SIngle Bypass Surgery: Exploratory

Post two in the series about removing and replacing a small plastic tube between the engine and the oil cooler in the beast that is my 1997 Audi A8:

Step one, Remove.

A healthy dose of patience paid off on this one.  After removing the front end of the car, I methodically got the serpentine belt off, then took another session and got the alternator out of the way, then drained all the oil out of the bottom of the engine and the oil cooler itself.

The next step was to get the oil cooler itself out, which involved loosening an engine mount, jacking up the engine just a few inches to get me access to three allen-headed bolts at the top of the thing, hidden under the exhaust manifold and holding the oil cooler onto the engine block.  The first bolt was the bastard.  You need a hex-head socket plus a three inch extension pus a universal plus a breaker bar plus some contortionist leverage to turn it.



Trouble was, in trying to get the hex socket into the bolt head, I never felt like I had a good connection.  And if I screwed this bolt up, I might as well throw the car away.  It's not worth paying to fix; I could buy another.  It's a thousand dollar car.  Anyway, with my mirror and flashlight I could tell the bolt looked a little mangled.

I gave it time.  I sprayed it with liquid wrench.  I tool an awl and poked around, trying to clear maybe some sand from the inside of the bolt head.  I tapped it as best I could in the small space I had to work.  All the usual bolt-freeing techniques.  Until I remembered heat.  How in the heck am I going to get any heat way down in there?  And without setting fire to all the oil on the engine?  Can't use a propane torch.  Can't imagine a soldering iron convecting enough heat back there.  Convection!  That's it! Cue Mrs. Toadroller's manly heat gun:



I got the socket and extension onto the bolt, then blasted away at the extension for about five minutes, letting the socket and extension conduct the heat up into the bolt.  I got what felt to be a good grip on the bolt and slowly, steadily applied pressure until ping! It gave way.  Good or bad, I was committed.  I ratcheted it up a few more times and it felt like a bolt turning.  My mirror sure seemed to indicate it was.  And so it came free.  Bolts two and three were in view and much easier to access and remove.  Down below for bolts four and five.  Ten minutes of wiggly-wiggly and voila, the cooler and the culprit: