805cut

Hey guys, new here and hope im posting this in the right place. Anyways, I recently bought a 1970 cutlass 350. The car runs great with no issues but i was just wondering about temp and oil pressure..

At a cold start the cars oil sits around 6 or 7, at about 1600 its around 17..

and i havet gone far but the motor seems to stay around 145 degrees

Dose this sound about normal?
sorry if this is a total newb question, but you got to start somewhere!

Thank you!

Dave Siltman

Sounds to me like your guages are not working properly. If they are electric guages, get mechanical ones. If they are mechanical and you are reading them correctly, I think you have a problem looming with that oil pressue.
Keep us posted---we will try to "steer" you in the right direction.

805cut

Thank you, the gauges are nice but i just dont know how good they really are.. the car runs solid, i know its full of oil so i dont know ill look into it

SBORule

Who makes the gauges?

Is the oil gauge mechanical or electric ?

Water temp sounds great.

Just don't go revving the engine, drive it like grandma would.

What oil filter is on the engine? If it is a Orange Fram, change to a Napa Gold filter.

Put some good 20w50 oil in the engine and see if that helps oil pressure.

Don't drive over 60 mph for any periods of time until you can figure out if you have low oil pressure or inaccurate gauges.

oldcutlass

All those readings for oil and temp are low for some reason. Your oil pressure cold should be somewhere between 40-60 lbs, warmed could be any where from 15 +++ depending on weight and age of oil.

Engine temps should be 160 plus depending on ambient temperature at idle.

I would, as mentioned above, verify that you have good readings.

bigD

i wouldn't drive it like that, it won't live!!! check the oil pressure with another gauge, if it's the same you need to check things out...

805cut

all the gauge are dakota electrics... that dont seem to want to calibrate either, but i was told the oil, batt temp and fuel all work but i doubt that.. the oil filter is a fram i think ill jus buy a oil gauge and hook it up see if it gives me another reading thanks for the reply!

805cut

Today i poped the hood and looked at what i thought must be the electrical sensors that run from the motor to the gauges, wiggled one of them took it off cleaned the connections went for a ride around the block and the oil gauge was around 45-47 but shortly after went back to its low numbers after 10 miles or so.

Sorry about this book of a post but can any of you tell me what these sensors are for? There both towards the front of the motor on top.

1335139049569.jpg
This is the one i messed with cleaned (seemed to help fpr a little)...
1335139070638.jpg
1335139107515.jpg

are these for my gauges? Could they be bad and need to be replaced? Or do i just have absolutly no clue as to what im talking about?

thanks!

coppercutlass

the top one is water temp and the one with the can is oil psi. It probably dropped because when the oil gets hot it thins out. Try a thicker oil like 15w40 with lucas petrolium additive and see if it bumps up the psi while hot. If the engine is worn the tolerances are loose once the oil thins out the psi drops because it does not fill in the difrence between the bearings and journals dropping the oil psi.

bigD

don't rule out heatsoak affecting the sender, 10 minutes of run time would be enough time for things to start acting up.

805cut

so your saying i should look into replacing them? im just trying to fix one thing at a time if i replace the oil and water sensor and i get better readings problem solved, if not then i know its more then likely the gauges.. idk these were thrown in so the wirings a mess.. im trying here lol

coppercutlass

Throw some mechanical gauges in it . go to autozone and buy a cheap set for 35 bucks.

MDchanic

Like Copper says, go buy a cheap set of mechanical gauges, hook them up, and compare the readings.

If they read the same, then keep your $700 gauges and enjoy them.
If they don't, then $700 gauges may not be worth quite as much as some people believe.

- Eric

tmbrennan

To take it one step at a time...

Your priority should be the oil pressure. I have a '71 350 and my oil runs from about 20 lbs (warm at idle) to 60 lbs at throttle. I run 10W/30. It sounds like your pressure is very low - so it's a bad guage, a bad sender, or a more serious issue. I would try hooking up another guage and see what reading you get. You should be able to pick up an inexpesnive gauge and it's pretty easy to hook up. Hopefully, you'll get "normal" readings.

Then, check your water temp issue. 145 is too cool, but you'd know if you were overheating. It sounds like there may be no thermostat installed. Have you checked? Without one, it's always going to run cool. The water temperature should be in line with your thermostat's rating - if it's a 195 thermostat, you should be running anywhere between 190 and 200 or so when fully warmed up.

If there's no thermostat, the guage is probably correct at 145. Install a thermostat (or a hotter one). You should be running around 190-200.

805cut

i was going to do this today but i got a litle scared about how to hook them up.. dose the line that the oil runs thru to the gauge screw in to the same spot the oil sender is screwed into? if i hook it up and get good readings ill just buy a new oil pressure sender from the company thatmade my gauges

thanks for the reply!

MDchanic

Read this, then get back to us.

- Eric

805cut

Put a cheap equus gauge on there... hooking that up was so simple!

anyways started the car (cold) and got about 45 psi on the gauge.. cant right now but ill take her out later see if everything seems normal

im going to order new water and oil senders from dakota today.. se if tha fixes my electric gauges

thanks everyone!

gregvm

I just installed a Dakota Digital gauge set a few weeks ago, (I recognized the oil sending unit from the pix), and it is not very accurate.

I had been running a mech. Autometer liq filled oil press gauge, and the dakota was reading a consistently LOW pressure of about 5-8 lbs. vs. the autometer at all rpm.

I verified the pressure with a second mechanical gauge.....the Autometer was spot on....the Dakota.....5-8 low across the board.

I think the sending unit is made by VDO.

Nice looking gauges.....not very accurate.

My .02
Greg

805cut

yeah i heard the same thing and i think im going to use mechanical gauges for my oil.. but now im even having issues with that so perhaps i really do have low oil pressure but that dosent make much sense since this morning it was FINE How did everything els work for you? and what did u put the gauges on? and yeah i believe it is vdo cause im pretty sure you can get parts from them for this unit.

MDchanic

Oil viscosity, like that of most liquids, changes with temperature.

As it gets hotter, oil gets thinner.

It's (figuratively speaking) thick as molasses at 40° below, but thin as water at 250°.

As your engine warms up, your pressure is going down. That is bad.

- Eric

805cut

i just bled the air out of the line... the gauge was at about 10 at warm idle giving it a little gs with my hand it responded up to about 25 not sure at what rpm tho but its getting a reading which is good.. theres still big pockets of air in there tho..

if this was happening to you, what would you do?

MDchanic

Look, air is compressible, but once compressed, it will transmit the pressure that is compressing it. This means that the response, over fractions of a second, of the gauge to changing pressure conditions will be "soft," but the actual readings over time will be accurate.

You need to get the air our of brake lines because you need IMMEDIATE respons if you jam on the pedal, and also because the master cylinder can only pump a small volume of fluid with each press of the pedal.
The oil pump is constantly pumping, and the reading doesn't have to reflect the exact right number every fraction of a second.

You have an oil pressure problem.

You need to assure that the oil in your car is the right viscosity (as has been previously mentioned), and if it is, then you need to take your engine apart.

- Eric

coppercutlass

15w40 rotella t with a lucas petroleum oil additive. It will bump the oil psi., it did on my friends old chevy atleast.

805cut

im going to change the oil... how manny qts of oil dose the 350 take?

and should i go with 15w40?

coppercutlass

I run it in my engine along with the lucas zddp additive . I have the big block pan so it takes 5 plus the filter. Yours should be 4 plus filter I think.

MDchanic

Five quarts, including the filter.

15W40 diesel oil is fine.

10W40 or 20W40 gasoline oil is fine, too, for your purposes.

We could debate the fine points of motor oils and ZDDP here, but for this experiment anything in that range is fine.

- Eric

gregvm

When you change the oil and filter, cut the oil filter open and look at the contents. This will give you an insight into if you have bearing issues.

My Dakota installation was in a '68 and the round gauge cutouts in the dash pad were the perfect size for the Dakota universal gauge set.

The water temp isn't very accurate either, BTW. It's off by 10 degrees LOW as well vs. me mech. Haven't calibrated the speedo yet to my VSS....

The VOLTMETER and fuel gauges seem to be right tho....

805cut

yeah im going to tackel that tm.

thanks for the advice tho these gauges are starting to becme a headache... but im starting to think its worn bearing clearences im sure when i split that filter i will know if thats what im dealing with here.

805cut

just a update.

cars still running with "low oil pressure" and running great! Ive since decided to drive it till it blows! and swap it out with a bit built up 455 and new tranny.. car shows know sign of anything being wrong. Hopefully it gets me thru the summer and ill do the drop over the winter!

thanks again everyone

Railguy

drive it like grandma would.

45 in a 55 with the left blinker on?
railguy

MDchanic

Sounds great!

Good luck with it, and I hope it lasts a long time.

It sounds like you're doing the right thing by setting up a Plan B.

- Eric

coppercutlass

Hey my girlfriends k5 blazer has poor oil psi and it has 165k on the original 350. We have the same plan., drive it till it blows.