Hi guys and girls,
So since I brought the car in 2006 I have been meaning to do something about the rusty bubbles on the sump. I assumed it was just surface rust and planned on cleaning it up and undershielding it. I didn't get around to it and after doing my last oil change found that a tiny amount of oil had seeped through the most rusty patch! I managed to clean the area up enough to seal it with two small aliminium plates and some liquid metal while I ordered a new sump which cost me £90. When the new sump arrived I noticed that the original paint/coating was very thin and scrapped off very easily. So I got it powder coated:
New bolts:
The powder coater actually told me after doing it that the original finish was crap and came off with no effort at all and that he wasn't surprised that it rusted at all. Nice...
Now to replace it. Now all I really had to go on was a Google search and the various posts I found on many forums about the job. Most said you have to lift the engine some said you didn't. I decided that if somebody had done it without lifting the engine that I could do it the same way. How hard could it be? lol.
So first the under tray has to come off. I won't detail how to do this for two reasons:
1. My undertray flew off at about 90mph once and was ran over. Since that I had to make a new way of mounting it with ali brackets and stainless bolts. (Rusty fitting was the reason the onl mounts failed).
2. If you can't get this off you should not attempt this job lol.
So the car up on ramps, in fifth, with the rear wheels chocked and the handbrake very firmly on.
Tray off you can see the drippy oil mixed with rain water on the tray:
With the tray off you can see the messy sump. After two weeks my bodge repair started to let oil through but it did well to hold out for so long. I don't recommend anybody repair their sump like this. If the oil comes out big style your engine is dead. I was checking the level before I started the engine each time and staring at the oil gauges the whole time the engine was running. I just couldn't not drive the car as I had a few things I had to do.
Now your problems may be greater then mine as I pulled the crappy heat shields off a while ago as they were rusty and annoying me and replaced them with less bulky wrap giving me a bit more room. One word about wrap while we are there. If you touch it your skin itches for ages and really REALLY don't get any of the fibres in your eyes!
First it was oil out while the engine was still hot (don't burn yourself here!)
The sump is held on with 14 yes 14! bolts which require and 10mm socket with an extension. I used a 1/4 set as some of the spaces are very tight and the bolts are not very tight at all even after being there for 12 years they came undo with very little force.
10 bolts around the front and sides of the sump come undone easily. The rear four are where the trouble starts.
The way the sump curves and the fact the the front subframe has a lip mean that there is only about 15mm clearance to get your fingers into and the bolts are a good 100mm or so up behind the sump. The pictures below really don't do it justice. I have put red dots where the bolts are hidden
from view to give an idea of how hard they are to get to.
I could see the corner two bolts but the two near the centre you can't even see let alone touch or get to. With a 1/4 extension and knuckle you can just about wiggle it around until is seats on the bolts and then undo them.
Brilliant I thought that's it I did the hard bit. No... not even close.
With all of the bolts undone I then moved to the dip stick pipe. You can't take the sump out with the pipe attached. The pipe is held with one bolt in the engine bay.
Once this is undone the pipe is held in the pan by two small o-rings.... and a pinch of rust. After pulling and twisting and tugging for about half an hour I eventually had to resort to laying underneath and clamping the pipe just above where it comes out of the sump with a small pair of mole grips. Eventually I wiggled the pipe out and found the reason it was so stuck. The end was all rusted up and the o-rings torn (probably where I pulled it out past the rust). Bugger I hadn't brought a new tube or o-rings not knowing that I needed them.
The tube removed with rust cleaned off.
Back under the car the sump is still held on with sealant. Bashing the sump with a rubber mallet did bugger all. In the end I had to pry it off with a screw driver being careful not to dent the block. Basically I bent the sump lip down at the edges until it popped off.
I thought at this point it would simply drop off. Nope.
Two things still hold it on.
1. The oil cooler modine is in the way so the sump won't go past it to drop down.
2. As the sump has the oil pick up inside it the pickup wedges inside and you can't get the sump over it due to it fowling the front subframe and the cooler modine. At this point you can't drop the sump down enough to undo the pickup either.
To solve this I decided to jack the engine. First I removed the jack plate. Next the two ARB mounts so I could pull the ARB out of the way of the engine mount bolts.
Next I undid both mount bolts.
Lastly I jacked the engine using a thin block of wood with a sock set in it which I slotted under this bolt:
This is probably not a great idea but I decided I was happy with it and I was stuck as I couldn't jack the sump at this point without reattaching it. I don't recommend jacking the way I did as you should be using an engine hoist. After jacking the engine, slide a piece of wood or similar between the subframe and mount where the gap opens up.
Fingers make very poor engine mounts.
With the engine jacked up about 20cm you then get enough clearance to drop the sump down more. I still couldn't get it off as it still fowled everything but I had enough room to undo the pick-up bolts a bit. This allowed me to wiggle the pick-up and let the sump come off.
Victory!
The view with the sump removed:
All of the old sealant then has to be removed. I used a stanley knife blade for this. I also found the the rear inner edges of the block are razor sharp and cut my fingers four times!
All cleaned up.
I then left the car for a while to allow all remaining oil to drip down as this will interfere with the new sealant. I then took some kitchen roll and cleaned all of the oil out as much as possible for the same reason. This gave me the maximum possible time before more oil dripped down making a mess again.
I applied a bead of 3 bond gasket sealant around the rim of the new sump and got it into position. Getting it in was again bloody difficult and I found that once you get it partially in you have to rotate it slightly to get past the modine. Once past the obstructions I re-tightened the pick-up bolts (you can't do this first as you need to be able to move the pick-up to get the sump on).
Then the sump was pushed on and the bolts done up. The first 10 were easy...
Now the rear four are even harder to get back on then to get out in the first place! When you get them out they are held still. To get them started in their threads on the end of a wobbly knuckle with no room for your fingers is near impossible. I got the two corner ones done as the jacking of the engine gave me just enough room to get my fingers up there. The middle ones were impossible.
I gave up and jacked the engine another 20mm or so which gave enough room to get my finger up there further and with a lot of patience and swearing got the last two to start in their threads. It's worth saying that it you jack the engine too high the mount bolts pop out of the subframe slots. Chances are that then when you lower the engine they will not fall back into the holes and you will have to fight the engine block until they drop back into place. If they are a little out you can slide a flat blade screw driver into the gap and tap the bolt so make it drop down into the hole. WATCH YOUR FINGERS!. From then on it's easy.
With all 14 bolts tightened (not too much as the block is pretty thin here) the engine can be dropped back into it's mounts.
Nuts are reapplied to the engine mount bolts the ARB put back into position and the brackets done back up. Jack plate is reattached.
Then the dipstick tube which I had forgotten about!
I cleaned all of the rust from the end and replaced the two o rings.
I will buy a new tube and o-rings but needed to use the car before these parts will arrive.
To replace the tube you simply wiggle it back down from the engine bay making sure it takes the same route behind the coolant pipes as it did before. Once the end of the tube is in you need to push the top of the tube the nearside so that the bottom of the tube is levered towards the offside and into the sump. I then applied a small blob of 3 bond around it where it enters the sump to prevent moisture causing more rust before I replace the tube with a new one.
Obviously bolt the tube back onto the block afterwards.
New sump!!!
Tighten plug with new washer and refill with oil.
Under tray back on and jobs a good'un (obviously check level etc as per oil change).
What have I learnt?
1. If your sump is rusty one day it will leak.
2. Changing the sump on an Impreza is a SHIT job.
3. You can undo all the bolts without jacking the engine.
4. You cannot get the sump off without jacking the engine or removing important things like the oil cooler modine.
5. The dipstick tube is a bitch to get off and quite hard to get back in.
6. If you are changing the sump just get a new dipstick tube and o-rings too.
The simplest method to do this would be to initially remove the engine mount nuts, jack the engine up on the old sump using a wood block and then chock the engine mounts with wood so you can remove the jack and keep the engine raised. Remove the old sump and replace with a new one. With all bolts fitted jack the engine on the new sump again using a block of wood being careful not to damage it and remove the chocks and then bring the engine back down into its mounts. I wish I had done it this way but I chose to believe the thread I read about being able to do it without raising the engine.
