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4.6 V8 oil light on


il-bob

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Guys, need some advice.

Problems started last sat, when fan cowling got out of place while offroading, blocked the fan and engine overheated causing the expansion tank to crack.

Towed it home, changed expansion tank, filled with coolant, started and let on idle to warm up. Ater a about 5 minutes, oil light started flickering and I switched off.

Checked oil level and was fine. Started again and after a couple of minutes, oil light back on.

What might be wrong now?

tks,

rob

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1st the obvious- check the wire to the sender / not earthig etc

Once your sure sender & guage is ok then its bad news

Cooking a V8, esp a 4.6 is a bad idea

Are you still loosing coolant or are top hose going rather solid / pressurizing ? - if so It could be head gasket - do a compression check cold and Hot

Re the Oil pressure - the oil may have along with the engine superheated broken down and run the mains / big ends out - thus hot your oil pressure drops

Chnage the oil and filter for something decent,and pray - the oil may be past its protecting best and not giving good pressure having browkn down under heat !

If the heads with new gasket don't sort out the coolant leaks then the overheating has damaged the block / liners.

Nige :(

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OH shi*e.....

engine isn't loosing coolant, at least for the short while I left it running. I also noticed that while top hose was warm, expansion tank was still cold. Head gaskets were done a couple of months ago because i had noticed a slight drip of coolant.

Will change oil today, and hope for the best. Am using BP Visco 3000 10W 40 http://www.bplubricants.com/en/products/visco-3000-a3b4-10w-40

tks,

rob

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My "Guru" Mr John Eales swears by Valvoline 20/50 racing

Its not a synthetic but is very high grade and very "Sticky" all I know is he uses this in ALL his V8 serp pre serp etc

and nothing else. Peeps will say that its the wrong oil, or its too thick, or bunnys will fall over and die if you use it in a serp engine

but many have on his advice I have passed on - and have NOTICED differences in bnoise levels and smoothness

Its also not spendy :) which is good :D In hotter climbs you need thick oils, period, but get this in it and see

Nige

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We always used SHPD Turbo Diesel oil I think its now called E7 much higher temp range than normal petrol oil and always been ok. On the single occasion Comp safari racing running SHPD and Slick 50 the rad got er bent and lost all its water bro kept racing engine slowly seized up changing down to eventually low range 1st it seizes solid. Right leave it till the end of the day. End of the day went to tow it back bugger me it started up and ran fine managed to drive it back and onto the trailer.

Can't knock that so I run that in all my engines now.

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Changed oil and filter today, but after 3 minutes on idle from cold the oil light came on.

Will change oil pressure switch tomorrow and hope for the best.

While I was at it, i connected my laptop to the ECU (Tornado ECU by RPI) via ODBC and noticed that there are no errors. Is it normal not to register any errors when low on oil pressure?

tks,

bob

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I used Lucas 20/50 in my V8s and 15/40 Lucas Magnol in the TDi, it has an oil stabiliser in it to make it "sticky". I run the LSE on their synthetic or semi syn, unlike many brands it's a high-percentage synthetic.

Anyhoo, the later V8s had internal differences, the journals had bigger diameters and along with strengthening the crank this increases the oil separation in the bearings, so that they could use a thinnner oil. IIRC they also had tighter clearences

Thinner oils create less drag and reduce fuel consumption, at the extreme this comes at the expense of engine wear.

Thicker oils, especially those with a wide viscosity band, tend to break down more because they rely on additives to get the viscosity, the base oil isn't that thick, so after a few thousand miles you might not have the oil you think you paid for.

I also used to use Comma 20/50, by the drum when Blue burnt lots of oil. It didn't last long enough to break down.

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