Filler neck Mercruiser 1985 470

[Ed_Green Bay]

I need to replace the filler neck for coolant on the coolant resevoir on an 1985 Mercruiser 470.

How do I get the broken one out? Is it brazed in?

When I replace with a new one, do I braze it in or can I epoxy it?

 

[Scott Danforth]

NO YOU CANT @#$%@#%@#$%$% EPOXY IT IN

yes, it is brazed in

super easy repair for anyone in the radiator/heat exchanger repair business

since you are in green bay - take your heat exchanger to Mike at Valley Radiator, tell him I sent you.

If you need aluminum welding, Mike is your guy

if you need engine work, Stop in and talk to Larry at Baril Engine next door to Mike.

and if you need your starter or alternator looked at, go to Green Bay Rebuilders on velp

 

[Ed_Green Bay]

Thank you.

Will do.

 

[DLNorth]

Dan

NO YOU CANT @#$%@#%@#$%$% EPOXY IT IN

 

[achris]

NO YOU CANT @#$%@#%@#$%$% EPOXY IT IN...

My thoughts exactly. :thumb:

 

[stonyloam]

Scott, I think he is talking about the filler neck in the reservoir, not the exchanger. I think the reservoir is cast iron (not sure) so don’t think it is brazed in. I think it is a press fit with an “O” ring and held in place by the overflow fitting. If I were to guess (and it is only a guess) you would remove the overflow fitting, pry the old neck out, replace the O ring and tap the new one in place, secure it with the fitting. 23-26 here https://www.mercruiserparts.com/bam/.../30895/908/100

 

[stonyloam]

The only thing the manual says is “if the reservoir requires replacing, transfer the parts from the old one”, so it sounds like the filler neck should pop out after you remove the overflow fitting.

 

[Bt Doctur]

Most are copper or brass.heat exchangers The necks are mostly soldered in place on the copper heat exchangers so trying to pry it out will destroy it.All the 470 res I`ve replaced had the filler neck already on it.

 

[stonyloam]

It’s the filler neck on the reservoir (where the pressure cap is), not the exchanger, at least that is what the op said. There is an O ring to seal it, so it can’t be brazed or soldered in, the heat would destroy it. As I recall mine is brass. This I believe the op is talking about https://www.boatpartheadquarters.com/Mercruiser-Fitting-Kit-Filler-Hole-22-13234A1-p/glm-21897.htm

 

[Scott Danforth]

remove the o-ring, braze in the new then.

either way, you cant epoxy it in place.

and if the OP takes it to Mike, the bill will be under $35

 

[stonyloam]

I don’t think so. The O ring appears to go under the brass piece. You can’t braze brass without melting it. I still believe it is a press fit that seals on the O ring. Yeah order the new piece and take it someplace, they will know what to do with it. Remember we are talking 470 here LOL! Remember to order a new reservoir to exhaust manifold gasket too. You will need to find out if you have an aluminum or iron exhaust manifold to get the correct gasket.

 

[Scott Danforth]

You can’t braze brass without melting it./QUOTE]

ROLTFLOL

I guess the million or so brazed heat exchangers that were manufactured with brass filler necks just during my short stint in the industry shouldnt have been able to be made then.

They braze brass and copper every day. And if you have the SN from the HX, the manufacturer can tell you who brazed it, and exactly what time it was brazed

 

[stonyloam]

I repeat it is NOT A HEAT EXCHANGER that he needs the neck for, he needs a new neck for the CAST IRON coolant reservoir that sit on top of the exhaust manifold. It is not soldered or brazed in. The heat exchanger is an entirely different unit. This is the exchanger https://www.mercruiserparts.com/bam/.../30895/908/120. This is what he needs to replace https://www.mercruiserparts.com/bam/.../30895/908/100 #21 and #22 There is NO FILLER NECK on the heat exchanger.

 

[stonyloam]

This is the part that he needs

 

[Scott Danforth]

I hear you. you are not hearing me

I also know that the standard filler neck that you show is pressed in on the 470, and when that continues to leak, you can also braze it to the reservoir, move on and go boating. it is also the exact same component that is also brazed in on most heat exchangers.

that little stamped part is about $1 (unless you get it thru mercruiser) then it is $28

 

[stonyloam]

OK I see, just thinking it is a lot easier to just pop the old one out rather than draining the system and taking the whole thing apart and replacing gaskets.