Coolant loss white plugs - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72c20customcamper · 07-12-2022, 02:52 PM

I am loosing a small amount of coolant on long trips . Used about a pint in 2500 miles . Pulled the plugs both 2 and 4 have white deposits . Truck is not overheating and runs fine with no smoke from exhaust . Did a co2 test on the coolant not a trace . Fluid stayed blue after repeated purging I even tested some with co2 from my beer tap and it Turned instantly yellow so the fluid is working . I’m thinking it’s most likely to be a bad intake gasket and not a cracked head or head gasket . Any opinions or recommendations would be welcomed.

72c20customcamper · 07-12-2022, 02:55 PM

Engine 350 with RV cam edlebrock performer manifold has 60k on it .

**AussieinNC** · 07-13-2022, 07:56 AM

The white deposits could point to a small cross cylinder coolant leak developing.
They could also be a sign of poor sealing of that area of the manifold to head surface. Check the manifold bolts for tightness.

The manifold could also be corroded in the ports 2-4 area thru to the coolant port in the head.

I have also seen plugs with these deposits when poor quality gas has been used or some additives have been used....however, the deposits would be on all or most of the plugs not just an adjoining cylinders pair.

I would replace all the plugs, run some Sea Foam thru a full tank of gas from another gas station and check all manifold bolts are tight.

On another note....am jealous of the beer tap....

72c20customcamper · 07-13-2022, 09:59 AM

I found the issue . Coolant leaking front passenger side . Going to check bolt torque on the manifold . If it’s good going to get some new gaskets

72c20customcamper · 07-13-2022, 03:35 PM

Bolts were loose and very rusty . Looked like RTV black was used as a thread sealant . Cleaned everything up just need to go get some real thread sealant .

**truckdude239** · 07-13-2022, 05:59 PM

Change the Intake gaskets

**cwcarpenter98** · 07-13-2022, 09:35 PM

Is it possible the intake bolts are a smidge too long and bottoming out in the head before you're getting full torque on the gasket? I mention it because of the 1st thread on each bolt pictured looking a smidge smushed

72c20customcamper · 07-14-2022, 02:58 PM

Don’t think there too long . I didn’t check but they can’t be longer than 1 1/4 “ which is correct length . It’s back together and no leaks .

**cwcarpenter98** · 07-14-2022, 03:03 PM

Good deal! I was just being extra cautious

**AussieinNC** · 07-14-2022, 03:10 PM

There also appears to be some water stains down the metal fitting in the manifold where the heater hose is attached.

There also appears to be some corrosion on the threads of the fitting where it screws into the manifold.

I assume you checked all the intake manifold bolts for tightness....

Great work !

72c20customcamper · 07-14-2022, 06:12 PM

Quote:

Originally Posted by AussieinNC

There also appears to be some water stains down the metal fitting in the manifold where the heater hose is attached.

There also appears to be some corrosion on the threads of the fitting where it screws into the manifold.

I assume you checked all the intake manifold bolts for tightness....

Great work !

All the others were tight and dry .

I drove it about 40 miles today . Area was totally dry put in a new clutch fan too old one was not working at all .

**The Rocknrod** · 07-15-2022, 12:22 PM

Good to hear hope it all works out from now on. I love clutch fans, I think everybody should have them.

72c20customcamper · 07-15-2022, 07:55 PM

Quote:

Originally Posted by The Rocknrod

Good to hear hope it all works out from now on. I love clutch fans, I think everybody should have them.

My son is a big Clutch fan .

07-12-2022, 02:52 PM	#1
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,141	Coolant loss white plugs I am loosing a small amount of coolant on long trips . Used about a pint in 2500 miles . Pulled the plugs both 2 and 4 have white deposits . Truck is not overheating and runs fine with no smoke from exhaust . Did a co2 test on the coolant not a trace . Fluid stayed blue after repeated purging I even tested some with co2 from my beer tap and it Turned instantly yellow so the fluid is working . I’m thinking it’s most likely to be a bad intake gasket and not a cracked head or head gasket . Any opinions or recommendations would be welcomed. Attached Images __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

07-12-2022, 02:55 PM	#2
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,141	Re: Coolant loss white plugs Engine 350 with RV cam edlebrock performer manifold has 60k on it . __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

07-13-2022, 07:56 AM	#3
AussieinNC Moderator Join Date: Jun 2017 Location: Cherryville, NC Posts: 2,155	Re: Coolant loss white plugs The white deposits could point to a small cross cylinder coolant leak developing. They could also be a sign of poor sealing of that area of the manifold to head surface. Check the manifold bolts for tightness. The manifold could also be corroded in the ports 2-4 area thru to the coolant port in the head. I have also seen plugs with these deposits when poor quality gas has been used or some additives have been used....however, the deposits would be on all or most of the plugs not just an adjoining cylinders pair. I would replace all the plugs, run some Sea Foam thru a full tank of gas from another gas station and check all manifold bolts are tight. On another note....am jealous of the beer tap.... __________________ Family and country before all others... 2006 Chevy Silverado (Daily Driver) 2012 Chevy Equinox

07-13-2022, 09:59 AM	#4
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,141	Re: Coolant loss white plugs I found the issue . Coolant leaking front passenger side . Going to check bolt torque on the manifold . If it’s good going to get some new gaskets Attached Images __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

07-13-2022, 03:35 PM	#5
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,141	Re: Coolant loss white plugs Bolts were loose and very rusty . Looked like RTV black was used as a thread sealant . Cleaned everything up just need to go get some real thread sealant . Attached Images __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

07-13-2022, 05:59 PM	#6
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,217	Re: Coolant loss white plugs Change the Intake gaskets __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

07-13-2022, 09:35 PM	#7
cwcarpenter98 Senior Member Join Date: Jan 2018 Location: Hickory Flat, GA Posts: 4,421	Re: Coolant loss white plugs Is it possible the intake bolts are a smidge too long and bottoming out in the head before you're getting full torque on the gasket? I mention it because of the 1st thread on each bolt pictured looking a smidge smushed __________________ Christian Carpenter 1963 C10 - Frankentruck 283, 3 speed with overdrive Overdrive wiring here 1963-ish truck bed trailer - Half-Wit 1981 C10 - Penny 305, th350 1995 Dodge Dakota Sport "I'll put it simple: if you're going hard enough left, you'll find yourself turning right." - Doc Hudson

07-14-2022, 02:58 PM	#8
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,141	Re: Coolant loss white plugs Don’t think there too long . I didn’t check but they can’t be longer than 1 1/4 “ which is correct length . It’s back together and no leaks . __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

07-14-2022, 03:03 PM	#9
cwcarpenter98 Senior Member Join Date: Jan 2018 Location: Hickory Flat, GA Posts: 4,421	Re: Coolant loss white plugs Good deal! I was just being extra cautious __________________ Christian Carpenter 1963 C10 - Frankentruck 283, 3 speed with overdrive Overdrive wiring here 1963-ish truck bed trailer - Half-Wit 1981 C10 - Penny 305, th350 1995 Dodge Dakota Sport "I'll put it simple: if you're going hard enough left, you'll find yourself turning right." - Doc Hudson

07-14-2022, 03:10 PM	#10
AussieinNC Moderator Join Date: Jun 2017 Location: Cherryville, NC Posts: 2,155	Re: Coolant loss white plugs There also appears to be some water stains down the metal fitting in the manifold where the heater hose is attached. There also appears to be some corrosion on the threads of the fitting where it screws into the manifold. I assume you checked all the intake manifold bolts for tightness.... Great work ! __________________ Family and country before all others... 2006 Chevy Silverado (Daily Driver) 2012 Chevy Equinox

07-15-2022, 12:22 PM	#12
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: Coolant loss white plugs Good to hear hope it all works out from now on. I love clutch fans, I think everybody should have them. __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?



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