Author Topic: M129.980 Engine oil cooler heat exchanger replacement  (Read 575 times)

Todd

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M129.980 Engine oil cooler heat exchanger replacement
« on: August 30, 2022, 21:02:19 »
The title should read:  The hell that is.....M129.980 engine oil cooler heat exchanger replacement!

My oil cooler is the long rectangular box style, fitted directly below the mechanical fuel injection pump.  It has always dripped a little coolant.  I've owned the car 30yrs (with the last 10 of that being stored until Jan.2019, and barely driven since.  For years I contemplated removing the cooler and having it resoldered at a radiator shop, but every time I got my courage up, I said, "no way that's coming out of there without an expensive, time consuming, fight." 

Today it was time to finally address the issue since I'm back to having the car in a state where it is driven almost daily.  I think it took about 2hrs to get the cooler out, and prior to getting started, I chased down the local Snap-On tool truck, and purchased an 1-1/16" crow foot, to fit the large nuts that secure the 2 oil pipes to the cooler, and to the oil filter stanchion.  The tool guy didn't have any metric in that size, and 1-1/16" fits with precision(in case you're wondering).  I have a good used cooler to install, but I took the radiator to the only radiator repair shop still in existence in this part of CA.  The guy is extremely talented and has been doing my radiator repairs for 20yrs. 
« Last Edit: September 01, 2022, 03:48:53 by Todd »
Todd

Benz Dr.

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Re: M129.980 Engine oil cooler heat exchanger replacement
« Reply #1 on: August 31, 2022, 03:30:14 »
I just did the same job on my car and it wasn't too bad. Biggest problem was getting the oil cooler lines off. After about 55 years in service I can hardly complain that it started to leak. IP did not have to be removed.
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Todd

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Re: M129.980 Engine oil cooler heat exchanger replacement
« Reply #2 on: August 31, 2022, 05:16:28 »
I too did not remove the injection pump.  I did remove the fuel filter cup, filter, and long bolt.  I also removed 1 power steering hose, from just the steering box, but left the other end attached.   It gave me a little more room to work that rear area of the cooler.  The inner oil pipe fitting on the oil filter stanchion came loose, instead of the oil pipe nut.  I was able to sneak the cooler out, with that shorter pipe still attached to the stanchion.  I purchased in inexpensive 24mm wrench, and slowly ground the open end thinner, so that it would fit between that stuck oil pipe nut, and the fitting on the stanchion.  The wrench was long enough to brace against the front area of the steering box, and hold that fitting securely, while I applied a lot more force to the oil pipe nut.  The nut finally broke free, allowing the pipe to be removed.

I installed my good used cooler.  I also had a better set of oil pipes, so cleaned those back to bare metal, and sprayed them with clearcoat.  This also allowed me to use a solid "long" pipe from cooler to stanchion, instead of the pipe that's always been on my car, which is a combination of a metal pipe connected to a rubber pipe.  I replaced that leaking rubber pipe back in the 90's, but didn't like how it looks now.  The long pipe also looks nicer/cleaner.

So the job is all done, and now I wait for the radiator to be returned.
« Last Edit: September 01, 2022, 03:54:18 by Todd »
Todd

Desertpagoda

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Re: M129.980 Engine oil cooler heat exchanger replacement
« Reply #3 on: September 10, 2022, 23:46:28 »
I have a complete, good , used cooler setup like this including the hard lines if anyone is in need...
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