Need help with oil pressure 87 tbi 350 with TH400 trans 4x4

Matt Frediani

Full Access Member
Joined
Oct 4, 2020
Posts
51
Reaction score
48
Location
California (Nor-Cal)
First Name
Matt
Truck Year
1987
Truck Model
GMC V2500 Camper Special
Engine Size
TBI 5.7 350
Greetings.
I have an 87 V2500 GMC 4X4 3/4 ton with a TBI 350 / TH400 / NP 208
Truck is original one owner before me. speedo shows 93k. Motor runs great. I tested sending unit and it was bad. it showed low oil pressure so I changed it out with the correct delco unit. Now it shows 60psi at start up, when driving it shows about 50 psi on freeway. when its up to temp at idle it shows 45psi.

What oil should I use? I have Lukas Hot rod oil in it now that is 4qts of 10/40 and 1 qt of lukas oil stabilizer. truck is not driven much. I would like to keep it as original ass possible for as long as I can.

Should I be running Lukas 5-30 oil to lower the oil pressure? the oil pressure seems high to me? any help would be great! thanks!
 

Attachments

  • IMG_0338.jpeg
    IMG_0338.jpeg
    147.9 KB · Views: 42

cstew47

Full Access Member
Joined
Feb 7, 2015
Posts
181
Reaction score
117
Location
colombia
First Name
craig
Truck Year
1978
Truck Model
K5
Engine Size
383
I have always been taught that oil pressure is like sex. You never get too much.
 

Snoots

Supporting Member
Supporting Member
Joined
Jan 23, 2013
Posts
6,892
Reaction score
12,124
Location
Georgia
First Name
Roger
Truck Year
1973
Truck Model
Jimmy Sierra
Engine Size
350
Nah. You're good. When it gets colder, you being in Nor-Cal, going to a 5-30 may be better. As is it sounds like you have real good OP, nothing to be concerned with.
 

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
4,111
Reaction score
7,516
Location
LI-NY
First Name
Derek
Truck Year
1985
Truck Model
K20HD
Engine Size
6.2L
Look in the manual. What does GM recommend?
 

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
3,523
Reaction score
4,749
Location
Washington
First Name
Todd
Truck Year
1986
Truck Model
K20
Engine Size
454
What oil you use is far less important than proper maintenance, which I’m sure a beauty like that receives.
Save for zinc content, virtually anything you buy off the shelf today will be way better than whatever was reccomended in 1987.
Personally I use 15-W40 Dino diesel oil in virtually every 4 cycle engine I own. The only 2 that don’t are snow bike gets Rotella T6 5-w40 because it’s a winter time machine/wet clutch and Mustang GT Triton engine variety gets OW 20 syn as recommended. Because the Ferds have some very small oil galley passages somewhere in that engine that reportedly could partially starve components if high weight oil used.
Small blocks and big block Chevy motors, 6.4 Hemi SRT, 258 inline Jeep, mowers, diesel truck, all get 15W40 whatever is on sale when I need oil. And have for many years.
So that would be my recommendation
 

JoeR Jr

Full Access Member
Joined
Jun 23, 2018
Posts
191
Reaction score
232
Location
Stokesdale, NC
First Name
Joe
Truck Year
1986
Truck Model
C10
Engine Size
6.0/4L80E
Greetings.
I have an 87 V2500 GMC 4X4 3/4 ton with a TBI 350 / TH400 / NP 208
Truck is original one owner before me. speedo shows 93k. Motor runs great. I tested sending unit and it was bad. it showed low oil pressure so I changed it out with the correct delco unit. Now it shows 60psi at start up, when driving it shows about 50 psi on freeway. when its up to temp at idle it shows 45psi.

What oil should I use? I have Lukas Hot rod oil in it now that is 4qts of 10/40 and 1 qt of lukas oil stabilizer. truck is not driven much. I would like to keep it as original ass possible for as long as I can.

Should I be running Lukas 5-30 oil to lower the oil pressure? the oil pressure seems high to me? any help would be great! thanks!

#1, As recommended already, it's not terribly important what weight oil you use. I'd run 10W30 with that oil pressure though. It's good pressure and providing plenty of lube and the lighter weight will help a little with the fuel mileage.
#2, Love that truck color scheme. Funny enough, I was working as a tech at a GMC dealer in those days. I ALMOST bought the same truck. We had one on the lot and I ended up buying a Monte Carlo SS instead.
Joe
 

Latest posts

Forum statistics

Threads
36,195
Posts
764,800
Members
25,352
Latest member
El82Blazer
Top