Tranny heat exchanger leaking coolant!

[vtyagi]

Well guys,

I was feeling pretty good... I just got done replacing my radiator, all hoses, water pump, thermostat. Put everything together, started the engine, checked for leaks...and guess what...the tranny heat exchanger is dripping coolant! drip...drip..drip..drip

RealOEM.com BMW E53 X5 4.4i Oil-cooler pipe/heat exchanger

Anyone replaced this unit? Is it typical for this part to leak with only 100K on the vehicle?

Anyone have any pointers? It seems like there are two quick-connects that need to be pulled out...and it should come right off. Seems like an easy job.

2001 X5 4.4L w/ 100KMiles

[flyingmachine]

most likely it's the rubber ring(#12 in your realoem link). I did that 1-2 years ago.

[vtyagi]

I thought it was the seal, BUT....the leak is coming from between the exchanger. It doesn't look like the leak is near the seal.

Was yours leaking near the seal or in the middle of the exchanger?

[flyingmachine]

Originally Posted by vtyagi

I thought it was the seal, BUT....the leak is coming from between the exchanger. It doesn't look like the leak is near the seal.

Was yours leaking near the seal or in the middle of the exchanger?

I would suggest you to trace the leak when it's still wet. Put fingers around those 2 ports where the rubber seals go and see if they're wet(don't do it right after you shut the engine. it's still HOT). I have strong feeling the rubber seal is the problem.

[Luke]

Anything leaking up by the trans thermostat will look like its leaking from the cooler. See if the leak is running down any coolant hoses from above and colloecting at the cooler.

[flatlander]

Originally Posted by Luke

Anything leaking up by the trans thermostat will look like its leaking from the cooler. See if the leak is running down any coolant hoses from above and colloecting at the cooler.

Is there a trans thermostat? I have coolant leaking from up above the trans heat exchanger. All the hoses near the multi-connector above the trans cooler appear to have coolant on them. And then I noticed coolant coming from the radiator core face too. If there is indeed a thermostat, has anyone replaced this before?

[Luke]

On the 4.4 there is a trans themostat that goes to the trans cooler.

Part 15.

RealOEM.com * BMW E53 X5 4.4i RADIATOR/EXPANSION TANK/FRAME

Mine was weeping badly after I replaced my radiator. Its probably an O ring inside it, but I replaced the whole thing.

[CharlieHustleX5]

Are you positive the leak is coming from the middle of the exchanger? It might just be residual coolant from the bleeding process. I've never heard of the exchanger leaking from the center. I've had mine for over 100k miles and its still fine (I assume).

[HPIA4v2]

Originally Posted by vtyagi

Well guys,

I was feeling pretty good... I just got done replacing my radiator, all hoses, water pump, thermostat. Put everything together, started the engine, checked for leaks...and guess what...the tranny heat exchanger is dripping coolant! drip...drip..drip..drip

RealOEM.com BMW E53 X5 4.4i Oil-cooler pipe/heat exchanger

Anyone replaced this unit? Is it typical for this part to leak with only 100K on the vehicle?

Anyone have any pointers? It seems like there are two quick-connects that need to be pulled out...and it should come right off. Seems like an easy job.

2001 X5 4.4L w/ 100KMiles

I did after I replaced my WP/thermostat back in Nov/Dec, the funny thing was the leaks continued with new heat-exchanger until about 2 days and now no leak what-so-ever. Weird indeed.

BTW, I googled the part number and found an online company in Texas who charge around $200 for it (brand new and OEM) with free shipping. The 0-rings come with it. Good luck or you can just drive run the engine until warm in the garage to see if the leak persist (never know, but it may save you a few bucks).

[01 BMW_X5]

Are you sure it is from the exchanger and not the new radiator?
You could have damaged the new radiator when putting it in. I have seen it happen before.
Take off the shroud and loosen the exchanger again so you can see if the leak is from the radiator or the exchanger