Oil cooler replacement

flash7210 · **Posted:** Sun Oct 27, 2019 2:08 pm

A blown oil cooler is gonna make for a big mess.
Hopefully this will help others deal with it.

First thing to do is drain the radiator.

To get to the oil cooler you will have to remove the air filter box, turbo inlet elbow, exhaust heat shield, and water pump inlet elbow. Removing the viscous heater could help and might as well remove the thermostat housing cause you’ll want to clean it out.

There are six nuts holding the oil cooler to the block.
Once you get those off you might find it hard to get past the motor mount bracket. So set the cooler back on its studs and grab a small pet bar. Pry up on the bottom lip of the cooler to bend it a little. Now you should be able to get it off.

GordnadoCRD · **Posted:** Sun Oct 27, 2019 9:53 pm

internal leak, or gasket leak?

flash7210 · **Posted:** Mon Oct 28, 2019 5:00 am

Internal leak.
Was quite difficult to isolate.

GordnadoCRD · **Posted:** Mon Oct 28, 2019 6:43 am

I'm still relatively new to the mysteries of the VMM, but in 3 years that's the first one I've heard of. What do you think? Metal fatigue?

flash7210 · **Posted:** Mon Oct 28, 2019 8:09 am

It’s either corrosion or erosion.
14 years, 230,000 miles, all it takes is pressure and time.

It seems to be made from a fairly high grade of stainless steel. Barely a speck of rust anywhere on it. It’s probably the cleanest piece of metal anywhere on the engine.

I would certainly prefer a air-to-oil cooler. Unfortunately it’s not something that can be easily deleted or bypassed. It’s part of the oil feed between pump and filter.

Oh, and it’s another one of those discontinued parts, woo hoo! :roll:

Thankfully I was able to find a eBay seller in Latvia who had a few in stock.

TKB4 · **Posted:** Tue Oct 29, 2019 8:57 pm

I have to assume that some of the smaller holes at the top of the gasket picture must be the coolant passages since there are only 3 large holes and it would be pretty hard to get flow in and out of 2 different liquids in only 3 holes. Are the three large holes all oil conduits?

I am curious how you proved the leak. Did you use pressure ? Maybe a brief explanation?

WWDiesel · **Posted:** Tue Oct 29, 2019 9:42 pm

TKB4 wrote:

I have to assume that some of the smaller holes at the top of the gasket picture must be the coolant passages since there are only 3 large holes and it would be pretty hard to get flow in and out of 2 different liquids in only 3 holes. Are the three large holes all oil conduits?
I am curious how you proved the leak. Did you use pressure ? Maybe a brief explanation?

Two of the holes are for oil, in and out.
The other single hole is for coolant entering into the cooler only. The cooler actually has a metal hose fitting on the back side for the heated coolant to exit the oil cooler.
The outlet hose connects directly to the large suction pipe of the water pump.
That is why there are only 3 holes in the gasket.

flash7210 · **Posted:** Wed Oct 30, 2019 8:38 am

Quote:

I am curious how you proved the leak. Did you use pressure ? Maybe a brief explanation

Yes. Pressure test.

Put a small section of 5/8 hose on the coolant outlet pipe end, with a plug in it, and a small hole for a air nozzle.
Clamped a piece of rubber over coolant inlet.
Filled the oil side of the cooler with water.
Applied 80 psi of air pressure.
Saw the bubbles.

TKB4 · **Posted:** Wed Oct 30, 2019 9:47 am

ww
Yes, now I remember that elbow piece that connects to thermostat that I had such a hard time connecting a hose to connects to the oil cooler !! Thats why looking at only part of the equation doesn't balance !!
Thanks

TKB4 · **Posted:** Wed Oct 30, 2019 9:53 am

Flash
Thanks for explanation. Same principle as the video I linked which was actually kinda obvious anyway but still a picture/video is worth a thousand words :ROTFL:

krb · **Posted:** Tue Sep 28, 2021 5:13 am

Anybody have these fail? I never hear about it so it must be rare.

I've been smelling coolant but couldn't locate a leak. Then the coolant was starting to disappear. I thought, oh no, the head gasket. But it wasn't showing up in the oil nor exhaust that I could detect.

Finally last night I saw gunk around the engine oil cooler. Could just barely see it from above and just a little better from below. Looks like oil + coolant. I'm hoping it's just the gasket as the oil & coolant aren't mixing internally, just weeping coolant.

It could possibly be that hose but I'm 99% sure I replaced it when I did the head gasket/timing belt. I replaced every hose I took off at the time.

Not looking forward to tackling this one, so much crap has to come off...

WWDiesel · **Posted:** Tue Sep 28, 2021 12:27 pm

Before going to all the trouble and work required to R&R the engine oil cooler, I would purchase and pour in some UV coolant dye in the coolant and run it for a while at normal operating temperature, and then inspect with a black light to see exactly where the coolant is coming from.

IDParts lists the gasket for the engine oil cooler,
OEM Number: 5142816AA
https://www.idparts.com/oil-cooler-gask ... e993f5ac9f

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krb · **Posted:** Wed Sep 29, 2021 5:27 am

I always wondered how they did that. It's that simple?

jlg89 · **Posted:** Tue Nov 08, 2022 7:35 pm

Head gasket went out on my 2006 CRD, exhaust into the coolant. After replacing the head gasket (reworked the head in the process), all of a sudden the oil & coolant were mixing. Turns out the oil cooler went out. Had to find one on eBay, got mine from Italy instead of Latvia. Maybe we can compare notes.

krb · **Posted:** Wed Nov 09, 2022 7:45 am

Sorry I never followed up. I did somewhere but apparently not on this thread...

Luckily, just as I started disassembly, I realized the thermostat housing was loose. Looks like when I reassembled the head I never properly torqued down the housing. Retorqued it and been fine ever since. That was probably about 5,000 miles ago.

I seldom get this lucky...

Oil cooler replacement

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