Did the maintenance on the charge air cooler today. QSB 6.7

[magna 6882]

I had to removed the front cap last year to recover a zinc that came off the the cooler looked clean but the idea i couldn't confirm how well it was greased is what was nagging me.the only interference items that needed to be pulled to allow me to pull the core was 2 bolt holding the trans cooler clamp and the air filter which was less work then pulling the whole thing and getting into more hose connections.It didnt have any visible grease that i could see but the o rings had grease on them. The last two haul outs i ask about having them do the work and they didnt want to play.

 

[Comodave]

The O rings aren’t the problem if they have grease or not. It is the core where it meets the aluminum housing. That needs to be liberally coated with Acco Metalube grease. You can’t see if there is grease in there or not just by pulling the end cap. You need to slide the core out and see what condition it is in and then renew the grease and new O rings when you put it back together. Tony Athens website sbmar.com has an excellent video on how to grease and service the cooler. If it has adequate grease the core should slide right out. Mine took 13 tons to push the core out. From the end the core looked good but when we finally got the core out the ends of the core were pretty plugged up with a calcium looking substance. But you couldn’t see that until the core was out.

 

[Steve DAntonio]

I have seen my share of leaking seawater cooled after cooler (SWAC) leaks, and in nearly every case they were a result of deferred maintenance or improper reassembly, and in many of those cases they destroyed the engine, or it was not economically repairable. If you have a SWAC do not ignore this maintenance requirement. Every engine that uses a SWAC has a maintenance (and sometimes replacement) schedule for this component, some are as short as 500 hrs. or 1 year, WCF. Others are as long as 6,000 hours, or 5 years, WCF. I too also strongly recommend pressure testing, to ensure the components, especially the O rings (these are easy to roll or twist), have been properly reassembled. Jacket water cooled after coolers (JWAC), require no routine maintenance other than coolant system flushing and coolant replacement.

 

[Comodave]

The pressure testing was the hardest part of the servicing by far. But critical to do.

 

[Pascall]

Interesting topic, does anyone have a photo of the test setup?

Regards,

Pascal.

 

[Comodave]

I just went out to my garage and took these photos. I have 2 different styles of aftercoolers on my boat. One original from 1998 and a new one from a couple of years ago. The new one has a drain on it but the older style doesn’t have a drain. The first photo is from the test fittings for the original style and the second photo is for the new style. The new style is much easier to test since the schrader valve and pressure gauge screw into the drain and I believe the anode holes. I would have to look at it again to verify what the holes actually are but my boat is in the barn and we got a lot of snow today so I don’t want to go to the boat to look. Then I use the black vinyl caps to seal the air inlet and outlet by using a hose clamp. The old style I use the fittings in the first photo but the problem is that is can be difficult to get the hose to seal and not blow the fittings off the aftercooler. I use double hose clamps and then a ratchet strap to hold them in place. After trying for an hour or so I can usually get them to stay on and seal up. I pump the air pressure up to about 22-24PSI and wait overnight. The pressure shouldn’t drop at all. Like I said the pressure test is the hard part of the servicing but it absolutely needs to be done. Otherwise you could really damage the engine.

 

[Pascall]

Thank you very much for the information, this clarifies things for me.

Kind regards,

Pascal.

 

[magna 6882]

I used a 2 inch cap on the water outlet then used a series of standard pvc fittings,a low pressure gauge ,a tee and a schrader valve. I also had one blow off due to not being tight enough. i also just used a hand tire pump for pressure. I also had one blow off so i learned quickly position the test so your not having to look at the gauge in the line of fire if something comes loose. I swapped things around so the gauge was on the side so i could look at it and not get hit in the face. I also had to grab the wifes countertop cleaner to check for leaks and they were numerous. I switched to rector seal for every fitting including the two zinc plugs. I think i spent more time chasing bubbles then i did pulling the core. In hindsight i should have started with rectorseal and spent more detail on the joints in my test rig. I even had a hose leaking from the nylon reinforcing in the factory hose. the bubbles were coming from center of the end of the hose so there must have been a defect in the lining of the factory hose.

 

[Comodave]

Yes, the testing is a PITA. I used a spray bottle with some Dawn to chase down the air leaks which were many at first. Gradually I got them sealed up.

 

[twistedtree]

You can also get test plugs like these for pressure testing house plumbing systems.

 

[firehoser75]

Pascal and others who are interested.
Check out Tony's tips on sbmar.com and/or the website forum for lots of useful info on how to do this servicing (videos and photos). I had never done one before and found it relatively easy after gathering (free) info from that site.
As others have stated, getting the testing apparatus setup and stopping any leaks from it was actually the hardest part, but testing to ensure no leaks is absolutely essential. For the same reasoning, I feel that testing of all the other saltwater cooling appliances is also essential. You don't want any (salt)water in your tranny, oil cooler, antifreeze, etc. either as it can lead to big problems and expense.
Many boaters leave aftercooler servicing too long and end up having to buy new if available!!! This is expensive compared to a few hours of a person's time.
Here are some photos of my "home made" testing setup with one of an apparatus (this photo from sbmar website) to test the core separately, which would make finding the cause of any "real" leak easier.

 

[DDW]

Since you are testing the water side of things, it may help for both leaks and testing sensitivity to fill it with water before pressurizing. This is what hydro testers do, just to keep from getting blown up. Since most of the volume will be filled with water (which is incompressible) any change in volume due to leakage will be much more apparent on the gage. And when something pops off because it wasn't tight enough it is less likely to shoot across the room.

 

[Comodave]

You don’t want to only test the core separately but also test the whole cooler after you install the core in the housing. Otherwise you can have a leak at the O ring and not know it.

 

[Pascall]

Excellent information!
Thank you all for posting the clear photos and detailed explanations!

Best regards,

Pascal.

 

[Comodave]

Excellent information!
Thank you all for posting the clear photos and detailed explanations!

Best regards,

Pascal.

No problem, glad to help.