Bad Oil HX-Check my math

Six weeks ago I topped off the oil on each engine with 1 qt. 3 wks/11 hrs later, I had to add 2 Qts of oil to the stbd engine. Today, another 3 wks and 11 hrs, I had to add another 2 qts. I've noticed a sheen on the water during this period, but I attributed it to cold engine idling with a sheen of fuel until the girls warm up a bit. Or maybe she needs a valve adjustment. Now I believe I have a leaking engine oil heat exchanger.

I've heard of these leaking and causing the oil level to rise due to raw water in the oil. In my case, it seems I've got the opposite...oil in the raw water. If so, I'm glad it failed this way and not the other!!

Here's the culprit.

NA004100CN Perkins 9" marine dual oil cooler Sen-dure 2299 2 7



I was actually very relieved to see it's only about $300. I was expecting much worse. So I'm planning on picking one up locally on Monday. Does that seem about right? Am I missing something else on a Perkins 4.236 85?

PS. No oil leaks beyond the norm of any 40 yr old Perkins with 3300 hrs. No smoke.

Thanks for the assist.

Friend of mine had his fail about two years ago. I don't remember what he paid but I don't remember it being exorbitant or I would have heard.
It too was the 4-236

Al
Check the inside diameter of you raw water hoses that hook up to it as my Perkins 6.3544M used the Sen-dure but it had 1 1/8" raw water.

C, Thx. There's also very good access and simple mechanics. I'm hoping for a smooth replacement.

Mike, I'll check but I think 1 1/2" is right. They're only 9 inches long, though.

Does anyone know of a good source for a 2-3 ft length of silicone hose that I could cut as needed to update the connections?

FlyWright said:

C, Thx. There's also very good access and simple mechanics. I'm hoping for a smooth replacement.

Click to expand...

Hope so too. Let us know. I've never had a "smooth replacement" of anything on my boat. Except for replacing the occasional bottle of rum. [emoji1]

Yes the 9" is the tube stack length, they have lots of different lengths and inlet sizes for Perkins on the Sen-dure site.

Post #4,
McMaster Carr, or WW Grainger, any quality industrial supply house.

Have you cracked the water line leaving the cooler and checked the water for oil ?
2 qt in 11 hours would give more than just a sheen

Hope all works out.
One more reason I'm considering moving my harbor freight TIG to the boat.

Get a length of water hose and bypass the water flow around the cooler. Leave water nipples of the cooler unconnected. Run engine with no water through cooler and see if any oil drips out. Or take it off and do a bench pressure check by pressurizing the oil side to say 50psi with air pressure and oil in the shell side.

You want to make sure there is a leak as 2qt in 11hrs is not outrageous. Cooler might be fine.

Come on Al! You are Jet pilot and mechanic. This is not rocket science.
Of course Exwife #1 who was one might disagree.

NASA rocket scientist I meant, sorry.

Perkins wised up 15 years or more ago and went with a coolant cooled HX with the Sabre marinization design.

If your cooler is indeed bad Al, suggest you change the one on the other engine too.

It would be interesting to observe the oil temps with and without the cooler. If you bypass as Ski suggests you'll have an interesting data point. Perkins found their engines often over cooled the oil when using RW exchangers.

sunchaser said:

Perkins wised up 15 years or more ago and went with a coolant cooled HX with the Sabre marinization design.

If your cooler is indeed bad Al, suggest you change the one on the other engine too.

It would be interesting to observe the oil temps with and without the cooler. If you bypass as Ski suggests you'll have an interesting data point. Perkins found their engines often over cooled the oil when using RW exchangers.

Click to expand...

I really thought about canning my oil cooler on the Lehman too as cool as I run it....especially when running the bus heater.

Very tempting, but I also haven't run the engine hard or in extremely hot weather either.

Fortunately Lehman coolers are pretty inexpensive at around $100 IIRC.

OK, I pulled it this morning. The RW ends are 1 1/4" and the RW lines are 1 1/8". I could easily accommodate the 1 1/2" size with these silicone reducers.



https://www.pegasusautoracing.com/p...pby_Qv4d36ri1giiPXl-oS5FCRguzzsTj8aAna98P8HAQ

I didn't notice the presence of oil in the water side of the cooler, but not much water flowed out when disconnected. I'm replacing it anyway. If time permits, I might plug one end of the oil side and apply water pressure to the other end of the oil side to see if it leaks. If I get to it, I'll report back.

Both oil coolers will be replaced. I like the idea of being able to bypass the cooler if needed to get home when underway, so I'll be stocking hoses suitable to bypass the oil and water sides in my spares.

Hopefully I'll be able to find one locally on Monday. My BIL and his 12 yr old son are coming on the 12th for a fishing trip from the least coast. I'd like to have the boat running in case we get a break in the weather.

Ski, do you see a risk of local ops (within 1 hr) with both the engine and tranny oil coolers bypassed as an interim fix if a replacement cannot be obtained in time? If it's a problem, we may just have to enjoy a marina weekend unless the replacement comes through.

Thanks all!!

At light load, engine can probably be run continuously without oil cooler. Look at your generator- no oil cooler. Some heat from the oil gets transferred to to coolant in the block.

Gear is not in same situation. Other than radiation and convection on the outside skin, there is no cooling. But also not much heat being created. Also at light load, it might be fine.

I'd have no problem doing a local run with no gear or engine oil cooler. Just don't push it and check it once in a while with temp gun. Gear skin temp limit to 200F, engine oil limit to say 240F at filter.

Thanks a million, Ski! That gives me a reasonable fallback solution for the short term, if needed. I also appreciate the temp numbers...I was kinda wondering about them after I posted.

Also, with twins, I'll be able to do side-by-side comparisons between the 2 engines.

For hose and fitting found this one that has much anything and price looks right: New-Line Hose and Fittings

Thanks, Lou. I'll take a look.

I was heading home from the boat with the oil cooler in hand and decided to stop at a nearby truck supply place for parts for a bypass. They had everything I needed for under $40.

18" of 1 1/8" hose...check.
2 nipples with compression fittings...check.

Then I made an immediate U turn back to the boat to install the bypass. It went as slick as greasy snot on a wet pig. I was done in under 30 mins so we're now up for local ops until the replacement arrives. Putting in the new one shouldn't take much longer than the bypass.

After a leak check, I checked the exhaust for oil and saw a few residual small drops that disappeared after about 5-10 minutes at idle. The engine got up to temp at high idle in the slip with no issues, but I didn't leave the dock or engage the transmission.

Thanks all and especially Ski and Sunchaser for helping me think outside the box for a short term solution. Now I can shop for the replacement with a little less pressure on last minute shipping and repair before the kid gets here.

Cheers!

Good job

I'm hanging my head in shame with that double zip tie fuel line hanger.

You weren't supposed to see that! Guess I've gotta change it now...

FlyWright said:

I'm hanging my head in shame with that double zip tie fuel line hanger.

You weren't supposed to see that! Guess I've gotta change it now...

Click to expand...

Well when it is working you know... Better not to check my ER! The PO did a 4 feet long wire sheathing with electric tape, very nice looking, especially after some year with the heat

I just had an interesting conversation with Brian of British Marine in Oakland. He was running his boat with a 4.236 down the coast and noticed the oil pressure at zero as he started his watch. (no alarms) He shut down and found his oil cooler had failed, dumping his oil overboard. He bypassed the oil cooler as I have here but didn't have enough engine oil. He only had gallon of vegetable oil, so he used that and ran the boat for another 30 hrs (!!!) to his destination. He said the engine never skipped a beat.

When he returned home, he opened up the engine and it was just fine. He also said that the tranny cooler on this engine handles only a light load of excess tranny fluid and does not have much impact on gear temps. He said it's not really under pressure. Kinda makes me wonder why they even bothered with the coolers.

Gotta love a Perkins! New cooler on order.

Got the new oil cooler in and it went smoothly. No spills, no dings, no errors. Now that I know it's a good fit, I've got #2 on order for replacement on the port side.

Thanks all for the advice and support. Now I've got a water hose and a couple oil line nipples in the fix-it kit as a bypass solution just in case! Maybe that's not a bad idea as a work-around for a critical engine component that typically lasts such a long time that it may not be practical to carry a spare oil cooler. But a bypass kit is cheap, light and compact.

Cheers!

BTW, even though I had installed the bypass kit for my BIL and nephew's fishing trip, I didn't run the boat out of the slip with it installed. The guys wisely postponed their trip until early March so we'll likely have better wx and fishing conditions.

So, unfortunately, I didn't have the opportunity to collect comparison data with and without the cooler. That public service comparison will have to wait for another day.