Heat Exchanger/Radiator Anatomy

[yachtsmanbill]

My faux pas... On this side it looks like the plate may just be stuck on a gasket. Permatex maybe? I would thred a few screws into it a few turns so that it doesnt drop off and smash yer toes; tap around it with a hammer; it may loosen up. I would put a little heat on it, maybe 150F to soften any sealant and then maybe ease a wedge under the plate, but use prudence.
I am under the impression that the core will be stuck in the fit... if you take the cover off of the other side, the reciprocal plate has threaded holes to run bolts into and push the core out towards this side. Otherwise youll have to pull it out from this side.
Better ask one of the expurts first tho... ;-)) ws

 

[Angela]

Thanks, Mike. I can envision that.

I thought this thing was made of cast iron. On the inside of the plates on the ends, it's bronze. But the exterior of the tank rusts like iron. And the plate on the bottom where the tranny cooler is looks like aluminum, but maybe not. Could it be that the tank is iron and the plates are bronze? If that's right, are SS bolts still OK?

This wasn't so hard in terms of "do I really need a mechanic." In fact, other than needing some muscle and some advice on how to pry stuff apart, it's pretty easy. It's not like I'm trying to tune an engine, or install liners and rings. It's simple water piping. If it leaks...keep working with it until it doesn't.

Mike, next, I'm going to make my intercoolers look just like yours! I'm a little more brave in the engine room today than I was last week. I can remember 5 years ago when just about everything on this boat scared the daylights out of me. One component at a time...

 

[Angela]

Yachtsmanwillie, I thought you were one of the expurts on engines!

 

[REBrueckner]

Angela:

(1) "The diagram, as well as the text, indicate that a zinc should be inserted into the inlet side and a pipe plug in that spot on the outlet side."

When you open the zinc plugs does water usually run out? If not, then the zincs sit in air 99% of the time...when the engine is not running....that's what MikeP and I found on our 8V71TI's....such zincs only protect when the engines are running...I ended up leaving mine out..no zincs there...the new owner had them both reinstalled by an old Hatteras hand....that's how HE had always seen them...

A pencil zinc on the inlet side will drop pieces that can clog the inlet cooling tubes.... or pass thru to the shower head.. A pencil zinc on the outlet side will drop pieces that can clog your shower head (where raw water is sprayed into your riser system). Netiher is good. That's why I left mine out...

(2) Once you have removed or loosened bolts, it's usually a good idea to remove the gasket and replace it as the set will be undone..and sometimes leak.

(3) On 8V71TI's I recall the heat exchanger core is removed via the INLET side of the expansion tank..not the outlet....your manual should tell you.

(4) Muscle: use leverage instead!!!!!....I just removed the anode (zinc) from my home hot water heater....it was totally gone... But even with the socket bar of maybe 14" I could not loosen it.....I had a 12" piece of pipe to put over the bar...still could not get....Bought a four foot length of black steel pipe from home cheapo...put that over the bar and the anode plug loosened easily with one hand..... but I had to brace the water heater against my basement wall with a length of wood because the whole thing turned....

A PSE&G guy told me "replace the anode, they go first, then your water heater tank corrodes and you have to replace THAT.." turns out SEARS sells lots of residential hot water heater parts..including anodes....not local plumbing supply places...go figure....

 

[yachtsmanbill]

Yachtsmanwillie, I thought you were one of the expurts on engines!

If you brought that boat home to the sweetwater seas, you wouldnt have to pull them coolers apart! LOL... BTW; happy holidays! ws

 

[Angela]

Rob:

No, there is no sea water in that thing unless the engine is running. So, if I don't need 'em; that's great - we won't put them back in.

I am replacing every gasket on this thing whether it was showing evidence of leaking or not - no sense in going this far and not finishing the job, right?

I didn't have room to use a cheater bar, and frankly, I was afraid to do it for fear of breaking the bolt off. Pascal didn't find it to be all that difficult, but it was just a wee bit above my own muscle power.

My hot water heater has an anode?????

 

[rsmith]

NOT! when u pull the zink if you old guys can still hear youll hear gurgle gurgle gurgle that will be the water draining back thru the system. The zink is normaly immersed until you break the vacuum.As far as them cloging up the exchanger BS . I worry more about electrolisis than a little spent zink mush in the exchanger.

 

[GJH]

Ditto Mr. Smith on the zinc. It is there for a reason. So is the one right at the raw water pump that is ahead of your intercoolers and fuel cooler. Replace them on a regular schedule and you win't have any "chunks" fouling anything. You know how the DD manual says to check them? Give it a whack on a hard surface; if it breaks at all replace it otherwise put it back in! They are so cheap that at that point, I just put in a new one anyway.

 

[MikeP]

My hot water heater has an anode?????"

Not any more!

 

[Bill Allen]

Almost all hot water heaters have them. Look just like the ones in your engines, you'll see a brass plug ususally on the top between the inlet and outlet on a top feed heater. Bill

 

[rsmith]

Almost all hot water heaters have them. Look just like the ones in your engines, you'll see a brass plug ususally on the top between the inlet and outlet on a top feed heater. Bill

The anode in the HW heater will make the water stink. I take them out when I put a new heater in. I have more than a dozen HW heaters in rental properties I own and have never had a problem. In a home setup tho there is a dielectric coupling on the waterside but I think thats more a shock prevention than anything. I'm sure its there for a reason but I can do without the smell

 

[Bill Allen]

I gotta admit I was in the plumbing business for almost twenty years and never changed an anode in a water heater. The only time I've seen any real smell from the water was when there was a well with a bacteria issue. Bill

 

[Angela]

I got that "retainer" plate off. The key was, like you guys said, a very, very thin, flexible putty knife and very, very gentle tapping all the way around.

The urge to pry it off once I got a corner started was great, but I resisted and kept at it, very gently (perhaps overly gently) like was trying not to break a piece of glass, until I could just pull it off with my fingertips.

Now, on to get that core out! Then, the great clean up can begin! You guys are the best! Thanks for your continued help. I really, really appreciate all the great advice. Like many things on this boat, I couldn't do it without you.

 

[REBrueckner]

I never thought about an anode on a boat water heater....some are steel, some are stainless steel, and maybe other materials....so some may have them, some not....I did not see one on a SS water heater I installed aboard my former Hatt, ATLANTIC brand I think, but I know the prior one was steel, likely original and close to 30 years old, and that RUSTED thru and leaked....

On engine raw water anodes, GJH has it right:

"Replace them on a regular schedule and you won't have any "chunks" fouling anything. You know how the DD manual says to check them? Give it a whack on a hard surface; if it breaks at all replace.."

That's an alternative to leaving them out at the heat exchanger. I just found it unecessarily expensive and time consuming....What I never understood was why the anodes were not inserted from the bottom instead the side of fittings...that way if there was ANY water remaining, at least part of the zinc would be immersed....in any case any potential corrosion should occur in the active metal...the cast iron expansion tank housing not the more delicate bronze tubes and assembly.

If you think anodes stink, test for the "smell of anodes" and see for yourself: next time you remove one from an engine, put it in a pot and let it boil for a few hours...see if it "stinks".....

I've never heard of metals (anodes) having much aroma one way or the other, but there is a possibilty that an anode might react with certain compounds in water.....and those could potentially release odors I guess....

 

[Angela]

There are two ways to do this;

Use a wooden block against the round part of the HE that is protruding from the big Oring and tap the wood block with a fairly heavy hammer, driving the HE out the other side. This may be difficult depending on the grip the Oring has on the HE/retainer - try to work some WD 40 into the surfaces of the HE/retainer at the o ring first.

Do the putty knife thing between the retainer and the tank, popping the retainer off the O-ringed end of the HE. Same problem with the Oring and how well it has now adhered to the HE/retainer. WD 40 will help.

Thanks, Mike. The core popped right out. I tapped on the round end gently with a block of wood, then just pulled it out the other end with my fingers. The O-rings were not stuck at all. I can pick them out with my fingers, once I lift an edge with a tiny screwdriver.

As ugly and nasty as this whole thing looks, it has been surprisingly easy to disassemble - no broken bolts, nothing seized, nothing tough to get off, etc. I've got my phosphoric, naval jelly, rusty metal primer, paint, and all the gasket sealant stuff, dielectric grease, etc. to get busy now. Won't have access to the air compressor until Monday, so no needle-scaling right now. I'll see how well it works with a wire wheel on the really cruddy parts (exterior parts) and go from there. So far, this has been relatively painless for a "boat engine" job.

 

[Angela]

Question:

The inside of the tank looks rusty. Now, I see why my coolant on this side always looked "muddy." Here is a photo. Is there anything I should do to the inside of this to treat the rust? Or should I just leave it alone after a washing/scrubbing? The gasket stuff came off pretty easy. I have just a few spots to clean up. The core is bright and shiney after a bath in the diluted green stuff. This engine really needed this. Next up...changing thermostats. Why not? I've gone this far already and I've the thermostats sitting around for over a year now. This is the engine that runs 10° warmer than the other. If all this doesn't cure the temp difference, then, it wasn't meant to be the same as the other.

 

[MikeP]

I'd bet money that the temp will drop that 10 degrees at least. I pulled mine this past summer due to temp creep at WOT. Boat neighbors (and me) thought the HEs looked basically clean BUT after dipping in muriatic/oxalic and re-assembling, the temps didn't creep. It takes very little to compromise the cooling system on these DDs. It appears to me that they were designed with minimal capability on the marine versions. I mean..look at the size of that HE you can easily hold the darn thing in your hand and it's not even a foot long...

HE

Dirty HE's that caused temps to go above 190 at WOT.

"Clean" HEs that held temps at/below 185. I don't really see much difference in "cleanliness."

 

[Angela]

WOW, Mike, those are tiny! Mine are much bigger. You must have the 8v71s??? Mine appear to be the size of two of those little ones. Do both of those go in one expansion tank, or is one for one engine, each? I've got the 8v92s.

Mine take 2 hands to carry. It was much heavier than I thought. I was surprised by the weight when I first pulled it out. Not overly heavy, but heavier than I thought it would be - it surprised me.

Yes, the acid bath did make a very visible difference in what it was like before, and even before, I thought it looked pretty good.

Also, at last I can say "HA!!!! I finally have an engine piece that is cleaner than MikeP's!" However, no one can see it. The rest of the engine room looks like crap. My HE's little pipes inside are bright shiney silver - not a spot of anything on it now.

 

[Genesis]

The original "marine" Detroit setup on power was about half to 2/3rds of what people later ran the horsepower up to. Unfortunately Detroit did not increase the size of the H/E when the power ratings went up. The result is that most recreational-service DDs are horribly under-cooled when the raw water is anything approaching warm, and in Florida in the summer sea temperatures are VERY warm. We have MID 80s in the bays around here in the summer time.

If you boat off the east coast or in the Great Lakes more than a few miles from shore (especially Lake Michigan or Superior) you won't have problems, but down here in the south.... oh yes you will.

IMHO this is THE biggest defect in DD recreational marine engines from a design perspective. Diesels of all sorts are notoriously intolerant of overheating and DDs are arguably the worst of any due to their complex head casting and the propensity of them to crack when they get hot, plus (for wet-liner engines) liner seal issues. The only meaningful defense for a boat operated in warm water is to keep the cooling system fastidiously clean and consider running water + a suitable additive package instead of glycol, as there's a ~8-10% cooling capacity increase that this gets you over the typical 50/50 glycol/water mix. Running water + additives is, of course, only an option if you are in place where freeze risk is not a factor, and with the the DD 7psi cap and typical operating temperature in the 170-180F range I take the trade-off of additional cooling capacity .vs. possible boilover elevation.

 

[Boatsb]

WOW, Mike, those are tiny! Mine are much bigger. You must have the 8v71s??? Mine appear to be the size of two of those little ones. Do both of those go in one expansion tank, or is one for one engine, each? I've got the 8v92s.

Mine take 2 hands to carry. It was much heavier than I thought. I was surprised by the weight when I first pulled it out. Not overly heavy, but heavier than I thought it would be - it surprised me.

Yes, the acid bath did make a very visible difference in what it was like before, and even before, I thought it looked pretty good.

Also, at last I can say "HA!!!! I finally have an engine piece that is cleaner than MikeP's!" However, no one can see it. The rest of the engine room looks like crap. My HE's little pipes inside are bright shiney silver - not a spot of anything on it now.

Angela you have 8V92's therefore larger HE and tanks. The others are from the 53 and 71's that were at lower to mid HP and required less cooling.