12-71 Heat Exchanger gland weep holes leaking?

[MVCaprice]

Recently I had the heat exchangers out of our 12v71's for cleaning. When I put the HE's back in I changed the glands, orings and all gaskets. After running a bit i started to see salt weeping coming through the orings and glands on the HE discharge side on the port engine at

higher rpm.​

In thinking about this problem and possible causes I am thinking there might be a couple scenarios that i could up against:

1) I somehow have the wrong O-rings installed. I called pc industries and had them look at the diameter of the Detroit orings vs the aftermarket orings and they are the same and i used the same part number on the other side. The oring seal p/n i am using is

5167746​

.

2) The exhaust sprayer may be clogged which is creating excessive pressure in the heat exchanger. I haven't looked but have read on this forum that they need to be cleaned from time to time.

I would suspect something else in the cooling system but the flow of water is salt only and i didn't have any other issues with the cooling system that i could tell. However I haven't checked the coolant yet so i need to look a little closer.

Anyone have any experience with a similar issue?

 

[racclarkson@gmail.com]

Retighten when hot and see if that works.

 

[Dan Mapes]

Ours had o-rings and gaskets on the end plates. The o-rings had to be in between the gasket and end plate.

 

[MVCaprice]

Ours had o-rings and gaskets on the end plates. The o-rings had to be in between the gasket and end plate.

Yes this is how ours are. There is an inner o-ring, then a metal gland and then an outer o-ring.

 

[VIKING63]

Did you install new metal rings also? They compress after used.

 

[MVCaprice]

Did you install new metal rings also? They compress after used.

Yes i did. They were only installed once!

 

[KPTIM]

Just talking about the exchanger assembly part of the cooler.
I leave in an area where barnacles run heavy and rebuild my exchangers ever other year.
I have experienced the leak you are referring to (the very first time I serviced mine) then I learned.

Few more comments here:

• There are an odd number of paper gaskets. Two gaskets on the side with NO O-rings and one gasket on the side with the O-rings. Sometimes it is not intuitive about where they go. If you use 4 gaskets to assemble the unit (two on the side with the O-rings) you will not be able to get enough compression on the O-rings and they will leak.
• No not reuse the crush rings.
• I found that the genuine DD O-rings and crush rings work better than aftermarket or O-ring crosses.
• If you do use aftermarket O-rings make sure that they are made from a material that can withstand constant exposure to both salt water and the coolant type you use.
• All of the gasket and O-ring surfaces need to be Very Very clean before re-assembly.
• Use a O-Ring assembly lube on the O-Rings during the assembly of that section of the exchanger.
• Do not use RTV to seal the gaskets or the O-ring surfaces. If you must use a sealant then use a proper thin gasket sealer compound!!!!
• You have to tighten up everything in a very uniform fashion!!!
• The design of this sealing assembly is that everything goes up rigid and should not need to be re-torqued after assembly.

I have a *.pdf detailed exploded view of the exchanger for a 8V71 which is almost the same as the 12V71 unit. I can send it to you in a e-mail if you like. Just send me your email address.

 

[MVCaprice]

Just talking about the exchanger assembly part of the cooler.
I leave in an area where barnacles run heavy and rebuild my exchangers ever other year.
I have experienced the leak you are referring to (the very first time I serviced mine) then I learned.

Few more comments here:

• There are an odd number of paper gaskets. Two gaskets on the side with NO O-rings and one gasket on the side with the O-rings. Sometimes it is not intuitive about where they go. If you use 4 gaskets to assemble the unit (two on the side with the O-rings) you will not be able to get enough compression on the O-rings and they will leak.
• No not reuse the crush rings.
• I found that the genuine DD O-rings and crush rings work better than aftermarket or O-ring crosses.
• If you do use aftermarket O-rings make sure that they are made from a material that can withstand constant exposure to both salt water and the coolant type you use.
• All of the gasket and O-ring surfaces need to be Very Very clean before re-assembly.
• Use a O-Ring assembly lube on the O-Rings during the assembly of that section of the exchanger.
• Do not use RTV to seal the gaskets or the O-ring surfaces. If you must use a sealant then use a proper thin gasket sealer compound!!!!
• You have to tighten up everything in a very uniform fashion!!!
• The design of this sealing assembly is that everything goes up rigid and should not need to be re-torqued after assembly.

I have a *.pdf detailed exploded view of the exchanger for a 8V71 which is almost the same as the 12V71 unit. I can send it to you in a e-mail if you like. Just send me your email address.

These are all great points. I used gasket tack to hold the gaskets on and no RTV. I did however have some tank imperfections that required jbweld to smooth out and seal. There are a couple bolts on the vertical part of the gasket that dont have much material behind them which can result in a bolt sealing leak if you are not careful.

 

[Oldlaxer1]

Just talking about the exchanger assembly part of the cooler.
I leave in an area where barnacles run heavy and rebuild my exchangers ever other year.
I have experienced the leak you are referring to (the very first time I serviced mine) then I learned.

Few more comments here:

• There are an odd number of paper gaskets. Two gaskets on the side with NO O-rings and one gasket on the side with the O-rings. Sometimes it is not intuitive about where they go. If you use 4 gaskets to assemble the unit (two on the side with the O-rings) you will not be able to get enough compression on the O-rings and they will leak.
• No not reuse the crush rings.
• I found that the genuine DD O-rings and crush rings work better than aftermarket or O-ring crosses.
• If you do use aftermarket O-rings make sure that they are made from a material that can withstand constant exposure to both salt water and the coolant type you use.
• All of the gasket and O-ring surfaces need to be Very Very clean before re-assembly.
• Use a O-Ring assembly lube on the O-Rings during the assembly of that section of the exchanger.
• Do not use RTV to seal the gaskets or the O-ring surfaces. If you must use a sealant then use a proper thin gasket sealer compound!!!!
• You have to tighten up everything in a very uniform fashion!!!
• The design of this sealing assembly is that everything goes up rigid and should not need to be re-torqued after assembly.

I have a *.pdf detailed exploded view of the exchanger for a 8V71 which is almost the same as the 12V71 unit. I can send it to you in a e-mail if you like. Just send me your email address.

Can you send me a copy? ralpop5 at gmail.com Thanks
John

 

[KPTIM]

Hi John,
Sent you a copy of the exploded view.

 

[Westfield 11]

This is the sort of information that should be in the FAQ's.......

 

[MVCaprice]

FYI, if you are looking for v71 parts schematics as mentioned above some of them are online. Powerline Components has a pretty decent component breakdown @ https://www.powerlinecomponents.com/catalog/v71_alpha_index.htm

 

[VIKING63]

Good evening, have you figured out the leak? I am on about my 10th heatexhanger break down. Every time I have to put it together twice.maybe three times The gaskets have a top and bottom. They are close, you can force them, but they will not be correct. Not sure if that is the case with yours, but just what I have come across. Once I got it right zero leaks. With or without rtv.

 

[MVCaprice]

Good evening, have you figured out the leak? I am on about my 10th heatexhanger break down. Every time I have to put it together twice.maybe three times The gaskets have a top and bottom. They are close, you can force them, but they will not be correct. Not sure if that is the case with yours, but just what I have come across. Once I got it right zero leaks. With or without rtv.

I hear you. The clocking of the gaskets is key. Once the bolt holes are lined up you are good. What I did was test fit them to look for fitment prior to using gasket tack to make sure the clocking is correct.

Unfortunately, The first leak I had was around the bolt holes. There was a depression on the inside so I used JB weld to build it up enough to seal properly on the inside of the bolt hole:

There is so little steel on the inside of the bolt that I want to call it a manufacturing/design defect. In any event check this! On this particular manifold it's only on one side.

However, my current issue is not the end cap to manifold thankfully. As you can see water is coming out of the weep hole. One trip out was enough to salt the crap out of the engine and leave water marks! It was undetectable until 1500 or so RPM. Now i know though to test run at the dock at higher RPM to ensure there are no leaks!

In any event, I took it apart on Saturday and what i think happened was that during installation I over crushed the glands and as a result reduced the seal on the oring enough where it started to leak. I bought new glands and orings and will try again. This time I will not use a rubber mallet to install the glands.

 

[KPTIM]

The metal crush glands need to be a slip fit on the exchanger ends.
If you have to force them onto the end of the exchangers (like with a rubber mallet) then as you tighten the end cap up both O-rings will not see equal compression. Only the outer O-ring will get compressed.

Sounds like you already know this.....

 

[MVCaprice]

The metal crush glands need to be a slip fit on the exchanger ends.
If you have to force them onto the end of the exchangers (like with a rubber mallet) then as you tighten the end cap up both O-rings will not see equal compression. Only the outer O-ring will get compressed.

Sounds like you already know this.....

Roger that my friend. I learned this the hard way!!!!

 

[MVCaprice]

Ok. Small update. I received new o-rings and glands. Took it apart. Put it back together by hand and all is well.

I went through and washed her down with salt away to get rid of the salt spray that got all over the motor as well.

Good times!

 

[cenger]

Picking up on this old thread, I took my Starboard heat exchanger apart for cleaning because the Starboard engine was running 7 degrees higher than the port (173 vs 180). I found one of the deflectors was bad and not channeling the water correctly. The deflector was replaced, and the exchanger was cleaned by a radiator repair shot. Just running Barnacle Buster would not have solved this problem, it's important to take the exchangers apart and inspect them. My question as I get ready to put everything back together is the torque spec for the water intake and rubber O-rings side of the exchanger (I have all new gaskets and crush washers per this thread)? When I took things apart I noticed there was not a lot of torque on the bolts.

 

[Captain Ralph]

It is the O rings that take the pressures, not the bolts or gasket. You can look up what a SS, 1/4 or 5/16 machine screw will take, but I just grease up a gasket and snug all down evenly with my finger tips.
I can't imagine more that a few ft/Lbs. The spec may be a tall inch/pounds.
Not much..
Oh, grease up those thick O rings well, They want to relax and form a easy seal when greased up.
None or not enough grease, they may not roll in place after their press fit and leak.
Remember, here is 90+ year old science. Grease was involved in everything.
I still grease all my DDC gaskets.