Manicooler - remove and inspect or not? (repost in Motoryachts)-gctid340216

[Guest]

I have a 1994 3288 w/150 Hinos. I have read a lot on the BOC about the manicoolers but am not sure if I need to remove and inspect them or not? Here is some information:

- 1250 hrs

- Third owner

- Boat was in fresh water, boat house kept on Columbia river until 2011

- Just drained coolant and it came out clear green with no signs of rust, looking into the manicooler from the filler tube things are clean and bright, no signs of build up or corrosion.

- Recent coolant tests showed Ph of 8.8 port and 8.6 starboard and 1 ppm aluminum for each sample. Ph is a little low but not excessively low (

[smitty477]

Welcome seabob,

Do you know if/when they were off last?

Any indications they have been serviced (fasteners, paint, etc)?

Do you have leaking at the end caps?

Do you have any leaks at the inspection plates or hose connections?

Do the overflow bottles have just a stain or do they have a film of mud at the bottom?

Is there a film of mud on the bundle straight down inside the rad cap when off?

How is the paint on the exhaust runners as they enter the manicooler . burnt off and indications of overheating?

Hope this helps

[Guest]

Thanks for the reply smitty477. I don't think the coolers were ever removed. I had a mechanic do a mechanical survey when I purchased the boat last March (2011). I asked him to focus on the coolant and manicoolers and he didn't note any issues with apparent hot spots but I will look closer on my next trip to the boat. I had coolant samples taken and tested. The results indicated Ph to be a little low but not other issues were noted other than low SCA level which is a moot point for a dry liner Hino. No high metals count was noted in the sample so I would guess that things are not coming apart inside.

I didn't get a chance to inspect the contents of the coolant recovery bottles yet...First Mate had me running off to a New Years party which cut my work-on-the-boat time short. I'm trying to remember now what I saw looking inside of the filler tube. There may have been a thin film of browninsh substance but the bottom of the cap was clean and any contaimination visible in the filler tube was very minor. There are no leaks.

I will take a closer look at the things that you suggested tomorrow (1/2/2011) and report back. I will also drain the manicoolers tomorrow. I would think that if there is mud build up it might come out or be obvious when I try to drain the cooler drain valve.

I'm planning to pull the exhaust elbows and risers and inspect them. Does the engine coolant need to be drained down to remove the risers and elbows??? I don't think so but maybe you can confirm?

[mmichellich]

seabob wrote:
Thanks for the reply smitty477. I don't think the coolers were ever removed. I had a mechanic do a mechanical survey when I purchased the boat last March (2011). I asked him to focus on the coolant and manicoolers and he didn't note any issues with apparent hot spots but I will look closer on my next trip to the boat. I had coolant samples taken and tested. The results indicated Ph to be a little low but not other issues were noted other than low SCA level which is a moot point for a dry liner Hino. No high metals count was noted in the sample so I would guess that things are not coming apart inside.

I didn't get a chance to inspect the contents of the coolant recovery bottles yet...First Mate had me running off to a New Years party which cut my work-on-the-boat time short. I'm trying to remember now what I saw looking inside of the filler tube. There may have been a thin film of browninsh substance but the bottom of the cap was clean and any contaimination visible in the filler tube was very minor. There are no leaks.

I will take a closer look at the things that you suggested tomorrow (1/2/2011) and report back. I will also drain the manicoolers tomorrow. I would think that if there is mud build up it might come out or be obvious when I try to drain the cooler drain valve.

I'm planning to pull the exhaust elbows and risers and inspect them. Does the engine coolant need to be drained down to remove the risers and elbows??? I don't think so but maybe you can confirm?

There is a tab under the cap. Supposed to be a full level indicator. Swipe it with your finger and if you get anythin tan or brown, manicoolers are overdue to be cleaned.

[Dave_Stevens]

Also consider getting a pressure testing kit. Pump system to 25 psi, wait 5 minutes and see if there are any leaks. You can buy these at most auto supply houses. As the tube bundle is supposed to be isolated from the manicooler casting by "O" rings, use an ohm meter to check the resistance between the the bronze tube bundle and the manicooler. If there is contact, there is risk of galvanic corrosion.

[Guest]

Thanks everybody for the good tips and advice. I will make checks recommended in the thread replies and report back. I had the cooling system closely looked at during my mechanical survey last year. The coolers were pressure tested and coolant samples analyzed. No problems found. I plan to purchase a pressure tester and make this check part of my routine preventative maintenance. The mechanic who did my inpection also used an IR thermometer to check temperature drop of from the cooler inlet and outlet housings during the water test. So I purchased an IR thermometer and will plan to make these checks annually to verify overall efficiency of the system. The main thing that I'm trying to do at this time is to decide if it's necessary to remove the manicoolers to inspect them. I'm trying to get to the point where I either convince myself that things have been maintained well enough that I don't need to bother or find evidence of neglect or problems that convinces me to yard them off.

[smitty477]

The coolant system is normally under 7#'s of pressure or less - no need to test it much further that that.

It is very possible to begin a leak that would otherwise not occurr.

In the overflow bottles and under the rad cap - when you look for acumulatons you are looking for something thicker than just a stain - it will have a little 'depth'

to it if you find the 'mud' there.

Hope this helps

[Guest]

Back to the boat today to finish draining the coolant and make some checks that were suggested. Here is what I found:

- Both overflow bottles had about 1/16" layer of "mud" on the bottom. Not sure but the bottles might have never been removed and cleaned. They are a little hard to get at and a it's a bit difficult to drain them without making a mess. I bet a lot of people might drain them but not take the time to pull them out and clean them.

- I drained the manicoolers via the drain port on the cooler and got about 1 3/4 gallons out of each. The starboard cooler didn't start to drain until I back pressured the drain tube a little (blew lightly on the drain tube for just a second) then it drained easily. Nothing but clear green coolant came out. The port cooler drained slowly at first but then normally when the drain was opened without needing to apply back pressure.

- Checked electrical continuity betweent the cooling bundle and the radiator fill neck. The meter read about 190 ohms resistance on the starboard cooler. On the port cooler the reading was erratic - had to scratch around to get a reading and reading bounced around once something started to display on the meter. Not sure I trust the cheap meter that I keep on the boat. Will take my better one from home and recheck. One thought is: is the mud conductive - i.e. can a build up of mud or coolant residue create a conductive path between the bundle and the cooler housing?

- Checked the exhaust runners. Runners on both engines look pretty good. Paint is not perfect on the runners toward the stern but it doesn't look like signs of excessive heat.

- No indications of end cap leakage.

There is probably some "mud" in the system but I'm wondering if some is "nomal" on a 15 year old boat? If not too contaminated, would use of a coolant flush (Prestone Super Flush) get it out? Also, if I did take the coolers off and clean them, would there still be "mud" left in the system in the block, water heater and red dot heater that will probably work it's way to the cooler again. So I guess this is about all the facts and data that I can get short of taking them off to have a look. Any more advise would be appreciated.

[smitty477]

Good news is that you have no leaks, no overheating at cruise, and no known problems.

Some smaller bad news is that manicoolers were likely never serviced and there is mud in the bottles and likely coating the tubes as well.

One thing to keep in mind is that the large "O" rings in the end caps will eventually take a set and get brittle over extended periods of time.

'If not too contaminated, would use of a coolant flush (Prestone Super Flush) get it out?" - Well yes but it is never nearly as thourough as when you take them off and really clean them. Since you are not overhaertinb and not leaking this might be a good compromise at this time. There is a TSB from Bayliner on how to do this but it really just says this: 1 Use correct ratio of flush and new water mix in engine 2. Run up to heat d then for another 1/2 hour 3.Drain and refill with clean water 4. run again to get a full flush, 5.repeat steps #3 & #4 again 6 Drain and refill with 50/50 low silicate antifreze and distilled water.

I will try and find the tsb anyway and post it.

"would there still be "mud" left in the system in the block, water heater and red dot heater that will probably work it's way to the cooler again"

Well no - it actually tends to stay wherever it is deposited and that is the problem in the manicooler where the heat needs to be extracted and the 'mud' becomes a local insulator.

Hope this heps

[smitty477]

cooling system tsb.pdf

Heat Exchanger Info.pdf

Here they are...

Hope this helps

[Guest]

Thanks smitty477, you've been really helpful. The one thing that has me more concerned than the mud situation at this time is the continuity readings on the starboard engine. If my meter reading is correct, 192 ohms would indicate pretty good electrical continuity. Other posts on the BOC seem to say that reading should be in the K or meg ohm neighborhood and that coolant and mud would not act to decrease resistance to a lower ohm reading. I might wonder why electrical continuity if absent when the bundle was assembled in the cooler housing might be there now? Unless the O-rings might collapse with age so as to allow end cap to bundle contact. This doesn't really sound logical to me. I'll double check the resistance readings with a meter that I trust better. I guess I'm starting to wonder too if the flush process might be as time consuming and difficult as pulling the manicoolers...less expensive though.

[Papa_Charlie]

One reason that the resistance isn't as high as a new system is the fact that debris and the aluminum that was reported in your cooling water are giving you lower resistance readings than a system that is clean. If you had metal to metal contact in from the bundle touching the resistance would most likely be much lower.

[Guest]

I don't want to hijack this thread but I have a question, the answer to which might interest SEABOB and others: Has anyone tried using one of those automotive backflow engine flush kits on the Hinos? They hook into one of the lines to the heater system and you hook a garden hose to it. I did this years ago on an old car I inherited that was overheating, and it flushed out a ton of rust and grit and it never overheated again. It seems this could be a practical way to really clean out the block and manicooler as long as there isn't some inherent danger in doing this to a diesel/manicooler cooling system?

Stu

[smitty477]

"Has anyone tried using one of those automotive backflow engine flush kits on the Hinos? They hook into one of the lines to the heater system and you hook a garden hose to it. I did this years ago on an old car I inherited that was overheating, and it flushed out a ton of rust and grit and it never overheated again. It seems this could be a practical way to really clean out the block and manicooler as long as there isn't some inherent danger in doing this to a diesel/manicooler cooling system?"

FWIW - these systems do not get a ton of rust or grit in them. Only 2 basic issues which arise from the manicooler:

1. The coolant side becomes contaminated and ends up precipitating out the silicate 'mud' on the insides which resists thermal tranfer causing overheating (and more mud).

2. The sea water side gets 'stuff' trapped at the end caps from a poor strainer, lost impeller pieces, zincs, and cork gasket failures reducing flow.

Although you would not want to flush a warm engine with cold water I do not see any other danger in thsi flushing. At the same time I do not see any real benifit to this type flushing either.

There are a number of ways to 'wreck' or add to a manicooler failure but only a few reaosmnbly good ways to clean one. This is basically true of all diesels fo this relative size and type.

Hope this helps

[RAVEN_SONG]

5 years ago we bought a 1993 w/twin 150's that largely was used in brackish water. I decided to go ahead and remove the bundle in the manicoolers and perform cleaning using muratic acid in a PVC tube as described on our blog. I also replaced the elbows (upper/lower) with the cast iron original ones. Our boat had similar hours and had very good maintenance records which included regular coolant changes. Did I find anything major with the system...no nothing that I wouldn't expect with a well maintained boat. Do I feel better crossing the Straits of Georgia with my family on board not worrying about engine failure YES! Thanks to this blog performing this type of work is "easy" with a little help and it gives you the peace of mind of knowing your boat and the assurance of if something does happen you'll know what to do. We are in the off season now, and now is the best time to take on such a project. I choose one major project a year and always do it during the winter months so we are ready for cruising in our oh so short summer.

My 2 bits,

Trevor[QUOTE]seabob wrote:
I have a 1994 3288 w/150 Hinos. I have read a lot on the BOC about the manicoolers but am not sure if I need to remove and inspect them or not? Here is some information:

- 1250 hrs

- Third owner

- Boat was in fresh water, boat house kept on Columbia river until 2011

- Just drained coolant and it came out clear green with no signs of rust, looking into the manicooler from the filler tube things are clean and bright, no signs of build up or corrosion.

- Recent coolant tests showed Ph of 8.8 port and 8.6 starboard and 1 ppm aluminum for each sample. Ph is a little low but not excessively low (