to replace the head gasket on a 4Y Toyota engine
here - By Snipes
head gasket on a 4Y is a pretty simple job, but if it is to last
it must be done properly. Also doing the headgasket may not be a
difficult job, but it would be a complete waste of time if don't
first find out why the head blew, like head gasket failure(old age,deterioration),
stuck thermostat, cracked head, blockage in the radiator, broken
viscous coupling , etc. If the problem was more than just head gasket
failure from old age, then the cause must first be addresses and
A basic step
by step rundown of the job, please note I may have forgot a step
or 2, so any input is welcome:
1. drain the
coolant in the block, the drain plug(bolt) is just behind the alternator,
below the exhaust manifold.
2. drain the coolant in the radiator by removing the bottom pipe,
disconnect the water pipe coming from the back of the head, disconnect
the water pipe at the top(between the radiator and head).
3. drain the oil via the sump plug, with a blown head the oil may
be contaminated with water. Remember to put the sump plug back,
or you may land up wasting 5 litres of new, clean, expensive oil(been
there, done that!)... remove and toss the oil filter!
4. loosen the bolt on the powersteering pump pulley, before removing
5. remove the powersteering belt and alternator belt.
6. remove powersteering pump pulley bolt and carefully wiggle the
pulley off the shaft.
7. behind this pulley are 2 bolts, remove them, as well as the one
at the rear of the pump steering pump. This should loosen the PS
pump from the mounting bracket, carefully remove the PS pump and
place it on the chassis below(upright, so it doesn't leak). Secure
it there with a piece of wire, so it can't fall off.
8. Remove and the carb linkages, disconnect the electrical plug,
disconnect the fuel pipe, disconnect the vacuum pipes(take note/take
pics so you know where each vacuum pipe goes for re-assembly), remove
the bracket holding the accelerator cable, remove the 4 nuts holding
the carb on the intake manifold, remove the carb.
9. Loosen the bolts holding the exhaust and intake manifold in place
(can be a pain the get these bolts loose, may want to spray them
with a penatrating oil first). Remove the intake and exhaust manifold.
You may have to disconnect the header-exhaust connection to remove
the exhaust manifold.
10. Unbolt and remove the tappet cover.
11. Unbolt the rocker shaft, each bolt little by little so the shaft
is lifted evenly, remove the rocker shaft, the pushrods can be removed
one by one, again mark where they came from so they can be returned
in the same position.
12. Using a power bar or the like, loosen the head bolts one by
one, 5 of them are under the tappet cover. Remove them and mark
where each one came from so they can be put back in the same place,
also be careful not to leave the washers behind.
13. Under the ignition leads on the head, are 3 bolts holding the
head in place, remove them.
14. The head can now be removed.
basically the reverse of this process. Have the head checked and
skimmed before starting re-assembly. You will need a new head gasket(use
the orginal Toy one or a Payen one), a intake/exhaust manifold gasket
and some decent gasket maker.
The most time
consuming aspect of the job is cleaning all the bits and pieces,
and carefully cleaning the mating surfaces on the block, head and
the head bolts, once the head is back on, the bolts should first
be torqued to 30nm each in sequence(I'll get the sequence from the
workshop manual this evening), afterwhich they must be torqued to
90nm again in sequence. You will need a good torque wrench for this
job. The head bolts must be re-torqued to 90nm at 1000km.
The valve stem
seals will have to be replaced by an engineering firm as special
tools are needed, like a valve spring compressor.
nuts will probably have to be replaced, as well as the nuts and
bolts on the header-exhaust joint.
is in an awkward spot, it's in the housing behind the alternator/PS
pump, where the lower water pipe from the radiator connects to the
engine, it is easier to access with the PS pump out the way.
4Y Hilux fundi's like Simoan and Allan will probably give more advise!