Intake or Head Gasket or Worse - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tobiaslescht · 03-07-2019, 04:08 PM

1967 K10 with a mid 1980s 350 engine. has been running rough for last 9 months with backfire after highway speeds. light white smoke out of passenger side tailpipe. couple weeks ago it overheated with coolant pouring out of the front of engine. Tried to refill but coolant poured out. Runs good without coolant until it gets too hot. Any suggestions?

**Wrenchbender Ret** · 03-07-2019, 04:27 PM

Could be worse. Can you tell were the coolant is leaking? It sounds like a bad head gasket or cracked head. If you have been "running without coolant till it gets hot" the engine is probably destructed. Pull the plugs on the pass side of the engine & check for water on the plug or in the cyl.
George

tobiaslescht · 03-07-2019, 07:17 PM

Quote:

Originally Posted by Wrenchbender Ret

Could be worse. Can you tell were the coolant is leaking? It sounds like a bad head gasket or cracked head. If you have been "running without coolant till it gets hot" the engine is probably destructed. Pull the plugs on the pass side of the engine & check for water on the plug or in the cyl.
George

I have only run it a couple times without coolant for about 5-10 mon max. The coolant is pooring out from where the large radiator hose meets the engine. It is not the hose or the connection to the engine that is leaking. Area is right where the alternator pully is.
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**truckster** · 03-07-2019, 07:44 PM

Are you sure it's not the water pump? There's a weep hole on the bottom side, and if it develops a big leak the water will come out fast.

tobiaslescht · 03-07-2019, 07:53 PM

Quote:

Originally Posted by truckster

Are you sure it's not the water pump? There's a weep hole on the bottom side, and if it develops a big leak the water will come out fast.

Thanks! I’ll check that. That wouldn’t explain light white smoke on the passenger side exhaust?
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Metaldoc · 03-08-2019, 02:36 AM

Is it automatic? It could be your vacuum shift module is done. Check for tranny fluid in the vacuum line

Myoldtruck · 03-08-2019, 08:14 AM

time for a new water pump and replace the hoses while your at it.

tobiaslescht · 03-08-2019, 08:41 AM

Quote:

Originally Posted by Metaldoc

Is it automatic? It could be your vacuum shift module is done. Check for tranny fluid in the vacuum line

Yes matted to a th350
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tobiaslescht · 03-08-2019, 08:41 AM

Quote:

Originally Posted by Myoldtruck

time for a new water pump and replace the hoses while your at it.

Great! Thanks for the help. Will update next week on progress.
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rpmerf · 03-08-2019, 11:07 AM

Pull the plugs. If one is strangely clean, you are burning coolant on that cylinder. If they are oily, you are burning oil on that cylinder. Black is rich. You can google around for images.

You can pressure test the radiator or run a compression test on the engine. If you run the engine and open the radiator cap and see bubbles, that is exhaust gasses pushing into the coolant.

tobiaslescht · 03-21-2019, 10:18 AM

Thanks everyone. Water pump replaced and truck back and running. Still a little rough and definitely rich. Going to adjust the Holley carb to see if that helps. There is also a knocking noise. Could this be a valve or rod problem?

sick472 · 03-21-2019, 10:49 AM

Knocking typically relates to a rotating assembly (rods, main bearings, psitons) problem as opposed to "tapping" which is usually valve, rocker, lifter related.

Can you more closely pinpoint the noise? I use a length of wooden dowel (like a shortened broom handle) and place one end against my ear and the other end on different hard surfaces of the engine. This really helps to determine where the noise is most prominent.

PAY ATTENTION!!! IF THE BROOM HANDLE COMES IN CONTACT WITH A MOVING COMPONENT OF THE ENGINE...YOU MAY HAVE A NEW COMPONENT IN YOUR HEAD!

Coley · 03-21-2019, 11:02 AM

Knocking sound?....or a ticking sound?....very important difference.
Spend time and carefully isolate the sound and where it is coming from.

Coley

rpmerf · 03-22-2019, 06:21 AM

stethoscope works good too. Be sure to check around all the exhaust ports.

03-07-2019, 04:08 PM	#1
tobiaslescht Registered User Join Date: Mar 2019 Location: Austin, TX Posts: 6	Intake or Head Gasket or Worse 1967 K10 with a mid 1980s 350 engine. has been running rough for last 9 months with backfire after highway speeds. light white smoke out of passenger side tailpipe. couple weeks ago it overheated with coolant pouring out of the front of engine. Tried to refill but coolant poured out. Runs good without coolant until it gets too hot. Any suggestions?

03-07-2019, 04:27 PM	#2
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,190	Re: Intake or Head Gasket or Worse Could be worse. Can you tell were the coolant is leaking? It sounds like a bad head gasket or cracked head. If you have been "running without coolant till it gets hot" the engine is probably destructed. Pull the plugs on the pass side of the engine & check for water on the plug or in the cyl. George

03-07-2019, 07:44 PM	#4
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,791	Re: Intake or Head Gasket or Worse Are you sure it's not the water pump? There's a weep hole on the bottom side, and if it develops a big leak the water will come out fast. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

03-08-2019, 02:36 AM	#6
Metaldoc Registered User Join Date: Apr 2015 Location: Ayr Ontario Posts: 1,122	Re: Intake or Head Gasket or Worse Is it automatic? It could be your vacuum shift module is done. Check for tranny fluid in the vacuum line __________________ Do it, Do it right, Do it right the first time

03-08-2019, 08:14 AM	#7
Myoldtruck Registered User Join Date: Sep 2015 Location: Mohnton pa. Posts: 208	Re: Intake or Head Gasket or Worse time for a new water pump and replace the hoses while your at it.

03-08-2019, 11:07 AM	#10
rpmerf Registered User Join Date: Feb 2011 Location: Parkville, MD Posts: 1,024	Re: Intake or Head Gasket or Worse Pull the plugs. If one is strangely clean, you are burning coolant on that cylinder. If they are oily, you are burning oil on that cylinder. Black is rich. You can google around for images. You can pressure test the radiator or run a compression test on the engine. If you run the engine and open the radiator cap and see bubbles, that is exhaust gasses pushing into the coolant. __________________ 1970 C20 Custom Camper - 350, TH350 1997 GMC Suburban 1994 Acura Integra GSR 1987 Dodge Daytona Shelby Z

03-21-2019, 10:18 AM	#11
tobiaslescht Registered User Join Date: Mar 2019 Location: Austin, TX Posts: 6	Re: Intake or Head Gasket or Worse Thanks everyone. Water pump replaced and truck back and running. Still a little rough and definitely rich. Going to adjust the Holley carb to see if that helps. There is also a knocking noise. Could this be a valve or rod problem?

03-21-2019, 10:49 AM	#12
sick472 Registered User Join Date: Jul 2015 Location: Sedalia Mo. Posts: 1,130	Re: Intake or Head Gasket or Worse Knocking typically relates to a rotating assembly (rods, main bearings, psitons) problem as opposed to "tapping" which is usually valve, rocker, lifter related. Can you more closely pinpoint the noise? I use a length of wooden dowel (like a shortened broom handle) and place one end against my ear and the other end on different hard surfaces of the engine. This really helps to determine where the noise is most prominent. PAY ATTENTION!!! IF THE BROOM HANDLE COMES IN CONTACT WITH A MOVING COMPONENT OF THE ENGINE...YOU MAY HAVE A NEW COMPONENT IN YOUR HEAD! __________________ He who is without oil shall throw the first rod. Compressions 8.7:1 1972 C10 1976 C10 (parts truck) 1985 K20

03-21-2019, 11:02 AM	#13
Coley Registered User Join Date: Oct 2011 Location: Victoria, B.C Posts: 3,794	Re: Intake or Head Gasket or Worse Knocking sound?....or a ticking sound?....very important difference. Spend time and carefully isolate the sound and where it is coming from. Coley __________________ ....for some men, there is experience, skill and effort....for the others...there is visa and UPS LOL 1966 Chevy 1/2 ton (Florida- Red/white) 1972 Chevy 1/2 ton (California- Blue/white) 2005 Chevy Silverado HD2500/Duramax 2000 Dodge Ram 1500

03-22-2019, 06:21 AM	#14
rpmerf Registered User Join Date: Feb 2011 Location: Parkville, MD Posts: 1,024	Re: Intake or Head Gasket or Worse stethoscope works good too. Be sure to check around all the exhaust ports. __________________ 1970 C20 Custom Camper - 350, TH350 1997 GMC Suburban 1994 Acura Integra GSR 1987 Dodge Daytona Shelby Z



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