Bad oil consumption, need some help !

[Royalmaas]

Basically i have a 87 7MGTE that loves to eat my oil as much as going fast. It uses probably around a 1 Quart pr 300 Miles... This can vary a lot depending on if i do any pulls or not.

I figured out it either have to be the Valve seals or the Turbo, pretty sure piston rings are good. Its said that the engine was overhauled back in 06`, so if im lucky it might just be the turbo ?

Anyway what im asking for is some tips at how to be sure if its either seals, turbo or maybe both ?

Im currently running a stock engine except for studs and a MHG. Turbo is set at 1Bar/14.5 Psi wich might be bit to much for that poor guy..

The smoke wich is coming when its at idle can go from being very thick and another day it can barely smoke. When im driving i cant see any smoke at all, but what people that have been driving behind me have said is that when i floor it, it spitts out one cloud then it just accelerates nice.

If im driving nice and dont boost to much, it doesnt consume that much oil that it does when im giving it pulls.

Thought it was good idea to add that im running on 5W-30 Toyota Oil wich might just make the case worse ?


Thanks in advance for any advices, this oil problem realy makes it a lot less fun to drive this beauty

Cheers, Roy

 

[radiod]

Take the downpipe off and check for oil on the hot side of the turbo/in the downpipe for turbo leakage. If your rings are that fried you'll typically have exhaust/smoke coming out of the filler cap if you remove that while idling. Valve stem seals leaking that badly would likely leave oil on top of the piston after letting the engine sit and cool.

Pulling the plugs will give you a good idea if you're getting oil in to the combustion chamber or not. You can check for oil on top of the pistons at the same time. A compression test wouldn't be out of the question as well to check the condition of the rings.

 

[IndigoMKII]

Instead of assuming your rings are still good and everything is in proper condition, run a compression check. Valve stem seals normally smoke the most at cold starts. How is your PCV? Is everything still hooked up properly?

Pull off your hot pipe leading to the intercooler and the downpipe checking for oil residue.

If your car is using that much oil, why continue driving it or pushing it hard? All it takes is for the engine to become oil starved once, and rod knock.

Also like radiod said, check the plugs after running it. Are they oil fouled? Peer into the spark plug hole with a flashlight or a boroscope if you have one.

 

[Royalmaas]

Wow thanks for the replys To answer some questions i have taken off the pressure pipe coming of the turbo, and there is a layer of oil inside it. Not sure if its like that all the way to the intercooler, but probably is... I gonna do a compression test and also check the sylinder and see if it has any oil on top of it.

Already im leaning towards the Turbo being the problem, but hopefully i`ll figure that out by tomorrow

 

[radiod]

Typically oil on the intake side piping is from excessive crank case pressure, typically caused by a plugged PCV or incorrectly routed PCV system. If everything in the PCV checks out then it's likely excessive blowby from rings not sealing properly. When the turbo leaks it isn't common to see it leaking in to the charge piping, it's much more common to see it leaking out the exhaust.

A compression test will definitely give you a better idea of what's going on. Let us know the results of what you find.

 

[Royalmaas]

Certainly will, thanks for the help ! I think the PCV System is working like it should, car idles great and doesnt go rough in any way. Also cant see any piping that looks like is leaking or plugged up. Will do these tests tomorrow and give a update

Also from what i can remember i noticed that there was some oil that was laying on the intake on the turbo, when i took of the intercooler piping.

 

[radiod]

A little oil on the intake side of the turbo is fairly normal. The PCV dumps in to the accordian hose and it will inevitably have SOME oil residue recirculating even in optimal operation, so that front lip of the turbo is an easy place to see some of that residue collecting.

Just for your own reference, here's the TSRM link to the PCV system:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=EC&P=5

 

[Grandavi]

I just went through something similar where I used a litre of oil in about 100 km (60 miles). Newly built engine with a new turbo and it turned out to be the turbo (at least that's what it appears to be currently). I replaced the 57 trim with a 60-1 trim and no smoking (had to take it on the highway and do a couple pulls to try to clear the system a little... ). The turbo doesnt really have "seals" its more of a pressed bearing (not sure how to describe it really) and it only takes a little bit of an issue to cause an oil issue. Mine would smoke heavy after revs and idling when hot, but not cold. Hoping my problem is solved (wont know for 100% sure until I have run it a bit longer, but seems to be solved with the turbo replacement). If you have a spare turbo to swap in sitting somewhere, that is a quick way to check as well (relatively speaking).
If you do pick up a second turbo, make sure you dont store it (or the other one) dry.. keep oil in it.

 

[IndigoMKII]

Grandavi, I believe this is the term you're looking for.

http://en.wikipedia.org/wiki/Labyrinth_seal

It's the same seal used on most turbine engines that I've worked on. It works like this, the pressure on one side of the seal is greater than the other side, keeping the oil from seeping through.

 

[Grandavi]

thats right.. some call it a pressed seal.. but I wasn't sure how to describe it : )

 

[Royalmaas]

I had written quite a text here for you guys but i managed to delete it all, so heres a short summary.

Checked top of pistons and they where oil free, also checked intake and pressure pipe for turbo wich unvealed that the compressor wheel on the turbo had some damage on the blade. It also had some play in the shaft, but not sure how bad it was.

So from what i can see the oil might dissapear through the turbo


Thanks for the help, gonna see if i can get a hold of a 57 trim anytime soon.

 

[Grandavi]

Could also be the oil cooler. Any puddles under car or is it "wet" under the front of the engine? Smoking conditions?

 

[7M4EVR]

I might have missed this but why would the tops of the pistons have oil on them? Could just have a very slight leak somewhere if u can't see puddles. Check all your oil lines you should be able to see caked on oil and grime if you have oil leaking somewhere. Check your turbo oil feed and return lines too. Most of all keep an eye on ur oil pressure. Don't want to lose a bearing because of something stupid.

 

[Royalmaas]

Since the consumption is as big as it is, its either the turbo or the seals. There is no leak under the car, its all coming out of the exhaust.

Oil pressure and temp is also good, tbh the engine itself is in a pretty good condition except for the oil consumption. Compression test was great and seals wasnt leaking down on the pistons.