Thread: Turbo oil seals and EGT?

Turbo oil seals are labyrinth type. They only leak when the pressure difference across them reverses.
This is usually due to engine issues providing more blowby and higher crankcase pressures.

Fix the engine problems and turbo stops passing oil.

Originally Posted by EvilGTV

I'm suspecting the oil seals on my Td5 Disco turbo are leaking somewhat

Why are you thinking they might be leaking?

Originally Posted by EvilGTV

Just wondering if anyone has ever noticed a rise in EGTs as a result of a turbo with stuffed seals (or noticed a drop in EGTs after replacing a suspect turbo without changing the boost)?

usually if you notice that youve done an execlent job of monitoring the gauges in the presence of an engine thats getting busy trying to show it crankshaft to the rest of the world.

if you turbo seals were leaking badly enough for that to be happening, you'd have had a runaway.

Originally Posted by EvilGTV

Just wondering if anyone has ever noticed a rise in EGTs as a result of a turbo with stuffed seals (or noticed a drop in EGTs after replacing a suspect turbo without changing the boost)?

I just remembered.

Back in 2005 I had a 4BD1T with completely shagged valve guides and seals along with dusted bores. It was recycling so much oil through the intake from the turbo that when you got it hot going uphill it would actually run-on for a bit at the top if you clutched in.
Oil consumption got to 1 litre per 100km. EGT was running about 150C hotter than normal (600C on the flat vs 450C).

In that case I did an insitu piston/liner/ring replacement and had the valve guides/seals replaced. All done over two weekends in a borrowed garage. These engines are great to work on.
EGT dropped back to normal, oil leaks stopped, oil consumption stopped, turbo had nothing done to it.

AFAIK they have an O2 sensor in the exhaust, and so I would presume (maybe incorrectly) if the reading is outside the permissible range, the computer would modulate the fuel/air to bring it back.

Originally Posted by Graeme

Why are you thinking they might be leaking?

Some play in the turbo shaft, a tendancy to fill the intake with oil (more than I remember being normal for a Td5). Occasional smoke out the back end even with the standard ECU... That, and the oil level hadn't dropped for weeks driving around town, but after towing the race car from Melbourne to Winton and back, I'd used a bit over half a litre of oil.

Only difference I can see to normal driving is much longer periods of time on boost climbing hills, which would suggest either turbo or boost related blowby. There's two fifths of bugger all blowby at idle, but who knows what happens when it's on boost...

Originally Posted by Dougal

It was recycling so much oil through the intake from the turbo that when you got it hot going uphill it would actually run-on for a bit at the top if you clutched in.
Oil consumption got to 1 litre per 100km. EGT was running about 150C hotter than normal (600C on the flat vs 450C).

Funny you should mention that, occasionally mine keeps accelerating for a second on changing gears (normally after revving hard in 1st picking a gap in traffic, but I have noticed it once or twice in other gears). Had been putting it down to a glitch somewhere in the pedal, but maybe not.

Best I pull the outlet hose off the new intercooler, and see what it looks like in there... Nothing really drained out of the old cooler though, despite appearing quite oily inside...

Seems like the consensus on the original question would be, yes oil burning through the intake will increase EGTs, but shouldn't really make a noticeable difference unless you're using a fair bit of oil....

You mention a standard ecu,are you using a NNN fash tuned ECU in a MSB TD5 motor????.
If so there is the answer to your EGT issues.
I run a tuned NNN ecu in my 1999 D2,dont have a pyrometer fitted,can see the water temp increase on Nanocom on long hills.
Andrew