After having its leaking head gasket replaced under warranty, this Delica needed its head bolts re-torqued.

Access to the head bolts on the 4M40 turbo diesel is easier than on many engines because the camshaft is not in the way. Half of the bolts are actually external to the cam cover!

Unfortunately in the Delica the engine sits mostly under the dashboard, which greatly limits access from above - and the intercooler is also mounted on top of the engine.

A blown head gasket is usually a pretty big deal, and generally happens due to excessive overheating or other engine problems.

This one was a bit different - because the engine was leaking coolant from the join between the head and the block, but had no other blown head gasket symptoms!
There’s no real way to fix it without replacing the head gasket though, which is a fairly big job.

After removing the head and gasket, it was obvious why it was leaking. A small crack was letting water from the cooling passages out to the side of the engine:

The cylinder head was sent off for machining (to make sure the sealing surfaces are perfectly flat) and cleaning. In the mean time, the block was cleaned up. It’s important to remove all traces of the old head gasket, sealant, and corrosion. I also cleaned the carbon that was built up on the pistons.

While the engine was apart, all the rubber hoses (now 20 years old) were replaced with new silicone ones to ensure future reliability. The heater hoses are a common problem on the CA18 engine.

The water pump and timing belt were also replaced while it was apart, so there should be nothing much to do for another 100,000km or so.

This car had a bit of a history of overheating.

It was taken to a workshop and had the head gasket replaced, but it continued to overheat. The workshop kept fixing the symptoms (blown hoses, etc) but not the cause!

By the time I saw it the head gasket was leaking badly and it was most likely that the head was damaged - making another head gasket replacement unlikely to be successful.

I sourced a replacement engine with half the k’s on it and swapped it over.

After a service, a bit of a tune and a general checkup the new engine was running nicely - and no more overheating!

This started out as a routine checkup of an Evinrude / Johnson 90hp outboard motor about to be put into use on a boat, until someone gave it a compression check and found one cylinder to be reading low - deciding it was in need of a rebuild.

I like to avoid rebuilds and other such expensive activities where possible, so thought it’d be worth seeing if the engine would run first.

After connecting up a fuel tank and battery it started up quite easily and seemed to run ok. After a brief run I gave it a compression test and found that three cylinders had a healthy 120psi, but one was down to about 70 - which is low, but not completely dead.

The head gasket was leaking a bit of water, as it had been removed previously and not re sealed, which may also have contributed to the low compression reading.

I pulled the cylinder head off to have a look inside and re seal the head gasket and found that the engine had obviously sucked something solid through it and munched the piston and head fairly extensively!

The piston obvously has had a hard time, but the cylinder walls actually looked ok. The most likely cause is that the engine has sucked a nut or washer through at some point.

The cylinder head was in a similar state to the piston, but it’s a lot easier to tidy up, so I was able to flatten out most of the sharp points.

I cleaned up the sharp edges on the piston as much as possible, then applied high temperature sealant to the head gasket and bolted it back together.

The engine fired up and ran quite smoothly with no more water leaks.

Another compression test showed compression on the bad cylinder to be up to about 90psi, so the engine will be used at least to test out the boat and decide whether it’s the right size, etc before spending big money on replacing or rebuilding it.