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diagnosis turbo oil leak


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Someone can tell me how can i check the car to make difference between an turbo oil leaks or valves stem seals oil leaks

(Always for the 260Z 2+2 i puchase seeing in my gallery)

When i run the car to 3000 rpm there was lot of smoke at the exhaust, but how can i define where is the leak?

when the car is at 800 rpm there is also little smoke (when it was cold)

the car can't take the road, so i didn't know if the turbo climb well on pressure.....

Thanks for help

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If you pull the turbo off the intake and find oil, you know it's the turbo. You might be able to see if you pull the inlet off the turbo, but it would be better if you pulled the turbo off the intake or intake plumbing. If you find no evidence of oil at the turbo, it has to be after the turbo, either in the valve seals or somewhere else. Sometimes you will see oil leaking round the turbo seal where the impeller housing bolts together, but not always.

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ok with you, but as the car is not mine (not yet), it will be difficult to take the turbo off to see, and i have no seal to take on after....

but I can try to ask if the seller is ok!

by take off the turbo i can esasly see if the turbo leak to the inlet, but if the turbo leak oil by the turbine to the exhaust it will be difficult to make difference with a valves seal leak?

spark plugs are not oily!

what are exactly the symptom of valves seals leak?

smoke at idle or at high rates, when the engine is cold or hot?

when you return to idle?

someone can tell me precision?

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Bpaccaud, These oil seals have been standing so you get two diffrent seal failures, the valve seals dry hard in possition and wear out from being brittle. Check, warm engine accelerate and come back to idle fine mist at idle then burst of smoke when you accelerate again valve seals.

Turbo bearing seals, these seals dont like sitting they flatten the feather edge with the main shaft when stationary the longer it stands the worse it gets. Test with a warm engine you should get small puffs of smoke when off idle 1000rpm+ for 2 minutes if the puffs are a lot is worse. if the turbo seal is realy bad put finger in tail pipe at back of car you should feel oil, if not look at exhaust joints under car fo oil dripping out. If the turbo is really bad there may be external leaks at either end of the centre bearing housing where the oil goes in and out.

This may save you taking the turbo off.

my 2c

Steve :classic:

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thanks for your help steve!

As you could see in my pictures about this car in my gallery the turbo is exactly dry on his seals but the engine run only one hour (after 3 years no running) i can't test the car because it was on a big hill and if i broken down i could't return to his parking!!!

i will test the car like you say next time!!!!

I suppose the valves seal are probably bad, but i prefer be sure about the turbo because it 's not same cost!!!:cry:

See you later


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My turbo (laser tx3/mazda 323 4wd turbo) leaked oil. Engine didnt smoke though. Most of the oil ended up in the intercooler. it was leaking on the intake side, not the exhaust.

If the engine is smoking constantly at idle worn piston rings is my guess. if you get a lot of smoe when you rev it after letting it idle for a while this also could mean piston rings. If you rev it and get a puff of smoke after letting off the pedal, it indicates worn valve guides, as oil is sucked down and burnt on over run (thats what it said in the book i was looking at, an interperated it to mean that. if i'm wrong let me know) ofcourse this was for non turbo cars so it could be the turbo if it smokes under acceleration.

I see by the photo it has a carbie bolted straight onto the turbo looks like a suck through arrangement.

Maybe you can take the airfilter tube off, lift the vacume plunger thing open and shine a torch in there to see if there is any oil in the intake side, though it would probably be in the engine intake side of the turbo i suppose, like 2manyZs says.

Compression test the engine. it just involves removing the spark plugs. Easy. that will give you an indication of the condition of the engine.

if you can take the carbie off the turbo, you can check the impeller shaft for play (up and downmovement, and endfloat, thats in and out).

That car looks in really poor condition (look at the corrosion on the OHC cover), I hope it's really cheap.

Be preapired to strip and rebuild the engine.

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Mr Camouflage, Yes it is, it was the only things the seller find to enrich the mixture:stupid: but below there is a big direct intake air filter.....(i take off the tea towl, as i could do it...)

Last time i take the compression ratio, because 3 spark plugs are black (normal, the carby is in poor condition and there is no oil in it) and 3 spark plugs are Wet (by fuel apparently), so the combustion it very bad for them....

probably i'll check the impeller shaft, but it usualy not representative for the oil leak, and i have no seal to take on the carby after....

For the car condition, after 3 years parking here (near the sea aliminium corrode very well, the body too...:(

i'll probably give 1000 Euros for it, but i must check differents point befor:ermm:

thanks for your reply


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