Wheres the Leak - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Noah96 · 03-03-2021, 02:28 PM

Hi all, got a question. Have a 1968 c10 with a 350 from a 70-80s truck, but P.O. said it leaks coolant not bad just enough to notice. Starts right up and idles just fine. It has cast heads so I think the head gasket would've blown before it warped the head, had it running for 5-10 mins and only thing I noticed was a small drip running down where the oil pan meets the block running along the length of the block (was parked on a hill). Seems to be coming from driver side. No sure if I have a hair line crack in the block, a head gasket issue, warped head or a bad freeze lug near the motor mount. Any info would be appreciated still really new to mechanic work.

palallin · 03-03-2021, 02:43 PM

Any water in the oil?

**Grumpy old man** · 03-03-2021, 02:55 PM

Use baby powder to find oil and water leaks . watch the video .

https://www.google.com/search?q=usin...rj_Aaxna3YBQ27

Noah96 · 03-03-2021, 02:58 PM

Quote:

Originally Posted by palallin

Any water in the oil?

None that I could see, I don't know if I need to run it longer but nothing showed on the initial 5-10 min idle. It was kinda dark I may have missed it gonna do a in-depth inspection tomorrow evening.

Noah96 · 03-03-2021, 02:59 PM

Quote:

Originally Posted by Grumpy old man

Use baby powder to find oil and water leaks . watch the video .

https://www.google.com/search?q=usin...rj_Aaxna3YBQ27

Thank you, I will check it out little tips/tricks like these are so useful.

gmc684x4 · 03-03-2021, 03:05 PM

Two main places look around the intake for leaks
And look at the water pump there is a weap hole it may leak from as well

geezer#99 · 03-03-2021, 03:06 PM

Check the weep hole on the bottom side of the water pump.
I had one leak and the coolant showed up on the trans inspection cover. Coolant ran on the oil pan rail from the pump to the back where it showed up.

Noah96 · 03-03-2021, 03:15 PM

Quote:

Originally Posted by geezer#99

Check the weep hole on the bottom side of the water pump.
I had one leak and the coolant showed up on the trans inspection cover. Coolant ran on the oil pan rail from the pump to the back where it showed up.

Will do, thanks!

**BigBird05** · 03-03-2021, 03:27 PM

You can buy a green dye to put in the radiator to check for leaks.

Noah96 · 03-04-2021, 07:53 PM

Ok folks got some pictures tomorrow gonna grab some coolant, some of the items above and a cooling system pressure tester. This is the only place on the block I could find coolant. Personally believe its the freeze plug behind the engine mount. Also the heater core isn't hooked up, I should plumb that up before pressure testing right?

geezer#99 · 03-04-2021, 08:22 PM

No need.
Actually better without it hooked up.

03-03-2021, 02:28 PM	#1
Noah96 Registered User Join Date: Aug 2016 Location: Danville Wv Posts: 266	Wheres the Leak Hi all, got a question. Have a 1968 c10 with a 350 from a 70-80s truck, but P.O. said it leaks coolant not bad just enough to notice. Starts right up and idles just fine. It has cast heads so I think the head gasket would've blown before it warped the head, had it running for 5-10 mins and only thing I noticed was a small drip running down where the oil pan meets the block running along the length of the block (was parked on a hill). Seems to be coming from driver side. No sure if I have a hair line crack in the block, a head gasket issue, warped head or a bad freeze lug near the motor mount. Any info would be appreciated still really new to mechanic work.

03-03-2021, 02:43 PM	#2
palallin Registered User Join Date: Jul 2002 Location: St. James, MO Posts: 1,239	Re: Wheres the Leak Any water in the oil? __________________ '69 Longstep K-10: 327/SM465/T-221/Closed Knuckle Dana44/12-bolt.

03-03-2021, 02:55 PM	#3
Grumpy old man Senior Member Join Date: Dec 2013 Location: Gods country East,Tn Posts: 8,545	Re: Wheres the Leak Use baby powder to find oil and water leaks . watch the video . https://www.google.com/search?q=usin...rj_Aaxna3YBQ27 __________________ 1967 Factory short bed - Old school '71 - 350 / 4bolt / 487 heads / Edelbrock C3BX Muncie M-22 4 speed / Hurst Comp plus Factory 12 bolt posi 3.73 / 255-70-15 Smoothed firewall / Factory cowl induction Power disc brakes / power steering / 3.5-5" drop

03-03-2021, 03:05 PM	#6
gmc684x4 Registered User Join Date: Jul 2012 Location: Whitehorse yukon Posts: 1,218	Re: Wheres the Leak Two main places look around the intake for leaks And look at the water pump there is a weap hole it may leak from as well

03-03-2021, 03:06 PM	#7
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,513	Re: Wheres the Leak Check the weep hole on the bottom side of the water pump. I had one leak and the coolant showed up on the trans inspection cover. Coolant ran on the oil pan rail from the pump to the back where it showed up.

03-03-2021, 03:27 PM	#9
BigBird05 Senior Member Join Date: Aug 2019 Location: Cheraw Posts: 1,305	Re: Wheres the Leak You can buy a green dye to put in the radiator to check for leaks.

03-04-2021, 07:53 PM	#10
Noah96 Registered User Join Date: Aug 2016 Location: Danville Wv Posts: 266	Re: Wheres the Leak Ok folks got some pictures tomorrow gonna grab some coolant, some of the items above and a cooling system pressure tester. This is the only place on the block I could find coolant. Personally believe its the freeze plug behind the engine mount. Also the heater core isn't hooked up, I should plumb that up before pressure testing right? Attached Images

03-04-2021, 08:22 PM	#11
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,513	Re: Wheres the Leak No need. Actually better without it hooked up.



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