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#1 |
Registered User
Join Date: Oct 2022
Location: Regina, Saskatchewan
Posts: 343
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Water pump/Thermostat Replacement Advice L6 250
Hey Guys, I have the front of my 250ci apart to replace the water pump and thermostat and do a bunch of other stuff while I'm in there.
Just a few questions though.. - Is it best to use the gasket alone or gasket with a light coat of silicone gasket sealant on each side? - Do any of the bolts need thread sealant incase they go into the water jacket? Doesn't look like they do to me.. - Is there a gasket for where the thermostat housing attaches to the block? The PO just had that siliconed on.. Anything else I should no before putting it back together?
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1971 Chev C10 - 250ci L6 w/3 speed on the floor Upgrades: Power Steering 3 Core Radiator 7 Hole Gauge Cluster Power Brakes (Incoming!!..) 1971 350 (Incoming!!..) |
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#2 |
Registered User
Join Date: Oct 2005
Location: Overland Park, Ks.
Posts: 5,216
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Re: Water pump/Thermostat Replacement Advice L6 250
I like to glue the gasket to the water pump & put a thin coat of RTV on the other side.
There is a gasket for the housing to the cyl. head. Put a thin coat of RTV on both sides of it. Its a good idea to put a light coat of RTV or never seize on the bolts. I don't believe any are wet but it prevents them from corroding. Do a trial fitting on a new water pump. Sometimes they don't clear the timing cover & will leak. You have to grind a little metal off the casting if it doesn't. George |
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#3 | |
Registered User
Join Date: Oct 2022
Location: Regina, Saskatchewan
Posts: 343
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Re: Water pump/Thermostat Replacement Advice L6 250
Quote:
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1971 Chev C10 - 250ci L6 w/3 speed on the floor Upgrades: Power Steering 3 Core Radiator 7 Hole Gauge Cluster Power Brakes (Incoming!!..) 1971 350 (Incoming!!..) |
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#4 |
Registered User
Join Date: Apr 2022
Location: Moorpark, CA
Posts: 757
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Re: Water pump/Thermostat Replacement Advice L6 250
I use Permatex "WP & T Stat" housing RTV (grey). Just a skim coat on gaskets, each side. For any bolts that do go into water jackets (IDK if any WP holes go into water jacket on the 250), use "thread sealer" (not RTV) which is typically white on bolt threads if they do go into water jacket
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#5 |
Registered User
Join Date: Jul 2007
Location: Toppenish, WA
Posts: 15,507
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Re: Water pump/Thermostat Replacement Advice L6 250
Great advice all the way around. We all have our favorite water pump/thermostat housing sealant that more often than not is what the person who taught us how to work on cars used. I'm going to remember the Permatex WT & Tstat rtv though. My go to on them has usually been #2 permatex.
The suggestion of just use a smear of rtv on the gaskets and surfaces is a great one, you don't need it on so thick that it squishes out in gobs around the housing.
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Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around. |
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#6 |
Registered User
Join Date: Apr 2022
Location: Moorpark, CA
Posts: 757
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Re: Water pump/Thermostat Replacement Advice L6 250
Often the mating surface on block on old engines is pitted some so the "skim coat" of RTV helps seal those mating surfaces. It also holds the gasket to WP as you mout it keeping the gasket in place
Permatex makes several types of RTV. Each one is more suited for either coolant, oil, high temp or trans fluid and are typically all hanging in the sealer section of auto part stores. Same for "thread sealant" (read not RTV) |
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#7 |
Registered User
Join Date: Oct 2022
Location: Regina, Saskatchewan
Posts: 343
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Re: Water pump/Thermostat Replacement Advice L6 250
Awesome, thanks guys! Going to pick up the gasket and some RTV tomorrow
__________________
1971 Chev C10 - 250ci L6 w/3 speed on the floor Upgrades: Power Steering 3 Core Radiator 7 Hole Gauge Cluster Power Brakes (Incoming!!..) 1971 350 (Incoming!!..) |
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