Water pump/Thermostat Replacement Advice L6 250

[Yamariv]

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?

[Wrenchbender Ret]

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

[Yamariv]

Originally Posted by Wrenchbender Ret

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

Awesome tips, thank you!

[72SB]

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

[mr48chev]

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.

[72SB]

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)

[Yamariv]

Awesome, thanks guys! Going to pick up the gasket and some RTV tomorrow