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Oil leak at turbo

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Oil leak at turbo

Postby Bmac193 » Sat Jul 11, 2020 4:07 pm

Hey guys
Got a 98 rodeo with a Chinese copy of the 4JB1-T engine and an after market RHF5 turbo. She keeps leaking oil from the turbo outlet hose. I've been to see a mechanic who suggested a high flow air filter and a catch can. I fitted a K&N air filter and a ryco rcc350 catch can which worked for a while but it's pulling oil past the catch can and leaking again. Thought the catch can might be full but it still happens even when there is very little oil in the can. I put the rocker cover off the old engine on as the new one doesn't have an outlet for the breather on the dipstick but this seems to make the problem worse. Not sure where to go from here, any suggestions would be much appreciated.
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Re: Oil leak at turbo

Postby jacksonliam341 » Sat Oct 30, 2021 5:45 am

Oil leaks can be caused by a variety of factors, the main factor being incorrect pressure within the compressor and turbine housings. Oil leaks can cause catastrophic damage to the bearing systems and occur within seconds of the turbocharger commencing operation.

When a turbocharger is installed correctly, it should NOT leak oil, however, there can be cases where oil leaks occur. The following highlights some of the main causes and signs of oil leaks.

An oil leak can also occur when engines are running on idle. The pressure within the housings is lower, which in turn can lead to a vacuum being created, causing the oil to leak into the turbine housing. Once the engine starts to run at normal speeds the pressures will be restored and the leaks will stop.
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Re: Oil leak at turbo

Postby geeves » Sat Oct 30, 2021 2:06 pm

Make sure we are talking the same hose. The hose from the turbo to the intercooler can seep oil. Messy but not uncommon. This oil is formed by engine blow by and travels from the rocker cover breather through the ventilation into the turbo and because its under pressure after the turbo is forced through the hose. Even an engine with unmeasurable oil consumption will have some. If your oil use is minimal ignore it
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Oil leak at turbo

Postby Jamessweet » Fri Feb 24, 2023 11:32 pm

Bmac193 wrote:Hey guys
Got a 98 rodeo with a Chinese copy of the 4JB1-T engine and an after market RHF5 turbo. She keeps leaking oil from the turbo outlet hose. I've been to see a mechanic who suggested a high flow air filter and a catch can. I fitted a K&N air filter and a ryco rcc350 catch can which worked for a while but it's pulling oil past the catch can and leaking again here. Thought the catch can might be full but it still happens even when there is very little oil in the can. I put the rocker cover off the old engine on as the new one doesn't have an outlet for the breather on the dipstick but this seems to make the problem worse. Not sure where to go from here, any suggestions would be much appreciated.


It sounds like you are experiencing an ongoing issue with oil leakage from the turbo outlet hose on your 98 Rodeo with a Chinese copy of the 4JB1-T engine and an after-market RHF5 turbo. You've already tried a high flow air filter and a catch can, specifically a K&N air filter and a ryco rcc350 catch can, but it seems that oil is still being pulled past the catch can and leaking.

You mention that you tried putting the rocker cover off the old engine on as the new one doesn't have an outlet for the breather on the dipstick, but this seems to have made the problem worse. At this point, you're not sure where to go from here and are looking for suggestions.

It's possible that the catch can you are using is not effective enough to handle the amount of oil being produced by your engine. You may want to try a larger or more effective catch can to see if that helps.

Another potential issue could be with the turbo itself. If the turbo is not functioning properly, it could be causing excess oil to leak from the outlet hose. It might be a good idea to have the turbo inspected by a mechanic to see if there are any issues that need to be addressed.

Lastly, you may want to consider consulting with a specialist who has experience working with the specific type of engine and turbo that you have. They may be able to provide more targeted advice and recommendations to help resolve the issue.
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Re: Oil leak at turbo

Postby Roadrunner » Sat Oct 14, 2023 3:02 pm

I realize that this is an old post, so am replying because there will be newbies looking for answers to their oil consumption problems, and I have learnt a lot from this forum so feel obliged to pass on some tips in return.
There are 2 places to look for the problem,the first being a worn seal on the turbo itself. You can buy a rebuild kit for your turbo for under $100., but if you don't mark the turbine wheel position on the shaft before taking it apart then you risk having an unbalanced turbo shaft which kills the turbo in about 10 minutes. (don't ask me how I know this!)
The turbo can be tested for oil leaks by taking off the air outlet hose from the compressor housing and putting a white or light colored piece of material over the turbo compressor outlet and revving the engine at around 3000 revs for a minute or so, If the oil is coming from your turbo you will see the oil droplets collect on the light colored fabric. With the price of aftermarket turbo's being very inexpensive it's easier to buy one from a reputable seller on ebay rather than rebuild the original turbo. I bought this one- https://www.ebay.com.au/itm/275528052086
It comes with a 24 month warranty so is a low risk purchase. (just make sure that you follow the installation instructions carefully as the turbo needs to be pre-lubed before engine start up. Mine is still operating flawlessly after 11 months now even though I run 12 pounds of boost. One word of warning though, the ebay turbine housing pictured has a very small wastegate hole (smaller than standard turbo size) so I took to it with a drill and grindstone to enlarge it as much as possible which gives you some free horsepower, and we can all do with some more horses!
The wastegate actuator has an adjustable rod too so you can wind it in a turn or 2 for some more boost....but don't go silly lol).

If your turbo isn't spitting oil out then the problem will probably be clogged up oil rings in your engine. This is relatively easy to fix, but do this at your own risk as I won't accept any responsibility for unintended engine damage.
The protocol goes like this- disconnect the positive wire that operates the on/off solenoid on the injection pump, take out your glowplugs, then pour around 150 mills of kerosene into each plug hole.(you will need a small funnel for this) then wait 6 hours and turn the engine over slowly with a ratchet and socket (17 mill from memory) attached to the power steering pump pulley nut, just turn the engine over slowly otherwise you might get a kerosine shower when the piston comes up to top dead centre. If you get some kero coming out of the glowplug hole then it needs more soak time. When you can turn the engine over by hand and not get any kero coming out of the glowplug hole it's time to do a second dose. another 150 mills of kero into each hole, then wait for 12 hours or more and slowly turn the engine over by hand, if you get kero coming out of the glowplug hole then you need to let it soak for another day or so...or however long it takes to have no kero come out of the glowplug hole.
Then it doesn't hurt to turn the engine over by hand half a dozen times to make sure that the engine doesn't hydrolock. Then turn the engine over by using the starter motor for at least 30 seconds to clear any residual kerosene that will be in the cylinders/pre chamber. Then replace the glowplugs and start the engine with a friend standing by the inlet manifold so that if the engine starts to burn the residual kerosene and takes off at high revs he can then block the inlet manifold opening with a piece of plywood to kill the engine. (this probably wont happen but it pays to cover your bases.) Just let the engine idle for 15 minutes on startup because the kerosene will desludge the engine so you need to catch the sludge with the oil filter, if you give the engine a heap of revs then the oil filter will probably activate the bypass and you will pump sludgy engine oil through the engine which can't be a good thing.
Then you need to change the engine oil and filter because it will be diluted with the kero that ran down past the rings, not to mention the carbon sludge that will be dissolved from your compression/oil rings.
It wouldnt hurt to do a compression test before and after this cleaning method. I got an extra 5 to 20 compression psi (depending on the cylinder) by doing this. Now my engines oil consumption has halved. There will still be some residual kerosene in your new engine oil,(because there will still be some of the old engine oil in the engine oil passages/oil cooler) so you can either leave it be and do some extra desludging for a few days if the oil pressure isn't affected too much, or you can do another oil/filter change. When I drained the engine oil I got an extra litre out of it, over and above the total engine oil and added kerosine amount , this can only be the dissolved engine sludge.
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