofty
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If it's a pre-serpentine engine, then 20W50 is the correct grade of oil. If it is a serpentine-belted engine (whether it has a dizzy or coil packs) then it'll run 10W40 or 15W40 due to the different oil pump arrangement. (Serpentine and a dizzy = rare front timing cover with late-style pump.) BUT - oil grade won't be the cause, the hydraulic lifters are the same part number regardless, right from the P6 rover up to the latest 4.6. Sounds as though you have a hot enrichment fault, I'd start by looking at the ecu's water temp sender. Oh, and do a compression test, you might have glazed bores.

-- Badger. B.H.Engineering, Rover V8 engine specialists.

now live but still under construction,

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No replys now for 3 weeks, away on business.

Reply to
Badger

Nope - I use 20W/50 in several customers 3.5's with no problem - I's be looking for the cause of the flooding, maybe leaky injectors filling the cylinders whilst stopped?

Reply to
EMB

Thanks chaps,

It is a serpentine belt system, so far its had both temperature thermistors changed, new throttle pot, tested stepper motor ( no fault) tested Lambdas ( no fault ), tested mass air meter (no fault), new coil ( just in case, but loads of spark anyway).

Have thought about leaky injectors, but the fault is more likely to emerge after the car has been stuck in traffic and hotter than usual ( can hear fan drive cut in) then leave car for 15 - 20 minutes, but if you do the same thing again it starts ok.

Is it possible to test the fuel rail pressure for leaking injectors while the engine is stopped?

I can see the test point, but am not sure if pressure leaks back to tank when pump is off.

would leaky injectors cause any other faults, emissions are normally good, well within tolerance, any other start apart from a very hot one is fine.

Lofty

Reply to
Lofty

If a petrol floods badly enough, the fuel will wash all traces of oil from the bores and rings, which will give symptoms as of low compression, especially on worn/higher mileage engines. This is a general observation of all petrol engines, not specifically disco's.

Terry

Reply to
terry

Thanks Terry,

A very good point, this engine has only done 37K and normally used for reasonably long trips.

I have narrowed the flooding down to the righthand bank ( drivers side), and its so bad when the fault occurs that petrol is seen weeping around the exhaust manifold to downpipe joint.

If the engine starts, it will only be running on the lefthand bank, the righthand exhaust manifold will be cold enough to touch.

I put the " cold side" down to the ECU shutting off that bank of injectors due to the Lambda sensor detecting an overfuel situation, but I am only guessing.

That was the only fault detected by the testbook, but it didn't say why it did it.

I hate intermittent faults.

Leaking injectors are still favorite, but would they only give a problem after being heat soaked?

All suggestions very welcome

Lofty

Reply to
Lofty

On or around Sat, 11 Sep 2004 09:44:02 +1200, EMB enlightened us thusly:

20W/50 was standard for a long time. Mind, I use "Castrol GTX for high mileage engines" in my current 3.5i.
Reply to
Austin Shackles

GTX is what I actually use - it's still a 20W/50 here.

Reply to
EMB

On or around Sun, 12 Sep 2004 09:37:16 +1200, EMB enlightened us thusly:

bah. 15W40 or summat here. it's increasingly difficult to get averagely-decent 20W50 in this country - plenty of utter s**te around and such as silkolene still make it for classic racers and the like, at ruinous expense. I did have some of the latter for the bike, mind.

Reply to
Austin Shackles

How much quality 20W/50 do you want? I'll ship it to you if you want to pay. Quality stuff retails here for somewhere between 8 and 10 quid for

4 litres.
Reply to
EMB

On or around Mon, 13 Sep 2004 07:23:40 +1200, EMB enlightened us thusly:

not using it any more, I've not got any old V8s with oil leaks.

Reply to
Austin Shackles

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