TOYOTA PREVIA 91-97 REPAIR MANUAL

3-52 ENGINE AND ENGINE (JVERHAUL

TCCA3P70

Fig. 188 Nuts and bolts will be extremely difficult to remove

when deteriorated with rust

Before removing any component of the exhaust system, ALWAYJ> squirt a
liquid rust dissolving agent onto the fasteners for ease of removal A lot of
knuckle skin will be saved by following this rule. It may even be w se to
spray the fasteners and allow them to sit overnight.

Flange Type

I See Figure 18!)

** CAUTION

Do NOT perform exhaust repairs or inspection with the engine or
exhaust hot. Allow the system to cool completely before
attempting any work. Exhaust systems are noted for shatp
edges, flaking metal and rusted bolts. Gloves and eye protec-
tion are required. A healthy supply of penetrating oil and rags is
highly recommended. Never spray liquid rust dissolving auenl
onto a hot exhaust component.

Before removing any component on a flange type system, ALWAYS

squirt a liquid rust dissolving agent onto the fasteners for ease of i jmoval.

Start by unbolting the exhaust piece at both ends (if required). Wh n

unbolting the headpipe from the manifold, make sure that the bolts are free

before trying to remove them, if you snap a stud in the exhaust ma lifold,

the stud will have to be removed with a bolt extractor, which often leans

removal of the manifold itself. Next, disconnect the component froi i the

mounting; slight twisting and turning may be required to remove tf e com-

ponent completely from the vehicle. You may need to tap on the cc nponent

with a rubber mallet to loosen the component. If all else fails, use;

saw to separate the parts. An oxy-acetylene cutting torch may be \i

the sparks are DANGEROUS near the fuel tank, and at the very leas

dents could happen, resulting in damage to the under-car parts, m

mention yourself.

ENGINE RECONDITIONING

Determining Engine Condition

Anything that generates heat and/or friction will eventually burn |r wear

out (ie. a light bulb generates heat, therefore its life span is limited

this in mind, a running engine generates tremendous amounts of b

tion is encountered by the moving and rotating parts inside the enc

With

th; fric-

neand

Fig. 189 Example of a flange type exhaust system joint

Slip Joint Type

I See Figure 190

Before removing any component on the slip joint type exhaust system,

ALWAYS squirt a liquid rust dissolving agent onto the fasteners for ease of

removal. Start by unbolting the exhaust piece at both ends (if required). When

unbolting the headpipe from the manifold, make sure that the bolts are free

before trying to remove them, if you snap a stud in the exhaust manifold, the

stud will have to be removed with a bolt extractor, which often means removal

of the manifold itself. Next, remove the mounting U-bolts from around the

exhaust pipe you are extracting from the vehicle. Don't be surprised if the U-

bolts break while removing the nuts. Loosen the exhaust pipe from any mount-

ing brackets retaining it to the floor pan and separate the components.

Fig. 190 Example of a common slip joint type system

heat is created by friction and combustion of the fuel. However, the engine

has systems designed to help reduce the effects of heat and friction and

provide added longevity. The oiling system reduces the amount of friction

encountered by the moving parts inside the engine, while the cooling sys-

tem reduces heat created by friction and combustion. If either system is not

maintained, a break-down will be inevitable. Therefore, you can see how