Coolant Leak - Temp Fix Needed

[brodie123]

Hi All;

Mercruiser 3.7 inline 4 (Dual) with Heat Exchange

I am in need of a temporary fix. One of our engines has a tiny hole (the size of a pen tip) in the cover behind the water pump which is the cover you remove the water pump and the stator etc. to remove.

Obviously this cover needs to be replaced but I need a temporary fix. The hole is on the vacuum side and I believe a patch would hold for now, but what do I use as a patch?

I have lots of material around the hole to support a patch but unsure what would work well. I was thinking of plugging the hole and then J-B Weld but I do not believe J-B Weld can handle the heat.

Any suggestions??

 

[brodie123]

Re: Coolant Leak - Temp Fix Needed

I just found JB Weld Hi Heat - it's a puddy, would this work?

 

[Bt Doctur]

Re: Coolant Leak - Temp Fix Needed

that hole should not be plugged. it is a vent hole, or tell-tale hole to indicate seal failure. plugging it could force A/F into the engine oil and ruin your day.
you need to post a pic

 

[brodie123]

Re: Coolant Leak - Temp Fix Needed

Wow... thanks for the heads up. I will post a pic asap.

 

[brodie123]

Re: Coolant Leak - Temp Fix Needed



I've uploaded 2 pics and put a white circle around what I saw as a hole needing to be patched. Please let me know if this is indeed a vent.

thx

 

[Bt Doctur]

Re: Coolant Leak - Temp Fix Needed

that is the weep hole everyone referrs to talking about the infamous 3.7 or 470/488 motor

 

[Bt Doctur]

Re: Coolant Leak - Temp Fix Needed

this link will take you to the manuals, there view and print only. Boatinfo - The library, containing manuals, brochures and other technical documents from the last hundred years!

 

[osborne looney]

Re: Coolant Leak - Temp Fix Needed

Yes that is a weep hole DO NOT PLUG !!!!!! unless you want to replace everything after you fill up crank with water
it is almost the end of the season up here -- try running with rad cap loose -check level often and bilge but if seals are NOT ALL THE WAY gone it might work - BUT REPLACE cam/ wp seals as soon as you can lots of articles in here on the way to do it right .:joyous:

 

[brodie123]

Re: Coolant Leak - Temp Fix Needed

Thanks. So is it just the water pump to pull off or does the balancer/stator etc. all have to come off?

 

[stonyloam]

Re: Coolant Leak - Temp Fix Needed

Read this: Mercruiser 470 coolant leak And don't worry, you do not need a lot of fancy tools, and you probably will not have to mess with the motor mounts. Yeah it will probably last out the season, just check the oil for coolant and make sure the hole stays clear and OPEN.

 

[brodie123]

Re: Coolant Leak - Temp Fix Needed

Awesome. Thanks everyone !!!

 

[brodie123]

Re: Coolant Leak - Temp Fix Needed

Hi All. I have the front pump cover off and all bolts removed including the oil pan bolts (front) - see pic below.

Problem is that I can't get the pump off. It looks to me like a nut, so reverse thread, turn clockwise to remove. I'm using a 3/4" socket and it's turning the motor for one and starting to strip for the other.

What's the best way to get the pump off? Impact gun on low??

Also, I assume the key on the crank shaft needs to be removed. What's the best way to remove that?

thanks in advance.

Chris

 

[stonyloam]

Re: Coolant Leak - Temp Fix Needed

It is a stud with an Allen head that the impeller is screws onto. You should be able to insert a Allen wrench in the end of the stud to hold it and turn the impeller off with a box end wrench. Yes it is a reverse thread, should be an arrow on the impeller to show which way to turn it off. #13 & 14 here http://www.mercruiserparts.com/Show...39469.png&inbr=908&bnbr=170&bdesc=FRONT+COVER Should come off.

 

[brodie123]

Re: Coolant Leak - Temp Fix Needed

Thanks. I got her off, she was just seized up a little.

Now that she's all apart, I'm having difficulty finding the Sierra part #'s that I need. Can anyone offer some help on that?

Here's what I need:

Timing chain gasket set - main cover and water pump cover
Cam water seal (Two)
Crank Oil Seal
Oil Pan Gasket (needs replacing)

Please feel free to add in any I'm missing.

Thanks !

 

[thumpar]

Re: Coolant Leak - Temp Fix Needed

If you have Napa up there take your serial numbers in. They have a parts book that is the same parts as Seirra.

 

[stonyloam]

Re: Coolant Leak - Temp Fix Needed

I would go with OEM seals #2 &#3 in the parts list. Sierra is fine for the others #18-4380. You can't replace the whole oil pan gasket with the engine in the boat, so if you messed up the front part of the gasket, just cut off the old gasket flush with the sides and get some gasket material anf make a new section, a little form-a-gasket in the corners should do it.

 

[Eric 3.7LX Alpha 1]

Re: Coolant Leak - Temp Fix Needed

Numbers are Mercruiser OEM(Quicksilver brand)
27-68714A7 Front Gasket Set
26-97530 Cam Seal (x2)
26-67388 Crank Front Seal
27-72479A5 Oil pan Gasket

+ Speedi Sleeves if needed don't recall the part numbers

 

[osborne looney]

Re: Coolant Leak - Temp Fix Needed

The sleeve that the speedi rep. got for my Napa guy is .875" size (Sleeve No. 99085)
(yes; 2 are required)= 3/4"

put on speedi sleeve over end of cam shaft and USE RED LOCTITE to secure -- if cam has any grooves wore into it it will leak !!! be sure to observe which way seals face as well

The sleeve for .875" goes up is from .866" to .875" (Sleeve No. 99812)

The sleeve for .866" (next smallest they offer) goes from .861" to .866" (Sleeve No. 99085)

cam seals C/R = 8700 and national seal # 471570

 

[brodie123]

Re: Coolant Leak - Temp Fix Needed

Thanks, that really helps.

There ARE grooves worn into the cam - I cleaned up the surface rust.

So if the leak continues (due to the grooves) does this mean a new cam is required?

 

[brodie123]

Re: Coolant Leak - Temp Fix Needed

I think I get it now, put a sleeve over the cam and let the new seals ride on the sleeve. Thanks!!