Hello everyone.
THIS POST WAS EDITED AFTER POSTING DUE TO COMMENTS. CHANGING THE TIMING BELT BECAUSE IT SNAPPED WHILE DRIVING CAN CAUSE SERIOUS DAMAGE TO YOUR ENGINE. PROCEED WITH EXTREME CAUTION.
First, the timing belt:
I have a ’98 V40 manual wagon. I was driving along, suddenly, I lost all power. The car cut out completely. Long story short, an actual mechanic happened to pulled over, and diagnosed the issue in less than 5 mins. Snapped timing belt. The belt should have been done during its 200,000 km service. It wasn't.
Due to circumstance I had to fix it myself. All my research said Snapped timing belt = bent valves. I have since completed the timing belt change, and as far as I can tell, the engine is ok. It has been pointed out that there still is a possibility of valves being bent, and the engine running. So proceed with caution. If in doubt, consult your mechanic.
Secondly, leaking rocker cover bolts:
I had two options; Helicoil, or bigger bolts. Personally I didn't believe I could guarantee no metallic shards would fall inside my engine if I used helicoils, so I used a bigger bolt. I will admit that this choice has weakened the bolt holes. Using helicoils are stronger, but I have had success with using a bigger bolt (M8 instead of the original M7). This option has worked for me. Again, if in doubt, consult your mechanic.
Tools: 1x drill (don’t use an impact drill, regular is fine), a compressor (or something to blow the holes out after tapping), 1x 8mm drill bit & 1x 7mm drill bit, electrical tape, and an M8 x 1 “fine” tapper. I used M8 x 35mm high tensile, fine thread bolts (I had to use a small washer as well as the bolts did not have a “flanged” head (works fine))
Steps 1: Wrap the tape around the 8mm drill bit leaving enough length to get through the rocker cover (mine is at 23mm from the tip)
Step 2: Using the 7mm DRILL BIT, drill out the entire hole. It will go fairly easily until you hit the bottom of the hole. If you use the 8mm drill bit. you are in real trouble.
Step 3: Using the 8mm drill bit, with the tape on it, open the hole on the cover. TOP TIP: take it easy, given the chance, the drill will bite into the soft metal and again, the creek. Hold the drill firm, take it easy, and you’ll be fine.
Step 4: Using the tapper, make a new thread. Even though you drilled the top, it will still try to thread it, just wind it in until it starts to “bite”. This part is slow and steady, I did 2 turns down, then a half turn out. If you don’t do the turn out, you will destroy the new thread, and it won't work. This takes a while, and must be done by hand. I went down about 55mm until I hit the bottom, then I carefully wound the tapper the entire way out.
Step 5: Blow out the hole. Keep in mind this will have plenty of very sharp, very small, pieces of metal flying out at high pressure. I wore safety glasses for that part.
Step 6: You should be right to insert your new bolt now. Wind it all the in and out just to make sure the thread is ok. I also put a bit of threading compound on the bolt as well
Images: The engine photo shows the new bolts I installed (top right), some originals, and the gasket paste bolt I told you about earlier (has been like for weeks now. Oops, I should fix that really) The other image is the drill bits, taping setup, bolts, and washer, and thread-locking compound (the two types of bolts are to show you can use either, or, it doesn’t matter)