4JH2-HTE Turbo

[stevec195]

1.5 years into our latest labor of love, I’ve come across a question. As part of numerous reliability up grades to my 22 year old 4JH2-HTE with 1400hrs, I removed the induction system to gain access to other plumbing. What I found was a bunch of engine oil in the inter cooler and induction system. Question is….this appears to me to be a water cooled turbocharger, so unless it has a separate oil feed on the mounting pad….where is the oil coming from?

[tkeithlu]

While disclaiming specific experience with that engine, I would suspect the oil seal for the lubrication of the turbo shaft.

[Ericson38]

Originally Posted by stevec195

1.5 years into our latest labor of love, I’ve come across a question. As part of numerous reliability up grades to my 22 year old 4JH2-HTE with 1400hrs, I removed the induction system to gain access to other plumbing. What I found was a bunch of engine oil in the inter cooler and induction system. Question is….this appears to me to be a water cooled turbocharger, so unless it has a separate oil feed on the mounting pad….where is the oil coming from?

I take it you removed the intercooler and engine oil came out. I have the same engine (1991) and just replaced the turbo (turbine wheel frozen to housing). I didn't have an oil seal leak. With only 1400 hours (we have 3100), your boat might have sat for a couple of years with no engine starts, so an oil seal is a possible culprit. There is only the one oil pressure feed on top of turbo coming from the oil line with the banjo fittings on both ends, and the drain line directly underneath it back to the oil pan (left side of engine).

[LeaseOnLife]

It could be blowby... an engine that old with that little hours had long times just sitting and may had times where cylinder walls rusted a bit.


The blowby gas does transport some oil, gets sucked by the turbo, then travels thru the intercooler, before being burned by the engine. Oil may well settle in the intercooler that way.


Check your blowby next time the engine is running, and you may ran the hose from the breather into a different catchment (old oil jar) than running it back into the engine.

[stevec195]

Thanks so much for your responses. I’ve measured breather pressure and that’s nominal so headed toward a turbo overhaul or new.

[skipperpete]

Turbo shaft seals leak oil, it’s just a tiny piston ring type seal trying to hold back 60 psi of hot oil and the leakage has a management system which dumps that leakage ( via internal passages) into the normal turbo oil drain and back to the oil pan ( sometimes called a Labyrinth). It’s not a positive seal. If the shaft seal leaks too much and the labyrinth gets overwhelmed then the excess appears at the intake manifold and intercooler, (the turbine side leakage disappears in the exhaust).
If crankcase pressure gets too high the the leakage can’t get to the gravity feed turbo drain and enters the intake manifold and intercooler. If the seals are really in bad shape it’s wise to follow the service manual advice regarding shaft wear limits and replace the turbine assembly..... the turbine is not an individual item , it’s permanently on the shaft but the compressor replacement is only a 10 minute job on your Yanmar.
Check the crank case breather for obstruction especially if there’s a PCV valve involved.

[stevec195]

Good on ya skippermate! Do you have any experience on how the new manufacturer Chinese turbos are holding up these days? I can find an Chinese unit for 850USD. That aside, none of the vendors are super good about revealing WHERE they’re from-even when the price is double
. Not anxious to spend twice as much just to find out I’ve bought the same unit.

[goboatingnow]

Originally Posted by stevec195

1.5 years into our latest labor of love, I’ve come across a question. As part of numerous reliability up grades to my 22 year old 4JH2-HTE with 1400hrs, I removed the induction system to gain access to other plumbing. What I found was a bunch of engine oil in the inter cooler and induction system. Question is….this appears to me to be a water cooled turbocharger, so unless it has a separate oil feed on the mounting pad….where is the oil coming from?

This is common failure as the turbo core ages.

Simply send it to a turbo rebuilder who’ll fit an balance a new core.

I did this in big KKK turbos £220 each to service

[Ericson38]

Originally Posted by stevec195

Good on ya skippermate! Do you have any experience on how the new manufacturer Chinese turbos are holding up these days? I can find an Chinese unit for 850USD. That aside, none of the vendors are super good about revealing WHERE they’re from-even when the price is double
. Not anxious to spend twice as much just to find out I’ve bought the same unit.

I went through this last spring. Could not find a rebuild kit at the time, Yanmar dealer prices were high (and someone at Yanmar when they went from paper to electronic parts applicability for older engines in Georgia has cross referenced the wrong turbos from IHI for the 4JH2-HTE....sent 2 non water cooled ones to California Yanmar dealership insisting they are correct).

So I used Turbo-Turbo from Fontana Ca, which sells Japanese IHI turbos. These are twice the price what the Ebay Chinese ones are. I personally don't want to experiment with China turbo parts (materials and balance come to mind), since changing the turbo is not that much fun.

I also took the time to go through the heat exchanger and verify end caps and sealing surfaces were good. I was really surprised that there was NO corrosion. I change coolant every 4 years, and this engine has no zincs.

Its a great engine, and I'm glad you aren't seeing any blowby from the breather. Take the time to change all the steel clamps and small rubber hoses while in there, and the water impeller.

Do you need a searchable parts .pdf ? Mine is 4 mbytes and too large to upload here.

[skipperpete]

Originally Posted by stevec195

Good on ya skippermate! Do you have any experience on how the new manufacturer Chinese turbos are holding up these days? I can find an Chinese unit for 850USD. That aside, none of the vendors are super good about revealing WHERE they’re from-even when the price is double
. Not anxious to spend twice as much just to find out I’ve bought the same unit.

I’m reluctant to use aftermarket turbo’s but if a customer buys one himself I’m ok with installing it. I can’t take the risk of a turbo self destructing if I recommend the cheap option because I’ll be the bunny doing the repair.... for free.
However, get on one of the go fast engine forums where the guys are doing amazing things with series turbo’s and very high boost pressures to get an idea of how long the aftermarket ones survive and how they fail ....because a cruising forum is the wrong place to ask the hard questions given that many of the yacht engines run below even “making boost” Rpm and many never even get used year after year to the point where the turbo’s corrode up from the wet exhaust humidity.
One other point is that your intercooler is a damned good filter so if you do go cheap and the compressor disintegrates it only ends up in the cooler fins, not the upper cylinder.
Pete

[ScottRhodes13]

Make sure you really have a problem before rebuilding or replacing the turbo. Even if you're not seeing blowby, there is oil vapor being sucked into the air intake, and I imagine it condenses when the air is pressurized and cooled. At 1300 hours your turbo should still be in good shape. I pulled mine apart last year after 2100 hours, and all the bearings and such were still well within spec.

That being said, the turbo should be cleaned regularly. It's not necessary to take it apart. Yanmar recommends spraying a cleaning solution into the intake while the engine is running, but I haven't had any luck with that. Instead, I remove it from the engine and clean the turbine and compressor vanes with solvent.

There should be a drain plug on the bottom of the intercooler that you can use to drain the oil out periodically.

[Ericson38]

Originally Posted by ScottRhodes13

Make sure you really have a problem before rebuilding or replacing the turbo. Even if you're not seeing blowby, there is oil vapor being sucked into the air intake, and I imagine it condenses when the air is pressurized and cooled. At 1300 hours your turbo should still be in good shape. I pulled mine apart last year after 2100 hours, and all the bearings and such were still well within spec.

That being said, the turbo should be cleaned regularly. It's not necessary to take it apart. Yanmar recommends spraying a cleaning solution into the intake while the engine is running, but I haven't had any luck with that. Instead, I remove it from the engine and clean the turbine and compressor vanes with solvent.

There should be a drain plug on the bottom of the intercooler that you can use to drain the oil out periodically.

Right....good advice.

I understood he had engine oil pour out of it when he took the intercooler off.

When I removed the lower drain bolt of mine, a little off white oil-water emulsion came out, but not a load of actual engine oil. In my case, the oil-water mix was from the breather vapor oil combining with condensation from the marine environment in general, over the years. Hence the drain plug, which is a good maintenance feature.

[kapnd]

Originally Posted by ScottRhodes13

Make sure you really have a problem before rebuilding or replacing the turbo. Even if you're not seeing blowby, there is oil vapor being sucked into the air intake, and I imagine it condenses when the air is pressurized and cooled. At 1300 hours your turbo should still be in good shape. I pulled mine apart last year after 2100 hours, and all the bearings and such were still well within spec.

That being said, the turbo should be cleaned regularly. It's not necessary to take it apart. Yanmar recommends spraying a cleaning solution into the intake while the engine is running, but I haven't had any luck with that. Instead, I remove it from the engine and clean the turbine and compressor vanes with solvent.

There should be a drain plug on the bottom of the intercooler that you can use to drain the oil out periodically.

Many boat owners voluntarily feed oil to the motor through the turbo by consistently overfilling the sump. Your motor specifications should tell you how much oil it needs, and that may not be consistent with the high mark on the dipstick.
This problem is sometimes exacerbated by motors installed on an incline, in which case the operator must ignore the dipstick marks, and find the sweet spot for their particular installation.
If you think your motor is using oil, and needs to be topped off regularly, you should let the level decline as you monitor it. You’ll likely find that the oil will stop declining when it reaches its actual optimal operating level.