Don’t risk a leak
Corroded oil cooler pipes can be a disaster just waiting to happen
1 Pick the right pipes
Your bike’s oil cooler is one of those components that’s mostly out of sight, out of mind. However, over many years service, the pipes carrying oil from the cooler to the engine corrode. This is a safety concern and will result in an MoT advisory or fail. To replace them with new, order up all the necessary parts, including O-rings, and familarise yourself with them.
3 Remove the cooler
Next remove the oil cooler pipes. If the pipes are very badly corroded, be prepared for them be extremely tight, so it’s best to remove the lower ones from the engine, and then remove the oil radiator and get it on the bench prior to removing the upper pipes. Make a note of the pipe routing, and where washers and O-rings are located.
2 Drain the oil and replace the filter
Remove the fairings if necessary, then start the bike and warm it up to temperature to aid the flow of the oil. Switch off the ignition, leave for 10 minutes, then remove the sump plug and allow the oil to drain. Undo the oil filter and replace with a new one tightened to the correct torque. Don’t replace the engine oil at this stage.
4 Time to turn up the heat
With the oil cooler safely on the bench, use a heat gun to try to help ease out the bolts securing the pipes. Penetrating oil might also help. If you decide to hold the cooler in a vice, be sure to secure it only by the old pipes, and not the delicate radiator section itself. Deploy reasonable force, screwing in backwards and forwards, until you feel the bolts begin to yield.
5 Clear out the corrosion
The old bolts had corroded inside the hole (the whitish powder was the alloy corroding and reacting with the bolt). Clean the corrosion away lightly using a round shaped file. We will be using new bolts but if you’re reusing the old ones, clean them with a wire brush.
7 Route the pipes
The pipes may be different shapes/lengths on each side, so double check carefully; these Honda VFR800FiW pipes are precisely shaped to bend round the downpipes. They also route neatly beside coolant pipes and brackets without any force needed to make them fit.
9 Torque it up
With the pipes now fully connected and the cooler installed, tighten the bolts to the torque specified in the workshop manual. Once everything is tight, check the clearances, paying close attention to the area where the pipes run next to the exhaust downpipes.
6 O-rings away
Replace all of the O-rings that seal the new pipes to the cooler and the engine – they can be easily prised out with a small screwdriver. Check against the old parts, then clean the surface contact area with a blast of brake cleaner and wipe with a clean cloth.
8 Grease the new O-rings
Install the new O-rings with a slither of grease, apply enough to prevent the ring from being dislodged when the new pipe is being fitted. Offer up the pipe and install the bolts, but don’t tighten them up until all the other bolts are fitted, and the clearances have been checked.
10 Top up and check
Add the correct type and amount of oil through the filler cap. Start the bike for around 30 seconds. Stop the engine and have a good look around at each point where the pipes connect, making sure there are no leaks. Do another check of the sight glass and top up oil if necessary.