1996 Chevy c1500 leaking and dropping 10 mm bolts

[Ethanm70]

My truck started leaking a couple days ago and I have no clue what it might be. It only leaks after it’s been driven. I looked under the truck to see what it might be and there was oil in a couple spots. It was on the oil pan, some lines that connect to the radiator, and right underneath the engine. I was gonna drive an hour to my grandfather’s and have a look at it with him but 10mm bolts have started falling out when parked after driven. So far 3 have fell any help diagnosing this would be gratefully appreciated.

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[Vanishing Point]

O.k. First things first!

1.) What is the year, make, model, and size of the engine? Are you the original owner, Is it an Automatic Transmission?
2.) What color does the fluid seem to look like, pinkish (trans fluid or power steering fluid), brown (motor oil)?
3.) Judging by your pics it seems that it might be the transmission cooler lines that run from the passenger side of the radiator along the bottom right-hand side of the engine block towards the automatic Transmission?
4.) Then again it might be your power steering line connections that go from the Power steering pump reservoir to the steering box.
5.) Then it might be the oil pan, or that a previous owner might have overtightened the oil pan bolts leaving them stripped out. Hence the reason why they are falling out on you randomly, or they could be loose?

If you have access to a repair manual for your vehicle, look-up the engine oil pan torque specifications and sequence of the oil pan bolts. And if it still leaks it might require a new oil pan gasket and Heli-coiling the stripped out pan bolts. Just be sure to steam clean or pressure wash everything underneath there so you can get a better idea as to where the leaks might be coming from, as well as to make your clean up easier when reinstalling your new or used parts back.


( What follows next is just an example of a 1995 parts catalog, again you need your year, make, model, and size engine for your vehicle). And neither is this the torque specs or sequence of your vehicle!

1.426 PAN-PAN KIT-REINFORCEMENT, Engine Oil

1. 92 CK2,3 5.7K(L05),EMIS(NA4) . . 12522684
   
   
2. 93 CK 1,2 5.7K(L05),M/TRNS(MG5) ,AIR INJN REACTOR
   
   SYS(K19), CALIFORNIA
   
   EMIS(NB2) ................................ 12518044
   

93 CK 1,2,3 5.0E(L03),5.7K(L05) . . 12518044 93 CK2,309 5.7K(L05),EMIS(NA4),

(EXC LEADED FUEL

EMIS(NM8) .............................. 12518044 93 C K 3 10,314 5i7K(L05),10000

1 135.00

1 97.75 1 97.75

1 97.75

1 97.75

1 97.75 1 90.75 1 97.75 1 97.75 1 115.00

PAN KIT, OIL(W/GSKT)(W/4 BOLT MAINE

GVWR(C7A),1 1000 GVWR(C7E),12000 GVWR(C7L),EMIS(NA4),(EXC LEADED FUEL EMIS(NM8), 9000-9200 GVWR(SINGLE RR W H L S ) ( 8 S 9 ) ...........................

93 CK3 10,3 14 5.7K(L05), EMIS(NA4),9000-9200

GVWR(SINGLE RR WHLS)

( 8 S 9 ) ........................................

1. 92 C2,3 5.7K(L05) .........................
   
   
2. 93 C2,3 5.7K(L05) .........................
   

92 CK1,2,3 5.0E(L03),5.7K(L05) .. 92-93 CK1,2,3 7.4N(L19) ................... 92-93 CK 1,2,3 6.5F(L65),6.2C(LH6),

12518044

12518044 10110839 12518043 10110837 10198992

6.2J(LL4) .................................. 23502600 _____________________ © 1993 GENERAL MOTORS SERVICE

1.277-1.426

f

PARTS OPERATIONS-LT TRUCK-53C ______________________ 1 3 8 (4-93)

1 122.00

CR/SHF BRG CAPS) (PG0-26, KIT3)

PAN KIT, OIL(W/GSKT) (PG0-26,KIT3) PAN KIT, OIL(W/GSKT) (PG0-26,KIT3)

PAN KIT, OIL(W/GSKT) (PG0-26,KIT3)

PAN KIT, OIL(W/GSKT) (PG0-26,KIT3)

PAN KIT, OIL(W/GSKT) (PG0-26,KIT3) PAN. OIL(5 QUART) (PGO-24,131) ... PAN, OIL(5 QUART) (PGO-24,131) ... PAN. OIL (PGO-24,131) ....................... PAN, OIL (PGO-53,417) .......................

PAN, OIL (PGO-7 1,43 1)

. . .

 

[Vanishing Point]

Oh, I forgot to mention that the front oil pan crankshaft seal or rear crankshaft seal could also be the culprit. That is why it is so critical that you wipe things down the best you can so that you can make a better determination as to where all this fluid is coming from.

 

[SUBURBAN5]

Looks like a 5.7

 

[SUBURBAN5]

I would put loctite on the threads of the bolts and make sure all are torqued and not loose. Also spray brake cleaner all over and follow the clues. I'm guessing your bolts are loose and I'm also feeling like the fan blowing oil. Making your bottom covered

 

[Ethanm70]

O.k. First things first!

1.) it’s a 1996 c1500 Silverado edition with a 5.7. It was originally my grandfather’s and he gave it to me a year ago for my 16th birthday. And it is an automatic.

2.) it’s brownish. Some of it is a very light watery brown while the oil on the pan and the skid plate is black. It’s definitely oil.

3.) yes the lines were leaking yesterday but it’s the bolts is what’s confusing me.

* thank you for all that it’s definitely given me some spots to reinvestigate after letting the truck run for a couple minutes.

 

[Ethanm70]

Update

I looked up the bolts that fell out and I have a pretty good feeling they are bolts to the transmission bellhousing

 

[SUBURBAN5]

You mean the black metal plate on the bottom?

 

[Ethanm70]

Yes

 

[SUBURBAN5]

Hmm doesn't explain the oil but. My bolts came loose there before lol. Put loctite. Guess the vibrations makes it back off. Least you found it. Awesome find.