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Discussion Starter #1 (Edited)
Need to do a service on my motor, the recommended oil grade is 10w40 but the cars comming up to 90,000miles and me thinks that is a bit thin! would i be doing any harm to run it on 20w50 to keep the oil pressure healthy.
 

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if the oil pressure is looking a bit low.....

the it could be time to re shell the bottom end. the oil presssure should have a minimum (see haynes manual) and rise to a max. the engine is a high spec one and i'd stay with the recomended type of oil, or u may risk blowing oil seals and stuff.

gav.
 

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Discussion Starter #3
Cheers mate :)

Its been fine until i changed the oil today, I replaced the filter and filled her up with 10w40 semi-synth was fine at first then i let her warm right up till the fan was cutting in and the low presure light was flickering on at idle (about 600rpm) but a slight touch of the throttle and two segments light up on the oil pressure gauge and its fine, take her right up to about 5k and the preasure goes right up.

So im thinking the oil viscocity is too low or the presure relief valve is not working correctly?!?
 

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tickover 600rpm??????

sounds a bit low to me, 8-900rpm is how mine sits but drops to 600rpm in drive (with the cams the tickover is well lumpy low down) basicly cos there is very little power that low down. it could also be a faulty oil pressure sender mate. go fo the cheaper options first. important to get it sorted asap as u dont want it knocking out the bottom end prematurley.

if u have to go up a grade, that to me is one of the cheaper options ;)
 

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The straight six engines do idle around the 600 - 650 rpm mark. My old 12v GSi used sit at about half way up the electronic guage at idle (or one below half if it was very hot) and go up towards the top at higher engine speeds.

That was using 10/40 semi synthetic at 137,000 miles.

Do not be tempted to put cheap 20/50 or similar oil in the straight six units, as they tend to gunge up the top end of the engine, causing oil starvation to the valve train.
 

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Discussion Starter #7 (Edited)
The engine runs silent other than the ticking of the injectors and slight sucking of the air box so I can't belive its got much wear, i would be expecting a knocking from the bottom end if the shells are excessively worn?

From cold start the oil pressure reads right up the guage at idle.

As for the pressure sender, does it live by the crank at the front right hand side? there is a big thing sticking out that looks like a oil pressure sender and the wires have been "crimp" connected which leads me to think it might be a bit of a bodge replacement!

Plus im wondering about the accuracy of the digital dash in general ;)
 

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Discussion Starter #8
Ive just been down to vuaxhall, and it seems there are about 8 different oil pressure sensors for that engine, the one required depends on the year and type of dash, so I am starting to to think maybe its the wrong sensor as the engine is from a newer car, and the sensor's wires are crimped on. :confused:
 
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