Pontiac Owners Club UK

Hi chaps, bit of a sense check here. Just filled up with petrol, V Power for first time as they's run out of normal unleaded, and coincidentally my oil pressure gauge is registering nearly zero at idle. Gauge rises to about two thirds when driving but this is lower than normal.
I'm using the same oil i always use 5/30 Magnatec and no other odd symptoms, temp fine, no leaks, drives OK but a bit perturbed by this sudden drop in oil pressure reading.

Anything else i should check to see if all is OK?

check battery voltage/charge rate as this may affect gauge

5/30 is quiet thin, use 10/40 in mine, though if it was ok before it shouldn't alter suddenly

Battery charge looks fine All other gauges working fine, i was sort of hoping sender issue but now getting worried about driving it if it's actually a problem with oil pressure.

Great timing, just been advised i'm in a redundancy situation Things come in threes so looking forward to the next one tonight

could be the sender, they are fairly cheap so worth changing to see if it helps.
unless a local garage can connect a workshop pressure gauge to it to test pressure
it could just be muck in pressure relief valve or something. no rattle from lifters?

poor ground ?

Ok so when engine has cooled the oil pressure reads at midpoint on gauge at high idle, seems that when it's hot it's barely registering at low idle. Sound like a sender issue?

banker wrote:Ok so when engine has cooled the oil pressure reads at midpoint on gauge at high idle, seems that when it's hot it's barely registering at low idle. Sound like a sender issue?

Unfortunately in my experience it's not a common symptom of a bad sender. It sounds like a genuine pressure issue either caused by the oil pump or something bad somewhere else in the engine. It's normal for oil pressure to be higher when cold as the oil is thicker and pressure drops as it thins out with engine temp but dropping to virtually nothing is not good.

I would still change the sender just to be sure as it's so cheap and simple compared to the other alternative!


Sorry to hear about your redundancy situation. I don't know what it's like to be there but there's always talk lately about our factory being closed down so I do worry!

Cheers Ian, bit of a bitchbut not the first time i've been in this situation working for RBS. Just need to wait 6 weeks to find out my fate
On the oil pressure side, guage was pretty much in the middle this morning and stayed there during trio into work, with only a small decrease at idle. Normally as you say the gauge is high when cold and drops when oil is warmer and thins, this morning stayed pretty much mid way when cold and hot. Is it the sender by the oil filter that's normally at fault?

I believe that is the sender for the gauge but not 100% sure on thirdgens.

Cheers, got one on order so i'll see if this fixes the issue

I think on your year the gauge sender is at rear of engine normally, the one by the filter is a fuel cut off (if pressure drops too low it cuts off the fuel pump)

Doh! Oh well, it's paid for so might as well fit it

Sender arrived today, fitted and oil pressure back to normal. Phew

Cool ! That's what you want

great news

i would as john said not use 5/30 its way to thin for a 350 imo, it goes like water when hot fine for modern engines as they run much closer bearing clearances then our older engines,i would use 10 /40 min and if you drive it hard i may also concider a addative as well to protect the bearing surfaces, its better with in reason to have a thicker oil than a thinner one in most cars before late 90s after this date many have sensors and will throw a warning light if to thick oil has been added

Cheers Jon, i think there's as many opinons about oil choices as options I probably will go for a 10/40 on next change

A close shave there James. Pleased you managed to get it sorted. Hope everything goses ok for you with the job situation.

Nice one James.
Sorry to hear about the work situation, hope it works out ok. That Fred bloke has a lot to answer for.

Indeed, this always goes round in cycles. It's all about cutting costs for the frontline though, going to be even more work to complete for even fewer people again

Retro wrote:A close shave there James. Pleased you managed to get it sorted. What's normal oil pressure when driving On mine the needle has always read in the middle on the gauge. I am never know if thats a good or bad reading

At operating temp and driving it's normally about mid way

banker wrote:Indeed, this always goes round in cycles. It's all about cutting costs for the frontline though, going to be even more work to complete for even fewer people again

And thats where capitalism's flaws raise their ugly heads! Always the big bosses trying to cut costs so either them or the shareholders get richer whilst the working people get worse off and have to do more for less and less. Growth growth growth, money money money, keep the common man down whilst we enjoy our bonus money and our mansions.

Dont get me started though. Socialist through and through...

always been a capitalist myself, I like having money and big cars
I've been to socialist countries, everybody poor as pi55 (except for those in charge)

Quick update, pressure all looking tickety boo after changing sender. After a few days guage starts reading lower, especially when hot so i swapped out oil again to 10/40 as suggested.
Guage shows mid point now when cold and driving but drops to less than 1/4 up from zero when hot
Car drives fine so other than sender what else could be affecting the reading?
Oh and i've still got a job Lost nearly 20 other managers in my office though

is there a local garage that have a workshop pressure gauge that they could hook up to check pressure?