New guy, old truck, oil pressure issues

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Thomas89

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Thomas
Truck Year
1987
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R10
Engine Size
5.7L 350cin
I know pretty much everybody on here has an old truck but mine is also a bit of a beater. Mine may not be worth the time, money, and effort to bring it back to glory but I just get so many compliments on it I think about giving it some love regardless.

Please forgive me for not being too familiar with forum etiquette. Just let me know what I do wrong and I'll change accordingly.

Mine is an 87 R10 which tends to throw people off. From what I understand it was the only year they gave it the R designation and is the last year for the square bodies of course.

I wouldn't mind getting ahold of a service manual if someone has one at a reasonable price. They don't come up often on ebay.

The repair at the top of my list is the oil pressure. It needs a good amount of time to warm up and usually after 10-15 minutes the pressure goes down to a more normal range. I've been told a million times that these old truck just need more time to warm up and that's totally fair. However, lately the needle has been stuck beyond maximum and the poor thing runs very rough. Sometimes it even dies.

My question is, what should I be looking for? Maybe the sending unit? The one Napa sold me isn't the one that's in it. Maybe it needs a new oil pump? I change the oil regularly and am currently running 5w-30. I thought the lighter oil would help. Thoughts?

Again, sorry if that post is too long.
 

Goldie Driver

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Welcome!

High oil pressure would not bother me as much as low oil pressure.

Having said that, if the gauge or sender are inaccurate then who knows what you have, really.

There are some really sharp gauge people here that hopefully will chime in. I cant remember which way it goes, but it seems if you ground the gauge wire your gauge should go full high. If so, it works.

It's a down and dirty test, and I may have said that backwards.

Is the oil level too high?
Is it milky ? You said it runs rough - does it smell like gas?

Has it been tuned up lately?

Any bad wiring under the hood?

Sorry I am not a lot of help, but hopefully I have given you some points to ponder, and some things to search for on the board.

If nothing else, a free bump.

:)

Best of luck!

Britt
 

82sbshortbed

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My BBC has a mechanical pressure gage in it. When first fired up it reads 45 to 50 at idle. After warms up it drops to around 35 to 40 at idle. I got 10w-30 in it.

My old one quit on me so put this one in and it works great now. Easy and cheap to install. I like the mechanical ones myself. I feel they're more accurate.

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But I'd go back to 10w-30 if I were you.
 

WFO

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Welcome from the Texas Panhandle.
 

Thomas89

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Thank you all for the warm welcome. Always a pleasure to meet like minded people.

Maybe someone can educate me on this. The sending unit Napa sold me is larger and only has a single wire. the one currently in the truck is much smaller and has two wires. What's the difference? Which one is stock for this model? I do have a gauge on the dash.

P.S.- I hope to learn more about mechanics and as much as possible about this truck in particular because I'm so fond of it. Should I keep this thread open with new questions or open a new one?

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Thomas89

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Lincoln City Oregon
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Thomas
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1987
Truck Model
R10
Engine Size
5.7L 350cin
Thank you all for the warm welcome. Always a pleasure to meet like minded people.

Maybe someone can educate me on this. The sending unit Napa sold me is larger and only has a single wire. the one currently in the truck is much smaller and has two wires. What's the difference? Which one is stock for this model? I do have a gauge on the dash.

P.S.- I hope to learn more about mechanics and as much as possible about this truck in particular because I'm so fond of it. Should I keep this thread open with new questions or open a new one?
 

Snoots

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The shiny one on the left is for a gauge.

Can't say that I've ever seen one like the one on the right.

It would help to know what engine you have and does it have stock gauges?

Welcome to GMSB!
 

Babs

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:welcome:
 

Curt

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Welcome.

Your distributor runs the oil pump.Running rough,odd oil pressure...I might check that.Also,even a cheap gauge screwed into your sender port might help confirm what your pressure really is.May have to use some bushings and nipples to adapt the gauge.
 

Grit dog

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Welcome, the one on the right looks more like a coolant temp sensor or knock sensor.
 

Curt

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Continued:

I wanna say a grease gun hose threads fits,your sender’s location but maybe not
 

1973c10

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Welcome :boti:
 

RedBeard_83

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Dave M

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Not too familiar with the later models, but the one on the right might be the control switch for an electric choke. The one on the left is definitely for a gauge.
 

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