Thread: TDI oil leak at bottom of Intercooler

Hi,
My TDI has the oil weep from around the bottom of the Intercooler. Am told it is from an oil mist / vapour entering the air intake after the air cleaner. Result of the black breather on the valve cover not working effectively.
Considering fitting an a oil catch can or alternatively the oil breather from Allisport shown in the link below.
Appreciate any comments and or advice to stop the oil leak.
thanks
James
https://www.allisport.com/wp-content...16/08/AS06.png

Originally Posted by Reads90

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The reason I ask is that all of a sudden my 300tdi has started sending out black smoke and overheating on long runs towing the trailer after years of being fine.

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First things I'd check:
1/. hose out the radiator fins and general area with a GARDEN HOSE! .. not a high pressure device. high pressure hose out will damage radiator fins.
2./ coolant flush. dump coolant, flush radiator. I just used the garden hose and watched if any muck came out. a little came out at first, then just clear water after a few mins.
The hard part is to remove all traces of old coolant, which if present just makes it hard to determine if the water is clear(ie. no rusty build up).
3/. run straight water for a short while. I ran mine for a few months to see if any new rusty colouration would return. none, so I thought I was good to add coolant again(I was wrong, as I still had heating up issues)


2a/. Going by some comments made here about CEM products, I gave their coolant flush/treatment product a try. Added the amount they specify to my coolant(ie. not straight water), due to my heating up issue.
With my first coolant flush, I thought I cleared the majority of it, but the CEM stuff produced more brown murk!. The green coolant made it hard to see exactly how much, so I did it all over again.
Straight water(ie. no added coolant) for a short while but this time with the CEM coolant flush. More brown murk(again!). Rad is obviously rusted up with more gummy crap than I thought it had the first time around.
So now this is my 4th coolant flush, and it's still producing brown murky crap. I ran it this way for about a month this time in summer, then again for a month with straight water(no coolant no CEM flush). 5th time now, straight water added CEM again and this time it stayed clear, a light green clear .. no browning at all. At this point I felt less unsure that there was no more rusty crap in the engine or radiator. Now I run straight coolant again.

Note that someone may chime in and warn against running straight water(ie with no coolant). it'll explode your engine or some such other stuff. My experience over the years is that straight water for a short time is of no consequence. I don't recommend running straight water all the time.
I do it only to determine if the cooling system is clearing up. hard to do if there is a colour tint to the water. each to their own.

Anyhow. whereas before I did all this, I used to regularly see up to 117°C on my (added) coolant gauge. The Discovery temp gauge is useless. even at 117°C it barely moved a mm or two from it's normal position.
I also changed the Waxtstat thermostat to a Tridon thermostat. A much better thermostat in my view as it opens up much more(more flow). Both supposedly 88°C stats.
Only problem now with the Tridon stat is that it takes a lot longer to build up heat in the engine(in winter). I run without the engine fan to compensate. Have yet to see over 90°C in the past two months without the fan.

Note that EGT and coolant(or engine) temp are linked. High EGT will give you higher coolant temps.
If yours is puffing black smoke, it must be running rich, and most likely under boost. It's very easy to adjust at a minimum the boost compensator. You need an EGT gauge to determine where your max boost fuelling should be.
Again very easy to do all this. I know zero about 300 Tdi's and I've still successfully done all these mods and tweaks to my(D1) Tdi. Where I knew nothing at all about this stuff, know I know a little. Do lots of reading .. don't be scared if you don't know anything about it.
The only tweak I've yet to do is to adjust the main fuel screw. At first because I had trouble breaking off the anti tamper doodad, and then because I've concentrated more so on fully understanding the boost compensation adjustments.

Do you have aircon on your defender? For me all those excessive temp issues in my D1 were always with A/C on. With A/C off, never an issue(I think max coolant temp was in the very low 90's).