I've attached a snapshot of my leak. As you can see, it's coming from over my steering box.

Any ideas on where it's coming from?

Car:
1991 300CE

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The o-rings for the oil cooler leak coolant in that general area. NOT a fun job to replace and are typically done with the water pump.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

Thanks Duxthe1,

This is going to sound like a "noob" question, because I am one, but does the oil cooler have coolant hoses attached to it? I thought only oil passed through oil cooler.

I'm leaking coolant just to the outside of the steering box, not oil.

I found a pic of what I think is a oil cooler, but unsure. If this is an oil cooler, where would the o-rings go on these hoses?

Thanks again...

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That is the oil cooler. The inboard hole will have a pipe carrying coolant, which is where the o-ring will leak.

FWIW, there are two types of oil coolers. Some route oil into a radiator and air will remove the heat directly. Others use coolant to remove heat from the oil, which is the type you have.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

Is there any coolant along the pan rail on that side of the engine?

__________________
2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

No coolant along pan rail. The highest point I can find leaking coolant is along the starter bracket. At the moment, the coolant has stopped leaking. Not sure why, but it makes it hard to find a leak at the moment.

So far, I have not been able to find the oil cooler that's attached to the oil filter. I have one of those bore scopes and I've looked all around the base of the oil cooler and I don't see it or the "V" hose and metal hose with the O-ring.

It was leaking a drop every 3 seconds, but now it seems to have stopped.

Thanks for your direction.

I am not trying to be funny but are you sure you are not out of coolant!

No problem... I do appreciate the help. I am sure I'm not out of coolant. In fact I just added more to the expansion tank and it still had some in it before I had to add.

I'm still inconclusive on my coolant leak search, but I took some photos and found some more info to research.

This appears to be a diagram of the oil filter cooler in question:

http://mb.ilcats.ru/part/class/1/ccode/F/cat/520/type/104/subtype/980/group/20/subgr//vers//imgno/2

I have a few images I took of the hoses with my bore scope. They're not great, but they show the pipes in question - I believe

I'm not too sure about the metal hoses in the last image. Does one of those carry coolant?

In any case, I have felt around all of these hoses and they all appear dry. However the "V" hose has dried coolant around the elbow. Still, it's pretty dry. Perhaps the leak is underneath - where I can't reach.

Does anyone know if removing the air filter would provide the necessary access to these hoses, or am I wasting time because the manifold also needs removal?

Thanks again

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None of those images are even close to the oil cooler. It is tucked away tight under the intake manifold, starting about 2/3rds of the way back. Even removing the intake still wont allow you to remove the pipe without also removing the water pump.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

I'm pretty sure my pic shows the o-ring hard line that goes into the oil filter cooler. The picture is not the greatest, but hopefully someone will be able to identify it by looks.

Anyway, after studying the diagram I posted above I was wondering if anyone has tried removing the hard line by only removing the water pump and not the manifold. It seems like it may be possible to undo the screw that holds the hardline to the manifold, but I'm unsure.

Anyone have any ideas if this is possible?

Thanks again for the tips. They have been very helpful.

Eric J.

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