Oil pan removal and reseal

[Blacklab467]

As a "stage 2" procedure of replacing the PCV system in my car a few months ago, I was concerned about the possibility of the PCV drain port in the oil pan being clogged and wanted to get the oil pan off and ensure that it was clear and also clear any gunk out of the oilpan before reinstallation. I also took the opportunity to replace the oil cooler rubber hoses, genuine Volvo replacements were about $45 and pretty easy to change. It's a very straightforward job for those contemplating this undertaking, I did however remove the transmission to subframe torque mount and also the passenger side motor mount for better access to the pan although I believe these steps to be optional, it just gives a little more room for the pan to be reinstalled without disturbing the Anearobic sealant. You can support the engine with a floor jack under the angle gear.
Removal of the pan is about 28 10mm and 2 14mm bolts of varying length. I used a piece of styrofoam to keep track of them and where they go:

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Once the pan is out, I discovered the requisite amount of sludge. Not too much and surprisingly the PCV drain was perfectly clear. I cleaned the pan out with Varsol first, then soaked the hard sludge with a product by Spray Nine Called "GREZ" for a few hours, then took the water hose and blasted it all out. The GREZ product worked very well with little scrubbing required. It should be noted that I've used Mobil 1 synthetic for the 100000 kms I've owned this car.

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I used the time while the pan was soaking to replace the rings on the oil cooler line inside the pan, replace the orings on the oil pickup tube, and replace the external rubber hoses on the cooler. The pan came out like new, although I wasn't able to remove the previous sealant from the flange, I tried acetone, Goof off, and some other chemicals I had in the garage...........I rolled the dice and decided that the sealant was perfectly smooth and would be fine for a second application on reinstallation.

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Below is the oil filter bypass valve, probably a good idea to take this out and make sure its clean and working. If you were ever wondering what your 11mm wrench is for, I think this is the only time I've ever used it!

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With the sealant applied thinly with a cheap paint roller, I offered up the pan and reinstalled and torqued the bolts. There is a very specific tightening sequence to be followed for these.
What happened here? Upon reinstallation the middle bolt on the transmission end didn't want to accept torque, my first thought was that it somehow got stripped. I left it in the hole and when I started the engine, there was a terrible shrieking for about 10 seconds prior to the bolt falling on the floor and looking like this:

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There was no leaking and the noise stopped after the bolt fell out, I resolved to source out another bolt from the wreckers, thinking that I'd somehow mixed the bolts up and put the wrong length bolt in the hole. Today I got another bolt (same length from the same hole) and it screwed right in and accepted torque so all's well. I've seen a picture of a similar incident on this forum where that bolt gets shaved by the starter teeth on the flywheel, but why did the first bolt go all the way in if it wasn't threaded properly?
All in all a pretty easy and satisfying job to have done. If you're going to drop the pan, consider also replacing: oil cooler hoses and seals, dipstick tube oring, and degreasing the underside of your engine and subframe where required.

[BlackBart]

Doing sort of the same thing this weekend
(way less complicated than yours, but I did use several baggies for the different bolt and nut types) -

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[volvolugnut]

Blacklab467,
Thanks for the detailed pictorial. I know how much effort it takes to produce this type post.
volvolugnut

Remember when most oil pans were stamped sheet metal and had about a dozen bolts? And almost always leaked?

[BlackBart]

Yes, I do.

[jonesg]

that bolt got slightly adrift and friction tightened against the flywheel.
I've seen before.

[Blacklab467]

Doing sort of the same thing this weekend
(way less complicated than yours, but I did use several baggies for the different bolt and nut types) -


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What the heck is that engine? Something marine for a ChrisCraft maybe?

[BlackBart]

Alfa Romeo 1600. Pan fits over the crossmember, then has a deep wide "batwing" pan with complicated oil baffles inside. Also air-cooling fins that hang out of the bottom of the car, right where speed bumps live.

I'm replacing the rear main seal, which means rear crankshaft bearing cap which means pan.

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[abscate]

There is an important part of the oil pan install where you put the four corners in loosely, the the horizontal bolts get torqued to spec. That pushes the pan into the right position so that the bolts don’t hang up. I do think you got the wrong bolt in somewhere , looking at that nicely machined bolt.

[Blacklab467]

I think jonesg is right about the bolt being adrift, all four bolts on the transmission end are the same length and the longest bolts on the pan. I took these out at the wreckers and they were all exactly the same length. Its very strange. I followed the tightening sequence to the letter with the horizontal bolts, then in pairs to the starboard side. Anyways, all bolts are in and it doesn't leak. Thanks for you help jonesg and abscate.