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Replacing the ucooler 1991 454

S

slauder

Regular Contributor
"I have 1991 crusaders 454 fre

"I have 1991 crusaders 454 fresh water cooled engines. I am replacing the ucoolers.

I'm not too sure which ones to order as when I searched the web and made a couple calls I found that a few different changes all around those years.

Best to remove the old ones first and find the cru# on the unit, and be able to bring it to a local supplier if need be.

I don’t see the remove/install instructions in the shop manual.

Is there a way to do this without a mess and without changing the engine and tranny oils?

Thinking to cap the oil connections if I knew the NPT and dia ahead of time. I changed engine oil 1-2 hours before I winterized. Anyone? Al?

PS I have borg warner velvet drive transmission. Does anyone change the tranny filter when you suck the AFT out? I was told not to years ago when I had a boat mechanic. “might be looking for trouble” if I recall.

Thanks,
Scott"
 
"You shouldn't have to cha

"You shouldn't have to change the fluids unless you suspect the cooler to be leaking. As far as removal, it's pretty straight forward. Shut off water supply, disconnect hoses (some water may spill), disconnect oil and trans lines (some fluids may leak, be ready to catch as much as possible with containers and oil diapers), remove the two clamps that hold cooler in place. Once the oil/trans lines are off, elevate the ends and the flow should stop. Also since the engine has not been run in a while a good ammount of the fluids may have drained back.
As to what cooler to buy, the Sen-Dure u cooler for crusaders has worked fine for me in the past. When you reinstall, be sure to turn water back on and run engine to recheck fluids."
 
"I know of two U cooler varian

"I know of two U cooler variants. The older one (yours and mine), have inverted flare fittings for the oil lines. The newer, injected style is Female NPT fittings. You might consider new oil lines as well. 20 years is a good service interval for those. About 9' of each the 1/2 and 5/8""
 
"Thanks Guys. I'm thinkin

"Thanks Guys. I'm thinking to start on the replacement this weekend. That means I lose some or most of the pink thats in the raw water side.

I know I've heard not to drain and leave empty because the air will cause rust, but its a matter of a few weeks before I fire them back up. Should be okay?

Dave, Are the flare ends re-useable. I guess i dont understand how the fittings work. It sounds like you procure the 9 foot lenghts and install your own ends?"
 
"Scott; Aeroquip FC332-08 xm

"Scott; Aeroquip FC332-08 xmission
FC332-10 engine; I recall ~ 9' each, but you should measure. I was able to reuse the brass fittings. It will take a fair amount of effort to push the hoses onto the barb fittings, but doable. Really lean into it with gloves and heat the hose up first with a hairdryer, dip the ends into ATF, use a wood or soft metal pad to push onto.

And, I've not ever replaced the tranny oil filter, nor do I think they typically need cleaning between overhauls. Every 30 years ought to about do it!!"
 
"I know of two different parts

"I know of two different parts, the difference being the orientation of the outlet raw water fitting. mine (mid 80's) use the "straight out the back" version. We replaced one a while back and that fitting was 45 degrees offset from the original. A couple minutes with the torch and a touchup with the spray paint can made it fully servicable.

Both the types I've seen had the oil passages as NPT in the cooler body. I moved the inverted flare-NPT adapters over to the new part. The inverted flare fittings are reusable.

A couple weeks without the pink stuff shouldn't hurt....I don't know about you but I'm not making any plans for an early (or normal) spring around here."
 
I may just drain it by the mai

I may just drain it by the main hose to the pump--but after reading all the posts about purging the air from the system and coolant overflowing from the resevoiur--now Im woundering... is it a big deal after I drain it to refill it I just thought you poured anti back in anf your done--am I missing something here. I have to say I just stumbled across this site and I am thankful I did and I truley appreciate the responses --regards dave
 
"Scott, My engines are 1992 a

"Scott, My engines are 1992 and I have used Crusader part # 97878. For me, It was a direct replacement

If you get the opportunity, try opening up the old cooler by de-soldering the cap. Peeking in side was a revelation."
 
"Al,
I will open it up. I kee

"Al,
I will open it up. I keep thinking its brasing skills, but it is just soldering skills like the plumbing I do around the houses.

anyway I wonder if i could safly verify more years of life after i open it? the resulting punishment for a ucooler failure is damn scary!

i remember an old alpha IO drive i had with a pin hole leak in gasket. ever time it cooled it sucked in some seawater.

a repeat with this boat makes me shutter..."
 
"As I understand it... The u-c

"As I understand it... The u-cooler is a replacement item and considered part of engine maintenance. I took mine apart for the fascination of seeing what makes them tick. Seemed like they were in good shape other than a few clogged honeycombs. After the 50/50 muriatic wash, I soldered and re-used them part of 2008 and all of the mid-atlantic season of 2009. The solder part with that yellow MAP gas cylinder was a VERY simple task.

You are right though, failure is a PAIN..."
 
"Scott:

plumbing type solde

"Scott:

plumbing type soldering is adequate for the exercise at hand....unsolder the U-shaped coupling piece...that's where all the interesting stuff happens.

As far as testing for remaining life, that's a tough one. i would offer that a pressure test on the oil sides at 125 PSI would be adequate. If it hold that pressure on both sides, it should be good for at least another year."
 
"Mark, for another year?...Tha

"Mark, for another year?...That being the case and the risk...I think I would replace it...AND for the record, I am going to replace the one I did over this spring before launch. NO WAY do I need the problems of a failed cooler this year"
 
"If the cooler will widthstand

"If the cooler will widthstand that much pressure, surely it will handle what the oil pump delivers; the gear's output is much less. I don't think it would deteriorate rapidly unless exposed to a lot of galvanic activity and that seems to be under control.

I agree that periodic replacement is a good idea.

What are you gonna do with those old u-coolers?"
 
"Well, now thatyou say that...

"Well, now thatyou say that...I usually just toss them into the metals container at the reclamation center. But you clearly have a thought ... I only am changing one though. The other is new."
 
"You got me all thinking now,

"You got me all thinking now, mine are 16 yrs old and have 900 hrs on them. If I acid wash them, does that get rid of calcium build up, or rust build up? Because if it is rust build up, then that means the walls of the heat exchanger are going to be thinner.
While we are on the subject of acid washing, can it be used to clean out the elbows and risers? I noticed a 20deg difference between the outboard elbows and the Inboard on both engines last year, still only around 127deg/147deg but still, it was different."
 
"Chris:

the intent of the a

"Chris:

the intent of the acid bath thru the raw water passages is to eliminate the zinc pencil residue and any organic matter that may have accumulated in those passages. The cooler is brass/bronze/copper so it doesn't rust. Given enough time, the walls will erode but usually on the thinner parts, not the casing.

An acid bath will help the risers, but it is really a bandaid. Those exhaust gases are really corrosive and given the heat, rust and failure are inevitable. If they have seen saltwater, they are normally due for replacement around 5-7 years, max."
 
"Now you've got me thinkin

"Now you've got me thinking too


I flushed out one of mine before I winterizing with a garden hose on one end and a bucket on the other. Probably not a great flush but better than nothing. I was going to do the same with the other side come spring.

Mine are 22 years old with 700 hours. Now that I've got the heat exchangers nice and clean, it proabably makes sense to remove the caps and do a good cleaning on these. All I had left were the hex caps from the zincs


I assume that you're removing them and doing work on the bench and not in place correct? I really don't want to mess around with 22 y/o oil lines but probably the best/safest way to do it.

I was going to replace those lines NEXT off season.


Bob"
 
i didnt remove mine from the b

i didnt remove mine from the boat...i couldnt get the compression fitting off without causing damage...worked great! 15 degrees cooler running (mine were insanely clogged!)
 
Any advantage using "Mercr

Any advantage using "Mercruiser Marine" brand full synthetic lubricant over a brand like "Mobil 1" full synthetic? My maintenance techs are hands down on the Merc brand stuff. I say pooee. I have twin 1992 454s with carbs. About 400 hours on each. Switched to full synthetic 100 hours ago on main engines and genset(Kohler 6.5 KW 230 hrs). Thanks for your input
 
"Ted,

Did you unsolder the

"Ted,

Did you unsolder the tops on both sides or just one?

Mark - when you said "u shaped coupling piece"... did you mean at the bottom of the cooler which connects both sides or the part that forms the "U" at the top (the input elbow)?

I think I'm going to give this a try in the next week or so. Worst case, I'll get new ones if I really botch it up but I already have MAPP gas and I'm comfortable doing soldering.

Bob"
 
"Bob,

Didnt even unsolder

"Bob,

Didnt even unsolder them. Went to the hardware and bought some clear hosing at the same diameter, hook it up to flow through backwards, poured the acid into the tube with a funnel, and poured until it came out the other side into an awaiting bucket. Waited about 10-15 minutes...grabbed the hose and flushed it out. I repeated it again as the acid was yellow and had HUGE hunks of organic junk and sizzling zinc.

Smelled like rotting grass. Amazing how much 'stuff' was in there!!"
 
"Sounds like a capital idea to

"Sounds like a capital idea to me, that 's what I'll be doing when I can finally uncover my beloved.....just another 2 months.....!"
 
"Copper does corrode, thru a p

"Copper does corrode, thru a process called "pitting corrosion". It has presented itself in fresh water plumbing systems in homes. See here: http://www.epa.gov/nrmrl/wswrd/cr/corr_res_copper_ai2.html
One of my u coolers went at 12 or 13 years. They are not cheap, but the process of fixing the pinhole oil leak aftermath in an engine or transmission is far more costly. In a non-salt environment, I'd keep them 30 years."
 
"Ted....That smell is the best

"Ted....That smell is the best definition, you nailed it. I did un-solder as my intent was just to see what was going on inside...I had never seen one before and I was intending on replacement so what harm could I really do?

Since it was such an easy thing to do, I simply re-soldered them and re-painted.
One NOTE: On the other engine side which I had ultimately thrown away, I had found a small rounded beach type stone stuck in the core of one side. How it got there may be 17 years of any owners guess with screens and strainers in place. I am going to replace the cleaned one due to its age. But it was a nice lesson."
 
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