4JH3te oil cooler

[daletournier]

I have the 4JH3TE 75hp turbo. Being the worrier that I am I think about things that can go wrong. The oil coolers on the 4Jh3e series have been mentioned several times over the years.

My engine has just over 1000hrs,it runs awesome but had very little use prior to me purchasing this boat and I wouldn't be surprised if the coolant prior to me changing it last year was the original.

I hate stupid things and yanmar did some stupid things on these engines ie. water pump">Raw water pump and oil cooler placement.

I'm not going to do it now but some stage in the near future I'm going to pull the oil cooler down and have a good look at it. It's in a difficult spot, even the hoses clamps are pain to get to.

°My question. Is the oil cooler on the 4jh3-te the same as the 4jh3e?

°Second question, is it feasible to use an after market oil cooler and remote mount it, never having to deal with its difficult position again?

°Third question. If the answer to above is yes, what aftermarket cooler do people use?

Thanks in advance.

[Paul L]

The coolant doesn't effect the oil cooler. The oil cooler is raw water cooled.

[daletournier]

Originally Posted by Paul L

The coolant doesn't effect the oil cooler. The oil cooler is raw water cooled.

Hi Paul, yer, realised that after I posted.

[Paul L]

Originally Posted by daletournier

Hi Paul, yer, realised that after I posted.

It sure seems like it would have been nicer to cool with coolant and reduce the corrosion on the well hidden oil cooler.

[kenbo]

Would 190 degree coolant be adequate to cool the oil? The size and number of passes would have to greatly increase I believe.

[Paul L]

Originally Posted by kenbo

Would 190 degree coolant be adequate to cool the oil? The size and number of passes would have to greatly increase I believe.

That's probably the issue. The cooler would have to be much larger, making it way more difficult for the Yanmar engineers to hide it in an inaccessible place.
Oh, and it would cost more.

[a64pilot]

Originally Posted by kenbo

Would 190 degree coolant be adequate to cool the oil? The size and number of passes would have to greatly increase I believe.

First I doubt your coolant is 190F, most Marine Diesels run lower than that I believe, but my experience is with older motors, maybe new ones do run that hot?
Then just as a point of reference, every truck, fast cars etc that have oil coolers, cool their oil with 195F coolant, or I have not seen any that didn’t.
Often times for big Diesels that idle a lot etc, they are as much oil heaters as coolers, but to answer your question, yes your oil can be cooled with engine coolant, as may of course are.
Automobiles seem to average an oil temp in the low 200’s, out little Marine Diesels don’t get their oil anywhere near that hot, and I cannot understand why not.
In piston aircraft it’s generally accepted that in order to cook off moisture that forms acid, your oil temp needs to run a minimum of 180F.
My 4JHE’s oil temp seems to be closer to 165 or so, and cooler than I’d like to see it, however I don’t run it very hard either, usually only 2000 RPM or so.

[IslandHopper]

The newer 4JH4-TE 75hp uses coolant (fresh water) for the oil cooler...

[kenbo]

Dale,

The 4JH3E and 4JH3-TE have different oil coolers. The part numbers are 129670-33000 and 129673-33010 respectively.

My point on coolant temp was that the delta T° between coolant and sea water was great enough to warrant a larger oil cooler with more passes if you wanted to achieve the same engineered oil temp.

The thermostat on my 4JH3E begins to open at 173°F and is fully open at 194°F. So 185 for a mildly loaded state would be my estimate

[model 10]

Originally Posted by a64pilot

In piston aircraft it’s generally accepted that in order to cook off moisture that forms acid, your oil temp needs to run a minimum of 180F.
My 4JHE’s oil temp seems to be closer to 165 or so, and cooler than I’d like to see it, however I don’t run it very hard either, usually only 2000 RPM or so.

I think they say 235 is the optimum temp for modern oil. Maybe we don't need an oil cooler so much? If I had a failure during passage, I can see by-passing the thing.

[kenbo]

Dale,

I believe the oil coolers on NA and turbo 4JH3's are constructed differently as well. The NA engine like mine have a copper nickel tube construction and from memory your is a casting of some sort, maybe cast iron?

The failure mode may be quite different.

[a64pilot]

Originally Posted by Ecos

I think they say 235 is the optimum temp for modern oil. Maybe we don't need an oil cooler so much? If I had a failure during passage, I can see by-passing the thing.

If you had the hose to do it. I think I could hacksaw my oil tubes and slide a rubber hose over the ends and clamp them and that would work. Looks like maybe 5/8” heater hose might fit?
A turbo engine obviously dumps way more heat into the oil than an NA engine as turbos run hot, and the center section is oil cooled.
Engines are really oil cooled more than water cooled.
Now think about this for a minute, the cylinder heads are water cooled, but the crankshaft, camshaft and all the metal parts that rub against each other are oil cooled.

My old 4JHE runs seemingly in warm water at 165 F, with its oil temp real close to that. However I’m running at I think less than 50% power, and I guess of course the engine has to be designed to have the snot run out of it.